A/C not cooling---Help

[FireTruckerWife]

Any suggestions. First time we've turned on the A/C , the fan works, but the compressor is not coming on to cool the trailer. Leaving Thursday for Mt. Shasta Rally, and no time to take to dealer. We installed the Comfort Control Center from Dometic, and until this week, couldn't try out the A/C-----too cold.

[DHenry]

FireTruckerWife, I am not familiar with the Confort Control Center, but double check your wiring and make sure that all connections are tight. Also check for low voltage, fuses that might be tripped. Good luck and we will see you at the Mt. Shasta get together.

[mazeeff]

Here are a couple of thoughts.

1. Did you install the "new" freeze control properly? You can not use the old one.

2. Make sure that the white connector on the ceiling control box is fully seated.

[rames14]

Also, don't overlook the fuses/breakers. I know when I was putting mine in I disconnected the fuses and was checking and hadn't put them all back in. Also make sure you didn't blow any fuses touching wires together. And, make sure the 110 breakers aren't tripped. Good luck and have a safe trip. If you don't get it running, try to find a Montana dealer on the way.

[firetrucker]

Well, it looks like the AC lost its coolant charge . I checked the voltage while monitoring the current as the fan, and then the compressor, came on. The voltage only dropped 3 V (117 to 114) (not bad considering the length of power cable between the rig and the garage). I heard the relay activate and the compressor start, and the current increased from 1.6 A (fan only) to about 7.5 A. All this while holding a digital thermometer up to the outlet. It was the only thing that didn't change. I put a call in to the mobile repair service that does the warranty work on the DuoTherm, and with any luck , we won't have to hope for a snowstorm at Shasta next weekend.

Bob

[sgf]

lso there is oil with the refrigerant,if the charge is lost oil comes out with it so check your roof,these rubber roofs and oil do not mix,we lost our charge also under warranty and they put a complete new unit on the rig and also had to replace the rubber membrane as a precaution,just something to look out for.

[firetrucker]

Update on A/C...the mobile repair service was out yesterday and confirmed my diagnosis to his satisfaction. He'll notify Dometic and we'll anxiously wait for delivery of the new unit. He suspects it was undercharged or not charged at all, but didn't check to see if there was any oil inside the unit.

We carried on quite a conversation while I tried to nonthreateningly watch his every move. He has been in the business over 20 years and had quite a few interesting anecdotes. He said that when he goes on a job now, no matter what his experience or intuition says, he takes out all his meters and instrumentation and hardly ever has someone complain about his charges.

He also asked if I had gotten a service contract. he said that more and more of the vendors seem to be trying to get out of payng what their contract calls for. Some want rebuilt parts to be used to repair units and will refuse to pay the cost of replacing failed unit with a new one. Unfortunately, too many customers don't know about the terms of their contract and give in to the companies.

He also confirmed what I have seen in the RV mag columns about companies honoring their warranties...if you mess with their equipment without checking with the company first, you can write off them honoring the warranty. One of the local RV dealers that sells Dometic recommended that we get the A/C recharged so we could get on the road. I had Sharon call Dometic, and their response was that we could do it, but we would also probably void the warranty.

It may cost you some time on your vacation, but it won't cost you the bucks!

Bob

[mazeeff]

Just out of curisosity, how did he determine that it was low on freon. RV A/C units have no pressure test ports, nor can they be re-charged without welding in a test port.

[firetrucker]

Mike,

He put a voltage meter on the line to make sure the voltage did not drop below specs, a clamp-on current meter on the ac line to the compressor, and a thermometer on the air coming out (he actually started with the back of his hand and then broke out the infrared thermometer as a double check).

Even though we could hear the relay click after the delay, the current meter confirmed that the compressor was running (it drew about 5.5 A, although I suspect it would draw more if it were properly charged). No cooling, no freon charge, or a broken shaft between the motor and the compressor.

Bob

[stiles watson]

Good job of using you head to get this solved. Thanks for posting the outcome and your observations.