Heat/AC failure in rigs with inCommand [Archive]

LHaven

02-10-2019, 11:26 AM

We just went through a bit of an exercise with our new 26RBSWE to get a manufacturing defect fixed. If your rig has an inCommand system and you're experiencing problems where your furnace or AC goes through periods of refusing to function, it may help you to read this. The tough part was getting three vendors on the same page so that they all realized that they had already seen this problem reported by many owners and that they had a fix for it.

When we took our unit home last fall, we immediately experienced a failure of the air conditioner to turn on (uncomfortable, since the temps were 100°+). The dealer didn't take me seriously, blaming it on my 30A receptacle. A week or so later, the problem disappeared all by itself, so I let it slide.

Come December, and now the furnace refuses to turn on… but only at night.

Through experimentation, I determined that when the temperature inside the rig (we weren't occupying it) went above 100° or so, the AC would not turn on; and when it went below 50° or so, the furnace would not turn on… bizarre, but technically plausible.

The dealer flat out told me he would have no idea how to even start troubleshooting a problem like that. I understood his position, but I needed it fixed.

Figuring it was a control logic failure, I called the ASA (inCommand) folks, who kicked the ball around the infield a couple of times, then told me they'd seen this sort of thing caused by the manufacturer-supplied HVAC controller they had to interface with. Keystone had no idea what to recommend except for me to take it in to a dealer (I told them the dealer had already thrown up their hands). Finally, I spoke to a different person at ASA, who told me quite definitely that they had worked this exact problem before, many people had experienced it, they knew the cause for sure, it was a particular model of HVAC controller from Dometic, and they gave me the name of the Keystone employee they had worked it with. Armed with all that information, I was able to get Keystone to tell me they had a service bulletin out on the problem, the fix was to replace the controller with a different model, and they would send my dealer the information he needed to perform it. We had the fix applied three days ago.

Unfortunately, the fix was incomplete. Last night, the ambient was 47°, and when I tried to turn the furnace on, the control panel showed "on" for about five seconds, then flipped back to "off" without turning on the furnace (acknowledging the failure and flipping off was new behavior, but still a failure). It did the same thing for the fan. However, when I used the iPhone app to turn the furnace on, it went on successfully (very strange!). Once the furnace was on, the control panel now could not turn it off (same behavior, flipped back after five seconds), but the iPhone could. Now, all these control signals go through the inCommand module, and some work and some don't, so I kicked this back to the folks at ASA and I'm waiting for a reply.

I wanted to put this out there for anybody who is seeing the same behavior (and if you're not seeing it yet, and you're still under warranty, you may want to see if your unit has this fault so you can get it fixed before it's a problem).

MarkEHansen

02-10-2019, 03:17 PM

I talked to my dealer about replacing the Dometic board in our rig (same as yours). They said they would have to see the problem before they could do anything about it.

I was getting frustrated with them when the general manager walked over and said "well ... we'll just run the air conditioner overnight to get it good and cold inside the cabin and then try the heat..."

They still have the camper (waiting on one or two of the warranty items on our list to be completed) but I was told the iN-Command/Dometic issue was one of those they've resolved.

I'm cautiously optimistic.

JRTJH

02-10-2019, 03:31 PM

...

but I was told the iN-Command/Dometic issue was one of those they've resolved.

I'm cautiously optimistic.

Not to wish you any "bad luck" but like when you pick out a new puppy, this is one of those times when you wish you'd have put a dot of red fingernail polish on that Dometic control board..... That way, with a quick glance, you'd know whether the dealer really resolved the issue.....

Hopefully they handled it without any way to verify......:whistling:

MarkEHansen

02-10-2019, 03:52 PM

Well, to be honest - I don't think I'm going to be camping in conditions which will trigger this particular defect, so I wasn't all that worried about it.

... at least not the <40 degree issue. Now the >100 degree issue? Hmmm, I could hit that :)

66joej

02-10-2019, 03:57 PM

I agree with John on this. Whenever the dealer has a special on servicing I jump on it. Being a bit anal I always take a marker and mark wheels ( rotation included) and oil filter (wipe it off and let it go). Have caught non work a few times. Didn't use the same dealer again. This used to be called "midnight oil change".

