Bill and Nancy's Furnace is cycling on and off every 2 minutes

[Bill and Nancy]

Its been in the 20s the last few days and it seems to be working like it should. What a difference it has made and it was a relatively simple fix for the cost of a $5.00 switch, a $35.00 batterie operated thermostat and a little bit of wire.  

Bill

[Bill and Nancy]

I’m back and I think I resolved my issue I had to wait until after the new year so I had some free time. After many phone calls and web searching I decided to try what I read on some other RV forums. This is not an uncommon problem and it drives not only me crazy but a lot of other people in the RV word. From what I can deduce the actual temperature sensor lives in the AC unit on the ceiling not in the thermostat mounted on the wall. This poses a problem because heat rises into the unit then it cools fast because it is against the roof and not on an interior wall. so I isolated the thermostat wires coming from the furnace and with the use of a DPDT switch I isolated the furnace from the AC altogether. Now the heat  in the trailer is controlled from the battery operated thermostat independent from the AC. If I put the switch up  I have heat controlled by the remote battery operated thermostat and no more cycling on and off. If I want AC I switch the switch down and now the AC works exactly the way it was wired originally using the Dometic thermostat installed by Oliver. So far it seems to have fixed the problem completely. Now that the cycling has stopped I plan to add a return  air vent under the front Dinette along the floor. That should help with the return air flow by taking the return air directly from the floor up front away from the supply air.
 

Sent from my iPad

[jpk323]

Hi Bill and Nancy,

We live in a parallel universe or at least parallel Olivers.  You have pretty much described everything I've experienced with mine from the troubles beginning while driving it home to WY, to being denied service at a couple of Dometic service centers.  The random frequency of the clicking drove us to buy electric heaters and just shut off the furnace.  We have Hull 1260 and I probably picked it up a couple of weeks before you did yours.  However, I didn't do all the data acquisition you did (great Job BTW).  I too am frustrated with Olivers response, "just take it to a Dometic service center", which as you said many don't service Olivers. 

I have a promising lead with an independent repair shop in ID which ONLY does sales and service service on RV equipment and add ons, not an RV dealer.  I'm putting him in touch with Ollie service (at his request) and hopefully he will fix it.  He diagnosed it over the phone as the control box in the AC unit which clicks frequently and randomly.

I will try the other recommendations by Chukarhunter as well as the link to GAP's thread.

I would be interested if anyone has put a list together of those places who WILL work on Olivers, or I'd be willing to work with some folks to put a list together.  I am a competent DIYer, but warranty work is supposed to be done by "qualified folks, right?

[topgun2]

1 hour ago, jpk323 said:

I would be interested if anyone has put a list together of those places who WILL work on Olivers, or I'd be willing to work with some folks to put a list together.

A couple of years ago, Oliver was putting together such a list (I think that a summer intern was involved but I might be wrong on this part).  I've never seen such a list but before I started trying to compile one from scratch I'd drop Matt Duncan an email to see what he might know.

Sorry for your problems and I hope that Bill & Nancy's solution does you some good.

Bill

[bhncb]

3 hours ago, jpk323 said:

warranty work is supposed to be done by "qualified folks, right?

If financial compensation is the primary objective, yes. Otherwise, a competent DIYer can retain their sanity by just fixing it and moving on.

[bhncb]

3 hours ago, topgun2 said:

I hope that Bill & Nancy's solution does you some good

I think it's important to understand the context of this "solution". My (mis)understanding is that Bill & Nancy's solution was to determine the point of failure, which it does quite effectively. If it is implemented as a permanent workaround for a component failure, the original problem still exists and there is an absolution of responsibilities.

While a separate battery powered thermostat is most likely a better way to control the furnace, there is no need for the implementation to maintain furnace control by both thermostats via the DPDT switch. Simply wiring the battery powered one in to control the Heat signal would also allow simultaneous use of other A/C functions, like heat or fan, while the furnace is operating.

[Bill and Nancy]

I decided to fix it my self because I dont trust a lot of the service people. Everyone I spoke to were hours away and i would have to take time off from work, and Im sure it would have been more than one trip. On top of that no one I spoke to would fix it under warrantee they would bill me then I would have to submit the bill to Oliver to try and get compensated. Jason from Oliver got me approved to send me a new thermostat for free but I dont believe it is the problem.When I finally decided to fix the problem my self it only took me a couple of hours to complete. I spent about $50.00 and It not only is working perfectly but I dont have to shut off the heat in order to see what the temperature is. The thermostat from Demetic that was installed by Oliver still controls the AC but the heat its controlled by a separate thermostat that I mounted above the passenger side bed. Its been in the 20's all week and its working perfectly. I also think that its using less propane because its not going on and off like it was before.

