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Generac Guardian™ 20kW Aluminum Standby Generator System (200A Service Disconnect + AC Shedding)

Generac Guardian Electric Generators and Accessories
Model: 6244
(Based on expert analysis, manufacturer ratings and customer reviews)
4.6 out of 54.6 out of 54.6 out of 54.6 out of 54.6 out of 5
110 Reviews
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  • Features
  • Specs
  • 41
  • 110
  • Articles
  • Accessories
Run Watts
Rated Watts
120/240 Single-Phase

Product Video Disclaimer: "PED is not responsible for any variances from the product in this video and the item you purchase. Please review all product specs prior to purchase."

Smart Circuit Standby Generator System
Restores power to your entire electrical panel automatically
Digital Power Management (DPM) protects against overload

Generac Smart Switch™ (RTSY200A3 - Included)
DPM technology allows for the smart control of 2 air conditioners
Service Rated ATS: Mounts between meter and main service panel
200 amp aluminum indoor/outdoor (NEMA 3R) cabinet

Evolution™ Digital Controller
Provides system status to compatible Generac wireless monitors

Aluminum Sound-Attenuated Weather Proof Enclosure
Lightweight material offers superior corrosion resistance
Reduces sound pressure to a low 66 dB(A)
Attractive styling with lockable access doors

Automatic Voltage Regulator
Regulates ouput voltage to ±1% which prevents damaging spikes
Safe for sensitive electronics like computers and televisions

Generac OHVI Air-Cooled Engine
Full pressure lubrication system w/ 2 year oil change interval
12" flexible fuel line and manual included

5-Year Limited Warranty & 24/7/365 Customer Care
Engine Brand
Generac OHVI
999 CC
Consumer Engine Warranty
5 Years
Commercial Engine Warranty
5 Years
Engine RPM
3600 RPM
Low Oil Alert/Shutdown
Product Specs
120/240 Single-Phase
60 Hertz
Surge Watts
20000 Watts
Rated Watts
20000 Watts
Fuel Type
LP/Natural Gas
NG Power Capacity
18000 Watts
LP Power Capacity
20000 Watts
NG Fuel Consumption @ 50% Load
205 (BTU: 205,000 BTU/HR) ft³/hr
NG Fuel Consumption @ 100% Load
308 (BTU: 308,000 BTU/HR) ft³/hr
LP Fuel Consumption @ 50% Load
2.08 (BTU: 188,760 BTU/HR) gallons/hr
LP Fuel Consumption @ 100% Load
3.85 (BTU: 349,388 BTU/HR) gallons/hr
Rated Amps
83 @ 240 Volts (Single Phase) Amps
Decibel Rating @ 7m
66 dbA
Transfer Switch
Automatic (Included)
Transfer Switch Amperage
Not Included (525 CCA)
A/C Ton Rating
2 x 5-Tons
Mounting Pad
Composite (Included)
Transfer Switch Style
Service Disconnect
ATS Load Shedding
ATS Poles
2 Poles
ATS Service Disconnect
Cooling System
Air Cooled
UL Listed
Grade Type
Made in USA
Assembly Required
541 Pounds
Product Style
Standby Generator
Product Length
48 Inches
Product Width
25 Inches
Product Height
29 Inches
Consumer Warranty
5 Years
Commercial Warranty
5 Years
  41 Questions
Q: Are there recommended installation distances from other items? I have an AC unit near where I would like to place the generator. Also, would it be okay to be under a porch? There is about 5' from the ground to the bottom of the porch.
by Matt from Pennsylvania on June 18, 2014

A: The minimum distances can be found in the installation guide we have available on the site on the product page under the specs tab in the download document section.....

Installation Guide

The unit needs at least 3 feet clearance on the sides of the unit for proper air flow and 3 feet from the front for proper maintenance. Also, the unit requires a minimum of 5 feet clearance from the top of the unit. These units cannot be installed under a porch. These units also require a minimum of 5 feet from any window, door or ventilation opening.

We recommend you consult with your local inspector or AHJ (Authority Having Jurisdiction) for your local code requirements as they can sometimes supersede the manufacturers recommendations.

by Mike, Product Expert

Q: I have the 20kW Generac with 200 amp ATS. Is there a way to get the exercise length of time to change from the set of 12 minutes?

I have been through every part of the edit and can find the time, date, etc, but no way to change the amount of run time for exercise. We have had moisture in the gen, and one of the suggestions was to run the gen exercise longer. But I have been through the manual, and did everything I could think of in the edit mode. This unit was purchased and installed in early 2013.

by Jim Biggers from New York on June 02, 2014

A: Special parameter changes are only available to authorized Generac servicing dealers as their sub-menus are password protected. I have checked with Generac and checked my servicing manual and there is no option to alter the exercise cycle run time on the Evolution Controller, this was only available on the older Nexus Controllers.

An option would be to run the generator once a month in manual mode for an extended period of time. I would recommend this as it would also be a good idea to do this in automatic mode allowing the generator to transfer power to make sure there are no issues running the home and allowing the alternator to produce power.

Any further assistance with this should go through your local Generac servicing dealer.

by Mike, Product Expert

Q: I'm interested in the Generac 14 kw standby generator and I want to power it with natural gas. All your other Generac standby generators show a wattage loss of about 2kW when powered with natural gas, but this one does not show a loss in the specs I have reviewed. Is this a misprint in the specs or is this a true output? If I power it with natural gas will it deliver 12 kW or 14 kW?
by Albert Leblanc from Michigan on May 06, 2014

A: This is not a misprint in the specification. The unit will produce 14kW when operating on Natural Gas and LP as tested at the factory.

Also noted on the manufacturers specification sheets is the following....

