Furrion T-stat glitch?

[AlexPeterson]

We have generally been heating overnight with a small electric heater, but for the recent cooler mornings we've run the furnace for an hour or two. The T-stat might read 62F when I turn the heat on, with a setpoint of 70. It has been working perfectly except for something strange this morning.

Here is what happened: the furnace came on, but the temperature indication on the t-stat seemed to be "frozen" at the original 62 reading. The actual temperature clearly went well over the setpoint, but the indication on the t-stat didn't change. I shut it off once it was clear it was much warmer than 70 in the coach. Once I turned it off, I noticed the indication then began to rise, stopping at 76. This took maybe 3-4 seconds after shutdown.

I will try it again tomorrow morning.

I was not able to find this particular problem through searches of this forum. I'm just wondering if anyone has see this.

Tstat we have:

[howson]

AlexPeterson

Is your thermostat one of the newer models (that has the temp sensor) or is it the earlier version where the temp sensor is in the air conditioner? See Furrion Air Conditioner and Furnace Thermostat Issue (Yes, Again)

Related to my first question, what fan speed was selected along with the heat mode? (Fan speed controls the air conditioner fan, not the furnace fan.)

[AlexPeterson]

howson Howard, I believe the sensor must be in the AC unit. The Tstat is in the bedroom, which gets much cooler overnight, seems to indicate the main room's temperature and not the bedroom (when only running the electric heater in the main room, furnace off). When heat selected, the fan shows -0- speed, which makes sense at it is the A/C only. It is working normally this morning...

[AlexPeterson]

howson Howard - thanks for that link, it hadn't showed up with my search. I extracted this from post #6:

First cold trip out in my new Imagine 2800BH. When we got to the campsite, thermostat read 43 degrees. I turned on the furnace via the Furrion thermostat and it fired right up as expected. We finished setting up camp and then went for a hike. 2 hours later I came back, opened the door to the camper and it felt like I was stepping into an oven. We take our shoes off outside and I could tell the floor was very warm - almost hot (due to the ducted heat being directed underneath. I walked over to the thermostat and it read 43 degrees!. In this unit, the furnace is located under the corner of the kitchen counter next to the sink. I opened up the under sink cabinet and could barely touch the sidewall it was so hot.

I immediately shut the furnace off at the thermostat, opened windows to cool down the interior and turned on the AC fan to circulate air. As soon as I turned on the AC fan, the ambient temp value on the thermostat display started jumping - finally topping out at 98 degrees (keep in mind this was after windows had been opened, etc.

After everything cooled down, I started the furnace up again. This time there was no way I was leaving until everything was working correctly so I sat there an monitored it for 30 minutes. Again, after the furnace had been running for 30 minutes, the room started feeling very warm, but the thermostat was only reading 48 degrees. Recalling the previous behavior, I again activated the AC fan and immediately the ambient temp reading jumped up from 48 to 72. The furnace then immediately kicked off since my set point was 68. After another 20 minutes or so, the ambient temp dropped below 65 and the furnace kicked back on. This time, with the AC fan still running, the furnace shut off on its own when the temp got to 69 degrees.

This is precisely the problem I experienced, although I was inside during the event so it didn't get more than perhaps 75 inside before I shut it off. It is not seemingly related to where the temperature probe is, but is a software flaw in the Tstat. The sensor was clearly warming up (ac fan not on), but the Tstat didn't recognize it was until I shut it off. A/C fan never involved.

[howson]

AlexPeterson

So...do you have the updated thermostat or the old (non-sensor) thermostat?

If the latter, running the a/c fan on low (should) solve the problem. This was noted in the quote from the thread, i.e. ...turned on the AC fan to circulate air. As soon as I turned on the AC fan, the ambient temp value on the thermostat display started jumping... Why? Because of the location of the sensor in the "old" setup as documented in that other thread.

It's a simple test to prove that this is correct or wrong--next time try running the furnace without the a/c fan on. If the temperature does not rise (as expected) as the camper warms up, turn on the a/c fan (on low) and then monitor the thermostat to see it responds. The readings (should!) change with the fan on.

If the readings on the thermostat do not change then there clearly is a malfunction in one of the components.

[AlexPeterson]

howson Howard, the sensor is definitely above the a/c filter, I just verified. The key part of this discussion is that everything has worked perfectly (temperature indication on the t-stat climbed as expected before furnace shut off), except that one time yesterday morning. It leads me to believe it is a software bug in the t-stat.

The apparent affect turning on the a/c fan might be related to software and not the fact that air was moving by the sensor.

The sensor being apart from the t-stat is a whole other issue.

[AlexPeterson]

Here we are one year later - the t-stat was working very well the last couple weeks, keeping the temperature very close to setpoint as it should. We only had the heat on overnight a handful of nights, but it was working. This morning I turned on the heat. The temperature being reported was 53F (the sensor is in the ceiling A/C plenum - a separate problem). The heat came on, warming things up nicely, but the temperature reported by the t-stat remained "stuck" at 53. I shut it off as it was obviously going to roast us out. (See post #6 by JimB33, this is a serious problem) I then put my fingers on the probe in the a/c unit for a few seconds, and the reading on the t-stat immediately warmed up to 80 something.

It is precisely the same problem we had a year ago, and I believe it has to either be a faulty sensor, faulty t-stat or t-stat software problem.

My intention is to buy this updated t-stat, which should in heat mode address any of the three possible problems mentioned in the previous sentence:




My understanding is that this system will use the probe under the t-stat for heat, and the sensor in the return ceiling a/c duct for cooling. Can anyone confirm this? Documentation on the details of this T-stat seems hard to find...

Additionally, for better A/C performance I plan to get the sensor extension kit from GD.

Thanks,
Alex