Cant turn Air conditioner off?

[Bill Martocchio]

I can't turn off my front AC on my 2020 Alpine. I have tried on the in command control and on the app on my phone. I had to turn it off in the fuse panel.

[chuckster57]

Have you checked the fan settings? If the fan is on hi or low then the fan will run without the compressor. It needs to be in auto.

[Bill Martocchio]

Have tried every fan setting. The system won't even let me change the temperature. Every time I try to change any of the settings in a few seconds it goes back to the previous setting.

[Bill Martocchio]

I checked the technical support web site and they suggested powering the system off and back on. It resolved my AC issues.

[chuckster57]

Originally Posted by Bill Martocchio

I checked the technical support web site and they suggested powering the system off and back on. It resolved my AC issues.

I’m glad you got the problem resolved.

[ChuckS]

When this happens again on your Alpine.. and it WILL it’s an indication that one or more relays in the gateway or control module for that Zone A/C 7nit is staying latched..

When this occurs the In Command system isn’t able to communicate across the CANBUS to tell that unit to shut down..

A “Complete Power Down” which means removing shore power AND 12 volts DC battery power will usually allow the latched relay to clear..

Just removing 120 volts AC power isn’t going to reset that latched relay..

Why? Because the gateway or control module has 12 volts DC applied to it at all times directly from power center 12 volt Bus Bar..

By removing 12 volts as well as 120 volts this also forces BCM to do a hard reset..

[jasin1]

Originally Posted by ChuckS

When this happens again on your Alpine.. and it WILL it’s an indication that one or more relays in the gateway or control module for that Zone A/C 7nit is staying latched..

When this occurs the In Command system isn’t able to communicate across the CANBUS to tell that unit to shut down..

A “Complete Power Down” which means removing shore power AND 12 volts DC battery power will usually allow the latched relay to clear..

Just removing 120 volts AC power isn’t going to reset that latched relay..

Why? Because the gateway or control module has 12 volts DC applied to it at all times directly from power center 12 volt Bus Bar..

By removing 12 volts as well as 120 volts this also forces BCM to do a hard reset..

Chuck I have the iN·command system and it’s working pretty good except for one glitch.. I had a second ac installed and it’s on the iN·command and no problems with that. My rear ac works but when it’s close to satisfying the tstat, the ac it will shut off for about 3 seconds and then immediately the fan will turn back on and it will run for another few minutes until it’s satisfied.
More of a irritation then anything ..also I notice a lag every now and then where the temp will climb maybe 4 deg and the ac doesn’t kick on but eventually it does and works fine... rv hvac systems are not my forte, at least the in command system is something I’m not familiar with.

[JRTJH]

Originally Posted by jasin1

Chuck I have the iN·command system and it’s working pretty good except for one glitch.. I had a second ac installed and it’s on the iN·command and no problems with that. My rear ac works but when it’s close to satisfying the tstat, the ac it will shut off for about 3 seconds and then immediately the fan will turn back on and it will run for another few minutes until it’s satisfied.
More of a irritation then anything ..also I notice a lag every now and then where the temp will climb maybe 4 deg and the ac doesn’t kick on but eventually it does and works fine... rv hvac systems are not my forte, at least the in command system is something I’m not familiar with.

That may be the "intended operation sequence" if you have your air conditioner fan set to "AUTO". The normal sequence is when the TStat calls for cooling, the fan will start on HIGH, the compressor will follow and when the temperature gets to 4F from the TStat setting, the fan will stop, change from HIGH to LOW and restart. The compressor continues during this time. When the temperature reaches the TStat setting, the compressor will stop, fan continues running on LOW for 60 or 90 seconds (depending on model) and then shuts down.

If the sequence changes to LOW fan speed and the temperature rises, the sequence is interrupted, the fan will stop (compressor continues to run) and the fan will change to HIGH speed and resume operation. When the temperature is again within 4F of the TStat setting, the sequence will occur again.

Essentially, the A/C runs on high fan and compressor until it's close to the TStat setting, then the fan changes to low speed and continues until the TStat setting is achieved. Then the compressor stops and the fan continues in order to push all the cold air out of the ducts (more to prevent condensation from pooling rather than environmental savings).

If the fan switch is set to HIGH or to LOW, the fan will run on that speed 24/7 and the compressor will cycle on/off as needed to maintain TStat setting.

[jasin1]

Originally Posted by JRTJH

That may be the "intended operation sequence" if you have your air conditioner fan set to "AUTO". The normal sequence is when the TStat calls for cooling, the fan will start on HIGH, the compressor will follow and when the temperature gets to 4F from the TStat setting, the fan will stop, change from HIGH to LOW and restart. The compressor continues during this time. When the temperature reaches the TStat setting, the compressor will stop, fan continues running on LOW for 60 or 90 seconds (depending on model) and then shuts down.

If the sequence changes to LOW fan speed and the temperature rises, the sequence is interrupted, the fan will stop (compressor continues to run) and the fan will change to HIGH speed and resume operation. When the temperature is again within 4F of the TStat setting, the sequence will occur again.

Essentially, the A/C runs on high fan and compressor until it's close to the TStat setting, then the fan changes to low speed and continues until the TStat setting is achieved. Then the compressor stops and the fan continues in order to push all the cold air out of the ducts (more to prevent condensation from pooling rather than environmental savings).

If the fan switch is set to HIGH or to LOW, the fan will run on that speed 24/7 and the compressor will cycle on/off as needed to maintain TStat setting.

Well that’s good to know! Thanks for the detailed explanation!

[JRTJH]

Originally Posted by jasin1

Well that’s good to know! Thanks for the detailed explanation!

Dometic doesn't put that information in the Air Conditioner manual, rather it's in the thermostat manual (where the temperature/fan control are managed). Seems backwards to me, but that's the way Dometic's documentation is arranged....

Here's the Dometic thermostat manual for the single zone digital thermostat. The dual zone is similar, just an "expanded function model". When Keystone incorporated the thermostat function into the In-Command system, the "documentation sort of fell by the wayside" but the rooftop A/C units still are looking for the same "control input from the temperature sensing function" regardless of where it's monitored.

In this manual, the fan function is explained on page 7 and the "HI/LO fan" is explained on page 11 in the "Special Features" section. That's where the >5 and <4 degrees fan speed function are documented. To me, it's a "round about way to explain the fan speed control" but, what the heck, it's Dometic for you.....

OOPS: Forgot to attach the pdf for the thermostat. here it is:

[Captainf2]

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