"Maximum wattage and current are subject to and limited by such factors as fuel BTU/megajoule content, ambient temperature, altitude, engine power and condition, etc. Maximum power decreases about 3.5 percent for each 1,000 feet (304.8 meters) above sea level; and also will decrease about 1 percent for each 6° C (10° F) above 16° C (60°F)."

Specification sheets can be found on the individual product pages under the Specs tab and within the download document section.

by Mike, Product Expert

Q: Is the housing for Generac Home Standby Generators (Model 6437) fireproof?

by Robert C. Vose III from Massachusetts on April 26, 2014

A: The following information can be found in the installation manual and the installation guide we have available on the product page under the specs tab in the download document section.....


The National Fire Protection Association has a standard for the installation and use of stationary combustion engines. That standard is NFPA 37, its requirements limit the spacing of an enclosed generator set from a structure or wall (Figure 1.10).

NFPA 37, Section 4.1.4, Engines Located Outdoors: Engines, and their weatherproof housings if provided, that are installed outdoors shall be located at least 5ft. (1.52m) from openings in walls and at least 5ft. (1.52m) from structures having combustible walls. A minimum separation shall not be required where either of the following conditions exist:

1. The adjacent wall of the structure has a fire resistance rating of at least 1 hour.
2. The weatherproof enclosure is constructed of noncombustible materials and it has been demonstrated that a fire within the enclosure will not ignite combustible materials outside the enclosure.
Annex A — Explanatory Material
A4.1.4 (2) Means of demonstrating compliance are by means of full scale fire test or by calculation procedures.

Because of the limited spaces that are frequently available for installation, it has become apparent that exception (2) would be beneficial for many residential and commercial installations. With that in mind, the manufacturer (Generac) contracted with an independent testing laboratory to run full scale fi retests to assure that the enclosure will not ignite combustible materials outside the enclosure.


The criteria was to determine the worst case fire scenario within the generator and to determine the ignitability of items outside the engine enclosure at various distances. The enclosure is constructed of NON-COMBUSTIBLE materials, and the results and conclusions from the independent testing lab indicated that any fire within the generator enclosure would not pose any ignition risk to nearby combustibles or structures, with or without fire service personnel response.


SwRI Website Link

BASED ON THIS TESTING AND THE REQUIREMENTS OF NFPA 37, SEC 4.1.4., THE GUIDELINES FOR INSTALLATION OF THE GENERATORS LISTED ARE CHANGED TO 18IN. (457mm) FROM THE BACK SIDE OF THE GENERATOR TO A STATIONALY WALL OR BUILDING. For adequate maintenance and airflow clearance, the area above the generator should be at least 5FT (1.52m) with a minimum of 3ft. (.91m) at the front and ends of the enclosure. This would include trees, shrubs and vegetation shorter than 12in. (305mm) in height. Vegetation taller than 12in. (305mm) in height must have a clearance of 60in. (1524mm). Vegetation not in compliance with these clearance parameters could obstruct air flow. In addition, exhaust fumes from the generator could inhibit plant growth. See Figure 3.1 and the installation drawing within the owner’s manual for details.

Generator exhaust contains DEADLY carbon monoxide gas. This dangerous gas can cause unconsciousness or death. Do not place the unit near windows, doors, fresh air intakes (furnaces, etc.) or any openings in the building or structure, including windows and doors of an attached garage.

by Mike, Product Expert

Q: If I purchase the 20KW aluminum generator with 200 amp transfer switch and load shedding, does the generator have a fire rating to be placed closer then five feet from my house?
by Joe Fletcher from Maryland on March 06, 2014

A: The installation guide shows the specific installation distance these units are tested and recommended for and they have been independently tested by the Southwest Research Institute and meet the requirements of NFPA 37, Sec 4.1.4.

Installation Guide

Please note that it is recommended that you consult with your local inspector or AHJ (Authority Having Jurisdiction) as local code can supersede manufacturers recommendations.

by Mike, Product Expert

Q: Can the generator be installed on the opposite side of the house from the electric meter and breaker panel? My propane tank and electric meter/breaker panel are on opposite sides of the house.
by Andrew from Pennsylvania on February 23, 2014

A: Yes, you can. It is more practical to run longer wires between the generator and the SE rated switch than it is to run larger gas pipe. Keeping the gas run as short as possible will aid in starting and ensure solid engine operation with limited elbows and such.

Of course, the wire gauge will have to be properly sized to carry the generator load over the distance - but that is less costly & less risky than running longer pipe.
by Mike, Product Expert

Q: Regarding the Generac 7kW fueled by Nat Gas . Spec states fuel consumption is 85 ft3/hr for 1/2 load. My question is what is this equivalent to in CCF?

by Ed from Pennsylvania on February 06, 2014

A: Natural Gas is usually measured by volume in the United States and is stated in cubic feet. A cubic foot of gas is the amount of gas needed to fill a volume of one cubic foot under set conditions of pressure and temperature.

To measure larger amounts of natural gas, "CCF" (centum cubic-feet) is used to denote 100 cubic feet, and "MCF" (mil cubic-feet) is used to denote 1,000 cubic feet.

With that said, due to the small amount of consumption you wouldn't convert the current ft3/hr to CCF.

However, if you are trying to calculate the cost in relation to therms listed by your natural gas company the conversion is 1000 ft3/hr equals 10 therms.

by Mike, Product Expert

Q: Just purchased a new Model 6244, 20kw for new home being constructed. In reviewing the manual I noticed there were no break-in instructions like there was with previous generac units I purchased. I'm having the unit installed by an electrician who is certified, but I'm always interested in keeping myself up to date on all of my equipment.
Is the break-in operation not needed as it was on previous units?

by Leon Coody from Louisiana on February 06, 2014

A: With the new 2013 Generac models break-in time is no longer required. All of the engines are run for 25+ hours by the manufacturer.

