Frequently Asked Questions

1. How long does it take to install a unit?

It will vary depending on the size of the unit. The air-cooled 6, 8 and 10 kW should take about 8 hours. The liquid-cooled 15 and 25 kW will normally take up to 14 hours over 2 days. The reason is that the air-cooled units can be placed on a prefabricated mounting pad. The liquid-cooled units, because of the added weight, will often require a poured concrete mounting pad. If the installer can locate a prefabricated mounting pad that will meet the weight requirements, the install time will be reduced accordingly.

The length of time is based on a "typical" application. It does not apply to extended runs of conduit or gas piping or placement of a unit in a location not near the incoming electrical service.
2. How do you size the generator?

The only completely accurate way is to have an electrician apply an amp meter to the circuits or appliances that are being chosen to operate under emergency backup power. It is recommended that the amp draw be measured as the appliance "starts up" when that appliance uses an inductive or resistive motor. For assistance with estimating the size of system your application requires, visit What Size System Do I Need?
3. How much fuel do the units use?
6 kW 8 kW 10 kW 15 kW 25 kW
Natural Gas-cu ft/hr 105 147 177 277 441
Propane-cu ft/hr (gal/hr) 38.4 (1.08) 55 (1.5) 75 (2.3) 110 (3.1) 175 (4.8)
These are fuel consumption quantities at 100% (full) load. It is unlikely that the unit would run at full load for an extended period of time.
4. The generator I've chosen has a 100-amp transfer switch. What if I have 200-amp service in my home?

It is always recommended that emergency circuits be isolated into a sub-panel with its own breakers. An isolated sub-panel will prevent the possibility of the generator becoming overloaded. Thus, the system will respond automatically.
5. Will 200-amp transfer switches be available for 6, 8, 10 and 15 kW units?

No. It is not electrically necessary. The outputs of these units are safely carried with the 100-amp switch.
6. What is the expected life of the engine?

A properly maintained engine should provide over 20 years of operation under emergency standby conditions. Keep in mind that the units are not intended to provide prime power (24 hours a day 365 days a year).
7. Where can I get parts?

Parts can be obtained through any authorized Guardian Dealer. The part numbers are located in the owner's manual.
8. What is the cost of a service/maintenance contract?

The cost will be determined by the installing dealer, based upon what service the customer requires for the system. Further, the cost will vary based on hourly labor rates in different parts of the country.
9. How much oil does the engine crankcase hold?

6 kW - 1.7 qts.   8 and 10 kW - 2.0 qts.   10, 15, 20 and 25 kW - 4.0 qts.   35 and 40 kW - 4.5 qts.
10. What type of oil is recommended?

For the 6, 8 and 10 kW air-cooled units: above 20° F use 10W-30, below 20° F use 5W-20 or 5W-30. After the first oil change, all-season 5W-30 synthetic oil may be used. API Service Class SG, SH or SJ should be used in all cases.

The recommended oil for the liquid-cooled units is 15W-40. All oils should be SAE rated high detergent oil that meets or exceeds API Service Class SF requirements for gasoline engine.
11. Propane tanks are usually rated by pounds. Is there a conversion that can be applied to the fuel consumption numbers?

Yes. For general conversion, propane weighs 4.24 pounds per gallon.

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