First thing is they have to be pretty close to level and they don't cool very quickly. Got to give them 4 - 6 hrs. The main causes of an ammonia based refrigerator cooling unit failures are restrictions internal in the unit or a leak. Leaks can be spotted by a yellow stain at the leak area. Restrictions can be rust that fell off of the inside of the tubing or material that comes out of solution due to being run un level and the solution got too hot. You can remove the unit and ... for real ... roll it across the lawn. Roll to the front, roll on the top, back, base, right side, top, left side, then to the base. Level it up real good and run it for 6 hrs. If not cooling, do the roll thing again and fire it up for 6 hrs. Still no cool? Probably no good. If they hadn't been run in a while then this may wake it up. Sometimes just driving it down a bumpy road will do it. But, restrictions don't go away. They may return.

Before you would roll it,  make sure that the means of heat were working. Check the gas to see if there is a pilot burning; that is all it takes to heat the boiler. To check the 12v or 120 v you will have to check with a meter if elec is going to the heating coils, then an amp probe to see if it is using the elec that is delivered to the heaters. The thermostat is only used in the 120 volt mode as for the 12 v, and gas they heat all the time.

Norcold is available at 800-543- 1219 and/or 800-767-9101., Norcold and Theford (the Porta Potty Co.) are divisions of each other.; If you call they will send sales brochures and info. These units are actually manufactured at: 600 S. Kuther Rd. Sidney, Ohio 45365, and I tried unsuccessfully, to buy from them, directly. The difference in price between the 3 way and 2 way refrigerator, is very little.