Basement air problem

[fputnam]

OK, here is the latest. I've run through the trouble shooting diagnostics as outlined in the 6537 manual. The proper led lights are coming on when the are supposed to and I'm reading the proper voltages on T11,T12, and T13 terminals. But, I don't hear any difference in the out door fan speed. After the second compressor comes on everything shuts down within 2 minutes. The line voltage drops from 122 to 120 volts when the #2 compressor fires up.

The outdoor temp was about 65 degrees today so I'm reluctant to blame an overheated condenser coil. Also the piping in the condenser coil is just warm to the touch, not hot. Maybe a blockage in the 2nd compressor piping?

Whatever speed the OD fan is running at, it starts flawlessly. So I don't think a capacitor is a fault. I would swap ID and OD fan capacitors but they have different part numbers so I assume different capacitance. So that's out.

Also remember I'm running off the generator so brown outs are not an issue here.

And, currently my only source for parts is NAPA.

Any more ideas?

[Bug512]

Personally I would call technical support.

[Obiwan35]

Originally Posted by fputnam

OK, here is the latest. I've run through the trouble shooting diagnostics as outlined in the 6537 manual. The proper led lights are coming on when the are supposed to and I'm reading the proper voltages on T11,T12, and T13 terminals. But, I don't hear any difference in the out door fan speed. After the second compressor comes on everything shuts down within 2 minutes. The line voltage drops from 122 to 120 volts when the #2 compressor fires up.

The outdoor temp was about 65 degrees today so I'm reluctant to blame an overheated condenser coil. Also the piping in the condenser coil is just warm to the touch, not hot. Maybe a blockage in the 2nd compressor piping?

Whatever speed the OD fan is running at, it starts flawlessly. So I don't think a capacitor is a fault. I would swap ID and OD fan capacitors but they have different part numbers so I assume different capacitance. So that's out.

Also remember I'm running off the generator so brown outs are not an issue here.

And, currently my only source for parts is NAPA.

Any more ideas?

There are two spades at the bottom of your printed circuit board labled Outdoor Common and Outdoor BLWR HIGH. Common is a heavy white wire and the HIGH is a heavy red wire. You should have 120 between these with both compressors running, otherwise your high blower outside is not getting power. The compressors then overheat and the unit shuts down. The techy's at Air Excel are excellent. Eric, especially. I had the same problem but when both compressors were called for, my outdoor fan completely shut down. Traced it down to an open on the HIGH fan wiring. The Outdoor BLWR High, to be specific.

[Duner]

Originally Posted by fputnam

OK, here is the latest. .........

Any more ideas?

Frank, if you have to pull your unit out, I have a procedure I documented with photos. You can download it here. You would be surprised at how easy it is to pull out and work on your own unit ....and save $500-1000. It's been 5 yrs now and many forum members have had great satisfaction by fixing it themselves and set me thank you's.

Since yours is a diesel pusher & mine is a gasser, I believe you just lower supporting brackets and then it slides out like mine. You don't have to disconnect any power or control wires, so that you can test and troubleshoot the unit with the lid off. Take a look at the procedure and size it up, you may decide this is something you can handle. If you end up with a refrigeration problem, most mobile A/C guys can work on it pulled out and not charge for the labor to get at the parts.

Good luck,
Bill "Duner"

[Bug512]

Thanks Bill. I pulled mine out a couple of weeks ago. Your instructions are great !

[NeilV]

Originally Posted by fputnam

OK, here is the latest. I've run through the trouble shooting diagnostics as outlined in the 6537 manual. The proper led lights are coming on when the are supposed to and I'm reading the proper voltages on T11,T12, and T13 terminals. But, I don't hear any difference in the out door fan speed. After the second compressor comes on everything shuts down within 2 minutes. The line voltage drops from 122 to 120 volts when the #2 compressor fires up.

The outdoor temp was about 65 degrees today so I'm reluctant to blame an overheated condenser coil. Also the piping in the condenser coil is just warm to the touch, not hot. Maybe a blockage in the 2nd compressor piping?

Whatever speed the OD fan is running at, it starts flawlessly. So I don't think a capacitor is a fault. I would swap ID and OD fan capacitors but they have different part numbers so I assume different capacitance. So that's out.

Also remember I'm running off the generator so brown outs are not an issue here.

And, currently my only source for parts is NAPA.

Any more ideas?

Brown out damage is accumulative from when you were on weak shore power. Once done even on the generator you will still have the damage dragging on the system. It could be getting a high draw going to the high speed mode on the outside fan.

[Obiwan35]

Originally Posted by Duner

Frank, if you have to pull your unit out, I have a procedure I documented with photos. You can download it here. You would be surprised at how easy it is to pull out and work on your own unit ....and save $500-1000. It's been 5 yrs now and many forum members have had great satisfaction by fixing it themselves and set me thank you's.

Since yours is a diesel pusher & mine is a gasser, I believe you just lower supporting brackets and then it slides out like mine. You don't have to disconnect any power or control wires, so that you can test and troubleshoot the unit with the lid off. Take a look at the procedure and size it up, you may decide this is something you can handle. If you end up with a refrigeration problem, most mobile A/C guys can work on it pulled out and not charge for the labor to get at the parts.

Good luck,
Bill "Duner"

Bill,
Have gotten real good at R & R ing my basement unit, thanks to your pioneering. Found an open in my High side outdoor fan. All systems go and have a spare motor in stock. We can hang meat within.

