AC problem

from the manual for my thermostat:

"Special Features

Auto Fan

When auto fan is selected the fan speed will vary depending on the
difference between the temperature set-point and the room temperature.
In auto fan the compressor and fan cycle On and Off with the
thermostat.

When the difference is:
>5º The fan operates on HIGH
<4º The fan operates on LOW"

The fan will stop and restart when it changes speed and the compressor will continue to run. Thought it was broken like most when I first got my current rig.

sk734 wrote:
Update
Dometic 3 wire single zone ac. Changed board and updated stat. Runs then stops until reinitialize or turn off and back on? No ice up works great when running. Could use some help. Anyone know the cure? Thanks in advance.

My bed room does that if I leave it on LO fan overnight....I just leave it on HI fan and its happy.

sk734 wrote:
Update
Dometic 3 wire single zone ac. Changed board and updated stat. Runs then stops until reinitialize or turn off and back on? No ice up works great when running. Could use some help. Anyone know the cure? Thanks in advance.

I have the same problem with my single zone unit. AC will run until temp is reached then shut off but won't come back on. I have to run through all the thermostat settings then it will restart.

I don't think it's a nice up issue either but haven't gone on the roof and checked yet.

Ron W

Update
Dometic 3 wire single zone ac. Changed board and updated stat. Runs then stops until reinitialize or turn off and back on? No ice up works great when running. Could use some help. Anyone know the cure? Thanks in advance.

Your AC is working as designed. It is designed to run on high fan until within a certain preset temp then reduce to low fan to hold the temp.

No I have not. I will talk to them-good idea. It's to bad this auto fan system driven by temp has come into play. I was perfectly happy with my prior rv that had a manual 2 speed fan setting. They are trying to build a better mouse trap?

I don't know why you would change the board AND thermostat. It's not likely that both are bad. I don't actually think it's likely that either are bad. Speaking as someone who has aimlessly thrown money at many problems over the years, I'd be hesitant to change anything until further diagnosis is performed. Have you contacted Dometic yet?

Thanks for all the post.

I have also Taped off any leaks some time ago.

WTP-GC wrote:
If I understand correctly, when the AC fan speed is set to "Auto" it will change between high and low on its own. Is that right?

If so, then that's the basic design of the system. If you find it switching frequently (comtinious changing every 30 seconds to a minute), then it's highly possible you have a duct leak at the unit. My brand new Grand Design had this problem from day one. Over on the GD owner's forum, this problem and solution have been discussed at length. If you remove the shroud (really easy), you might find that the duct is not well sealed where it interacts with the return air duct. This causes the thermostat to get erroneous readings and short cycle. The solution is to get duct tape and seal up every single nook and cranny in there that would allow this to happen. It's pretty self-explanatory when you're looking at it. Put the shroud back on and you're good to go.

Of course..."IF" this is the problem you're experiencing...

Yes that is the case. I am wondering if I going to have to change out the board and stat.