(22 XL) GE AC works but HeatPump silent

[twp5253]

And this has been working so well during my extended stay at Camp Dynamax. I was all set to visit the Freightliner Service folks. If I run the Thermostat down to 60 and turn the Cool on, everything works.
When I put the thermostat up to 75 with inside temps at 68, and select HeatPump I was getting some noises like a fan but now total silence. The HeatPump and the Icon above it are flashing? I think I may have seen an F4 at one point?

I do have Micro-Air softstarts and I am not able to Bluetooth connect while the fwd unit is trying to start in Heat Pump Mode. I think its the thermostat not actually telling the unit to start?

Any ideas?

It is not too cold because I got this from their web site as my manual does not even mention the unit has a heatpump function?

"Operates below freezing
Heat pump operation with ambient conditions as low as 25F"

[twp5253]

So I downloaded the worthless manual for the AC unit that does not even mention HeatPump capability. Same manual comes with RV.
I downloaded the manual for the Thermostat and that was very informative. It was not 'Locked Out' per se due to cold. That temp is outside temp = 25 degrees.....I know this unit will operate at 31 based upon several days of Elkhart having that temp when I woke up. (Greg likes to begin work at 0600)

In HEAT-PUMP modes, a flashing HEAT-PUMP
icon indicates that the unit is performing an autodefrost.
In HEAT-PUMP+FURNACE mode, while auto-defrosting,
the unit will use the furnace.

So I let the unit run in that mode for 30 min. Still not able to get the heat pump to start. I then searched for the 12 volt fuse that would shut it down. Yes, the GE unit runs on 12volt. Found fuse, both Thermostats went dead....waited....Fuse in and they came back from the dead. Fwd unit now works in both AC and Heat Pump mode. Greg is really going to be happy that I fixed this....he has spent a lot of time on my RV....He is a STAR!

As soon as Micro-Air finishes their Thermostat for this GE unit, I will be getting at least one of them. By the way, Micro-Air tech support was busy emailing me on a Sat. morning helping with the troubleshooting of this problem. Micro-Air for the win!

[Reverse_snowbird]

Glad you found a fix that works.

However, heat pumps really don't work well at temps below 40 and at 25 degree outside temperatures, you really need to be running your furnace.

[twp5253]

Originally Posted by Reverse_snowbird

Glad you found a fix that works.

However, heat pumps really don't work well at temps below 40 and at 25 degree outside temperatures, you really need to be running your furnace.

I would say the lowest I have seen in the last 3 weeks has been 31 degrees outside and I am willing to bet the farm you don't have GE AC/Heat Pumps. In other posts I have given the parameters I have witnessed first hand. Their performance is phenomenal. Pretty sure the best numbers I saw was with outside temp at 34 degrees and after 20min of operation, my forward HeatPump was pushing 98 degree air out the main vent. Inside air temp was probably 74 by the time I measured that fantastic output. I got to 74 with the HeatPumps only on that occasion. Greg the service manager for Dynamax walked into my coach at 0600am and was amazed at the hot air coming out of my heat pumps. He is a believer now!

As for running the furnace (Aqua Hot) I have always had the system on so that my utility/wet bay would have protection from the low temps. I have that thermostat set at about 38 degrees. I can hear that system in operation if everything else is not running.

[Retired JSO]

Our dometic heat pump will run but blows non heated air below 42 degrees. It will stop all together below 40 degrees.