It is important to follow the maintenance instructions located within the owner's manual....Here is the link to review the basic copy but keep in mind that the manuals provided with the unit are based on your serial number and can vary slightly.

Basic Owner's Manual

by Mike, Product Expert

Q: Does every generator come with a NG setting? My generator arrived and looking at the knob it looks like it's rotated to LP. Does it just rotate clockwise/counter clockwise? Tried to rotate it, but it will not move.

by Darrel Jones from Arkansas on January 18, 2014

A: All of the air cooled home standby systems are dual fuel and operate on either natural gas or LP. The units are set for natural gas from the factory and if LP is needed they are converted to LP by turning the knob.

Per the owner's manual/installation guide - Page 15....."The generator was configured for natural gas operation at the factory. Switching over to LP Vapor is a simple procedure.

Turn the valve towards the marked fuel source arrow until it stops. If needed, use pliers to break free in correct direction of arrow. Fuel knob will rotate 180° and slide into the mixer body when converting to LP."

We recommend using a thick rag to cover the fuel knob when using pliers so you do not crack the plastic as we have had reports of this happening and it is not covered under warranty. The only way to replace the knob is to replace the entire throttle body which is extremely expensive and needs to be done by a certified Generac technician.

by Mike, Product Expert

Q: I just got a Generac 20kW generator installed at my house. The plumber and electrician said i need to replace the oil filter every 100 hours. I wanted to buy a few of the oil filters to have on hand however when I went on to purchase them there was a note that the pack oil filter is not the same as in the maintenance pack. I just wanted to know the difference and what I need to buy just in case we lose power soon! Thank you!
by Maria Aughavin from New York on January 02, 2014

A: Generac's maintenance requirements on their home standby systems is 2 years or every 200 hours (Check your owner's manual).

The maintenance kit comes with the 200 hour/2 year oil filter (Extended Life) and the bulk package comes with their 1 year oil filters.

With that said, we recommend checking your oil every spring and fall to make sure it looks good and if needed to just go ahead and change it. Also, you will want to keep in mind that when you have extended outages you will need to check the oil level every 36 to 48 hours and top off as necessary. Air cooled engines will burn through oil during long run times so it is very important to maintain the proper oil level.

Note: All above information is available within your owner's manual.

by Mike, Product Expert

Q: Will a 3/4 inch (0.75") line that my plumber installed to the pad, power the Generac 20kW unit which uses more cubic feet of NG than the other 2 similar models? My gas meter is only 12 feet from the point of connection to the generator. According to the online instructions, its where the line will enter the generator.
by Walter from Alabama on January 01, 2014

A: The smallest pipe size you can use on the 20kW generators is 1 inch with a maximum distance of 20 feet if your natural gas pressure is within 5 to 7 inches of water column. If you have lower pressure the maximum distance is 10 feet if the pressure is within 3.5 - 5 inches of water column.

Here is the link we offer on the site to the installation guide which covers pipe sizing and distances.....

Installation Guide

by Mike, Product Expert

Q: Would winter time installations of automatic generators be good or bad?

by Ron Mills from Michigan on December 30, 2013

A: You can install a generator at any time. However, it would be based on if you are putting down a concrete base as it will not set in cold temperatures. If you are putting down crushed stone or pea gravel it should be no problem.

You can also go with a GenPad (Gen Manufacturer Specific) which is a preform concrete base, so no concrete curing time. These can be installed in any temperature.

Generac GenPads

by Mike, Product Expert

Q: What does AC shedding mean?

by Dan U. from Michigan on December 29, 2013

A: The following How-To-Library article will help explain AC Shedding.....

by Mike, Product Expert

Q: Q: Guys I need a 20 kW natural gas home stand by with a 150A service rated transfer switch. Is this available as a package deal?
by Harry Donovan from Virginia on December 01, 2013

I think for a 20KW generator you would always need a 200A service rated transfer switch. Although he does not say, I think he is implying that his breaker panel is 150A. It is ok to have a 200A service rated transfer switch feed a 150A breaker panel. The better solution would to be replace the 150A breaker panel with a 200A one. In most cases the line going into a 150A breaker panel is already rated for 200A (an electrician would need to verify this).

by Craig Bizjak from New Jersey on December 11, 2013

A: Generac currently does not package any of their generator systems with the 150A transfer switch. You would need to purchase the generator by itself (6250) and the transfer switch separate (RTSY150A3).

Note: Some local codes allow the use of a 200A transfer switch in a 150A service as the transfer switch is only a pass through device when you are on utility power and protected by your existing electrical panels main breaker. When operating on generator power the generator itself has its own main breaker of 90A since the generator produces 83A.

If you have an interest in the Briggs & Stratton line they do offer a prepacked option which includes a 150A automatic transfer switch.....The following link shows the available prepacked 150A home standby systems......

150 Amp Home Standby Generator Systems

by Mike, Product Expert

Q: I have a low pressure nat. gas line in my residence, what is the largest generator I will be able to run without doing major updates ?

by Chuck from Ohio on December 10, 2013

A: The Generac line of home standby systems can now operate on low pressure natural gas. Their low fuel pressure requirement is 3.5" to 5" of water column (1" of water column = 0.036 PSI).....0.123 PSI to 0.18 PSI. This would be for all sizes from 8kW up to 20kW.

Proper sizing of the generator is crucial to the success of any generator installation and requires a good working knowledge of electricity and its characteristics, as well as the varying requirements of the electrical equipment comprising the load.

A certified electrician needs to be consulted for proper sizing and installation of any generator.

