Air Conditioner not working. Help Please

Thank you all for responding with great ideas,

The weather cleared up a week ago and I did test the AC by turning the fan by hand while having the AC in the ON position. The AC started but stopped sometime later.

I quickly ordered a Fan Condenser from Dometic that arrived a few days ago. I installed the new condenser and put everything back together. Now when I turn the AC "ON", it runs for a minute or so (with a very loud noise) and then it stops. All that remains is a deep humming noise. Let it sit for a few minutes, start the AC gain.. same thing... Starts and stops..

Any ideas how I can proceed with further testing or swapping out of parts.

Thank you for all your help

Simon

Most have a single fan motor driving both blowers- though some do have separate motors.

Which fan should the OP be concentrating on? I thought the roof fan was for the condenser core only and there is a fan that blows air inside the RV located behind the ceiling grate?

Yes you still might have a bad run capacitor, but make sure you're looking at the correct fan.

Hard start cap is for the compressor motor only. Fan motor has a run cap only. Yes, it is probably bad.

This....

A bad fan capacitor would be my first thought. You can easily check by spinning the fan blade and turning the power on- if the blower keeps running, the fan capacitor is bad- if you can spin it backwards and it keep running, the fan capacitor is definitely bad.

Usually when my Air Conditioner hums it is due to LOW AC VOLTAGE from the camp ground pedestal connection.

I always have one of these RV AC VOLTMETERs plugged into a receptacle where i can glance at it when turning on my Air conditioner. This model is great as it has the SAFE ZONE printed in "GREEN"...


Gives me the warm fuzzy feeling...

I also have this setup with me for checking the camp ground pedestals before hooking up my 30AMP SHore power Cable but I have to admit I don't do this as much as I used to..


Roy Ken

Thank you for the comments/suggestions.

The fan does not run at all. But it does turn by hand. So all it probably mean is that the motor is not stuck.

I will go back up in the roof and check carefully if the part mentioned above is damaged. Thank you for the tip. It's raining right now though.

What about a bad capacitor. I hear folks talking about that as a common culprit. Would that disable the fan from working?

Simon

Does your fan turn at all? You might have a fried fan motor....Does your evap coil get cold?

Tim

I suspect the hard start cap has failed.
Take the cover back off and look for a black thing with two connections on top thats about the size of a roll of half dollars.
It may even be physically damaged - look to see if the top is lifted and/or leaking stuff out of it.
This is a cheap part and you should be able to get one from any RV supplier.

Here's a fuzzy pic of a failed part: