Coleman Thermostat Issues

[Craig P.]

I have had a problem with my Coleman A/C thermostat, since I bought the coach five years ago...it was one year old at the time. The t-stat is a dual zone, model RVComfort.zc.

Occasionally when using the A/C, the t-stat would cut out and display a "00" reading. This would in turn prevent the A/C compressors from re-starting, allowing the interior of the coach to get very hot during the summer. This initially only happened occasionally, but now it is happening frequently. When this occurs, the only way to reset it is to momentarily shut off power to the t-stat. It will then reset and work normally when power is restored. Since this requires manual intervention, I do not feel safe leaving our dog alone in the coach during the summer.

When this initially started happening, I contacted Coleman, and they said it was some sort of 12V interference, more than likely the result of fluorescent lighting. I went through an elimination process to try and eliminate the lighting and found that the lighting was never on when this occurred. Coleman sent me a new-t-stat and a filter to try and reduce what they deemed an interference. This seemed to help until recently. The interruption is now occurring almost daily. The t-stat they sent me 3 years ago will no longer work, so I re-installed my old one which I kept.

I have tried many remedies including installing a secondary ground wire, as suggested by another member. This unfortunately did not work either.

Has anyone else run into this? If so, have you found a permanent fix?
Craig

[RV Wizard]

It is probably dirty DC power caused by florescent light or charging section. Turn every thing in coach off and one at a time turn on florescent lights until the T'stat acts up. This will be the problem and a new fixture will correct the issue. If it is a constant problem be sure to check the charger or converter's charging section for dirty DC power.

[Craig P.]

Quote:

Originally Posted by RV Wizard It is probably dirty DC power caused by florescent light or charging section. Turn every thing in coach off and one at a time turn on florescent lights until the T'stat acts up. This will be the problem and a new fixture will correct the issue. If it is a constant problem be sure to check the charger or converter's charging section for dirty DC power.

The florescent lighting was the first thing Coleman had me eliminate when this problem first developed. I rarely use my florescent lighting and it has never been on when this has occurred.

This only occurs when operating the A/C. It has happened while hooked up to shore power and while operating the genset. That being the case, would dirty DC power come into play? If so, how would I go about checking the converter for dirty DC power?

Thanks.

Craig

[RV Wizard]

Use a digital AC volt meter and check the coach's DC power on the meter. If you have a way of turning the charger on and off, check the voltage in both modes. If you do not have a way to turn it off, disconnect the power cable feeding the battery bank.

[FreshAir]

FWIW, I also had my T stat resetting to 00 when I first received the MH. However my problem was thought to be caused by a new brand of florescent light fixtures Fleetwood started using in 2005. The Light Manufacture sent me all new fixtures but that didn't help, they were aware of the possible T-stat problems caused by the ballast in some florescent fixtures. An Engineer at the light manufacture co. was working with me on this and after replacing the light fixtures with no success told me that he didn't think the problem was entirely to blame on their fixtures although it only occurred while the florescent light within a few feet of the T-stat was on.

The Engineer said that regardless of what is causing the problem they have a fix for it. He sent me a filter that I just unplug the cable to the T-stat, plug in the filter, and then plug the cable to the filter. Very professionally made and the plugs matched my setup. Never had another failure in the 5 yr's since.

I don't know if my AC would have caused the problem as I never used it before I fixed the problem. I wonder if you have a two AC units and only the one closet to the T-stat is causing your problem? Anyway, something is inducing noise to the T-stat. Probably to the DC circuit or maybe the temperature sensor lines? Maybe a starup capacitor, a noisy motor, ect., etc. in the AC. A filter may be the simplest fix.

Pat

[Craig P.]

Quote:

Originally Posted by FreshAir The Engineer said that regardless of what is causing the problem they have a fix for it. He sent me a filter that I just unplug the cable to the T-stat, plug in the filter, and then plug the cable to the filter.

Pat,

Did you get the filter from the light manufacturer or Coleman? Per my OP, the filter that Coleman sent me failed to solve the problem.

Quote:

Originally Posted by RV Wizard Use a digital AC volt meter and check the coach's DC power on the meter. If you have a way of turning the charger on and off, check the voltage in both modes. If you do not have a way to turn it off, disconnect the power cable feeding the battery bank.

I'm not good at that sort of thing, so I'll have my mechanic son check it for me, thanks.

Craig

[Paul R. Haller]

Why not add any home grown or commercial choke to the power lead of your t stat? Check with any auto audio store for one. This is a common problem in audio with poor filtering of noise in the DC + lead. Sometimes just a ferrite bead can solve the problem but often a commercially made transformer choke must be used to filter out hum.