When analyzing the electrical load, consult the manufacturer’s nameplate on each major appliance or piece of equipment to determine its starting requirements in terms of amps and voltage which can be calculated to watts using Ohms Law (Amps x Volts = Watts).

When choosing the generator output select a rating that is approximately 20 to 25% higher than the peak load (for example, if the load is about 8 kilowatts, select a 10 kW generator).

A higher rated generator will operate comfortably at approximately 80% of its full capacity and will provide a margin of flexibility if the load increases in the future.

Note: Applications such as commercial, all-electric homes, heat pump systems or geothermal systems require special installation procedures and a certified electrician must be contacted to evaluate and install these types of systems.

by Mike, Product Expert

Q: Guys I need a 20 kW natural gas home stand by with a 150A service rated transfer switch. Is this available as a package deal?

by Harry Donovan from Virginia on December 01, 2013

A: At this time Generac does not pre-package their home standby systems with a 150A transfer switch. You would need to purchase each item individually.....

Generac Generator Model 6250

Generac Switch Model RTSY150A3

Another option would be the Briggs & Stratton line of home standby units which do come with a 150A packaged option....The following link shows the available prepacked 150A home standby systems....

150A Prepackaged Home Standby Systems.

by Mike, Product Expert

Q: Can I use the 100 amp 16 circuit transfer switch with a 20 KW Generac?

by George Bristol from Nebraska on November 23, 2013

A: You cannot use the 16 circuit Generac transfer switch with the 20kW Generac home standby unit. The internal wiring is not suitable for the amperage output capacity of the 20kW unit.

The following switches are recommended for use with the 20kW Generac unit allowing specific circuits......

Generac GenReady Indoor Load Center - Model 5449

Generac GenReady Outdoor Load Center - Model 5454

Generac LTS Load Center with Load Shedding (16 Circuit) - Model RTSJ200A3

by Mike, Product Expert

Q: The install guide says The minimum LP tank size is 250 gallons.

My customer was hoping to avoid this type of tank since it is required to be at least 10' from the house and would need trenching where ledge is. Any idea why they specify it like this?

My customer wanted to go with less obtrusive 120 gallon tanks that are allowed next to the house. Is it just based on capacity or is it more to do with pressure or regulators?

by Rob Saccardo from Massachusetts on November 21, 2013

A: The tank size recommendation is based on BTU output, capacity and temperature. However, some propane suppliers will state a 120 gallon tank is sufficient for a 20kW standby generator but a 120 gallon tanks usable fuel amount is less then the tank size which will also vary depending on temperature.

The fuel consumption of a 20kW is 2.08 gallons per hour when operating at 1/2 load capacity and if calculated into a days use you will be using just under 50 gallons of fuel.

A 120 gallon tank has 72 usable gallons with the BTU output varying depending on temperature. A 120 Gallon tank BTU/HR output capacity based on 40 degrees F is 248,240 BTU/HR and a 20kW, at start-up, requires 349,388 BTU/HR which is more then a 120 gallon tank can supply. To properly size a generator to your fuel source you need to size it to it full load start-up BTU/HR requirements.

A 250 gallon tank has 150 usable gallons with the BTU output also varying depending on temperature. A 250 Gallon tank BTU/HR output capacity based on 40 degrees F is 507,600 BTU/HR and is well within the requirements of the 20kW generator.

With that said, a 120 gallon tank does not offer enough BTU/HR output capacity to supply a 20kW generator. This is why Generac recommends a minimum 250 gallon tank with strong recommendations for a larger tank.
by Mike, Product Expert

Q: If I'm not around when my home standby generator is running, what type of protections systems do the Generac units have?
by Josh from New Jersey on November 13, 2013

A: The generator may have to run for long periods of time with no operator present to
monitor the engine/generator conditions. Therefore, the generator is equipped with a number of systems to automatically shut down the unit to protect it against potentially damaging conditions. Some of these systems are as follows:

• Low Oil Pressure Sensor
• High Temperature Sensor
• Overcrank Sensor
• Overspeed Sensor
• RPM Sensor
• Under-frequency Sensor
• Undervoltage Sensor
• Overvoltage Sensor
• Internal Failure Sensor
• Low Battery Voltage Alarm

The control panel contains a display which alerts the operator when a fault condition occurs. The above list is not all inclusive. For more information about alarms and control panel operation, see Section 3 (Operation) in the owner's manual.

by Mike, Product Expert

Q: What size bolts are required in the concrete slab to anchor the 20KW unit?
by David Gehm from Missouri on November 12, 2013

A: According to Generac you would use 3/8 inch lag bolts that are of sufficient length to mount the generator to the concrete.
by Mike, Product Expert

Q: What type of oil should I use in my Generac home standby generator?
by Jim from Illinois on November 11, 2013

A: The maintenance section in the Generac's home standby owner's manual lists that the oil type is based on temperature ranges specific in your area.....

SAE-30 above 32º F (0º C)
10W-30 between 40º and -10º F (4º and -23º C)
Synthetic 5W-30 for all temperature ranges

All new models come with SAE-30 oil in them and have been test run at the factory for 25 hours and no break-in is required. The first oil change would be at 2 years or 200 hours, whichever comes first.

by Mike, Product Expert

Q: I'm not sure if this falls into the repair area but, I'm concerned about the sound this generator produces. Is there a way to lower that? Is there sound proofing approved for use for the interior walls of this type of home standby? My neighbors bedroom window will be 20ft from where I plan to install the generator. I would prefer doing something inside the generator as apposed to some type of fencing or other external methods.

by Mark H. from New Jersey on October 23, 2013

A: The manufacturers make every effort to reduce the sound of their generators as best they can keeping within NFPA and UL requirements. There are currently no options or parts available to install inside home standby systems to reduce their db(A) levels.

