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digNbubbs · 01-04-2007, 01:04 PM

I have been having issues with one zone of the t-stat. Zone 1 furnace would turn on and run and run and run. No matter where I set the temp, it would not shut off.

I have the Duo-Therm Comfort Control t-stat. I checked out the manual in case I was missing something stupid. I checked the forward temperature sensor as suggested in another post. See picture of the sensor here

To solve the problem, I used a "reset routine" that I found out about. I am posting it for educational purposes, and will claim ignorance if you blame me for messing up your t-stat

<UL TYPE=SQUARE>
<LI> Turn t-stat off
<LI> Hold Mode and Zone buttons in (top and bottom buttons)
<LI> Turn t-stat on
<LI> When you see "FF" release buttons
<LI> Turn t-stat off
<LI> Wait 2 minutes
<LI> Turn t-stat on[/list]
That seemed to take care of the t-stat issue. It now cycles on and off like a normal furnace

--kev

digNbubbs · 01-04-2007, 01:04 PM

I have been having issues with one zone of the t-stat. Zone 1 furnace would turn on and run and run and run. No matter where I set the temp, it would not shut off.

I have the Duo-Therm Comfort Control t-stat. I checked out the manual in case I was missing something stupid. I checked the forward temperature sensor as suggested in another post. See picture of the sensor here

To solve the problem, I used a "reset routine" that I found out about. I am posting it for educational purposes, and will claim ignorance if you blame me for messing up your t-stat

<UL TYPE=SQUARE>
<LI> Turn t-stat off
<LI> Hold Mode and Zone buttons in (top and bottom buttons)
<LI> Turn t-stat on
<LI> When you see "FF" release buttons
<LI> Turn t-stat off
<LI> Wait 2 minutes
<LI> Turn t-stat on[/list]
That seemed to take care of the t-stat issue. It now cycles on and off like a normal furnace

--kev

"007" · 01-04-2007, 04:39 PM

Thanks for the info "kev" alot of us have the Duo-Therm t-stat.

I'm sending this down to RV Systems & Appliances also.
They usually have a white cage over that sensor looks like someone removed it, the two screw holes are still there.

bandcworkhorse · 01-04-2007, 05:11 PM

My thermostat problem is that the cycle times are too short. Three to five minutes on, then as little as 50 seconds off. (Fan times; burner ops are even shorter.) Before I try to find the anticipator circuit inside the stat, I'll try this reset procedure. Thanks for the info.

MonacoMama · 01-04-2007, 05:58 PM

Kev-
I think I am gonna print this post out so ...
1. I have instructions on what to do AND
2. I know who to blame if it doesn't work!

digNbubbs · 01-04-2007, 08:17 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by "007":
Thanks for the info "kev" alot of us have the Duo-Therm t-stat.

I'm sending this down to RV Systems & Appliances also.
They usually have a white cage over that sensor looks like someone removed it, the two screw holes are still there.

</div></BLOCKQUOTE>
Glad you found it useful

There was a cage over the sensor - I had removed it to make sure the sensor was poking out of the wall sufficiently.

M*Mamma - I will deny all knowledge....

--kev

paz · 01-05-2007, 03:08 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by bandcworkhorse:
My thermostat problem is that the cycle times are too short. Three to five minutes on, then as little as 50 seconds off. (Fan times; burner ops are even shorter.) Before I try to find the anticipator circuit inside the stat, I'll try this reset procedure. Thanks for the info. </div></BLOCKQUOTE>

Please let us know how the reset works out for your problem of short cycles. I have a similar problem with short cycles, although not quite as short as yours.

Gary RVRoamer · 01-05-2007, 04:55 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">My thermostat problem is that the cycle times are too short. Three to five minutes on, then as little as 50 seconds off. (Fan times; burner ops are even shorter.) Before I try to find the anticipator circuit inside the stat, I'll try this reset procedure. Thanks for the info. </div></BLOCKQUOTE>

Short cycling in heating mode is usually not a t-stat problem. There are two common causes:

(1) A heat duct is too close to the t-stats sensor, causing it to warm up quickly while the rest of the room remains cool. The t-stat thinks it is warm and shuts off, but cools off as soon as the heat stops blowing on it. Close the offending vent or put some kind of deflector on it and see if that changes the cycling.

