Resolution of AC Fan Issue

[SeattleLion]

Like others who have reported it here, our AC would turn the fan off and then on again every few minutes while cooling. Some members wrote about workarounds like putting the fan on manual. I brought our unit back to the dealer to correct our rather long list of defects. The AC fan issue was one of them. Since I don't have the trailer (at the dealer), I can't be sure but I believe the brand is Dometic. In any case, the manufacturer is replacing the unit under the warranty. So, no need to suffer with the problem or leave the fan on all the time.

 

[Jim.Allison]

Replacing because of this specific issue?

 

[SeattleLion]

The dealer didn't share his diagnostics with me. The issue is that the fan goes on and off (compressor keeps running) while cooling. The fan turning off and on is unrelated to the thermostat which is still calling for cooling.

 

[Garypowell]

This is interesting as every main A/C unit I have owned has turned the fan off between fan speed changes. Other than that the units worked just fine.

I would as, as you have time, to find out if they found something else wrong while they were looking at the unit.

Thanks

 

[danemayer]

The dealer didn't share his diagnostics with me. The issue is that the fan goes on and off (compressor keeps running) while cooling. The fan turning off and on is unrelated to the thermostat which is still calling for cooling.

Since this symptom seems to be the normal operation on so many rigs, I'll be interested in hearing back from you to see if Dometic actually replaces the unit under warranty.

 

[SeattleLion]

Since this symptom seems to be the normal operation on so many rigs, I'll be interested in hearing back from you to see if Dometic actually replaces the unit under warranty.

Dometic is replacing the unit. The dealer is waiting for the shipment to arrive, hopefully on Monday. They agree it is not normal.

 

[dennych1]

Hi Bob I got the 3160 around the same time as you. I was wondering if you found the fan extremely loud. My wife hates the noise. Our old AC in our Everest which was 7 years old was no where near as noises. Just want to see if you found yours very loud.
Dennis

 

[SeattleLion]

Hi Bob I got the 3160 around the same time as you. I was wondering if you found the fan extremely loud. My wife hates the noise. Our old AC in our Everest which was 7 years old was no where near as noises. Just want to see if you found yours very loud.
Dennis

Both AC's are incredibly loud. We hate that. They are louder than I remember in our Kodiak (a year ago).

 

[SeattleLion]

I just spoke to the dealer. First, I don't think that the fan speed changed at all when it went off and then on. The service manager said that the result of the diagnostics was that the control board was defective and was turning the fan on and off in error. That's what I figured to. Also, I noticed that the sound of the fan, when operated it manually, didn't seem to change between high and low speed, so I suspect that's part of the problem too. The new one is arriving at the dealer today.

 

[branson4020]

Do some of these AC's actually have automatic fan speed adjustment? Mine is hi/lo - strictly manual control.

 

[Tombstonejim]

I just spoke to the dealer. First, I don't think that the fan speed changed at all when it went off and then on. The service manager said that the result of the diagnostics was that the control board was defective and was turning the fan on and off in error. That's what I figured to. Also, I noticed that the sound of the fan, when operated it manually, didn't seem to change between high and low speed, so I suspect that's part of the problem too. The new one is arriving at the dealer today.

Yes Both of mine will automatically go from high to low fan speed when the temperature gets to within 2 degrees of the set temperature. And will go fro lo to high if the temperature starts getting hotter than the set temp.

 

[scottyb]

I thought there was something wrong with mine until a thread last week, where almost everybody that replied said there's did the same thing. Now I am wondering if there is a flaw in the circuit boards on all of them.

 

[SeattleLion]

This is interesting. I suspect part of my problem is that my fan has no "low". That may be the controller issue. I noticed that low didn't sound any different than high. Both are the same.

 

[branson4020]

Yes Both of mine will automatically go from high to low fan speed when the temperature gets to within 2 degrees of the set temperature. And will go fro lo to high if the temperature starts getting hotter than the set temp.

Not sure I understand the point of this feature. Does it shut off entirely when it reaches setpoint, or does the fan just stay on low even when the compressor kicks off?

 

[SeattleLion]

Not sure I understand the point of this feature. Does it shut off entirely when it reaches setpoint, or does the fan just stay on low even when the compressor kicks off?

All of these units turn the fan off when the target temp is reached unless you manually set the fan.

 

[TandT]

Yes Both of mine will automatically go from high to low fan speed when the temperature gets to within 2 degrees of the set temperature. And will go fro lo to high if the temperature starts getting hotter than the set temp.

Yes, this is the way our's works.Trace

 

[branson4020]

OK, so now I REALLY don't understand the point of this feature. Also, mustn't it be implemented in the thermostat?

 

[SeattleLion]

OK, so now I REALLY don't understand the point of this feature. Also, mustn't it be implemented in the thermostat?

The idea is that the high fan is noisy (no kidding!) and the low fan is quieter. Also, as the room gets to the desired temperature (the thermostat handles this), when the thermostat senses that the room temp is withing 2 degrees of target, it signals the AC to go to low fan. This lets the room "coast" to the target temperature and makes it less likely that the room will get too cold.

 

[wdk450]

Gang:
Reading this thread from the primary complaint of fan going off made me think that there is most likely a relay to control the fan on the Air Conditioner control board. This relay may have undersized contacts which are pitting out and failing, from the arcing due to load switching.