Your only option is location or sound barriers installed around the unit while keeping within NFPA and manufacturers distance requirements for proper fire protection, air intake and exhaust output.

We recommend consulting with your local inspector or AHJ (Authority Having Jurisdiction) as to the specific local code requirements.

by Mike, Product Expert

Q: Is the Smart Switch the actual Automatic Transfer Switch? Or are they different? The specs says that there is an automatic transfer switch included.

by Joseph P. from New York on October 21, 2013

A: The "smart switch" is the automatic transfer switch. The ATS has an internal load manager that will load shed up to 2 AC units preventing the overload of the generator at start-up.

by Mike, Product Expert

Q: I have a new 2013 Generac generator and I'm wondering what oil it came with? I would like to top it off properly after the installation.

by John from New Jersey on October 18, 2013

A: The Generac 2013 automatic standby generators are shipped with a SAE 30 non-synthetic oil. If you are located in an area that receives snow, it is recommended to perform an oil and filter change to switch to a synthetic 5W-30 oil to promote proper generator operation. The cold weather kit is also recommended.

The appropriate intervals for oil changes and other maintenance items will be located in the owner’s manual in the Maintenance Schedule.

Current production models do not require any break in, so if the Maintenance Schedule in the owner's manual indicates that oil changes only need to be done every 2 years or 200 hours, you could drain the existing oil and switch to synthetic 5W-30 right away.

by Mike, Product Expert

Q: Is it possible to hook up more than one transfer switch to a generator?
by Ron from Pennsylvania on October 11, 2013

A: Thank you for your interest in Electric Generators Direct!

The Generac Guardian series home standby generators may be paired with up to three transfer switches so long as they are all supporting the same electric service.

When connecting two of the switches, there will be no additional hardware required. A third switch will require an additional relay to be installed. This can be obtained from your Generac Service Technician.

We have the multiple switch diagram published for your convenience;
Multiple Switch Schematic
by Mike, Product Expert

Q: Does the 200 amp service disconnect that comes with model #6244 rain tight rated ?
by Jerry Bollman from Texas on October 02, 2013

A: Thank you for your interest in Electric Generators Direct!

The Generac 6244, 20kW Home Standby Generator System is packaged with a 200 amp, whole house transfer switch. This device, the Generac RTSY200A3 is rated as a NEMA 3R enclosure which means that it has been tested and approved for safe and reliable outdoor operation.

by Mike, Product Expert

Q: Hi Jim

Can the Flex line be connected direct to generator if its inline (no bends)?

by Gadi Goldress from New York on October 02, 2013

A: Thank you for your inquiry.....

Per the installation guide you cannot attach the flexible fuel line directly to the generator (Page 18).

Gas line connections should be made by a certified plumber familiar with local codes.

by Mike, Product Expert

Q: Q: I just purchased a 20KW generator and would like to know the max distance that I can run 1/2 inch steel pipe to my generator?

by Johnnymack from Rhode Island on September 28, 2013

A: Per Generac you cannot us 1/2 inch pipe at all on a 20kw or any of their air cooled generators as this does not provide enough volume of fuel to the unit.

Here are the fuel pipe requirements on a 20kw Generac Model 6244 or 6250.....

Natural Gas:

1/2 Inch: Cannot Use
3/4 Inch: Cannot Use
1 Inch: Max Distance 20 Feet
1-1/4 Inch: Max Distance 130 Feet
1-1/2 Inch: Max Distance 305 Feet

Liquid Propane Vapor:

1/2 Inch: Cannot Use
3/4 Inch: Max Distance 15 Feet
1 Inch: Max Distance 115 Feet
1-1/4: Inch: Max Distance 480 Feet

Add 2.5ft per any bend, tee or angle in the pipe to the overall distance.

Gas Pipe sizing is one of the most commonly made mistakes. A properly sized gas pipe is critical to the proper operation of the generator. The generator inlet size has no bearing on the proper gas pipe size.

by Mike, Product Expert

Q: Purchased Model 6244 being delivered tomorrow. Would you recommend purchasing the Generac cold weather kit? (Paramus, nj)

by Howard Schwade from New Jersey on September 18, 2013

A: Thank you for your inquiry!

When temperatures fall below an acceptable level, the thermostat activates the battery warmer maintaining optimum battery temperature and also activates
the crankcase oil heater for the best generator starting.

This kit is recommended for generators installed in regions where the temperature regularly falls below 32 degrees (Fahrenheit).
by Mike, Product Expert

Q: Does the Smart Switch provide surge suppression? If so, does it provide surge suppression for both the generator line and utility line?
by Bill Pierce from Rhode Island on September 06, 2013

A: The RTSY200A3 is equipped with fused links in order to prevent unexpected and damaging surges. The generator itself is fitted with a 2-pole main breaker which will prevent further damage to the machine.

Generac also has solid-state, frequency compensated voltage regulation. This state-of-the-art power maximizing regulation system is standard on all Generac models. It provides optimized fast response to changing load conditions and maximum motor starting capability by electronically torque-matching the surge loads to the engine. Digital voltage regulation at ±1% and THD (Total Harmonic Distortion) less then 5%.

by Mike, Product Expert

Q: Can the 200A transfer switch be swapped out to a 150A for the same price?

by Steve Steffe from New Jersey on August 24, 2013

A: These units are prepackaged by Generac and the kit cannot be changed or altered.

If you need the 150A transfer switch you can either purchase the generator (6250) and the switch (RTSY150A3) individually which is a little more expensive or you can use the prepackaged unit with the 200A switch.

Since the transfer switch is a pass through only while on utility power this will meet most local code requirements. However, some local inspectors will not allow this.