(2) Inadequate or blocked heating ducts, resulting in insufficient flow through the heat exchanger. This results in high internal heat in the furnace and a safety device called the High Limit Switch shuts down the burner while the fan continues to run to expel heat. Within 30-60 seconds the heat exchanger cools off and the High Limit condition goes away, allowing the burner to re-start. This is called cycling on the high limit and is fairly common in RVs. To fix it, inspect for crimped ducting, excess length of ducts (especially the flex coil stuff), dust or dirt on the air intake screen, and outlets that are closed (the little plastic knob may turn but the outlet may not actually open). Once plenty of air is flowing through the duct system, the short cycling should go away.

digNbubbs · 02-23-2007, 09:48 AM

I needed to bring this post back from Oblivion because it now has a real resolution.

To recap, I was having issues with the Zone 1 (front) furnace not shutting off. I called tech support and they walked me through the reset procedure above.

When I was on the phone with them, I had the t-stat real low (55 deg) so that I could see if it would turn off. I didn't think about setting it at a normal temp and testing it. Over time, I found the furnace would turn off only when the t-stat was set real low. I put a digital thermometer at the forward temperature sensor to watch for a pattern. It was usually off by about 15 degrees or so, but nothing real consistent. Example: t-stat would be set at 55 degrees, would cycle furnace off at 70-75+ degrees.

Over using it for a while, in different climates, I found that the heat pump and the A/C was short cycling. The compressor would kick on, and then off real quickly.

I had this problem looked at when I dropped into the Monaco Service Center in Wildwood, Florida. I went through all of the above anecdotal evidence. There were several guesses thrown out. The tech checked the positioning of the temp sensor, then removed the cover to the front A/C unit. This is what she found:

The coiled wire bundle is the remote temperature sensor! After pulling the ceiling light, she was able to find the broken end of the sensor that was installed. She was able to re-run that lead and connect it to the A/C unit.

It appears that something happened to the original sensor - possibly a broken connection or something during manufacturing - and the factory shoved another up inside the A/C unit. Maybe it was one of those "I will get that right after lunch" things

Regardless of how it happened, it now works great. The furnace, heat pump, and A/C all cycle on and off as they are suppose to.

Thought I would follow up on this odd problem.

--kev

paz · 02-23-2007, 01:07 PM

Thanks for the follow-up. There were a lot of guesses and suggestions, but that's not something you would expect!

ronboc · 02-23-2007, 02:49 PM

Hey Kev -

Who was your tech at Wildwood?

digNbubbs · 02-23-2007, 05:11 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by ronboc:
Hey Kev -

Who was your tech at Wildwood? </div></BLOCKQUOTE>

I had a team

Brady was the service writer, the main tech was Halley, Jim helped out with the slide, and Todd helped with the monitor replacement. They all did a great job, and we had them over for Coronas after they finished up on the first day. Ang made them all cookies for after lunch snack

--kev

MonacoMama · 02-23-2007, 09:33 PM

...Ahhhh.. NOW HOW THE HECK DO YOU EXPECT US TO FOLLOW UP AFTER CORONAS 'N COOKIES!!! ... LOL ..glad you got a solution to your problems ...but .. did you have to make it hard on all of us who have to follow you after service?

ronboc · 02-24-2007, 03:18 AM

Now before MonacoMama and digNbubbs go and jump me for tugging this off-topic a bit

, I'm going to plead that this follows Kev's repair job and service-experience at Monaco....

I too have had the same superb assistance from that team (Brady, Jim, Todd and HayLee). They are the best in my book (not that I'm slighting any of the others there whom I'd assume are just as qualified, but I really and truly don't want to have enough things go wrong that I experience EVERYBODY there).

When were you there, Kev? Todd had mentioned a few of them got together recently and wished he knew I was still there that afternoon. Bet we were there at the same time (early January?).

If anyone gets a chance, ask Todd how he came to be known as "Mr Hankee" (of SouthPark fame). Did he wash his hands before working on your coach, Kev?

See there? It's still on the same topic (sorta).