Propane fridge repair

[Smitty Two]

Sometime soon I'll be taking a 45 minute drive to look at a friend's DC powered propane fridge. I've never even seen one of these. She says it hasn't worked for months, but recently a solar power expert has been working up there, repairing things. Now the fridge works, sort of. As she describes it:

There is an ON/OFF slide switch which is now mysteriously backwards; the ON indicator light comes on with the switch supposedly in the OFF position. I'm thinking this is a SPST that just got pulled and reinstalled backwards, but maybe not.

The burner will light, and cool the box to 34F, when she presses the start button. However, once the fridge warms up, it won't re-ignite automatically.

What tools should I take, and what should I be looking for?

[Wayne Boatwright]

On Thu 16 Dec 2010 11:39:04p, Smitty Two told us...

I'm sorry, but I have no answers or suggestions.

Just wanted to say that I've always been fascinated by the natural gas and kerosene powered refrigerators and gas airconditioners of many decades ago. The fridges reqired no electric power whatsoever and werwe often purchased by families in rural areas without electric service. From what I understand, gas a/c was more efficient to operate than electric units, with many fewer moving parts to wear out.

Good luck with finding what you need.

[The Daring Dufas]

The sealed unit contains a mixture of ammonia, water and hydrogen which is in a specific ratio. When the refrigeration unit is repaired, a refill cylinder containing the proper mix must be used to completely replace the gas charge. It's a very interesting old and proven technology but you must know what you're doing or the darn thing will never work. If the cooling unit is defective, the usual repair is to remove the whole assembly from the refrigerator case and replace it with a re manufactured unit. The repair depots have the proper equipment to replace the ammonia, water and hydrogen charge.

TDD

[jamesgangnc]

By "manual pushbutton" do you mean one of those piezo spark generators such as are found on grills? Because if it has one of those then most likely it has a pilot light.

[Pete C.]

If it's like the RV refrigerators it will indeed have a pilot light if it uses a manual piezo igniter to get it started. The DC is presumably just used for a circulator fan to keep temps more even and the unit would actually operate without power.

[Pete C.]

Absorption chiller, interesting stuff. These days they are common in little RV refrigerators, and in big industrial refrigeration, particularly where there is waste heat available from another process to drive the chiller. I've heard the factory fish processing ships use absorption chillers powered off waste heat from the ship's engine(s).

[jamesgangnc]

Yes, they are common on devices that have a pilot but the location of the pilot makes it difficult to relight it when it goes out. Particularly with propane since running out of propane results in all the heating devices pilots being exstinguished. It should have the typical pilot detection setups that are common to gas appliances with pilot lights. The tube type or the millivolt setup.

[Pete C.]

That parts diagram shows the unit to have an electric reigniter. I believe these are normally intended to reignite the pilot if it gets blown out by a wind gust, as opposed to operating as a fully intermittent ignition system. It should be pretty obvious if there is a pilot burner by the thermocouple when you look at the unit, and if that pilot is going out when it shouldn't.

[Wayne Boatwright]

On Fri 17 Dec 2010 08:04:32a, Pete C. told us...

Thanks for the info!