We recommend consulting with either your installing electrician, the local inspector or your local AHJ (authority having jurisdiction) to see if it is allowed in your area.

by Mike, Product Expert

Q: What is the recommended time frame to change the break-in oil on my Generac 20kW generator?

by Karin Green from New Jersey on August 10, 2013

A: All of the new 2013 Generac Home Standby generators have been pre-run at the factory for 25 hours. So, no break-in period is required.

by Mike, Product Expert

Q: I just purchased the Generac Guardian 20kw model 6244 from your site. I am planning to pour the base this weekend for the generator. My question is what size should I make my pad? I would like to set the anchors in the concrete before it dries. What kind of anchors is recommended and what size should they be? What Type of oil is recommended and do I need to purchase an oil filter?
by Mark Muczynski from Michigan on July 30, 2013

A: The installation drawing is available on the site under the specs tab in the download document section. This will provide dimensions of the generator where you will want to make the pad at least 6 inches larger on all sides. You will also find the location of the holes for mounting the unit to the concrete pad. Generac recommends 3/8 inch lag bolts designed for concrete.

Installation Drawing

You will also find the owner's manual available where it discusses proper maintenance and oil requirements based on temperatures in your area.

Owner's Manual

When changing the oil it is also recommended to change the oil filter. The following link is for the recommended maintenance kits available for the Generac model 6244...

Basic Maintenance Kit

Maintenance Kit with 5W30 Synthetic

Maintenance Kit with 10W30 Synthetic

Maintenance Kit with 10W30 Standard
by Mike, Product Expert

Q: What is AC shedding?
by Ken Phillips from Texas on July 14, 2013

A: The following article will help explain....


by Mike, Product Expert

Q: Could you please advise regarding the Generac 6244 vs the 6250?
The pros and cons of one vs the other, any preference recommendation?

by John O'hearn from Maryland on June 26, 2013

A: They are exactly the same generator except one comes with a transfer switch and the other one is the generator only.

Model 6244 includes the 200A Automatic Transfer Switch.

Model 6250 is the Generator Only.

by Mike, Product Expert

Q: What size NG line for 18 kw generator?
by Bill from New Jersey on June 13, 2013

A: The pipe size is based on the distance the generator is from the fuel source.

***The 18/20kW requirements are:

Natural Gas (NG)-

3/4" - Cannot Use
1" Pipe - Max 20 Feet
1-1/4" Pipe - Max 130 Feet
1-1/2" Pipe - Max 305 Feet

Liquid Propane Vapor (LP) -

3/4" - Max 15 Feet
1" Pipe - Max 115 Feet
1-1/4" Pipe - Max 480 Feet
Note: LP Pipe sizes are using a second stage regulator.

The pipe sizes are measured by inside diameter (ID) to include any fittings, valves (Must be full flow), elbows, tees or angles. Add 2.5 ft. per any bend, tee or angle in the pipe to the overall distance.


The generator inlet size has no bearing on the proper gas pipe size.

Note: Refer to NFPA 54 for NG or NFPA 58 for LP codes.

Note: Required fuel pressure for natural gas is 3.5 to 7 inches of water column and the required fuel pressure for LP Vapor is 10 to 12 inches of water column.

by Mike, Product Expert

Q: I know the manufacturer recommends either a concrete, crushed stone or pea base. Would I be better off with a concrete slab rather than the other two alternatives? Would I have less vibration and noise with the generator mounted to the concrete slab?
by David Berkowitz from New Jersey on May 24, 2013

A: Thank you for your interest in Electric Generators Direct!

When installing one of these 20kW generators, my recommendation would be to mount the unit on a concrete slab. Keep in mind that these units are extremely heavy, a property that my cause settling over time with a gravel base.

In regards to the vibration, the generators are equipped with rubber dampeners to minimize the movement of the motor and generator assembly. The generators are also equipped with flexible fuel lines so that the noise is not transmitted throughout the entire mechanical piping system. If mounted and anchored properly, your generator should not create much noise due to vibration.

by Mike, Product Expert

Q: 1) Is it practical to have lift gate service place 20kw generator directly onto a trailer with 12" side rails?

2) Is there any need for the mounting pad to be designed for vibration absorption?

3) Would you advise placing directly onto a mounting base of 3" deep pea gravel, and eliminating a hard mounting pad? Thanks.

by Jerry Mitchell from Alabama on May 11, 2013

A: Many customers meet the driver and use the lift gate service to lower the unit onto either a truck bed or a trailer.

Manufacturer recommends either a concrete, crushed stone or pea gravel base with a minimum thickness of 3 inches. They also recommend anchoring the unit using the installation holes.

Installation Drawing

by Mike, Product Expert

Q: What is the best way to mount one? Is there something you can buy or is it ok on a cement base or a treated wood box? Do they vibrate a lot? I purchased a 20kW unit from you.

by Robert Tetley from Michigan on May 11, 2013

A: Per the manufacturer these units require either a concrete, crushed stone or pea gravel base with a minimum of 3 inches of thickness.

Yes they do vibrate and they recommend mounting the unit to the base using the mounting holes per the installation drawing.

Installation Drawing

by Mike, Product Expert

Q: Does the Nexus advanced wireless monitor 5951 work with this unit? Is a DLM 5937. Required to drop out A/C?
by Ed from Delaware on May 07, 2013

A: Yes, according to Generac you can use the Advanced Wireless Monitor with the new Generac Evolution controller. They also offer the Mobile Link for use with the generator which allows monitoring through your cellular device.

Generac Model 6463 - Mobile Link

For AC shedding the switch is already equipped to handle up to 2 AC units without additional parts.

If you need to load shed additional large load items you would need to start with the PMM Start Kit (6199) which includes the needed starter and then up to 3 more individual PMM modules (6186).

