Basement AC Sanity Check - Page 2

bruceh · 07-31-2014, 06:21 PM

Quote:

Originally Posted by 1ciderdog

I don't want to sidetrack the thread to much but I have a basement air question. The compressors are very loud on my basement air. I've been in RV parks and walk by other Winnebagos with basement air running and they are not loud. It is not the fans - I can turn the fans on and the sound is not bad but the "roar" of the compressors is not good. Is this normal on older (2004's) or do I need to pull the unit and have the compressors rebuilt/replace? Oh, they do provide cool air. Thanks for any thoughts, comments.

Its kind of a sidetrack.

There are two fans in the AC unit, inside and outside. When you turn on the fan from inside, you are (of course) turning on the inside fan. The outside fan that only runs for AC or heat is the noisy one. For this, you should look at Duner's write up.

You might be mistaking the noise from the outside fan for compressor noise.

1ciderdog · 07-31-2014, 06:31 PM

Bruce, Thank you for the response. I had no idea there are two fans. The inside fan you mention is in the basement unit, right? I'll read Duners write up and maybe answer my questions.
Again
Thanks

NeilV · 08-01-2014, 08:16 AM

Quote:

Originally Posted by bruceh

The thermostat has called for #1, it does not know that it hasn't started.

I was surprised by the voltage readings also. I measured at the run capacitor leads that go directly to the compressor motor. Nothing has been disconnected. When I get home, I will check again with a different meter.

They are staged start with a delay between them. Compressor 2 also should not start unless the temperature difference between set and room temp is greater than a few degrees. If compressor 1 fails to start the countdown on the time delay switch should not activate to start the second compressor. I have a straight cool with no heat pump and this is how it has worked for the past eight years.

bruceh · 08-01-2014, 09:58 AM

Quote:

Originally Posted by NeilV

They are staged start with a delay between them. Compressor 2 also should not start unless the temperature difference between set and room temp is greater than a few degrees. If compressor 1 fails to start the countdown on the time delay switch should not activate to start the second compressor. I have a straight cool with no heat pump and this is how it has worked for the past eight years.

The sequence that I am observing is:

One degree difference between set point and ambient, indoor and outdoor blowers start, compressor #1 relay engages, voltage appears on the run capacitor, compressor #1 does not start.

3 degree difference + , same as above but compressor #2 relay engages and compressor #2 starts, outside blower goes to high speed.

There is no feedback mechanism to the thermostat. It makes a call and assumes that its demands are carried out. It has no idea of the actual status of compressor #1. Look at duner's thermostat conversion chart for the wiring.

I have run this experiment numerous times and tried reversing it for heat with the same results.

bruceh · 08-01-2014, 10:25 AM

Quote:

Originally Posted by bruceh

In case anybody else needs it, the part # for the thermostat is:

6535-3442

I used an amazon.com search for that part # and found 4 vendors.

Correction, it was ebay.com.

DancinCampers · 08-02-2014, 12:24 AM

The difference between the heat and cool mode is that in the heat mode, all fan/compressor activation is controlled by the pc board, not tstat, once the tstat calls for heat. Both compressors always operate in heat mode, you should not have to raise set point to turn on the 2nd compressor. Indoor and outdoor fans should run in hi speed mode.

Also, if the #1 compressor tries but does not start, it will trip its internal overload, and you should see a pattern as it continues to try to start.

Once you call for heat on the tstat, the amp display, if on 30amp or gen, should start low, then higher for compressor 1, then higher as #2 starts.

In the cooling mode, turn off the breaker for #2 compressor, and see if you get any cooling on #1.

Have you swapped out the start capacitors.

NeilV · 08-03-2014, 07:56 AM

Quote:

Originally Posted by bruceh

The sequence that I am observing is:

One degree difference between set point and ambient, indoor and outdoor blowers start, compressor #1 relay engages, voltage appears on the run capacitor, compressor #1 does not start.

3 degree difference + , same as above but compressor #2 relay engages and compressor #2 starts, outside blower goes to high speed.

There is no feedback mechanism to the thermostat. It makes a call and assumes that its demands are carried out. It has no idea of the actual status of compressor #1. Look at duner's thermostat conversion chart for the wiring.

I have run this experiment numerous times and tried reversing it for heat with the same results.

The mechanism is internal to the Basement unit. The thermostat only sends that there is more than 2 degrees differential and signals for the 2nd compressor to start. A call to AirXcell to talk to a tech would not be a bad idea. What do the diagnostic lights on the control board inside the basement air unit indicate?

bruceh · 08-04-2014, 10:25 AM

Quote:

Originally Posted by NeilV

The mechanism is internal to the Basement unit. The thermostat only sends that there is more than 2 degrees differential and signals for the 2nd compressor to start. A call to AirXcell to talk to a tech would not be a bad idea. What do the diagnostic lights on the control board inside the basement air unit indicate?

The green LED is on as long as I have 110. The blower low speed red LED is on when only compressor #1 is called for. When #2 is called, the high speed blower red LED is on. That's it for LEDs on the board.

What I find more interesting is that the appropriate relays are engaged for compressor operation. When compressor #1 relay is engaged and the compressor does not engage, this tells me that the circuitry is doing its job and that the problem is closer to the compressor; e.g. capacitors, overload, compressor motor.

I will still replace the thermostat to repair the intermittent #2 problem.

bsamole · 08-05-2014, 10:01 AM

I have a 31 page PDF service manual for Coleman model 6535 series. I don't know how to post a PDF file if you want it let me know how to send it.

bruceh · 08-05-2014, 10:25 AM

Quote:

Originally Posted by bsamole

I have a 31 page PDF service manual for Coleman model 6535 series. I don't know how to post a PDF file if you want it let me know how to send it.