Bill

[Bill and Nancy]

I believe the problem will still happen because the temperature sensor is in the AC unit on the ceiling. On a cold day the furnace flame would light then when the temperature was reached inside the trailer according to the temperature bulb in the AC unit the flame would go out. But before the cool down cycle would even finish and before the fan shut off the flame would re light because the temperature bulb in the unit is against the cold roof. The heat rises up to the AC unit  causing the flame to go off It then cools enough in about 45 seconds to re-light the furnace. This went on for about 2 hours until we just decided to shut the heat off so we could sleep. The next morning it was 45 Degrees in the trailer and 22 degrees outside.  We tried camping 3 other times with the same problem making the trailer almost useless to us. With the fix It no longer does this, it works like expected. As far as running the AC for circulation its not necessary, plus its very noisy. We just run the fantastic fan with the cover closed like a ceiling fan and its quiet and does the job. Im sure there are other ways to deal with this problem but this has seemed to fix the problem and it was cheap and easy. Another plus for us is we may switch to a different ac unit that is quieter and it will be completely independent of the heat.

Bill

[bhncb]

19 minutes ago, Bill and Nancy said:

I believe the problem will still happen because the temperature sensor is in the AC unit on the ceiling.

I think this is a misconception that likely arose because some Dometic thermostat models have an option for a remote temperature sensor. The CT model used in Olivers do not offer this capability and the temp sensor is integral.

Also, I made an edit to my previous post to clarify the DPDT switch operation.

19 minutes ago, Bill and Nancy said:

Another plus for us is we may switch to a different ac unit that is quieter and it will be completely independent of the heat.

Strongly suggest this. Heat pump is the way to go for all-season usage.

[Steph and Dud B]

On 12/3/2022 at 11:24 AM, Mike and Carol said:

From what I’ve seen over the years, the number of owners who regularly camp in severe conditions is small.  

I recently heard the results of an industry survey that says the percentage of RVers who do winter camping is increasing.

[jpk323]

 

11 hours ago, bhncb said:

If financial compensation is the primary objective, yes. Otherwise, a competent DIYer can retain their sanity by just fixing it and moving on.

Thanks bhncb.

I am a firm believer that hassle has costs on the soul as well (time on the phone dealing with people who won't help, missed camping because your rig is tied up for a month, alcohol to you calm down instead of enjoyment😃).  Bill's solution is right up my alley as well as improving the heat throughout the hull by adding return vents forward.  I would spend more in diesel getting it to Idaho (closest "possible" repair to me) than this fix would cost.  Now when I screw it up and burn up the trailer....... just kidding!

Once there is enough feedback on the TRUMA quieter units, we may upgrade.  We live part time in Texas and AC is a MUST.  

[Bill and Nancy]

5 hours ago, jpk323 said:

 

Thanks bhncb.

I am a firm believer that hassle has costs on the soul as well (time on the phone dealing with people who won't help, missed camping because your rig is tied up for a month, alcohol to you calm down instead of enjoyment😃).  

Jack we live in new england and We don’t like the heat either. As a matter of fact we are heading out to go skiing in a few minutes. We had planed to use the trailer while skiing so heat is a must. But on the flip side like I said we live in NE so when the temperature gets above 70 the ac is on high. The way I have it hooked up now you just flip the switch and you are back to the way it came wired from Oliver and your heat and AC works just like it did before the modification. If you or any one else wants to talk or needs better pictures just shoot me an email. 
Got to go skiing and have a scotch at the mountain

Bill and Nancy

[dewdev]

On 1/8/2023 at 5:15 PM, Bill and Nancy said:

I’m back and I think I resolved my issue I had to wait until after the new year so I had some free time. After many phone calls and web searching I decided to try what I read on some other RV forums. This is not an uncommon problem and it drives not only me crazy but a lot of other people in the RV word. From what I can deduce the actual temperature sensor lives in the AC unit on the ceiling not in the thermostat mounted on the wall. This poses a problem because heat rises into the unit then it cools fast because it is against the roof and not on an interior wall. so I isolated the thermostat wires coming from the furnace and with the use of a DPDT switch I isolated the furnace from the AC altogether. Now the heat  in the trailer is controlled from the battery operated thermostat independent from the AC. If I put the switch up  I have heat controlled by the remote battery operated thermostat and no more cycling on and off. If I want AC I switch the switch down and now the AC works exactly the way it was wired originally using the Dometic thermostat installed by Oliver. So far it seems to have fixed the problem completely. Now that the cycling has stopped I plan to add a return  air vent under the front Dinette along the floor. That should help with the return air flow by taking the return air directly from the floor up front away from the supply air.
 