Generac Model 6199 - PMM Starter Kit

Generac Model 6186 - PMM Only

by Mike, Product Expert

Q: What is the difference between the Generac model 5875 and their new model 6244 since they are the same size?
by Jim from Illinois on May 02, 2013

A: Generac's model 5875 was the best selling generator on the market and Generac went ahead and improved on the design, warranty and ease of installation after listening to consumer reviews and technicians.

They bumped up the warranty an additional 2 years to give it a solid 5 year overall which is one of the highest rated on the market.

They improved on the generator controller by upgrading to a new technology and moved from their very good Nexus design to the new and improved Evolution controller. This new controller has a back-lit interface with LED's that shows the generator status at a glance.

The new Evolution controller includes maintenance reminders and logs, battery condition (no guessing) and over a half-dozen additional alarms the Nexus controller did not have. This thing rocks!

They upgraded the engine to include a no choke carburetor which helps with all weather starting. They changed the fuel selector for natural gas and LP to an easy knob that is easy to access and change fuel type with ease (No tools required).

For the installers they made several changes to help with installation costs and time, minimize errors and accommodate current and future electric code interpretations by re-engineered some of the wiring connections.

With the changes to the carb and engine they were able to change the low fuel pressure rating for Natural Gas down from 5" of Water Column to 3.5" of Water Column. This will help tremendously with low fuel pressure areas in the country so the meters do not need to be changed as often.

With all of these upgrades they have performed I believe Generac's newest model is one of the best out there and comes highly recommended.

by Mike, Product Expert

Generac Guardian 6244 Reviews & Ratings
Overall Rating
4.6 out of 54.6 out of 54.6 out of 54.6 out of 54.6 out of 5
I'd Buy It Again (73)
Price (42)
High Quality (41)
Reliable (31)
Easy To Use (31)
Bad Instructions (16)
Heavy (9)
Low Quality (7)
Expensive (5)
Unreliable (4)
90% of respondents would recommend this product to a friend
110 Reviews  Sort by 
Charles C.
Purchased from Electric Generators Direct
Purchased 1/29/14
Total Reviews
2 Reviews
Most Helpful Positive Review
5 out of 55 out of 55 out of 55 out of 55 out of 5
The Talking Generator
I purchased this generator in February 2014 and it was installed in March the same year. The instructions were very easy to follow, have not had any problems with this generator. The company Power Equipment Direct was very helpful in acquiring this generator and very prompt in shipping this generator.

I have found this generator as exactly as described and it has showed to service my house very well. I am well pleased with the purchase of this generator and the service of the company I... more
Charles Recommends This Generac Guardian Product
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Michael W.
Grand Bay, AL
Purchased from Electric Generators Direct
Purchased 5/23/13
5 out of 55 out of 55 out of 55 out of 55 out of 5
Love This Generator!!
I've been very happy with my generator. I've been through numerous storms, the latest being Hurricane Nate, which was pretty close to a direct hit. My EG came up in 17 seconds and ran for over 24 hours until my power was restored. I bought and installed this unit myself, but I did sign up for a service contract with a local company to maintain it for me. The big benefit there was a modification came out on the gas valve I wouldn't have known about without the service guys.
Pros: I'd Buy It Again, Easy To Use, Reliable
Michael Recommends This Generac Guardian Product
Michael's Experience With Electric Generators Direct
Web Site


"Excellent service and delivery."
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Roger Nelson
Sargeant, MN
Purchased from Electric Generators Direct
Purchased 9/6/13
Total Reviews
4 Reviews
Total Helpful Votes
70 Helpful Votes
5 out of 55 out of 55 out of 55 out of 55 out of 5
Happy Customer
An elderly couple called and wanted a generator installed so they would not have to worry about a power loss. After several calls to wholesale houses I went online and Electric Generator Direct showed up first. A phone call later and talked to some nice people I had a generator coming.

In two days it showed up, the next day the cold weather kit came. Since this was a whole house one I had to cleanup the utility pole and build a batter board to mount a distribution panel and transfer switch.... more
Pros: Price, Easy To Use, Quiet, Reliable
Roger Recommends This Generac Guardian Product
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Kim M.
Santa Fe, TX
Purchased from Electric Generators Direct
Purchased 6/17/13
Total Helpful Votes
49 Helpful Votes
5 out of 55 out of 55 out of 55 out of 55 out of 5
Love My Gen!
Well this project started as " I want a small generator to power a few things." Ended up with the standby. It was easy to install, (self install). We had placed one at a business prior. After installation and testing we placed it under a load. A/C unit, water heater, well pump & septic pump, lights, & fans. It did not skip a beat. I am ready for the next outage.

The only two bad things that happened: the box that the gen came in had been damaged and it scuffed the paint a... more
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Pros: I'd Buy It Again, Easy To Use, Quiet, Fast
Cons: Bad Instructions, Packaging
Kim Recommends This Generac Guardian Product
Kim Would Recommend Electric Generators Direct To A Friend
Web Site


"Easy to buy! Saved hundreds by buying online with no tax."
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Purchased from Electric Generators Direct
Purchased 1/2/14
Total Reviews
2 Reviews
Total Helpful Votes
31 Helpful Votes
5 out of 55 out of 55 out of 55 out of 55 out of 5
Smooth And Quiet!
It's truly working smooth and quite!......No screaming motor bouncing all over the place!.....When I started the engine, I immediately noticed that it is a very well balanced machine!.......Plus, its streamlined appearance would look good at any location!... I placed a regulator on the natural gas, 2 lb, 1" line at the rear of the generator like Jim suggested, to provide the correct pressure for excellent engine performance.

