* RV Refrigerator Maintenance *
By serger

22 July 2002

When I bought my new to me travel trailer I found out from the seller the refrigerator didn’t work. I thought it wasn’t a big deal because they are so simple it had to be easy to fix and we bought the trailer. When I went to work I told my friends what I had been told and the first thing out of their mouth was, "Did you Burp it?" I had no idea what they were talking about and so they enlightened me.

Apparently, when an absorption cooler as this type of refrigerator is called sits unused for a long period of time the chemicals inside it stratify out in to separate layers and the ability of the unit to work stops. Reactivating the unit requires you to mix the chemicals. To do this you rotate the unit in a circle so the unit is completely inverted. That’s called burping a refrigerator.

This requires you to remove the unit from its mounting compartment. First you turn of the gas and electricity to the unit. Then you unscrew the gas connection and disconnect the electrical wiring if any. Note: if the unit is hard wired and doesn’t use a plug in connection you need to mark the wiring as you disconnect it and write what you did down so you won’t forget and possibly hook it up wrong. Some of the refrigerators have both 12 volt and 120 volt wiring along with circuit cards you can fry.

What I did was to disconnect the gas. I then removed the door so I’d have something to grab onto. Next I removed the mounting screws that held it in. With my wife helping we slid out the unit and sat it on the floor of the trailer. These things can be very heavy with sharp metal edges, so don’t’ bust a gut or slice yourself. We then laid it on its side and looked at the mounting compartment for it. On most all of the older travel trailers I have seen there is water damage in the refrigerator compartment. This is because the access panel for the burner assembly is louvered and the vent stack where the heat of operation is exhausted are both open to the outside elements. Historically, the material used for construction in most of the trailers is cheap plywood or particleboard. In the case of my trailer the particleboard was very warped and sagging. It was cut out and a piece of 5/8^th inch plywood was laid down. One thing I do with my gear is to winterize it by sealing the air holes so snow and rain are excluded.

We then turned the refrigerator in its top and listened to the gurgling of the fluids in it moving around. So far so good, two hours later we turned it on its side. Two hours later we placed it back on it’s top and reinstalled it. After a half hour I hit the piezoelectric switch and waited. Two hours later the refrigerator was ice cold.

When you reinstall the gas line you need to brush the fitting with some soapy water. If it bubbles, there’s a gas leak and you need to fix it. If there are hard wire connections make sure the wiring is bright and the mechanical connections tight. Also look at the wiring drawing you made so you can hook up the connections properly, otherwise you might just Poof the controller board if the unit has one.

While you have the unit out, look for corrosion of the piping. This is indicative of incipient fluid loss failure. Also look for damage/bending of any radiator fins. If there is any damage such as bending, you need to straighten out the fins to improve the flow of air on the fins and increase the life of the unit. Do this on the inside of the unit also. Wipe off all dirt, mold, mouse droppings etc. You want as clean a surface as possible to promote efficient heat transfer to the air that moves the heat around. Next observe the flame from the burner when the unit is asking for cold e.g., when you open the door and leave it open. A good rule of thumb is the flame should be a robust blue. If it is yellow tinged or sickly looking like a pilot light you probably have burner problems and the burner assembly needs cleaning or replacement. Also if this is the case the ability of the machine to cool will be noticeably degraded.

Another area that needs a look at is the door seal. It should be clean and tight. If there are tears or gaps in the seal, you are losing cold from the unit. The same applies for a door that is skewed and leaking air.

After reactivating my refrigerator and being told I needed to write an article on what I did I started researching for information on absorption refrigeration and found the following site. They are a company that sells and refurbishes absorption refrigerators, along with supplying parts for them. They have a very good diagnostic section on how to troubleshoot and correct problems with these machines, as well as enough theory of operation to give you a well-rounded knowledge level to check out your unit. As near as I can tell there are several hundred pages of information on these units. If they weren’t copy written I would have printed most of their information here. I down loaded the information and service bulletins I needed to keep my systems operational and printed them out. It’s that good. The name of the company is rvmobile.com.

Thanks for the read.

serger