LHaven

02-11-2019, 02:01 AM

The threshold is more like 50°. We're 25 miles outside Phoenix and we get that on winter nights, as well as 100°+ much of the summer.

LHaven

02-11-2019, 10:42 PM

Unfortunately, the fix was incomplete. Last night, the ambient was 47°, and when I tried to turn the furnace on, the control panel showed "on" for about five seconds, then flipped back to "off" without turning on the furnace (acknowledging the failure and flipping off was new behavior, but still a failure)... I kicked this back to the folks at ASA and I'm waiting for a reply.

False alarm. Turns out the minimum settable temperature for the old gateway was 54°, and for the new gateway, 55°. My thermostat was still set to 54° from long ago, which is now an "invalid" setting for the new gateway, so the control panel hiccuped when I tried to start the furnace. Once I bumped the temp, the furnace worked fine, and the control panel will no longer let it return to 54°. Problem completely solved with the new gateway. :hpyclp:

ken56

02-13-2019, 06:19 PM

Kudos to you. Its people like you that pursue an issue like this that turns out helping many others. Those that have had the dealer run around know this all too well. Thanks for sharing your experience.

ajk170

02-13-2019, 07:19 PM

Ihaven- so if I understand this correctly, the dealer needs to replace the HVAC controller? Since I'm not all that smart on this stuff, is the controller the digital thermostat that hangs on the wall and "controls" the zones or something that's up in the ACs or down in the "In Command" box in the basement?
Thanks!
-Andy

LHaven

02-17-2019, 10:35 PM

What has to be replaced is the HVAC gateway.It's a discrete box that hangs right in the center of the AC cavity, which you can see with the filter cover removed.

There are serial and model numbers on top where they can't be easily read, but I took a photo of them using my smartphone in selfie mode. It's a Dometic product. The numbers on my original component were marked as part #3313191.000.

When I put my repair through the dealer, there was a delay because the various part and serial numbers I reported weren't part of the range authorized by the original service bulletin, but it was verified that my parts failed the same way, so now I presume they are.

BlueJay Traveler

05-21-2019, 06:48 PM

I picked up my 26 RBS cougar at the beginning of April 2019. I had it home one week and slept in the unit over the weekend. Temperature was below 40° and furnace had issues the first night. Everything worked fine until 3 AM. That’s when I noticed I had a fuse blown. After replacing the fuse I’ve noticed the AC unit would Click when IN·command was calling on the furnace to ignite. The furnace fan would engage normally but would never attempt to fire. Over the next few hours the furnace would try to ignite and burn for several seconds and then shut off. Over the next few weekends we slept in the camper several times while having the same problems. The furnace would run perfectly for a while and then The in command would attempt to start the furnace, that’s when the AC unit would click several times and the furnace would never attempt to fire. I found that when I would disconnect the power plug in the relay control box and plug it back in the system would reset and the furnace would work for a while. I took the unite to the dealer and they have no idea what is wrong. How can this problem still be happening? Very disappointed

LHaven

05-21-2019, 06:52 PM

I had this exact same symptom right after the dealer fixed the gateway module problem, and I had to bring it back. It turned out to be construction debris (sawdust and styro chips) fouling the sail switch in the furnace. They had to remove the entire unit and it was a month all told before we got our rig back.

In general, you will be finding a lot of sawdust for the first couple trips. I also had styro waste plugging up the intake screen on my toilet, with the result that I had almost no water flow the entire three weeks of our first trip.

jim1

05-22-2019, 09:32 AM

We've had similar issues in our 2019 315 Cougar. Our furnace would quit igniting usually at the best times 2-4:30am. It would try to cycle on but wouldn't light. My fix was to go outside with a flashlight and screw driver, and remove the furnace cover and toggle the power switch on and off till it started to work again. The diagnostic sticker in the furnace cabinet indicated 1flash every 3 seconds was a airflow/limit fault. Took it to the dealer who had it for 2 weeks and couldn't find anything wrong asked them to replace the sail switch or the whole furnace. Called Krapstone and they denied any issues with the furnace. The unit is an inbred cross between Atwood crap and Dometic junk. The dealer put in a new sail switched it's still working. So who knows? I'm just getting very disappointed with paying good money for something that has no quality or backing by Krapstone even under warranty. It seems to me their just hoping to out wait doing anything until the warrenty is done.

daji

04-04-2021, 06:17 AM

I have a 2019 Fuzion 373 that has a similar problem. I brought in into the dealer after telling them the symptoms. When it is cold out side the heat will not turn on. Nothing happens. It is like In-command does nothing. You can try turning the heat on and off in any of the zones multiple times and the system does nothing. Also noticed the fan won't even turn on. I did notice the In-Command system only reads down to 40 degrees. At first I thought the camper just did not get as cold inside as outside but after paying attention a few times I know that when it is 23 degrees out there is no way the camper is 40 degrees inside because I would feel the deference.