Sent from my iPad

Bill:

Glad you have solved your problem.

Could you provide a little more information to supplement your pictures like:

1. I assume the junction box was existing. Where is that located in the Ollie?

2. What is this DPDT device you are referring to? Is this DPDT device the switch you talk about?

3. Where did you locate the DPDT device in the Ollie?

4. It looks like you extended all the wires from the junction box to the DPDT switch. Which wires were extended to the new thermostat?

5. Looks like you installed the new thermostat in the back corner of the Ollie near the attic. How did you route the wires from the DPDT switch to the thermostat?

Thanks for a great job you did in researching and solving your problem.

Happy skiing

[Bill and Nancy]

Ok I did some more test to confirm my beliefs based on comments from bhncb and jpk323.  To be honest I’m kind of surprised with what I’ve found. Bhncb believes there is not a remote heat sensor in the AC unit. Jpk323 said he had a phone call with an independent RV repair person and he believes it’s the control box in the AC unit. If it turns out to be either the Dometic thermostat on the wall or the control box in the AC my solution does not fix the problem it just circumvents it. So today I ran the heat connected exactly like it was wired from Oliver and then warmed the Dometic thermostat with a blow drier. To my surprise the furnace shut shut off. So this would lead me to believe it is either a faulty thermostat or the control unit in the AC . Oliver said they will send me a new thermostat and to try it. If it fixes the problem then that’s that. if it doesn’t then it must be the control box in the AC. In any case if it turns out to be the control box I don’t think I will replace it unless the AC is also messed up because of it. The heat works great the way I have wired with no cycling or clicking in the AC. 
 

It’s never easy
Bill

[jpk323]

Bill, Did you ever get to test a new thermostat from Oliver and did it solve your problem?  Also, did you get a wiring diagram from Dometic or are the wires factory labeled as per your photo.  got my parts in to bypass and will commence surgery shortly.  I am still trying to get possible repair shop and Oliver to talk to each other so no new news there.  I appreciate your lead on this.

Jack

2022 Elite II Hull #1260

Ram 2500, 2018 Land Cruiser (in the works)

[Bill and Nancy]

9 hours ago, jpk323 said:

Bill, Did you ever get to test a new thermostat from Oliver and did it solve your problem?  Also, did you get a wiring diagram from Dometic or are the wires factory labeled as per your photo.  got my parts in to bypass and will commence surgery shortly.  I am still trying to get possible repair shop and Oliver to talk to each other so no new news there.  I appreciate your lead on this.

Jack

2022 Elite II Hull #1260

Ram 2500, 2018 Land Cruiser (in the works)

No I’ve been playing email tag with Oliver for months. They said that they got approval from Dometic to send me a new thermostat but is back ordered. I haven’t gotten an update in weeks. No I never got a schematic either but there are two wires that come out of the furnace and they are labeled thermostat. It was pretty straight forward. In my drawing what I labeled thermostat is the new thermostat I mounted on the wall.  It was -13 degrees this past weekend and the way I have it wired works perfectly no cycling on and off. My wife spent a better part of today in the trailer and she said the heat worked perfectly.
Feel free to email me if you have any questions 

bill

[johnwen]

On 1/9/2023 at 3:40 PM, Bill and Nancy said:

Another plus for us is we may switch to a different ac unit that is quieter and it will be completely independent of the heat

Hi Bill,

Too bad engineers don't have to use the equipment they design.  :)  This is a bit off topic and I apologize but you mentioned it in your post.

We swapped our AC out for the Truma...Oliver's service did it.  As it was done less than a month ago, I don't know if it will keep up with the summer heat.  I will tell you that I didn't realize the fan runs all the time in auto, the compressor just kicks in and out, but it's hardly noticeable.  From what I understand the Houghtons do the same thing.  I was told it was designed like that to keep the whole unit from cycling on and off, thus preventing unnecessary wear and tear on the unit.  It is much quieter and I suggest you see it in action for yourself and determine if it's good or bad for you.  For me...I think I would do it again given Dometic's disaster of A/C engineering.  Here ends my rant!

John

[Chukarhunter]

 

On 11/13/2022 at 6:50 PM, Bill and Nancy said:

It comes on, warms up and once it gets up to temperature it cycles on and off every minute or two constantly.

