Basement air problem

fputnam · 06-11-2013, 09:38 AM

Hi everyone. We have a 2005 34 foot Itasca deisel pusher with the Coleman 6535 basement heat pump.

Until 2 weeks ago, the air conditioning worked perfectly but has now developed a problem. If I turn off the breaker for the number 2 compressor the unit will cool all day long. If I turn on the breaker for the #2 compressor it will cool for about 5 minutes then both compressors shut down even though the thermostat is not satisfied. An additional piece of info is that we are dry camping and running the a/c off the generator as needed.

As we all know, you need both compressors running to do any real cooling in the summer.

I have gotten into the heat pump wiring compartment and reseated all the connections and found no obvious damage or burnt wires. So I've run out of ideas. Any suggestions on what else I can do to troubleshoot or solve the problem?

We are in Frisco Colorado right now and are thinking seriously about heading to Denver to try and find a reputable RV air conditioning repair shop. When I check the Airxcel website it suggests Western Dynamic in Golden, CO and DM RV Repair in Loveland, CO. Any one have any comments on either of these repair shops, or other suggestions? Our schedule and direction is flexible so other recommendations in other cities are welcome also (as long as they are west or north from here). Well, OK, so our direction isn't entirely flexible. We're heading to Washington state and there's a lot of hot air between here and there.

In the meantime we're staying high in the mountains where we don't need air conditioning.

Thanks for your help.

rgvtexan · 06-11-2013, 10:43 AM

I have been told by other RVers that a good HVAC shop can repair the basement systems, most times for less than an RV dealer. Many RV Dealers sublet the work on ACs and pocket a surcharge.
Good luck with your needs, keep us posted on the outcome.
And Welcome to WA. when you get hear. Come up to NE corner and visit Grand Coulee Dam and beautiful Lake Roosevelt. There are many NP Campgrounds around the ~150 mile long lake with over 600 miles of shore line.

Bug512 · 06-11-2013, 12:50 PM

Hello, you said that the unit worked OK two weeks ago. Were you plugged into shore power at that time? Reason I ask is I wonder if the energy management system is shutting the compressors down?

Another route to go is call Airxcel. They have a technical support, maybe they can walk you through it.

And, yes a residential / commercial HVAC company will be able to make any repair on that unit. All technical information can be found on Airxcel's website.

Best of luck and let us know what you find out.

HD4Mark · 06-11-2013, 01:00 PM

See if this is any help. I also have a nice write up by on removing the unit if you are interested.

fputnam · 06-11-2013, 01:19 PM

Well we were in Texas plugged into shore power where the a/c ran for 10 days straight without shutting off. There were one or two instances after that before we got into cooler weather where we ran the a/c on generator power without problems.

Also with the 2compressors running and the battery charger running we don't exceed 29 amps so I don't see how the EMS would be shutting down the compressors due to overload conditions, but what do I know?

I'll check later today.

Jimooo · 06-11-2013, 01:25 PM

What happens when you are on generator power does it still trip #2 compressor ?

When is the last time the evaporator and condenser coils were cleaned?

Did you amp #2 and #1 compressors while running?

While #2 compressor is running is it blowing cool air?

Check voltage at compressors .make sure fans are cycling .

Maybe a sprung breaker or weak. Make sure that your A/C is calling for the secondary compressor to come in, set t-stat at least 5 degrees from room temp to cycle secondary compressor.

You could have high head pressure due to dirty coils, freezing coils, low on refrigerant , fans not working.

Good luck, hope this helps

James

clyon51 · 06-11-2013, 01:51 PM

Quote:

Originally Posted by fputnam

An additional piece of info is that we are dry camping and running the a/c off the generator as needed.

I don't know squat about your coach, the particular EMS or the genny. Based solely on what you said above, have you checked the genny to make one of the breakers aren't tripped?

I'll crawl back in my hole now

fputnam · 06-11-2013, 04:29 PM

My answers are below in parentheses.

When is the last time the evaporator and condenser coils were cleaned? (as far as I know, never. However I can see through the fins. There appears to be no blockage)

Did you amp #2 and #1 compressors while running? (I didn't bring an ampmeter with me. However, on the EMS panel, the amperages don't seem to be out of line with what I'm used to seeing)

While #2 compressor is running is it blowing cool air? (Yes)

Check voltage at compressors .make sure fans are cycling . (Good idea. The condenser fan is running when the compressors are running. Conversely, the condenser fan is off when the compressors are off)

Maybe a sprung breaker or weak. Make sure that your A/C is calling for the secondary compressor to come in, set t-stat at least 5 degrees from room temp to cycle secondary compressor. (Both compressors are running, like I said for about 5 minutes, before they both shut down. The thermostat has not reached it's set point at that time. No breakers have switched off, unless I did it.)

