Community Forums

TQ60 · 07-23-2012, 04:11 PM

Yet another issue with an old AC.

We have a 1989 CC with the Ducted Dometic units front and rear.

The rear unit compressor now will not start, have replaced start cap and verified all windings on the compressor are not open or shorted.

Have not used the rear unit more than a couple times, so we are not certian that it ever worked since we owned the unit, so it could be trashed or just stuck.

Considering repair or replacement, compressor is cheaper than replacement, but new unit not compatible with old controls, so for something we do not use often we may be better replacing compressor.

Ours has the digital thermostat in the wall, so not an easy swap, me may be able to swap the control board in a similar model unit, not sure if that has been done before.

Would like to find a possible used unit where someone else may have replaced both when one died, that would be a win-win for both, or maybe a dealer who could have a used one.

Installed model number is 620015.101

Also wondering if there are any troubleshooting tips other than the basic checks that we could apply, if the compressor is stuck are there tricks that techs can do to possibly free it up?

nightriderrv · 07-23-2012, 05:47 PM

I would call dometic tell them what you have if your just swapping top unit they just plug in to the control you might beable to use the same control it's worth a shot

RV Wizard · 07-24-2012, 02:54 AM

Here iRV2 Forums - Files - Duotherm Air Conditioner Service Manual
is the service manual for the unit. You also need to verify the t'stat is sending the correct signal for the compressor to operate. Good luck, stay safe and keep us posted.

TQ60 · 07-24-2012, 09:23 AM

Thanks for the manual, it is for the newer versions, but the basics are the same.

The signals are correct, voltage is measured at the compressor, the AC unit is a favorite spot for yellow-jackets so it is real fun to work with "the help".

Will do a second review of the service manual to see if there is anything we missed.

Did check with Dometic, gave a list of parts that were the upgrade, a new thermostat was in the list.

TQ60 · 08-13-2012, 10:52 AM

So we did our homework, discovered some tricks from the commercial folks, reversing the start and run windings and beating with hammer to possibly un-stick the stuck rotor, no go.

So it is toast.

A friend also had a Dometic cooling unit go out, so we searched "Dometic" on craigs list looking for either old fridge or ac units.

Located a pair for heat pump models that were a gas tank away, tey are only 7 years old, they were too small for the dessert, so they were upgraded to 15K units.

Got them home over the weekend, cleand them up and combed out the fins, work great, so they will go in soon.

Now the coach has a total of 7 heaters...and it does not get that cold here...