Model#: GRCN6438

What are the different product conditions?

Brand new items;Full manufacturer warranty available
Manufacturer inspected, repaired and tested items; CPO 60 day money back guarantee
Open Box
New or Recon items with possible minor cosmetic damage; CPO 60 day money back guarantee
Returned items inspected, repaired and tested by CPO technicians; CPO 60 day money back guarantee

Generac 6438 Guardian Series 11kW Automatic Standby with 200 Amp Transfer Switch (CARB)

Free Freight Shipping »
(continental U.S.)

Freight Orders

Freight deliveries require a delivery time be scheduled and someone must be present at the time of delivery to inspect and sign for the merchandise. A representative from the freight carrier will call the phone number entered at checkout to schedule the delivery.

Liftgate Service

For freight deliveries, you have the option of adding a liftgate to your delivery. A liftgate is the device that lowers a product from the truck to ground level.

CPO recommends adding liftgate service for freight deliveries exceeding 100 lbs if you do not have a loading dock or fork lift at the delivery address. Additional charges may apply. The liftgate option will be presented during the checkout process.

Please note that liftgate service only ensures the product is removed from the truck. We recommend you have the additional help of two to four people to move the product to its desired location because drivers are not required to assist.

Requesting liftgate service after ordering may result in additional charges and delays.

This item is no longer available.
It has been replaced by the GRCN7033.

Product Overview


Generac Guardian series provides the automatic backup power you need to protect your home and family during a power outage. Connected to your existing LP and natural gas fuel supply, it kicks in within seconds of determining power loss automatically and runs for as long as necessary until utility power returns.
  • Powered by the innovative Generac OHVI engine specifically designed for generators
  • TruePower technology provides clean, smooth operation of sensitive electronics and appliances
  • Evolution Controller is the next generation of intuitive controllers featuring a multilingual, two-line LCD text display with color-coded, backlit buttons
  • Tool-less fuel conversion makes it easy to switch between natural gas and LP fuels in the field without the need for tools
  • Low oil pressure shutdown system to prevent catastrophic engine damage due to low oil
  • Skewed stator produces a smooth output waveform for compatibility with electronic equipment
  • Electric ignition/spark advance combine to assure smooth, quick starting every time
  • Revolving field allows for smaller, light weight unit that operates 25% more efficiently than a revolving armature generator
  • Pre-wired, color-coded conduits ensure the easiest, trouble-free installation
  • Weather protective steel enclosure ensures protection against mother nature with a hinged key locking roof panel for security
  • Superior noise reduction with enclosures lined with sound reducing foam panels
  • Hour meter tracks usage between maintenance sessions
  • Guardian Series 11kW Automatic Standby with 200 Amp Transfer Switch - 6438


Series: Guardian Series
Length: 48 in.
Width: 25 in.
Height: 29 in.
Weight: 407 lbs.
Amperage (LP Vapor): 45.8
Amperage (Natural Gas): 41.7
CARB Compliant: Yes
Cooling System: Air
Enclosure Type: Steel
Engine Displacement: 530cc
Engine Make: Generac
Engine Model: OHVI V-Twin
Engine Speed (RPM): 3600
Fuel Consumption at 100% Load (LP Vapor): 1.92 gal/hr.
Fuel Consumption at 100% Load (Natural Gas): 195 cubic ft/hr.
Fuel Consumption at 50% Load (LP Vapor): 1.18 gal/hr.
Fuel Consumption at 50% Load (Natural Gas): 124 cubic ft/hr.
Fuel Type: Propane (LP Vapor) / Natural Gas
Motor Phase: 1
Noise Rating (dBA): 63
Rated Watts (LP Vapor): 11000
Rated Watts (Natural Gas): 10000
Transfer Switch Amperage: 200
Transfer Switch Included: Yes
Transfer Switch Voltage: 250V
Voltage: 120/240V
Voltage Regulation: Automatic



