ATF: Bighorn - 15 k BTU AC behaving strangely

[SeattleLion]

We are out for a weekend. Our first trip in our 3160. The livingroom AC is behaving strangely. While it is running, every so often, the AC's fan cuts out for a second or two and then restarts. I can hear the compressor running, so the AC isn't totally shutting down. The thermostat is calling for more cooling all of the time.

I'm sure this isn't normal. Advise please.

 

[wrgrs50s]

I'm glad that you ask, because I have the same issue. If I have mine on auto fan it does exactly as you described, but when on Hi or Lo fan it runs continuous with no problem. It's really annoying.

 

[pegmikef]

I don't know if is in your A/Cs, but I was just reading that a lot of A/Cs have a freeze safety where if the coils reach 28 Degrees F, it will shut off until the coil reaches a temperature of 55 at which time it will restart. I can see this happening if it is not really hot and humid. Anyway just a thought.

 

[JanAndBill]

It is normal ours does the same. It also apparently has something to do with the outside temperature being close to your thermostat setting

Sent from my XT1030 using Tapatalk

 

[jayc]

I believe it's normal. It only occurs when the a/c has to work hard to get the interior temp down, as when we just arrived at a new park and the trailer is hot. It never happens again after reaching the set temperature on the thermostat. I was in a friend's trailer a few days ago when they arrived and their's did the same thing.

 

[SeattleLion]

I believe it's normal. It only occurs when the a/c has to work hard to get the interior temp down, as when we just arrived at a new park and the trailer is hot. It never happens again after reaching the set temperature on the thermostat. I was in a friend's trailer a few days ago when they arrived and their's did the same thing.

In our case, it only happens the first half hour or so when we turn on the AC. It is independent of outside temp...for example, tonight we had a power failure for 4 hours. When power returned I turned the AC on. Outside temp was 75 deg. The AC had just turned on after being off for 5 hours. There is no way the coils could freeze that fast, especially with that outside temp. It happened earlier in the day when the outside temp was 85 deg F.

As you describe, it seems to only happen in that first 30 min to an hour. It is annoying and I think we need an expert from the manufacturer to let us know if this is "normal" or not.

No AC I have ever had before did this.

 

[JanAndBill]

In our case, it only happens the first half hour or so when we turn on the AC. It is independent of outside temp...for example, tonight we had a power failure for 4 hours. When power returned I turned the AC on. Outside temp was 75 deg. The AC had just turned on after being off for 5 hours. There is no way the coils could freeze that fast, especially with that outside temp. It happened earlier in the day when the outside temp was 85 deg F.

As you describe, it seems to only happen in that first 30 min to an hour. It is annoying and I think we need an expert from the manufacturer to let us know if this is "normal" or not.

No AC I have ever had before did this.

This is something new for me also, which is why I first called Heartland. They didn't have a clue, so I called Dometic, who told me it was normal, and to not be concerned. They are also the ones who told me about the outside vs inside temp setting.

 

[Garypowell]

Same thing happens to my 15k unit. The fan will shut down only to restart 15 - 20 seconds later. For me there is no pattern except it seems to happen after a long run to cool off just as it reaches the set temperature. May be the controllers have fuzzy logic?

My bedroom unit acts just as you would suspect off and on. No in between fan off.

i am leaving tomorrow on two month trip so very little time. Maybe someone can call dometic and get an official answer.

 

[f250dieseldad]

Ours does the same thing. It seems to happen when it is reaching set point. Can't decide if it wants high or low speed fan. I turn it to high fan for a while then back to auto and all is well.

 

[SeattleLion]

Ours does the same thing. It seems to happen when it is reaching set point. Can't decide if it wants high or low speed fan. I turn it to high fan for a while then back to auto and all is well.

I am not aware of different fan speeds. All I have is the thermostat that controls the AC. So far (no seriously high temps yet) all it does is go on and off. When I first start the unit, it turns on and off randomly. It's off only a second or two and then back on. I am pretty sure the compressor keeps running since it keeps cooling. If the compressor shuts off, even for a second, the unit has a 2 minute recycle wait to avoid damaging itself.

 

[wrgrs50s]

If you have the Single zone Dometic thermostat it will have as the first option to select fan speed " Lo, Hi, or auto. To use this feature you have to select fan, then hit the + or - to select the Hi or Lo position, then select AC and it will run continuous on Lo or Hi no matter where the thermostat is set. In fact it has confused many, because it will run the fan even using the heat setting. If You leave it on auto it will cycle as you've described, but only run the fan motor when AC is selected.

 

[wrgrs50s]

The users guide provides instructions for operating the fan mode. Go to tools at the top of this Heartland page and select it, then scroll down to users guides and select, then select heating and cooling guide and go to page 4. You'll find info on your thermostat and fan settings here if this is the type you have.

 

[SeattleLion]

If you have the Single zone Dometic thermostat it will have as the first option to select fan speed " Lo, Hi, or auto. To use this feature you have to select fan, then hit the + or - to select the Hi or Lo position, then select AC and it will run continuous on Lo or Hi no matter where the thermostat is set. In fact it has confused many, because it will run the fan even using the heat setting. If You leave it on auto it will cycle as you've described, but only run the fan motor when AC is selected.

I just run it on "AUTO". I got the impression that some units will automatically vary the fan speed. Ours doesn't appear to do that. I'm not sure I would anyway since the amount of air coming out of the vents is pretty low velocity even on high. I know how to use fan mode, by the way. It's simple.

 

[wrgrs50s]

I am not aware of different fan speeds. All I have is the thermostat that controls the AC.

Sorry, I misunderstood your statement here. I think I understand now, you were talking about the other comment of it switching back and forth between lo and hi speed when in auto mode. I was thinking that was what mine was doing also. I guess I will need to try mine again to see exactly what it does. All I know at this point is that it's annoying, so I just select hi or lo to avoid it. I'd sure like to know if this is something that's wrong and can be fixed. I would rather run in auto mode. It's hard for me to think this situation is normal, I cant imagine the purpose. I'm hoping someone can tell us that really knows.