You could have high head pressure due to dirty coils, freezing coils, low on refrigerant , fans not working. ( I'll check again for dirty coils)

( Thanks for the great suggestions)

Good luck, hope this helps

James[/QUOTE]

dengraham · 06-11-2013, 07:06 PM

fputman,
What size is your generator and what is the amp output? If your hot water tank or refrigerator is on electric you will quickly go over the 29 amps. Are you running the microwave or an electric heater? Hair dryer? Vacuum? Satellite? Just wondering?

Jimooo · 06-11-2013, 07:36 PM

When you can amp the compressors when
running to see what they are pulling.

I could be the high pressure switch shutting both compressors down, you can bypass it by jumping out around switch to eliminate that , but do not leave jumped out it could short compressor motor.

It might be short cycling due to low freon charge?

Hope this helps,

James

Bug512 · 06-11-2013, 07:48 PM

Being that there are two separate circuits there would be two pressure switches, probably internal to the compressor, if one was to open there would be enough heat displacement off the condenser to keep the other compressor running.

Low charge, most of the time (on a small system) when there is a leak the charge is gone.

Personally I would call technical support and have a meter handy.

Iwillbeit · 06-11-2013, 08:41 PM

You might consider checking the water drain on the evaporators. I know my home unit quits when the drain is clogged and the water backs up. I can only assume that your MH heat pump has a similar safety switch . Just a guess on my part. Please keep us updated on what you find out. I have good friend that has an 04 with the same basement ac. I know he will be interested in what the problem is. Good luck!

fputnam · 06-11-2013, 10:39 PM

We have a 7.5 kW generator so it can handle a 50 amp load just fine. With both compressors running they draw about 20 amps which seems to be normal for this unit.

The only other thing operating at the same time is the battery charger.

Today I again watched the EMS panel to see if the amperage spiked just before both compressors shut down. It didn't.

So now I'm back to wondering if it's a high pressure switch or maybe a dirty coil. The coils seem fine, maybe I just don't see the dirt.

Bug512 · 06-12-2013, 04:10 AM

With two compressors running you should be up around 27-29 amps depending on ambient air temperatures.
Sounds like one of the compressors is running flat (no charge).

I recently had a crack in my condenser on circuit #1, while I had the unit out I also noticed that the indoor blower had worked it's way loose and was not distributing all the air into the ductwork.

Your best bet is to call technical service and or a HVAC shop. See if you can download the technical information for the service technician.

Jimooo · 06-12-2013, 06:27 AM

Maybe you should call a HVAC service tech, sounds like the charge is low, he would have to install a high and liquid side taps to check charge, lock unit and pump down freon, also clean coils with proper coil cleaner, check fan clearance and clean blower.

Good luck,

James

Boris and Natasha · 06-12-2013, 07:16 AM

We had a problem with our basement air for 14 months. (Took it to Forest City for repairs, to no avail!) We finally had success in Loveland, CO...north of Denver...at DM Mobile RV Repair. We highly recommend! They have a shop where they can handle big jobs. Don is quite knowledgable with these basement air systems, and is very familiar with the folks at Coleman/RVP. He also has a residential AC guy he works with who will do refrigerant work, if needed. (We couldn't find anyone else in the Denver metro who would tackle that.) Good luck!

NeilV · 06-15-2013, 01:52 AM

You didn't see a high draw so it would seem it is not the most common issue with the starter discs on the capacitors. You would also hear the heavy pull on the generator if that was the case. If you read the trouble shooting docs on the website you will get the info you need to read the diagnostic indicator lights inside the control panel of the basement air unit. Still verify that it is not an issue with low voltage from the generator or transfer switch. All of my issues with the basement air stopped happening once I installed brownout protection (auto former) in my coach.

fputnam · 06-16-2013, 09:23 AM

We certainly appreciate all the responses we've received. Based on a suggestion from Eric we have determined that the high speed OD fan is not working based on an auditory analysis. Today I hope to once again open up the side panel and watch the led indicator lights to see if I can narrow down the problem a little more. Maybe I'll get lucky and it's just a bad relay. Otherwise I have no idea how to access the OD fan without dropping the whole heat pump unit.

My fallback fix is an appointment with DM RV in Loveland on the 25th.

NeilV · 06-16-2013, 09:56 AM

I believe that there is a pillowblock with a bearing that requires lubricating on the outside blower however if you do not have an AutoFormer brownout conditions at most campgrounds do burn out the hard start units on the motor start capacitors which can also prevent the blower from getting up to speed. The black plastic covers on them may or may not appear melted when they go. If the fan tries to start and just buzzes then it is most likely the hard start device however they should be replaced as a set with the capacitor.

Hopefully it is something simple in the control panel and not a mechanical failure that will require dropping the unit.

Doug Sage · 06-16-2013, 05:07 PM

I would strongly recommend you go to Turbos Mobile RV Service in Monument, CO. 719-487-9119. They know what they are doing with basement air conditioners. Your heat pump has two radiators or coils: The one you can see through the grill on the side of your RV. The other is hidden inside. Mine had the same problem you are describing and they took the unit out and discovered that the indoor coil was very dirty and moldy. They cleaned it thoroughly and it has run fine ever since.