Everything worked exactly as engineered.........Every test... more
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Pros: I'd Buy It Again, Price, High Quality, Quiet
Walter Recommends This Generac Guardian Product
Walter Would Recommend Electric Generators Direct To A Friend
Web Site


"I didn't make my decision overnight. I really studied the matter because it is an investment in safety, security and comfort, that also increases the value of your home. I looked at every generator and every local and online dealer. After much time and deliberation, I made the wise decision of going with Electric Generators Direct. I can now say "wise" because I can look back at the experience with the satisfaction of knowing that the decision that I made was the right one! They were super people to work with and were knowledgeable about the product. The product was shipped quickly and safely to my location......And free shipping????.... How great is that???"
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Mark G.
Ponca City, OK
Purchased from Electric Generators Direct
Purchased 11/17/13
Total Helpful Votes
27 Helpful Votes
5 out of 55 out of 55 out of 55 out of 55 out of 5
Okie Diy W/ Assist
Recently retired and made the purchase of the generator a priority. Ordered the generator and it was delivered right on time with no shipping & tax as advertised.+++ Poured the pad, ran the gas line, ran the electrical conduit and mounted the ATS, but took the advice from the reviews and had Generac do the final tie-in and make initial startup. All went well and the unit made its first exercise run this weekend without a hitch. I would and have recommended not only the purchase of a... more
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Pros: I'd Buy It Again, Price, Easy To Use, Features
Cons: Lid Latch Seems To Be Only Issue
Mark Recommends This Generac Guardian Product
Mark Would Recommend Electric Generators Direct To A Friend
Web Site


"Great Experience!!"
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Purchased from Electric Generators Direct
Purchased 1/2/14
Total Reviews
2 Reviews
Total Helpful Votes
31 Helpful Votes
5 out of 55 out of 55 out of 55 out of 55 out of 5
Glad We Have The Security
The power went off and my Generac took over!.... My wife cooked lunch and then she dried some clothes. The air conditioner is working also, along with two TVs and several lights. Life remains normal with Generac. I am so glad we have the security provided by owning a Generac generator.
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Walter Recommends This Generac Guardian Product
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Wilmington, DE
5 out of 55 out of 55 out of 55 out of 55 out of 5
Don't Hesitate To Purchase
Model 6244 natural gas. Did a lot of prep work myself (designed layout, dug trench, poured 6 inch concrete pad, back filled trench). Had mechanical contractor pull permits for NG and installed piping. Master electrician, Rob at Connective Power Services in northern Delaware, Tri-State area, performed all electrical work and start-up and services it. Zero problems with excercise each week. First power failure, started right up. I highly recommend this generator.
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Pros: High Quality, Price, Reliable, Features
Vince Recommends This Generac Guardian Product
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Brian F.
Spokane, WA
Purchased from Electric Generators Direct
Purchased 4/24/14
Total Reviews
6 Reviews
Total Helpful Votes
23 Helpful Votes
5 out of 55 out of 55 out of 55 out of 55 out of 5
Great Peace Of Mind!
I'm thrilled to be the owner of this new Generac standby generator. My brother-in-law lives next door, and we bought both of our generators at the same time. This is a very slick product and appears to be very well designed and thought-out. The overall layout and accessibility to the generator is very good, and Generac has put a lot of time into showing you how to install the generator and to maintain it for the long-haul. I haven't had a power outage yet, but it has come on every Saturday... more
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Pros: I'd Buy It Again, High Quality, Exceeded Expectations, Seems To Have Been Designed With My Rural Modest Acreage In Mind
Cons: 2 Panels Excessively Complicated Single 400a Panel Overpriced
Brian Recommends This Generac Guardian Product
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Ronkonkoma, NY
Purchased from Electric Generators Direct
Purchased 10/19/13
Total Helpful Votes
216 Helpful Votes
5 out of 55 out of 55 out of 55 out of 55 out of 5
Peace Of Mind
Thats what its all about...Peace of mind! EGD website couldn't be easier to navigate through. 20kW Generac arrived sooner than expected. Hired my own electrician and plumber (which turned out to be a lot cheaper) and fired it up...Started without a hitch! Runs everything in my 2800sq ft. house. Couldn't be happier...Also purchased the cold weather kit and the mobile link...Both up and running as well...
Pros: I'd Buy It Again, Price, Easy To Use, Reliable
Cons: Heavy
Chris Recommends This Generac Guardian Product
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Larry W.
Boswell, PA
Total Helpful Votes
108 Helpful Votes
1 out of 51 out of 51 out of 51 out of 51 out of 5
No Service And No Customer Service
Purchased on 12-27-12 at Lowe's in Somerset, PA. Arrived with delivery to my residence in March without any owner's manual or installation guide enclosed. Installed using downloaded instructions guide from website by certified electrician and certified plumber (natural gas).

On May 13, 2013 unit was started and would not continue to run displaying alarm shutting down. Generac Service department refused to provide info indicating gas line was insufficient. Installed larger gas line with... more
Cons: Low Quality, Unreliable, Bad Instructions
Larry Does Not Recommend This Product
Mike, the Generator Expert
Product Expert
Since you generator is still under warranty. I would suggest contacting Generac directly @ (888) 436-3722 x5381 to find a servicing dealer in your area that can come out to you home for warranty service.
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5.0 out of 55.0 out of 55.0 out of 55.0 out of 55.0 out of 5
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Shop for the Generac Guardian™ 20kW Aluminum Standby Generator System (200A Service Disconnect + AC Shedding) at Electric Generators Direct. Research Generac Guardian 696471062441 standby generators air-cooled generator online. Find Generac Guardian 6244 standby generators air-cooled generator & 6244 Guardian Generator System features and specifications.