I have that manual.

Thank you.

bruceh · 08-06-2014, 04:02 PM

Replaced the thermostat this morning. No change on system #1 and #2 still runs although it should continue to run.

I have pulled the unit out and swapped the overload from #1 to #2 with no change. Measured the resistance on the compressor motors and they are the same.

I don't know how to check coolant on these things. Sounds like either coolant or bad compressor.

wagonmaster2 · 08-06-2014, 06:29 PM

Quote:

Originally Posted by bruceh

In case anybody else needs it, the part # for the thermostat is:

6535-3442

I used an amazon.com search for that part # and found 4 vendors.

Does Winnebago use the same black Coleman-Mach True Air Residential Central Heat & Air thermostat for all their coaches, especially any with the Energy Management system? Will your part number match/fit the place the old one comes out of?
Really appreciate this as just today in 93-96 degrees in a campground I thought I had lost my #2 compressor. After reading about looking for the easy fixes first I wiggled the slide switch for Cool/Gas/Elec Heat and my #2 compressor came on. Now in just over 2 hours the inside temp has dropped from 82 down to 75. Man, what a relief.

wagonmaster2 · 08-06-2014, 07:35 PM

Quote:

Originally Posted by bruceh

In case anybody else needs it, the part # for the thermostat is:

6535-3442

I used an amazon.com search for that part # and found 4 vendors.

I found that number on Amazon for $143, is this a reasonable price or did you find a better one?

bruceh · 08-06-2014, 07:51 PM

Quote:

Originally Posted by wagonmaster2

I found that number on Amazon for $143, is this a reasonable price or did you find a better one?

ebay $119 + shipping is the one that I bought. If amazon includes S+H is will be a push.

Should be the same for all Winnys.

Be aware that you will be going from a 3 pin to a 4 pin. What I had to do is cut off the 4 pin and attach the leads to a 3 pin. Just match colors and you should be OK. The orange lead is not used.

wagonmaster2 · 08-07-2014, 10:19 AM

Quote:

Originally Posted by bruceh

In case anybody else needs it, the part # for the thermostat is:

6535-3442

I used an amazon.com search for that part # and found 4 vendors.

Is this the correct thermostat that will turn on the #2 compressor after the 2 degree change? I understand some will and others won't so since that seems to be my problem (the #2 compressor is intermittant about coming on after the temps change the 2 degrees or more) I want to be sure I'm ordering the correct thermostat. Really appreciate getting that part #.

bruceh · 08-07-2014, 10:32 AM

Quote:

Originally Posted by wagonmaster2

Is this the correct thermostat that will turn on the #2 compressor after the 2 degree change? I understand some will and others won't so since that seems to be my problem (the #2 compressor is intermittant about coming on after the temps change the 2 degrees or more) I want to be sure I'm ordering the correct thermostat. Really appreciate getting that part #.

Yes!

I was having two problems. Compressor #1 does not come on, not fixed yet.

Compressor #2 was intermittent and came on when I jiggled the thermostat, fixed by the new thermostat.

Note my correction to ebay not amazon.

bruceh · 08-07-2014, 02:13 PM

As a final check of my sanity, I swapped the wires on the compressors. The compressor #1 wires were too short to reach compressor #2 but the wires from #2 did reach #1.

When I fired it up, as expected indoor and outdoor fans started up and drew about 9 amps. When #2 was called for, the current surged briefly (just like when it was wired to #1) and settled in at 11 amps which would be the outdoor blower on high speed.

So as a result of this, I am pretty convinced that compressor #1 is not functioning. Either its motor is locked up or the Freon has leaked away.

This claims to be a sealed unit so I am kind of stumped for a next step.

I called all of the local residential AC repair places and none of them would touch it and, yes, I did tell them that this is a residential unit.

Unless I can figure out how to take the next step, I will have to take it to one of the RV places on the Airxcel web site. None of them are all that close, they don't seem to have parts in stock.

Any recommendations near Fresno, Salinas, Monterey or San Jose? Paul Evert in Fresno is off the table.

wagonmaster2 · 08-07-2014, 03:03 PM

That's really a bummer that none of the local residential AC repairmen would look at your unit. I had always heard if you had the unit out where they could reach it that any of them would check/work on it. I was about ready to panic when my #2 compressor wasn't coming on but after reading the Forum I started jiggling/wiggling the slide switch on the inside thermostat and #2 kicked in. Think I'd better get a new one on order but wanted to make sure it would be the one that calls for #2 when the temp changes 2 or more degrees.
I feel your frustration but thank you for all you information. And I know the feeling of having to go a distance for any work. 120 miles has been my shortest with 800 the longest to FC.
Good luck on your repair, and keep us all informed of your progress. Members like you having to find a fix is what makes this such a great Forum.

Duner · 08-07-2014, 08:35 PM

Bruce,

I had good luck locating a company that does mobile a/c repair for the Thermo King units on truck refer semi-trailers. I suggest calling a big truck repair shop in your area and find out the company that does the work on refrigerated truck trailers.

I had the unit out, lid off and on a stand that allowed the air to blow out the bottom so unit could run unimpeded for operational testing. I had a leak in a copper line, which he soldered, added a Schrader valve, pulled the vacuum and installed the freon......and was done in 45 min. $115 and I was back in action and once again a happy camper.

Good luck,
Bill

Starsekr · 08-08-2014, 01:00 AM

Is there some re-wiring that needs to be done to change from the obsolete 6535B3352 to the 6535-3442? Looking at the pin-out requirements in the 6535 service and maint. manual, and the wall thermostat brochure from RV Products, the freeze sensor contacts that go to pins 1 & 3 are not used, in fact pin 1 on the new thermostat connector is empty and pin 3 is listed as a generator auto-start.