I brought it in after describing the symptoms and letting the dealer know about posts like this and below is what they did.

1)diagnosed furnace, upon testing found that furnace blower will run, and furnace will ignite for approx 10 secs and cut ignition. then repeat. found board is not sensing flame and has failed, board will require replacement. tested igniter as well, removed from furnace and tested continuity. tight area to work to get furnace in and out due to water heater, water pump and plumbing in the way, because of this will take longer to remove and install furnace. 03/24/2021 4:59 PM removed furnace, then removed board and retested on bench, found this did not fix issue, then took mew igniter and retested, furnace worked properly. removed new board and reinstalled old board, furnace still worked properly. installed furnace back in unit and tested for proper operation.

Got the camper back and the heat worked fine when I got it into the driveway (In Command read 46 degrees) . The next morning the heat would not come on. The In Command read 40 degrees and it was 28 degrees out side. Tried multiple times tuning off and on and nothing worked. After turning the electric fireplace heat on for an hour still nothing but In Command still showed 40 degrees. Finally I got a hair dryer and pointed it at the living room temperature sensor. In Command shot up to 44 degrees then 87. The Heat was set for 76 degrees but did not come on. Once in command fell back to 71 degrees reading I turned the heat off and on on the in command system and the heat came on.

I repeated the process the next day and found that the heat would not come on when the In Command reads 40 degrees on the display. Once I got the hair dryer to get the RV in Command sensor up to around 58 degrees, and I turned the heat off and on through the console, the heat came on. Even when the in command went back down to 44 degrees the heat stayed on.

So it looks like there is an issue where the sensor has to tell the In Command system the temperature is above the bottom out reading of 40 degrees on the In Command system for the heat to come on. After having the RV at the dealer for the heat and other issues for almost 5 weeks I will give them this information and bring it back next spring to have it fixed when they preform the annual roof inspection. I still have an extended warranty of another 3 years so it should be covered. At least the hair dryer gives me a work around.

JRTJH

04-04-2021, 06:28 AM

daji,

Your symptoms are a well documented issue with the HVAC control box located in the main air conditioner on your roof. Warming the thermostat above 50 or cooling it to below 100 is the "key" to identifying the control box issue. The manufacturer has changed the control box, updating the electronics in it to reprogram the operation. This has eliminated the issue for nearly everyone who is experiencing symptoms like yours.

You'll likely find problems this summer if the interior temperature in your trailer rises above 100F and the A/C won't turn on to cool your trailer.

Talk to your dealership about changing out the control box and you'll probably have a "troublefree HVAC system"....

MarkEHansen

04-04-2021, 06:30 AM

Welcome to the forum, Daji!

This is a known problem with iN-Command. I believe there is also an upper temperature, above which the A/C will not come on. Speak to the service manager at your dealership. They should contact Keystone if they really are not aware of the issue. I think there's even a recall for this issue.

They should be able to replace a control board (not sure which one) and be done with it.

Good luck.

LHaven

04-04-2021, 12:27 PM

They should be able to replace a control board (not sure which one) and be done with it.

It's the Dometic HVAC gateway box, which hangs in the middle of the inside of your AC cavity. Until you can get it replaced, you're going to have to travel with a hairdryer and an ice bag. 2019 is definitely the model year for this particular problem.

LHaven

01-02-2022, 11:57 AM

So last night, we were expecting the first below-freezing temperatures since I got my rig three years ago. After crawling into bed, I realized I had forgotten to prep the trailer, and inCommand is telling me it's 34° in the rig. So I set the thermostat as low as possible (55°), and turned on the furnace remotely. After ten minutes or so, it became obvious nothing was heating up, so I dressed up and ambled out to the trailer. Turned the furnace on from the display panel. Click from the Dometic gateway box, then... nothing, no pre-heat fan noise, nothing. Did it a few times. Checked the range to make sure the shop hadn't valved off the propane. Finally set up the ceramic heater for the night, turned on the tank heaters, and went back to bed.

