Rear A/C Gremlin

[Ken Sair]

Having a very strange problem with the rear ac. We are in Phoenix and temps are 100-110 every day.

Oops, 2007 Contessa

Rear ac comes on. Runs fine. Sometime after we are asleep it starts to cycle on/off as the temperature dictates. It needs constant cooling starting around 7am. However, the condenser will not kick on until room temp reaches 82, 10 degrees above the 72 set on the thermostat, around 10 o'clock. Then runs fine until the next day.

Now, had a repair guy out to replace the control board and thermostat last Friday. Worked great Saturday but Sunday morning produced the same symptoms, no ac until the 10 degree difference. Fan would run on low and high but shutoff when switched back to auto.  On both Sunday and Monday, the ac would then come on and work fine if it was turned off for two hours or so.

Tech scratching his head and Dometic not much better.

Today, it would not come on at all. Ann left at around 10 and turned it off. She got back home and turned it on at 7pm. Came right on and works fine.

Weird. Is there some time warp in AZ for rear ac's. can't think of any logical explanation why it runs 14-16 hrs with no problem but won't come on in the morning, unless its shutoff for 2-3 hours

Help! Ken

[Edward Buker]

Ken,

Because the compressor on temp seems to be regulated by the inside temperature being 82 it would seem that the signal has to originate at the thermostat or the temp sensor if it is remote. If you have another thermostat in the living room area I would exchange the two and see what happens to help trouble shoot this issue....it is a strange one. Possible that the tech in handling the parts put one of the originals back in, stranger things have happened in the heat of battle.

Later Ed

[Ken Sair]

Thank Ed. I did try that. No change. Now, a little twist. My bride turned the thermostat to 68 in the rear. Yesterday it came on and stayed on. I have not talked to her today yet.

That really makes no sense as it will never get to 68 this time of year.

Ken

[Tim Westman]

Ken,

Sure sounds like a sensor to me.  In my current coach I had a similar problem but I can see what the sensor is reading.  Sometimes it would read accurately and the AC would operate properly.  More often than not however, the AC had to be set about 15-20 degrees lower than normal to get the AC to come on because the sensor was reading the wrong ambient temperature (it was showing lower than actual temperature).  Replaced sensor and all is well.  Before I replaced the sensor the AC would appear to run when the fan was set on either HI or LOW speed but not on AUTO.  Of course, under that scenario, only the fan would run and the AC portion would not...is that true for yours?

Good luck...hope you find the problem...I know you need the AC!

Tim

[neil omalley]

Look at where the placement of your sensor is.  In my case('05 Thunder) the placement for my sensor is directly below the exhaust air from the A/C Guess what?  As soon as the sensor senses cool it shuts down even though the room and the surroundings are still overly warm?  Yours too?

[Ken Sair]

Thanks Tim, it gets better. Sensor has been in the same place for over 6 years with no problem. We do not believe it to be a location issue at this point.  Its been running fine when set at 68. After much time on the phone with Dometic they also are replacing the 'freeze sensor'. We made an appointment for WE morning to have this installed.

So, as our world turns we came home late last night and found the front AC not working. Fan running but the compressor was not. Shut it down and restarted this morning. And heard one of my least favorite 'clunking' noises. I have heard this sound before. Compressor trying to kick on with no luck. Last time it was a compasiter. About the size of a lipstick tube. It contains a quarter size disc between two springs. It broke in two and lost the connection. Easy fix and even I was able to do it.

So, tomorrow bright and early they can fix both AC's. Really, Aug and Sep in Phoenix and I lose both AC's?

Wishing real bad I was at the rally in Oregon where I belong

Ken

[Edward Buker]

Ken,

You know capacitor issues make a lot of sense here. They are required to get the compressor to start. They take a lot of heat and abuse and do not always fail outright, they can break down. When things cool down compressor wise, and pressures equalize, the capacitance may be enough to allow the compressor to start and when it is hot and not fully equalized maybe not. If the fan is running but the compressor is not it would mean that the thermostat has told the air to come on if using auto mode for the fan setting. It sounds plausible that this may be part of your issue...

Later Ed

[Ken Sair]

Well, it turns out the front AC was toast. It would not work under any conditions. So, the extended warranty company got to buy me a new one. As always, they would only pay the lowest price they could find online, $925 in Texas. It was $1200 here in Phoenix. Since they dont pay shipping, to bad for me. On the good side the AC arrived the next day and not a week later. It does get a bit warm here this time of year.

So, the not so funny news. The new AC requires a 12 button thermostat to operate. They would not approve that replacement as my '5 button' thermostat was not broken. The AC was broken but not the thermostat, hence they only replace/repair 'broken' parts. So, I get a new AC but no way to operate it. Doesn't quite live up to the contract is my opinion. If it was in good working order and broke, it should be made to be in good working order under the contract. What the hell good is a partial repair. Defies all common sense and logic.

Anyway, letters of protest already in the mail. It worked out to $225, worth fighting for.

Ken