Dometic roof are motor shot. How easy to replace?

[lacofdfireman]

We have a 13.5 Dometic Roof top air that the motor has gone bad. Getting some quotes now to have the motor replaced. I was wondering if this is a DIY job or if it's time to just replace the entire unit. Rear bedroom unit is same size and still running good. This one that is bad is our main living area unit. Also considering since it's 7 years old just replacing the entire unit. If I did this how hard of a job is it to DIY? Or is it better just to pay someone and have it done right? If it's plug and play then there are no worries for me to just do it myself but if it involves wiring and other stuff I will just pay to have it done.

Also where is the best place to buy a new unit? And should I upgrade to a 15K roof air? Also what should I expect to pay for a new one? Any help would be appreciated..

[lacofdfireman]

I do appreciate all the help everyone has given me. I'm hoping I bought the right part today for my A/C. Does this look like the Start capacitor that everyone is telling me to check first off before I change out the entire A/C unit?



Also when I take off the cover for the A/C will it be obvious where this is or is it hidden under or inside another cover somewhere?

I'm not home until Monday and have a trip planned for leaving on Thursday that week. I'm going to try and get my son who's 16 to take the cover off and see if maybe it's something he can swap out and check if it works or not after changing. If it doesn't work I'm just going to order an entire new A/C so I can have it working for our trip. It's already over 100 degrees where I live and would be miserable without both A/C's going.

Also my A/C is a Dometic DuoTherm 13500. I'm hoping this Hard Start Capacitor is the right one for my unit. The guy at the RV Parts counter said it's universal between Dometic units... Fingers crossed that this will work..

[jhilley]

Here is a source for the motor

RV Motors for AC

[lacofdfireman]

jhilley wrote:
It shouldn't be much different to install. i don't see why you would need to change the thermostat, but you might want to change to a new digital type. I would check to see if there is a mobile tech in your area, they seem to be better than the RV dealers. That quote is outrageous. I found several with a Google search. This one looks good

Jim's RV Service

Jims RV is who directede to this other guy. Jims does not do A/C work.

[jhilley]

It shouldn't be much different to install. i don't see why you would need to change the thermostat, but you might want to change to a new digital type. I would check to see if there is a mobile tech in your area, they seem to be better than the RV dealers. That quote is outrageous. I found several with a Google search. This one looks good

Jim's RV Service

[lacofdfireman]

Just realized that I have a ducted A/C system. I went to Camping World to look for A/C units and they said that since mine has a wall thermostat that it would be a ducted system. Is this right? I know I do have like 4" round vents in my ceiling but if I remember correctly this a/c also blows directly out of the unit itself also. Will this make the installation of a new unit a lot more complicated? They also said that I would have to replace the wall thermostat also. Will this involve fishing wires through the wall?

[jhilley]

That quote is definitely more than a replacement new unit. As mentioned it could be the capacitor or just physically bound up. Try freeing it up and lubricating first. Then try a start capacitor. You could use the one from the working unit.

[lacofdfireman]

Here is a copy of the quote that the repairman gave me to fix the A/C unit...



So how to I know if it's a starter capacitor problem. Also is this a unit specific part or are they a universal part. Reason I ask is I am 500 miles away from my motorhome but by a Camping World where I could go check for a part but don't have any idea what Dometic unit I have other than it's a 13500BTU unit.

Also how do you know if this is the problem. Like I stated early the repairman said the unit when I would switch to Fan on and AC on would blow air for about 20-30 seconds then shut off. He said that the AMPS were around 7-8 and should be less than 2.5. Does this sound like a start capacitor problem? Or a blown Motor. I thought all along that it was the fan motor that was bad but when talking to the repairman after getting the quotes he said its the condenser motor that is bad.

Guess at that price I might as well replace the entire unit. Should I stay with Dometic so I don't have to switch out the thermostat inside the coach or go for a Coleman? 15000 or 13500 BTU Unit?

[wa8yxm]

I see variable information in this thread.. First, there are two motors in the Rooftop A/C. one blows air around the other circulates coolant (The compressor) which is bad.