Went out to shut it off this morning, it's 65° in the rig. Tried turning the furnace on again to see if I had a furnace problem or the old inCommand problem had come back— worked first time. :banghead:

So it looks like inCommand is back to its old tricks, despite my already having swapped out that suspect Dometic gateway box.

By 6 PM tonight, it's slated to be under 50°— I'm going out to test the furnace for this failure one more time then (if so) it's back on the horn to ASA.

markcee

01-02-2022, 12:44 PM

LHaven

01-03-2022, 04:27 PM

Update: Last night we weren't expecting freezing temps, but low enough to do some experimentation. As the outdoor and cabin temps dropped, I attempted to start the furnace at 49°, 44°, and 39° (it didn't get much lower than that). Every time, it started flawlessly. So either the new inCommand/Dometic failure temp is between 34° and 39°, or something weird is happening with my furnace.

Anyway, I'm not going to bother with it anymore. I've got my electric heater and electric blanket, and if it is a thermostat-related problem, I've got a working HWH to heat up a facecloth and dupe the thermistor into thinking it's warmer in the cabin long enough to get the furnace cranking.

mikec557

01-03-2022, 07:29 PM

I don't know if this info is useful to you or not, but we just camped two nights in below freezing temperatures... not necessarily by choice. We were driving back to Sun City West from Texas when a cold front moved in.

Temps were expected to be low 20s to high teens the first night and low 20s the next night, Kerrville TX and Las Cruces NM respectively.

We were concerned the water lines in the belly would freeze. I set the InCommand to 70 degs throughout the night, both nights. Everything worked as expected. I should add that during the first day the inside RV temp during the day was in the low 70s using just the electric fireplace, using the InCommand HVAC only at night.

The morning we left after the first sub-freeze night, it was mid 20s. The day was supposed to be very cold for a long time. I decided to "run" the furnace while driving down the road. I set it to 55, the lowest temp the InCommand has, and figured it will work or it won't. It worked perfectly. And, no frozen water lines. Did the same the second day of driving.

Maybe all this worked because the temp inside the camper was never too "low"?

BTW, ours is a 2020 Cougar 26RBSWE (built 10/2019).

LHaven

01-03-2022, 09:24 PM

Maybe all this worked because the temp inside the camper was never too "low"?

The original inCommand/Dometic gateway issue was that the furnace would fail to start if the cabin temp was <50°, and the A/C would fail to start if the cabin temp was >100°. When the cabin temp is temperate, neither of these issues would show up. In both cases, spoofing the thermistor with artificial heat or chill can end-run the issue.

I'd be really spooked about running the furnace while on the road, but in your case, I'm not sure I see an alternative. I would definitely be willing to turn on the tank heaters, though, as I'm pretty confident they're DC.

FullTimeAdventure

01-04-2022, 01:08 AM

I have a 2021 Montana and I think I’m having the same issue. It’s in the 30s outside and the other day the panel showed 0 degrees ambient temp and furnace would not come on. It would immediately switch off after I turn it on and nothing would happen.

Now today, the ambient temp reads 41 and will not move however the furnace will turn on but continuously run because it thinks it’s 41 inside. Very strange.

I’m full time in the rig and have been stationary for the past 6 months so the temp inside have always been maintained but a few days ago I started a move across country and for the first time since I’ve owned it the inside temps dropped close to freezing while on long travel days. Not sure what to do from here. I have the Coleman AC units with the whisper quiet ducts so I have no idea where the gateway is. I looked under the little filters and there’s nothing. Maybe on the roof under the shroud?

travelin texans

01-04-2022, 08:50 AM

I'd be really spooked about running the furnace while on the road, but in your case, I'm not sure I see an alternative. I would definitely be willing to turn on the tank heaters, though, as I'm pretty confident they're DC.[/QUOTE]

If the temps were to be cold enough I would run the furnace while traveling, never an issue.
Also every mile of travel with all the rvs I've owned had the fridge running on gas, also never an issue.