I may have stumbled on a simple cause for your frequent furnace cycling, especially when it is colder.  I had not been very pleased with the Dometic CT thermostat in my 2020 LE II and had at one time experienced the clicking noise but only when I tried to change the deadband from 2 degrees down to 1 degree.  I occasionally experienced erratic performance from the thermostat and more so when the temperature dropped rapidly outside to temperatures below 45-50 degrees.  I recently decided to change out to a new wifi thermostat (Micro-air Easy Touch RV), primarily because I store my trailer outside across town at my son's house and his wifi reaches the trailer.  It now allows me to turn the furnace off and on, monitor the cabin temperature and change the temperature setting from my home or anywhere else. I can also monitor when the furnace is actually running or not from anywhere.

When changing out the Dometic OEM thermostat, I discovered that there is an almost 1 inch diameter hole behind the Dometic thermostat that the thermostat wires come out of and this hole is directly behind a big hole in the back of the thermostat.  The hole is large enough to allow a significant air exchange between the cabin and the basement/hull cavity between the outer hull and the inner hull. 

I think what is happening is when the furnace is running, the return air into the furnace is naturally creating low air pressure in the basement that pulls return air from the cabin through any penetration between the cabin and the basement/hull cavity.  Most of this warm cabin air is pulled into the basement through the return vent at the rear curbside floor, but some air is pulled out of the cabin into the basement through other small openings such as around the drawers, etc.  It will also pull warm cabin air through the thermostat and out through the hole behind it.  This is not a problem although it could cause the thermostat to occasionally turn off earlier than it should. 

The real problem occurs when the furnace shuts off and warm cabin air starts exiting the cabin through the max air vent if open or other small air gaps around closed vents and the windows creating convection air currents.  This creates a low pressure situation in the cabin which will cause much colder basement air to be drawn through the basement scuppers and into the cabin through any and all penetrations between the basement and the cabin, including cold air from the basement exiting the hole behind the thermostat and through the thermostat into the cabin.  It is not unusual to have the basement temperature be 20 or more degrees below the cabin temperature.  I believe that as soon as the furnace turns off when say the cabin temperature is 65, almost immediately a small current of much colder 45 degree air starts flowing out the hole from behind the thermostat, through the thermostat and into the cabin.  This sudden inrush of much colder air into and through the thermostat causes it to quickly restart the furnace again and once again warm air gets pulled into the thermostat causing it to quickly turn the furnace off, which causes cold air to almost immediately begin entering the thermostat from behind and the cycle repeats itself.

You can test my theory by unscrewing the Dometic thermostat and let it hang away from the wall and put a piece of tape over the hole behind it.  If the rapid cycling doesn't happen anymore, you may have found the cause of your issue. 

Me, I am going to seal the hole in the wall behind the thermostat to seal off the air flow, and then put some little pads on the back of my new thermostat to hold it about 1/4 in off the wall to break the thermal coupling between the thermostat and the colder wall.

[Bill and Nancy]

1 hour ago, Chukarhunter said:

 

I may have stumbled on a simple cause for your frequent furnace cycling, especially when it is colder.  I had not been very pleased with the Dometic CT thermostat in my 2020 LE II and had at one time experienced the clicking noise but only when I tried to change the deadband from 2 degrees down to 1 degree.  I occasionally experienced erratic performance from the thermostat and more so when the temperature dropped rapidly outside to temperatures below 45-50 degrees.  I recently decided to change out to a new wifi thermostat (Micro-air Easy Touch RV), primarily because I store my trailer outside across town at my son's house and his wifi reaches the trailer.  It now allows me to turn the furnace off and on, monitor the cabin temperature and change the temperature setting from my home or anywhere else. I can also monitor when the furnace is actually running or not from anywhere.

When changing out the Dometic OEM thermostat, I discovered that there is an almost 1 inch diameter hole behind the Dometic thermostat that the thermostat wires come out of and this hole is directly behind a big hole in the back of the thermostat.  The hole is large enough to allow a significant air exchange between the cabin and the basement/hull cavity between the outer hull and the inner hull. 

I think what is happening is when the furnace is running, the return air into the furnace is naturally creating low air pressure in the basement that pulls return air from the cabin through any penetration between the cabin and the basement/hull cavity.  Most of this warm cabin air is pulled into the basement through the return vent at the rear curbside floor, but some air is pulled out of the cabin into the basement through other small openings such as around the drawers, etc.  It will also pull warm cabin air through the thermostat and out through the hole behind it.  This is not a problem although it could cause the thermostat to occasionally turn off earlier than it should. 