4.9 / 5.0
297 Reviews
5 Stars
4 Stars
3 Stars
2 Stars
1 Star
Yes, I would recommend this to a friend (2)
Great during Hurricane Irene in CT
Hurricane Irene hit CT on August 28th, 2010. That morning at 7 am we lost power. The unit detected the power outage and kicked in as scheduled 15 seconds later. Then it ran... and ran... and ran... until August 31st at 1 am. After all that time it burned through only 40% of two large propane tanks (80 gallon tanks) and it could have run another three days easily (6 days total). Since it is on propane, it is relatively quiet to the other units in the neighborhood. It was trouble free and gave very even output no matter what the load was on the unit with its 20 circuits. For a 3500 square foot home, including the basement, it powers about 65% of the devices (lights, water pump, septic system pump, electronics) and makes staying in the home easy while my neighbors either (A) went to hotels or (B) struggled with their portables, refilling their tanks every 6 to 8 horus of use. I recommend this unit as you will be hard pressed to do better.
August 31, 2011
Originally posted at
Got us through Hurricane Sandy
After being without power for 6 days following Hurricane Irene, we decided to invest in a natural gas powered house generator. It was our best investment ever! Following Hurricane Sandy, we lost power for 8 days, and our Generac generator made it bearable. We had heat, water from our well, hot water to shower, didn't lose any food. We were taking in lots of our neighbors. So happy we made this decision. Highly recommend!
November 7, 2012
Originally posted at
Great Backup Generator
This unit was purchased and installed 2.5 years ago. It still works as advertised in a residential area. It has been been needed and used approximately 24 hours in this time frame for anything as short as 10 minutes to 4 hours. I have all essential home equipment and services on backup as well as many non-essential services. I also have exterior plugs available to run extension cords from for neighbours if need be. I suppose noise could be an issue however, I feel it is a matter of priorities. As I do live in NS, Canada a cold weather kit is essential to ensure proper operation in the winter. I have a 3500 sqft 4 bedroom home and this meets all of our needs. At most I would recommend a 17KW unit if you can get one at little above cost. Costco in Canada now has them and I am considering swapping to the larger unit. Overall, our experiences with this unit have all been positive. Great deal, quite satisfied.
September 19, 2011
Originally posted at
This product does everything I need for 3200 sq. ft. home.
I wish I would have gotten this sooner. It is nice to have the piece of minde. The 10K unit does everything I need and more. Typically outages are a day or less but we had a 4 day one. I really appreciate knowing my familyt has everything they need in an outage. The unit is very quiet compred to portable units. I would definately recommend this to anyone in the market for a back-up generator.
November 28, 2011
Originally posted at
Peace of mind
This is one of the best investments i made, the shipping was fast, had my uncle hook it up who is a certified electrician only took him 4hrs and he said the electrical panel and parts were very well built. I lost power for an hr couple days ago fired right up and had no problems, exercise function works like it should I am a very pleased customer.
July 7, 2012
Originally posted at
Generac10KW Installed and running!
I just completed the installation of a 10KW generac. In short it's awesome. I did it all myself and it works beautifully. I’d highly recommend this unit to anyone! It runs my whole house! 10 seconds after the power goes out it fires up and 5 seconds later the power’s back! If you want peace of mind in the winter or in a storm just get one!
October 20, 2012
Originally posted at
This product is realiable
Since owning our whole house generator it gives us piece of mind that we will never be without power. What a relief. We are now always prepared.
March 28, 2014
Originally posted at
This unit far exceeds expectations
I was given a time of 9am to 11am for arrival. They were backing in my driveway at 0900 on the dot. Jay and Charlie were amazing. Constantly working and very friendly. They answered all my questions!!!! Wish more service people would follow suit.
March 9, 2016
Originally posted at
Great peace of mind
Generac has officially come out with a product that makes have a standby power system at my home a seamless effort.
October 10, 2011
Originally posted at
I am very happy with my 10k generator, It was there when I needed it.
I am very happy with my 10k generator, It was there when I needed it, I had my power go out on me three times in the last couple of months and it was sure a comfort to know I had a good product like my Generac Generator.
October 10, 2011
Originally posted at

Questions & Answers

Start typing your question and we'll check if it was already asked and answered. Learn More
Browse 5 questions Browse 5 questions and 6 answers
Do all Generac standby generators come with a pad to sit on or do I have to buy one for it ?
Gene on Aug 12, 2016
BEST ANSWER: You will have to purchase the pad separately.
Do you provide installation for Generac Systems?
PHIL on Dec 29, 2015
BEST ANSWER: CPO does not provide installation for Generac Systems, your best bet is to contact Generac directly at 888-436-3722 and find a local installer through the manufacturer
My 3 ton a/c has 65 amps starting and 16 amps running. will the 11kw handle this starting load?
Joe on Jun 28, 2015
BEST ANSWER: Yes, this model will be able to handle the 65 amp starting draw.
I can't get into EDIT on the menu. I have tried pressing ESC many times but EDIT does not appear.
(I want to edit TIME/DATE and EXERCISE TIME.)
Can anyone help?, Bob
Bob on Jan 20, 2015
BEST ANSWER: For assistance, please contact Generac directly at 1-888-436-3722
Where is the generac 6438 made?
Bob on Feb 8, 2014
BEST ANSWER: Generac is manufactured in Wisconsin.



For a period of three years from successful activation of the unit (one (1) year or one thousand hours, whichever occurs first, for units in international markets), Generac Power Systems, Inc. (Generac) warrants that its standby generator will be free from defects in material and workmanship for the items and period set forth below. Generac will, at its option, repair or replace any part(s) which, upon examination, inspection and testing by Generac or an Authorized/Certified Generac Service Dealer, is found to be defective.


Any equipment that the purchaser/owner claims to be defective must be examined by the nearest Authorized/Certified Generac Service Dealer. This warranty applies only to Generac emergency automatic standby generators used in "Standby" applications as Generac has defined Standby. Scheduled Maintenance, as outlined by the generator owner’s manual, is highly recommended. This Scheduled Maintenance should be performed by an Authorized/Certified Generac Service Dealer. This will verify service has been performed on the unit throughout the warranty period.


