Duo Therm Heat Pump problems

[PizzaGuy]

I suppose I should have posted this in another section but I thought I would give my fellow Monaco owners a shot at helping me to go in the right direction.

I have two roof top AC/Heat Pump units, and two furnaces in my diplomat. The rear unit is not working in either heat pump or AC. I am sure the compressor is working because 1. I think I can hear it and 2. When on generator I can see the amp guage on the ems go from 7 amps draw to 14 amps.
The fans work at all speeds from the comfort control center so I have communication from the ccc to the unit.
I have not checked the thermostat in the rear of the coach yet and will tomorrow. I have the service manual but it is very hard to read as it covers just about every unit they ever made.
I hope someone out there in Monaco land has experienced a similar problem and can give me some help.

Thanks in advance
Don

[MonacoMama]

PizzaGuy..."Been there - Done that" .... SacsTC's last thread that he posted has the "Aftermarket part" you need. He bought it on Ebay. You can do a search in the "MH - Problems, Solutions & After Market" forum where he posted his question... Oh wait...I'm sorry - It was moved to the "appliances" forum somewhere south of our Monaco forum.

Good Luck..it is not that expensive to fix!

[MonacoMama]

PizzaGuy...I went a searchin' and found the thread here...I am not sure if there is enough info in the post OR the PHOTOS..so feel free if you need more info...Sacs won't see a PM if you send it to him...

[PizzaGuy]

Thanks MM, I did a search in Appliances before I posted my problem. A lot depends on the title in the search. I came up empty with mine. Thanks for directing me to the location. I will look at my start capacitor in the morning and let you guys know if that was the problem.

Ps thanks for asking me to sign up as a friend. I feel special ----

Don

[Diplomat Don]

Pizza Guy.....Before you do anything, unplug the telephone line type plug from the rear A/C first. Leave it unplugged for a few minutes and then plug it back in and give the A/C a try one more time.

[MonacoMama]

Hey Dip-Don.. the 2007 Diplomats all have/had BAD AC capacitors...

PizzaGuy - DipD's solution for everything is to unplug that plug!!

[Sixpack98]

The easiest thing to do is reset the comm link between the AC and Tstat using Dip Don's procedure. A bad start capacitor is a likely suspect. Turn on the AC and have the Tstat turned way down, stand under the AC and and listen for the compressor trying to start. The current draw will cause the fan will slow slightly. There is an initial delay of about a minute or so before the compressor tries to start. If the capacitor (or compressor) is bad the AC unit will cease trying to start the compressor and retry in about a minute. I don't know if there is a limit to how many times it will try to start. If the compressor tries to start but does not the likely suspect is the start capacitor. Follow MM link. If the compressor never tries to start it is likely a Tstat or temp sensor. You might try swapping Tstats connections between the two AC's and see if the problem moves to the front AC and the rear AC starts working. It could also be a reversing valve problem. This valve is controlled by the Tstat demand for either heating or cooling. Swapping the Tstats can provide a clue here. If that does not work I would suspect a reversing valve problem. They are generally very reliable but can get stuck. Not a problem easily fixed by most of us.

mark

[PizzaGuy]

I appreciate all of the suggestions. I tried the Diplomat Don suggestion this morning only because it is the easiest test to do. I am at home so I was plugged into 20 amp shore power. On the EMS when I turned on the rear ac I was pulling 6 amps. Then in about 2 minutes, it spiked to 16 and then down to 11. I heard the compressor start at the same time. So, it is unlikely it is the start capacitor. It was cold here thins morning (62) so a good test of cool air was not really possible. I will try again later when it warms up.

We were in Paso Robles (101 degrees) two days ago. That was when the unit failed. Went to the Journey concert at the California Mid State Fair.. WOW--

We were at the Wine Counntry RV Resort. Clean, nice park, overpriced, small slots. Sorry MM, I didn't take pictures.

So more tests later on in the day. Thanks again everyone

Don

[PizzaGuy]

Duo Therm part 3. Unplugging the telephone line was no help. I also did a reset of the confort control center. No help there either. Both the "run" and "start" capicators tested good. Next step was to check the "Electrical Kit" (that is what Dometic calls it). Kind of a odd test. Use a trouble light and test from common to all of the other wires that go to the roof. Power to Low Fan, Power to High Fan, no power to reversing valve or comperssor. Ordered a new Electrical Kit today. $108 total price. My local RV service center can't get me in until Aug 10 and we have a trip scheduled for Aug 16. I have to get it fixed before then. I will keep you posted.
Don with a Diplomat ---

[PizzaGuy]

During my last 4 years in the Air Force, I was part of the team that put spy satellites in orbit. We had a phrase when someone did something dumb. It was One Delta Ten Tango. When spelled out it is IDIOT. I just gave myself the award. When testing the electrical control box I forgot that there is no power to the reversing valve or the compressor for 2 minutes. It just came to me about 30 minutes ago and about 30 minutes after I ordered the part. Just cancelled the part. So now I know the problem is up on the roof. Say good luck don

[Rex]

Don, the reversing valve sometimes sticks. Give it a good rap with a large screwdriver or small hammer and see if that fixes the problem.

[PizzaGuy]

Rex, I did the tap thing to no avail. But I will try it again. My new plan is to take the cover off of the front unit and compare voltage readings with the rear unit. This should isolate it to either mechanical or electrical.
Thanks for the suggestion
Don

[MonacoMama]

PG..(Don)...I am going to suggest spendin the little bit of money and ordering the following off of eBay...even if it isn't the problem this time... you WILL need it down the road later - and the part is not expensive. (We still think it is the problem-but we aren't there to know for sure) We will now carry extra ones -just in case!



You can find more info at the link above in my other post.

[Rex]

Or get the hard start capacitor here if you don't want to search eBay:

Parts Master
888-476-3580
http://www.azpartsmaster.com/Product...Kit__SPP6.aspx