This, in my opinion, is an engineering fault of the t stat and they blame everyone else for their under engineered crappy product. If Coleman has a problem with ac in the dc feed confusing their t stat, "Fix It", rather then continuing to blame others. You could also replace that cheesy Coleman t stat with a hunter digital stat and also solve your hysteresis caused by a crappy analog t stat. In stick homes those old t stats went out in the mid 60s but Coleman still makes them because they are really cheap to manufacture 5 decade old technology in China.

I'm amazed Coleman is still in business making this cheese for RVs but that's just my opinion.
-Paul R. Haller-

[Craig P.]

Paul,

The problem with using a residential t-stat is that I need a t-stat with two separate zones. I haven't seen a residential model designed that way, but I could be wrong.

I wasn't aware of a choke available from an audio store. I will look into that.

Thanks.

Craig

[JC2]

Quote:

Originally Posted by Paul R. Haller Why not add any home grown or commercial choke to the power lead of your t stat? Check with any auto audio store for one. This is a common problem in audio with poor filtering of noise in the DC + lead. Sometimes just a ferrite bead can solve the problem but often a commercially made transformer choke must be used to filter out hum. This, in my opinion, is an engineering fault of the t stat and they blame everyone else for their under engineered crappy product. If Coleman has a problem with ac in the dc feed confusing their t stat, "Fix It", rather then continuing to blame others. You could also replace that cheesy Coleman t stat with a hunter digital stat and also solve your hysteresis caused by a crappy analog t stat. In stick homes those old t stats went out in the mid 60s but Coleman still makes them because they are really cheap to manufacture 5 decade old technology in China. I'm amazed Coleman is still in business making this cheese for RVs but that's just my opinion. -Paul R. Haller-

Why don't you tell us how you really feel.
I agree 100% with what you say but it seems to be much easier/cheaper for some manufacturers to blame the consumer. I had a Coleman 13500 BTU AC/Heatpumpump go out about 1 1/2 yrs ago and was kind of dissapointed that it only lasted 5 yrs. When I contacted them with my concerns, they wouldn't help as the warranty was up. Unfortunately poor customer service, no pride in workmanship and lack of quality seems all to common today.

[FreshAir]

Craig, I got the filter from the light mfg. Liteco Inc. I have the same model T-stat as you. When I had the problem 5 years ago, Fleetwood said they never heard of the problem. I had also changed the Gomfort T-stat. No fix.

At the time, 2005, Liteco Inc had just received the contract from Fleetwood to supply the florescent light fixtures for some of their models. Liteco engineering was aware of the problem even tho Fleetwood denied any knowledge of it. Liteco wanted the contract and would not point any fingers at other Fleetwood products in order not to cause any problems. I worked with Liteco engineering to check what we could, I'm no stranger to electronics, but finally Liteco basically said if we send a filter/shunt to fix the problem would you be OK with that? I was.

We also thought we may be fixing someone else's problem. There are so many things in RV wireing that can cause goofy glitches to happen, loose connections, a miss driven staple, AC and DCwires running parallel, on & on. It might come down to one of those Fix IT, Don't Explain problems.

Pat

Good luck, you have some good help here.

[Craig P.]

Quote:

Originally Posted by FreshAir Craig, I got the filter from the light mfg. Liteco Inc.

Thanks Pat. Is this the same Liteco Inc. that you dealt with?

Craig

[Jim2]

when I (and several other members of the Discovery Owners Assoc) had this same issue years ago (RF interference locking up the thermostat) , Coleman/RV Products always tried to blame it on the flour light fixtures. some folks did reduce the problem by changing to shielded ballasts, but like you I rarely use the flour lights and my thermostat would lockup in the dreaded 00 condition in the middle of the night with no lights on. Many other potential sources of RF interference are found in most RV's these days.
In my case and several others the problem was permanently fixed after RV Products revised & improved the electronic circuit board in the thermostat. they were up to Rev J the last time I was involved in this. Since upgrading that board I haven't had the issue re-occur in the last 3 years.

[FreshAir]

Craig, I'm pretty sure it is but it won't come up on my saved favorites list. There must have been an E=mail address change for them?

The folks that sent me the replacement fixtures had an address of;
Liteco,
A Divesion of Optronics
420 Roske Drive
Elkhart, IN 46516

PN of their light fixtures, 17918372

Pat

PS, should you want, I can pull the panel and see if there is a number on the filter they sent me. I think it's one they designed.

[Craig P.]

Pat,

I just spoke with a rep. from Liteco in Elkhart. She had no idea what I was talking about and said that Liteco does not have any such filter. Can you double check the filter for me? I'd greatly appreciate it!

Craig