17' Series Dometic B2200 rooftop ac noise 17.56 OB

[hilltopcrew]

Hello there fellow travellers,
We have a Dometic Rooftop A/C unit in our 2010 17.56 Expanda OB, that is making this noise that sounds like a small electric pump motor inside it running for around 3-5 seconds, shuts off for another 3-5 seconds and keeps on doing this cycle on and on. Only happens when the 240v mains is turned on regardless whether the unit is running or not. You can can still hear it kicking in and switching off when the A/C is running or just the fan by itself.
I've never noticed it before until yesterday at home.
I have searched everywhere trying to find a reason for this on, off, on, off and on again pump like noise to no avail.

Any help would be greatly appreciated and welcomed.

Cheers
Rick

 

[hilltopcrew]

Ok so I've narrowed the noise down. It's both condenser fans. Item number 27 on the diagram.

 

[hilltopcrew]

Both are making the same noise like a tiny pump cutting on and out. Are they meant to be quiet? Hope so.

 

[hilltopcrew]

Has anybody experienced the pulsing noise with the condenser fan before. Trying to find out if its common faults.

 

[John Bosel]

Hello i seem to have the same thing happining has anyone found out what is going on or how to fix it cheers