JRTJH

01-04-2022, 09:18 AM

If I have my facts right, the 2021 Montana High Country and the 2021 Montana DO NOT have In-Command. It is an option, available in the Montana series ONLY with the Legacy Package. So, looking at a Montana, if it has a "molded fiberglass rear panel" it likely has the In-Command system. If it has a "flat aft panel" then it probably has a conventional thermostat and not the In-Command "limitations".....

Proud

01-07-2022, 05:42 PM

Here is the bulletin from Dometic. I have the same issue on my recently purchase 2019 fusion 369( no known warrantee) . I haven’t contacted Dometic yet but I was wondering others experience. Is it a recall item? Can I expect the part(s) for free? Do all three gateways need to be replaced if I have 3 ac’s? Will they provide the parts for do-it-selfer or shop only. ( the gateway box is over 100 bucks if Dometic doesn’t back)
Thanks in advance, Jp

LHaven

01-07-2022, 05:48 PM

Thanks for the bulletin. I never had a copy of that.

You don't say what year your trailer is; I gather from your comment that you are not the first owner. (Please fill out your "User CP" so this information will appear in your postings.)

Your warranty for such stuff from Keystone is only one year.
Dometic warranties, on the other hand, tend to run two years, which is nice.
If there is a "service bulletin" on this issue, it's sort of like (but not officially) a "recall," so Dometic may do it for free or may cut you a deal on the fix... you'd have to call them and ask.
In any event, your unit would have to have inCommand, as it's not an issue otherwise.

Proud

01-09-2022, 10:11 AM

I found some more info on subject, see attached.
Also hoping someone can answer questions I stated above. Thanks

LHaven

01-09-2022, 12:10 PM

I think all the questions that remain unanswered are questions about what Dometic is willing to do for you, and the only way to get answers to those is for you to call Dometic and ask.

You haven't yet explained why you think you have no warranty on a 2019 trailer.
Don't forget to fill out your userCP signature.

JRTJH

01-29-2022, 05:58 AM

I found some more info on subject, see attached.
Also hoping someone can answer questions I stated above. Thanks

If the warranty is still valid, after one year, Keystone no longer processes warranty claims (it's in the Keystone Owner's Manual) and the responsibility to contact the item manufacturer for warranty repairs falls on the dealer or the trailer owner. As posted by LHaven, the only way you're going to find out what Dometic will do for you, in your situation, as the second owner of their product, is to contact them and ask how to "process a warranty determination and a warranty claim"... What they did as a "good will gesture" or as an "oversight that slipped through as an approval" for someone else won't do you much good.

You need to talk to Dometic and see how they want to handle "your situation". If their answers are favorable, then great. If they tell you no, then you're likely going to be on your own. As a second owner, if there was no transfer of warranty (also required in the Keystone Owner's Manual) then you may find that omission gave everyone an "out to deny any future claims" or they may register the remaining warranty (if there is any) and process your claim....

Talk to Dometic to get the answer. Speculation from other's won't be a binding response on whether they approve/disapprove a claim from you. Every situation brings a different potential to move to a different branch in the "approval logic tree worksheet"...

Proud

02-20-2022, 07:55 PM

So I have follow up information. Keystone did replace the gateways (all 3) by mail directly to me after a little back and forth emails. Dometic also offered to replace if I took trailer to authorized service center. Seems like a logical outcome with the company literature that is out on the web admitting the engineering programming error.
I’m just glad we have a forum like this one, to make this info public knowledge. I can’t imagine the frustration of trying to turn on hvac below 40 or above 100 and nothing happening. Thanks, Jon

LHaven

02-26-2022, 01:05 PM

After ten minutes or so, it became obvious nothing was heating up, so I dressed up and ambled out to the trailer. Turned the furnace on from the display panel. Click from the Dometic gateway box, then... nothing, no pre-heat fan noise, nothing. Did it a few times. Checked the range to make sure the shop hadn't valved off the propane. Finally set up the ceramic heater for the night, turned on the tank heaters, and went back to bed.

An update, for the record:

Temps were scheduled to reach 31° again in the wee hours Wednesday (2/23). When I got out to the rig, the cabin temp was in the mid 30s. The furnace again refused to even attempt to start. I huffed into the thermistor to raise the reported cabin temp above 55°, and turned the heating system off and on again, but it changed nothing. Again, I left the ceramic heater, the tank heaters, and the water heater on overnight to combat the freeze.