If it is the blower you won't be needing 2 people.. I will describe the blower motor replacement on a Carrier Air V,, the one you have should not be much different. this includes the tough part.

Remove top cover

Remove inner cover on condenser coils, loosen the set screw on the fan and slide it off the end of the shaft if you can

Remove the upper electronics/connection board cover (2 screws) this part will likely be different (perhaps not needed) on yours, Remove evoprator cover.. On mine this involved both screws and push to release latches.. Again may be different on yours.

Using straight blade screwdriver un-latch latches that hold motor to cradel (Put blade in the "hook" on the end of the thing and rap firmly down with hand while prying out slightly.

Unplug motor wiring harness and lift out blower assembly.. Loosen set screw on blower cage and slide it off.

Re-assembly is reverse.

NOTE: you may only need a new start condenser,, (on mine it's in the electrical box, on some it's on the motor).

One person, perhaps half an hour on the roof.

- Page 2 -

If it is the condenser, then replacement of the entire roof unit is indicated

THIS IS a two man (At least, i'd like to have 4) job. Dealer used 4 men and a front end loader.

[sailor_lou]

Make sure the motor is bad before you purchase a new one. The starting capacitors could be the problem, but I found that both mine would bind up after sitting over the winter. I was able to mechanically free them up and after lubricating the bearings (both ends) with a light electrical motor oil they have work flawlessly for the last 3 years. Good luck.

Lou
05 Travel Supreme Envoy

[jdevans22]

If the motor is bad it can be replaced on the roof.Turn off the breaker, Remove the motor an fan. Mark the wire leads. Get the name and part no. You should be able to find what you need on line.

[Golden_HVAC]

You will not require a crane or forklift, but if you have one handy, it can help a LOT. The weight is only about 100 - 145 pounds, so not a do it yourself job, but a couple of close friends, it is pretty easy, especially if you can park a pickup next to the RV, and be 5' off the ground when you lift the A/C up to the 11 or 12' tall roof.

Having the forklift with a nice solid top pallet will also be handy, so you can stand on it while lifting the A/C onto the roof. It also gives you a place to put the A/C instead of setting it on the roof and possibly damage the roof from the bottom of the A/C unit.

The wiring is pretty simple. If you have a wired thermostat, mainly found on ducted A/C units, make sure that you write down the wire connections and terminal letters.

I also think that a 10 MFD capacitor will fix the problem for about $10. Unless the fan motor will not turn on it's own while not plugged in.

Fred.

[chuckftboy]

Someone mentioned the run capacitor and he is probably correct. If the capacitor fails, the motor will draw high amps and go out on internal overload. these motors have sleeve bearings and unless they are in really bad condition, they normally won't stop the motor from running, though they could get pretty noisy. the fam motor is fairly easy to replace even for a first timer though the unit is a bit easier once its on the roof. If you decide to upgrade to a 15,000 BTU check the the current draw rating before you purchase. Most 13,500 are on a 15 amp circuit and most 15,000's require a 20 amp circuit. Don't worry about your gen handling it. 6.5 kW can handle far more than even 2 15's will put on it

[ScottG]

Last time I checked, a replacement motor with fan was about $150. So if it was doing the job for you then that would be a much cheaper alternative and it's an easy job to do, just a few screws and an electrical connector.

[Bird_Freak]

If its the fan motor its a piece of cake to swap and not expensive.

[lacofdfireman]

I believe it was the fan motor. Basically you can hear it click on when I switch it to cool but it's not pushing any air. The repairman said that it was showing it was using like 7amps or something like that and that it should be under 2.5amps or something like that and that ones compressor motor was showing around 9amps. The rear one that is actually working correctly he showed me the amps and it was like 1.9 with the compressor motor at like 9 amps.. The rear one cools nicely. Even with the front one when you put it on fan on high it will run for about 2 minutes then the fan will shut down. He told me it shuts down to keep from burning up the unit. Kinda a fail safe so to speak. I don't really know how to check stuff myself. I just have to take peoples advice... I appreciate all of yours.. I agree that is seems way to new to go bad. Especially considering that it probably has less than 100hrs on it. He said the bearings he thinks are bad...