The real problem occurs when the furnace shuts off and warm cabin air starts exiting the cabin through the max air vent if open or other small air gaps around closed vents and the windows creating convection air currents.  This creates a low pressure situation in the cabin which will cause much colder basement air to be drawn through the basement scuppers and into the cabin through any and all penetrations between the basement and the cabin, including cold air from the basement exiting the hole behind the thermostat and through the thermostat into the cabin.  It is not unusual to have the basement temperature be 20 or more degrees below the cabin temperature.  I believe that as soon as the furnace turns off when say the cabin temperature is 65, almost immediately a small current of much colder 45 degree air starts flowing out the hole from behind the thermostat, through the thermostat and into the cabin.  This sudden inrush of much colder air into and through the thermostat causes it to quickly restart the furnace again and once again warm air gets pulled into the thermostat causing it to quickly turn the furnace off, which causes cold air to almost immediately begin entering the thermostat from behind and the cycle repeats itself.

You can test my theory by unscrewing the Dometic thermostat and let it hang away from the wall and put a piece of tape over the hole behind it.  If the rapid cycling doesn't happen anymore, you may have found the cause of your issue. 

Me, I am going to seal the hole in the wall behind the thermostat to seal off the air flow, and then put some little pads on the back of my new thermostat to hold it about 1/4 in off the wall to break the thermal coupling between the thermostat and the colder wall.

That sound very plausible. my original thought was that the temperate was being taken from the control unit within the ac on the ceiling. But after thinking about it I tested it by putting a blow drier directed at the thermostat and it shut the heat off proving my original assumption wrong. I think you may be on to something with a draft through the wall. But  so far my solution is working perfectly so unless something changes I will leave it the way it is. I actually like it better because the thermostat that I installed shows the inside temp and the heat setting simultaneously unlike the Dometic thermostat. The remote unit you installed sounds like a good idea, I may switch to that at a later date. If I get to use my trailer like I hope and money allows I most likely will change out the AC at some point for a quieter one.

Bill
 

[Bill and Nancy]

On 2/7/2023 at 5:45 PM, Bill and Nancy said:

That sound very plausible. my original thought was that the temperate was being taken from the control unit within the ac on the ceiling. But after thinking about it I tested it by putting a blow drier directed at the thermostat and it shut the heat off proving my original assumption wrong. I think you may be on to something with a draft through the wall. But  so far my solution is working perfectly so unless something changes I will leave it the way it is. I actually like it better because the thermostat that I installed shows the inside temp and the heat setting simultaneously unlike the Dometic thermostat. The remote unit you installed sounds like a good idea, I may switch to that at a later date. If I get to use my trailer like I hope and money allows I most likely will change out the AC at some point for a quieter one.

Bill
 

I finally got the new thermostat from Oliver about a week ago and today was my first chance to switch it out. To my surprise it has seemed to fix the problem. Its 35 degrees outside and I cranked the heat up to 62 degrees and it started and shut off without all the crazy clicking sound coming from the AC unit and stayed off for almost 15 minutes before coming back on. No more cycling off and on. Ran for about 10 minutes and shut off when the temperature was reached. It seems to be working like it should. Apparently it must have been defective from the beginning.👍

[jpk323]

1 hour ago, Bill and Nancy said:

I finally got the new thermostat from Oliver about a week ago and today was my first chance to switch it out. To my surprise it has seemed to fix the problem. Its 35 degrees outside and I cranked the heat up to 62 degrees and it started and shut off without all the crazy clicking sound coming from the AC unit and stayed off for almost 15 minutes before coming back on. No more cycling off and on. Ran for about 10 minutes and shut off when the temperature was reached. It seems to be working like it should. Apparently it must have been defective from the beginning.👍

Ha! And today I just finished rewiring and adding the second thermostat and it works as well as you said, thanks Bill.  I still have my open ticket with Oliver and no word from the repair guy so maybe there were a bad batch of Thermostats.  I'm only 5 hulls ahead of you.  I'll see if I can get a new one out of them as well.  

[Bill and Nancy]

2 hours ago, jpk323 said:

Ha! And today I just finished rewiring and adding the second thermostat and it works as well as you said, thanks Bill.  I still have my open ticket with Oliver and no word from the repair guy so maybe there were a bad batch of Thermostats.  I'm only 5 hulls ahead of you.  I'll see if I can get a new one out of them as well.  

I think will continue to use the one I wired in it’s been working perfectly plus you can see the temperature without turning the heat off. I never used my AC to date so the new Dometic will have to run the AC. It’s possible that the old one that was screwing up the heat would also screw up the AC. They sent me a new one and it only took  me about 5 minutes to swap it out. I have to send the old one back for credit.