Jay Skinner
2001 Winnebago 40J
Ultimate Advantage

[HD4Mark]

Originally Posted by Duner

Frank, if you have to pull your unit out, I have a procedure I documented with photos. You can download it here. You would be surprised at how easy it is to pull out and work on your own unit ....and save $500-1000. It's been 5 yrs now and many forum members have had great satisfaction by fixing it themselves and set me thank you's.

Since yours is a diesel pusher & mine is a gasser, I believe you just lower supporting brackets and then it slides out like mine. You don't have to disconnect any power or control wires, so that you can test and troubleshoot the unit with the lid off. Take a look at the procedure and size it up, you may decide this is something you can handle. If you end up with a refrigeration problem, most mobile A/C guys can work on it pulled out and not charge for the labor to get at the parts.

Good luck,
Bill "Duner"

Bill,
We have used your write up a few times to pull our Coleman. Had it out at least 3 times and used the part numbers to replace the OD bearing, motor and squirrel cage. Ours is a DP and you are correct about lowering the bracket. There is a large bolt on each side that a little WD-40 will help with then just crank them down until you can remove the metal plate on the top. The wiring can be left connected and then pull the unit out far enough to work on. At a CG we dragged a picnic table over and put some leveling blocks on the bench to support it.

Thanks for the instruction they were priceless when removing it the first couple of times. Now we are getting to be experts

[Ramzfan]

Originally Posted by Bug512

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.

I never exceed 20 amps with my air conditioner only, even when both compressors are operating.

[Bug512]

For the model 6535-671 the total is 24.7 Amps, this is both compressors running and the fan speed on high.

My replacement condenser comes in next week so I will have two operational stages again. With two compressors running but only one having a charge I was at 20 amps.

Here is the data sheet.

[NeilV]

Originally Posted by Ramzfan

I never exceed 20 amps with my air conditioner only, even when both compressors are operating.

That is entirely possible depending on the outside temps and such. They are not always going to draw max amps. Usually when you see max amps being drawn consistantly you are probably in extreme temps or plugged in to a system with low voltage or suffering a brown out.

Browout/Low Voltage is probably the #1 cause of AC failure in motorhomes as far as I am concerned. To me a brownout protection device such as the Hughs Autoformer which boosts low voltages back to where they should be is about the best investment an RV owner can make.

[Duner]

Originally Posted by NeilV

That is entirely possible depending on the outside temps and such. They are not always going to draw max amps. Usually when you see max amps being drawn consistantly you are probably in extreme temps or plugged in to a system with low voltage or suffering a brown out.

Browout/Low Voltage is probably the #1 cause of AC failure in motorhomes as far as I am concerned. To me a brownout protection device such as the Hughs Autoformer which boosts low voltages back to where they should be is about the best investment an RV owner can make.

I agree 100% with Neil.

Also the newer composite plastic squirrel cage for the outdoor blower drops the current demand by about 1 amp as compared to the original metal one. It is so much quieter now out under the patio awning, it's a very good investment/upgrade.

[NeilV]

Some folks only put in a SurgeGuard however when it shuts you down for low voltage and its getting near to or past 100 degrees out most people are going to hit the bypass and run the AC anyways.

I lost the inside blower motor and the hard starts on the compressors during one trip up the East Cost due to brownouts during a heatwave in 2006 and got the Hughs Autoformer immediatly afterwards. I have not had another problem with burnt out equipment since then.

[jerichorick]

A common problem is the starter capacitor. That will definitely trip the breaker if it shorts. Pulling the basement air out can be a challenge because of the back riser plenum. Once that is free the unit should come down without hanging. I recommend separating the first joint of the plenum than retape when you put it back in place. Tape falling off is another common loss of efficiency but not related to your problem.

Hope this helps.

Rick

[CPO_Retired]

Have you found what the cause of your problem is?

I had the exact same problem and it was caused by compressor #2 burning up. Any good HVAC person can repair it. If you like to repair your motorhome you can remove the AC unit and have the HVAC guy replace the compressor. That is what the RV repair place is going to do.

[fputnam]

Thanks for all your suggestions and help. The way the story ends is that the factory determined both the indoor and outdoor fan motors were failing. The indoor fan was not moving enough air thus causing the freeze probe to open and shutting down the whole unit.

The outdoor fan motor squealed on startup as it has done for the 4 years we have owned the coach. Dumb me, I thought it was sheetmetal vibrating when the compressors started.

Also the outdoor fan and coil compartment was filthy. Of course there is no way to clean it without dropping the whole heat pump unit.

So two motors and one unit cleanup later we are back on the road and once again cool and quiet. Thank you DM RV in Loveland, Co.

[Bug512]

Thanks for the update. Glad you are all fixed up.

[Boris and Natasha]

Glad to hear Don and Mary Ann got you fixed up and chillin' again.

Safe travels!

Mary

P.S. Someone in this thread mentioned Turbo's. They are an RVP recommended tech on the Front Range, and we had them look at our basement AC last summer. Really nice folks. But, they don't do refrigerant work, so they couldn't help us. That's when we sought out DM RV Repair in Loveland. They got us fixed up.

[sgtstriker]

This may have just solved my mystery. My A/C repair guy insists that my system is working properly although it never cools my rig down sufficiently when the ambient temp is above about 80 degrees. Friday I was at his shop and he showed the temp differentials between air entering via the filter and what was coming out of the roof registers. There is about a 20 degree variance - at his shop - in the shade. But, he said that he had had the system running for about three hours and when we exited the rig I looked for condensation on the ground. There was not a drip. The service guy was a little confused at that point. I am awaiting another call from him as I type... It would be interesting if opening a drain ends up solving this problem.

[Bug512]

Sounds like the condensate drain is plugged or you are in e very dry but hot environment.