I have a ticket out to ASA to see if they have any ideas or advice.

I spend a good hour or so disassembling, cleaning, re-greasing, and reassembling our little ceramic cube heater, as it looks like we may be relying on it more than expected.

LHaven

03-01-2022, 02:36 PM

And some clarification from ASA Electronics, the inCommand people:

I've attached our HVAC explanation guide which shows the gateways and explains how the gateways are the thermostats and iN•Command is [only] a window to the thermostats...

iN•Command is not reading the temperature of the room. It is the gateway that is connected to the wall sensor, and then reports that temperature, using our display...

Dometic's version of the gateway did have issues with firing the furnace below 40° and firing the AC above 90°. This should have been resolved with the replacement, but we cannot tell you how to confirm this...

So it sounds to me that rigs with that model Dometic gateway would have shown this bad behavior regardless of whether they were attached to inCommand or just a conventional thermostat. Possibly this model of gateway was installed only in rigs that were slated to be outfitted with inCommand, which is why the problem shows up only there and thereby gets associated with inCommand.

LHaven

03-01-2022, 03:54 PM

OK, now a question.

I took a photo of what I always thought was my gateway box, inside the A/C air intake cavity, only to find out it is exactly the same box I had before the replacement, and it says "ReLay_ControlV4.hex" on the bottom. The web sees to agree that this is a "relay box" and so probably not the gateway.

Though I can't locate any canonical diagrams for my own unit, all the gateway positioning diagrams I can find for Dometic gateways have them located somewhere inside the roof cowl, which I'd have to pull off to inspect what model I have installed. Is that accurate? If so, I think I'm going to abandon any idea of doing that.

(D'Oh! Diagrams for my own unit are right there on the reverse of the Tech Bulletin... and that's exactly where the gateways are.)

So I shipped off a complaint to Dometic and I'll wait to see what they say.

LHaven

03-06-2022, 09:02 PM

Dometic's response was basically that they can't debug a problem over email, and I should have my dealer look at it. That would be a waste of time, as the problem is intermittent and I will bet you a donut that the dealer will never be able to see it happen.

So I'm out in the trailer tonight cleaning up and getting ready for a trip. It's 60 outside, and 61 inside, and I set the furnace to 68, and once more nothing happens. I can hear a click from the relay box in the ceiling air conditioner, but the furnace doesn't even try to turn over. I applied the suggested fix from the Dometic service bulletin for the factory gateway that had the original problem, which is to set all the controls for the desired operation, then cut power to the air conditioner for a couple minutes, and when you return power it should do the right thing. But that didn't work either.

So I'm about to leave on a trip knowing that my furnace is almost certainly going to do me dirty. I can't even do simple board diagnostics from the outdoor hatch, because my model doesn't have an outdoor hatch – everything is buried deep under the refrigerator. I am just bummed having quality problem after quality problem with this rig.

LHaven

03-06-2022, 09:08 PM

I just had a thought – I removed power from the air conditioning unit using the circuit breaker, but the furnace is a DC device, which implies that the gateway inside the A/C cowl on the roof has to be a DC device as well, so I should've pulled some fuse instead. I once mapped out which fuses went where, but I never identified any for the furnace, inCommand, or stuff that I can't even see under the air conditioning cowl on the roof. I suppose more study is required.

MarkEHansen

03-07-2022, 06:36 AM

One way to remove the power would be to pull the negative lead from the coach battery.

Are you sure the problem is not the control board in the furnace? The wires for the furnace go through the outside fridge access on your trailer, so you can inspect power at that point. If you have power on the 12V lines and show 12V on the two thermostat lines and the furnace still doesn't light, then it seems like the problem is in the furnace itself - likely the control board.

I can provide more details about this if you want.

JRTJH

03-07-2022, 06:40 AM

Often times there's a fuse in the "digital Dometic thermostat" that will keep a "memory charge" on the control unit. Sort of like using a 9 volt battery pluggedn into a cigarette lighter socket to maintain a car's memory system during battery changeout...

If you want to "remove power from the control circuit" the best, most effective way, is to unplug from shore power, then remove BOTH battery terminals and then, to be sure, short the battery terminals together for 1 minute. I know that's considered "overkill" by most people who work on these things, but I've seen many (way too many) when someone has a battery backup in a bedside alarm clock or has a 12 volt "jumper/charger/air compressor" plugged into 12 volts to recharge that device and when you disconnect the battery on the trailer, that jumper/charger backfeeds "just enough power" to keep the memory circuits charged...