Limited comprehensive coverage on mileage, labor and parts listed.


Limited comprehensive coverage on parts listed


(or 1000 hours, whichever occurs first) – Limited comprehensive coverage on labor and parts listed.


Extended Warranties are not available on units sold into International Markets.

  • 1. Warranty begins upon the successful activation of the unit.
  • 2. Unit should be Registered and Proof of Purchase and Maintenance must be available.
  • 3. Warranty is transferable between ownership of original installation site.
  • 4. Warranty only applies to permanently wired and mounted units.
  • 5. Any and all warranty repairs and/or concerns, must be performed and/or addressed by an Authorized/Certified Generac Service Dealer, or branch thereof. Repairs or diagnostics performed by individuals other than Authorized/Certified Generac Service Dealers not authorized in writing by Generac will not be covered.
  • 6. A Generac Transfer Switch is highly recommended to be used in conjunction with the generator set. If a Non-Generac Transfer Switch is substituted for use and directly causes damage to the generator set, no warranty coverage shall apply.
  • 7. Steel enclosures are warranted against rusting for the first year of ownership only. Damage caused after receipt of generator is the responsibility of the owner and is not covered by this warranty. Nicks, scrapes, dents or scratches to the painted enclosure should be repaired promptly by the owner.
  • 8. All warranty expense allowances are subject to the conditions defined in Generac's General Service Policy Manual.

  • 1. Any unit built/manufacturer prior to April 2010.
  • 2. Generac generators that utilize non-Generac replacement parts.
  • 3. Costs of normal maintenance (i.e. tune-ups, associated part(s), adjustments, loose/leaking clamps, installation and start-up).
  • 4. Units sold, rated or used for "Prime Power", "Trailer Mounted" or "Rental Unit" applications as Generac has defined Prime Power, Trailer Mounted or Rental Unit. Contact a Generac Distributor for Prime Power, Trailer Mounted or Rental Unit definition.
  • 5. Damage to generator system (including transfer switch) caused by improper installation or costs necessary to correct installation.
  • 6. Units used for Prime Power in place of existing utility power (where utility power is present) or in place of utility power where utility power service does not normally exist.
  • 7. Fuel connections other than conventional utility company supplied natural gas systems or conventional LP vapor withdrawal systems.
  • 8. Any failure caused by contaminated fuels, oils, coolants/antifreeze or lack of proper fuels, oils or coolants/antifreeze.
  • 9. Steel enclosures that are rusting due to the improper installation, location in a harsh or saltwater environment or scratched where integrity of paint applied is compromised.
  • 10. Failures due, but not limited, to normal wear and tear, accident, misuse, abuse, negligence or improper installation. As with all mechanical devices, the Generac engines need periodic part(s) service and fluid replacement to perform as designed. This warranty will not cover repair when normal use has exhausted the life of a part(s) or engine.
  • 11. Failures caused by any external cause or act of God, such as collision, theft, vandalism, riot or wars, nuclear holocaust, fire, freezing, lightning, earthquake, windstorm, hail, volcanic eruption, water or flood, tornado or hurricane.
  • 12. Damage related to rodent and/or insect infestation.
  • 13. Products that are modified or altered in a manner not authorized by Generac in writing.
  • 14. Covered warranty labor rates are based on normal working hours. Overtime, holiday, or emergency labor costs for repairs outside of normal business hours will be the responsibility of the customer.
  • 15. Any incidental, consequential or indirect damages caused by defects in materials or workmanship, or any delay in repair or replacement of the defective part(s).
  • 16. Failure due to misapplication.
  • 17. Telephone, cellular phone, facsimile, internet access or other communication expenses.
  • 18. Living or travel expenses of person(s) performing service, except as specifically included within the terms of a specific unit warranty period.
  • 19. Expenses related to "customer instruction" or troubleshooting where no manufacturing defect is found.
  • 20. Rental equipment used while warranty repairs are being performed and/or overnight freight costs for replacement part(s).
  • 21. Costs incurred for equipment used for removal and/or reinstallation of generator, (i.e.: cranes, hoists, lifts, etc.)
  • 22. Planes, ferries, railroad, buses, helicopters, snowmobiles, snow-cats, off-road vehicles or any other mode of transport deemed abnormal.
  • 23. Starting batteries, fuses, light bulbs and engine fluids.




Any implied warranties which are allowed by law, shall be limited in duration to the terms of the express warranty provided herein. Some states do not allow limitations on how long an implied warranty lasts, so the above limitation may not apply to purchaser/owner.




Some states do not allow the exclusion or limitation of incidental or consequential damages, so the above limitations may not apply to purchaser/owner. Purchaser/owner agrees to make no claims against Generac Power Systems, Inc. based on negligence. This warranty gives purchaser/owner specific legal rights. Purchaser/owner also may have other rights that vary from state to state.