Ac problems

Mcaruthers68 · 06-28-2020, 09:32 AM

My dometic ac is acting up. I’ve cleaned everything and lubed things. My bedroom ac fan motor shuts off but there’s a slight hum but can still feel cool air drifting out of the vents.. I will turn on the unit low or high set the temp to a temp. The unit never struggled to kick on, it blows air immediately and pretty strongly. But it varies. Some times it takes 10 mins, sometimes it takes 45 or more. But the process is the same.. starts off strong, everything works great.. but as time progresses the power of the air starts to taper off until there’s no air coming out of the vent, and the blower/fan has stopped completely. But the humming stays until a few minutes later what I’m assuming is since the fan isn’t blowing things are heating up and it kicks off.. if I wait a while. I can repeat the process.. anyone have any ideas.

**flybouy** · 06-28-2020, 09:39 AM

Sounds to me like the coil could be freezing over. When it freezes solid no air can flow even though the fan still funr (the humming). When this happens take off the return air cover where the filter is and take a look inside.

**chuckster57** · 06-28-2020, 09:40 AM

If I had to hazard a guess, I would say the fan motor is a probably getting ready for a permanent vacation. You can replace just the motor.

Mcaruthers68 · 06-28-2020, 12:14 PM

You think? Ugh.. that’s $195.. plus it doesn’t look like an easy thing to switch out.. oh I was hoping for an easier remedy. Lol.. I really appreciate your input ..

ChuckS · 06-28-2020, 04:09 PM

It’s a fairly easy job with a few basic hand tools and patience...

https://www.dyersonline.com/dometic-...fan-motor.html

This fan is for the 13.5K Dometic... not sure if you have that one or the 15K unit...

If your unit has dual capacitors you may have a run capacitor that is failing

Mcaruthers68 · 06-28-2020, 06:24 PM

Yea it was my initial thought.. but no freezing . No ice .. I wish this was the problem

Mcaruthers68 · 06-29-2020, 06:25 AM

So with the research I’ve been doing trying to understand the damn AC units.. I’ve come across this several times and don’t know how true it is.. but I have the options for the fan to run high or low.. a few posts I’ve read says to always run fan on high.. is this right?

**flybouy** · 06-29-2020, 06:35 AM

Quote:

Originally Posted by Mcaruthers68

Yea it was my initial thought.. but no freezing . No ice .. I wish this was the problem

Quote:

Originally Posted by Mcaruthers68

So with the research I’ve been doing trying to understand the damn AC units.. I’ve come across this several times and don’t know how true it is.. but I have the options for the fan to run high or low.. a few posts I’ve read says to always run fan on high.. is this right?

Then sounds like the capacitor or the motor. Could be motor windings open up when it gets warm, thermal overload on motor failing under heat, etc.

Yes, IMO run the fan on "high". I've never found that much sound difference between the 2 speeds. I also run the fan on "manual" (running constantly). Again, my opinion, it keeps the camper a more consistent temp by constantly mixing/blending the air. Also running it filters more air than having it only run when the compressor runs. I'd rather wash the dust off the filter that wiping down everything to remove the dust .

It's a personal choice, there is no "right" or "wrong" way to operate it.

Mcaruthers68 · 06-29-2020, 06:44 AM

Quote:

Originally Posted by flybouy

Then sounds like the capacitor or the motor. Could be motor windings open up when it gets warm, thermal overload on motor failing under heat, etc.

Yes, IMO run the fan on "high". I've never found that much sound difference between the 2 speeds. I also run the fan on "manual" (running constantly). Again, my opinion, it keeps the camper a more consistent temp by constantly mixing/blending the air. Also running it filters more air than having it only run when the compressor runs. I'd rather wash the dust off the filter that wiping down everything to remove the dust .

It's a personal choice, there is no "right" or "wrong" way to operate it.

Thanks.. I’ve bit the bullet last night and ordered a new fan motor.. $185.. ouch but hopefully this is the problem.. should arrive in a few days... should be enough time for me to educate myself on how to install it. I’m nervous, I hate electrical work..

I normally do the same, I run my fan all the time to keep air constantly moving in the rig.. didn’t think there was much difference in high or low speed other than amount of air flow.. but wanted to ask, these units require strange things. Thanks again

**flybouy** · 06-29-2020, 06:50 AM

There's really no great mystery, they are essentially a big window unit (I.e. packaged or self contained) with a separate thermostat & fan control. Replacing the motor should be straight forward and I'm sure there's videos to be found on the web.

Take your time, use caution removing the fan blades not to bend them or hit the coils with the fan blades. Good LUck!

wiredgeorge · 06-29-2020, 07:21 AM

Quote:

Originally Posted by Mcaruthers68

So with the research I’ve been doing trying to understand the damn AC units.. I’ve come across this several times and don’t know how true it is.. but I have the options for the fan to run high or low.. a few posts I’ve read says to always run fan on high.. is this right?

If you have the fan on low and auto the A/C can freeze up. To determine if frozen, take the lower unit off and look for ICE from inside the cabin looking up.

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