So, to "remove all power from the system" unplug shore power, disconnect BOTH battery terminals and short them together. Look at your "sweep second hand on your watch" and leave the terminals shorted for a full minute.

Then, retry your furnace controls.....

LHaven

03-07-2022, 05:28 PM

MarkEHansen

03-07-2022, 06:19 PM

Thanks for the tip on killing all possible power. If it was a one time fix, I'd do it right now, but Dometic says it has to be done every time the gateway balks, and it isn't a permanent fix for the problem.

As for debugging the furnace through the refrigerator port, it was a good idea, but I don't see that I get any access to the furnace by going in that way. There's a partition, and the furnace is under it. (Image)

On the bright side, if the furnace gets 100% balky, I can have my dealer look at it when I bring it in to swap the propane regulator, and he'll be able to see it fail first time.

Sorry if I wasn't clear. On the left of that cavity are the 4 wires going down to the furnace: +12v -12v (GND), +Thermostat and Thermostat.

You can check these wires for power. If they have the correct power on them and the furnace doesn't light, the problem is with the furnace, not the gateway or anything else.

The +12v feeds the furnace controller. Of the two thermostat wires, one comes from the furnace with +12v to the actual thermostat (iN Command in our case) and when the thermostat is calling for heat, it will send +12v back on the other thermostat wire.

So, if you check those wires and find +12v on the power and both thermostat wires, the furnace should kick on.

You'll find the wires on the left side of that cavity. There will be a hole going down to the furnace from there. You see those 4 wires come up through that hole and then connect with 4 other wires, bundled together with a zip-tie and held in place with some spray foam. Just pull the bundle from the foam enough that you can get VOM probes in under the crimp connectors.

Attached is a picture with the wires pulled lose from the foam and about to be pulled down through the hole (I replaced these wires with longer ones so I can pull the furnace out of the cavity when I need to do repairs/maintenance):

LHaven

03-07-2022, 08:12 PM

OK, assuming I'm looking at the right bundle, i see a red and two blues, and probably a white or black I can't see; I assume the blues are the thermostat. I'll check out my own rig in daylight and hopefully Amos wired it the same. It's short-time, and we may have to do this trip with only the ceramic heater and tank heaters (four subfreezing nights forecast).
(So happy DW happened across a free electric blanket, it will surely get its first real workout.)

MarkEHansen

03-08-2022, 06:46 AM

Yes, the thermostat wires are both blue. they will have label sleeves on them to identify "Thermostat" and "+Thermostat". The power wires are red (for +12v) and I don't remember the other color - I think white, but it doesn't really matter, as it's the only other wire in that 4-wire bundle.

ChuckS

03-08-2022, 08:38 AM

I am guessing that you have the Dometic LCD thermostat .. it interfaces via a control relay junction box. Your unit most likely doesn’t have a gateway

The roof AC unit control board is where the furnace blue signal wires should be connected to as shown in second image

I’ve identified the relay that is most likely having an issue and nit letting the furnace get its signal source down to the furnace control board to turn on

The second image shows your relay junction box as well as the roof control board

You can go on the roof and temp connect the blue (+) to complete the circuit and the furnace should then run

NOTE ..
This is a temp check ONlY to verify furnace receives the 12 volt source signal down to its control board to run.. there is NO Thermostat control while this is jumpered

LHaven

03-13-2022, 10:24 AM

I am guessing that you have the Dometic LCD thermostat .. it interfaces via a control relay junction box. Your unit most likely doesn’t have a gateway

Not sure if "you" means "me" or somebody else, but I definitely have both inCommand and a gateway.

I'm buffaloed. We got to our destination, expecting to have to survive on our space heaters, and so far (four nights) the furnace has worked flawlessly, including our first night when we had to warm the rig up from road temperature, which was low 40s. And three of those nights were sub-freezing.

So I have to say, my first guess is simply that "some wire is loose" and the trip shook it back into connecting.

I guess when I get home, I'll just have to lengthen up those feed wires and learn how to extract the unit from the cubby under the fridge, then get to it.