Adventurer 35U Basement AC Troubleshooting

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John Canfield

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The thermistors aren't a 'switch' - their resistance varies with temperature. They send a 'signal' to the thermostat that either the condenser or evaporator are frozen.

My basement air model number is 6537C871 and it is no longer available as a complete unit.
 

DBarton02

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Would jumping the blades on the board not work to determine if they're bad?
How would you be able to know for sure they were faulty?
 

Ray-IN

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I've never had a problem with my board -(yet), so have not had a reason to do any testing. Sorry I'm not any help. John knows more than I about the electrical end on the unit.
 

Ray-IN

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I just remembered a similar problem I had when we bought this MH. #2 compressor would not run. Turned out the wire terminals at the controller were severely corroded, cleaned them up and the unit has run fine ever since.
 

cbeierl

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...
As far as replacing the entire unit, the side discharge type is not available but the top discharge still is available. ...
Are you sure about that, John? My understanding is that the discharge (i.e. the outgoing cold air) in on the (left) end of all of these units (connecting to the ducts going up the rear cap) and the air intake is either on the top [6537-] or on the (back) side [6535-]. The model with the top intake is the one no longer available (and the one I have :( ).
 

John Canfield

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Are you sure about that, John? My understanding is that the discharge (i.e. the outgoing cold air) in on the (left) end of all of these units (connecting to the ducts going up the rear cap) and the air intake is either on the top [6537-] or on the (back) side [6535-]. The model with the top intake is the one no longer available (and the one I have :( ).
Fairly certain Chris, replacing my entire unit was my first choice but not available - at least 18 months ago.
 

cbeierl

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Fairly certain Chris, replacing my entire unit was my first choice but not available - at least 18 months ago.
The Parts Catalog for your 40AD shows that you have the same 'top return' (6537-) unit that I have:

1* 105620-16-000 EA A/C - CENTRAL - RIGHT HAND/HEAT PUMP - TOP RETURN

That's the unit that no longer available. Whereas the OP has the unit with the side/back return (6535-), according to the Parts Catalog for his coach:

2* 105620-12-000 EA A/C - CENTRAL - RIGHT HAND/HEAT PUMP - 12,000 BTU COMP - W/HEAT PUMP
 

cbeierl

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Just fyi, the 2004 Horizon 40AD DOES have the unit with the side/back return (6535-) (see Parts Catalog) and has some add'l ductwork that brings the air return to the top. But, at least according the the Parts Catalogs, they switched to the top-return model for the 2005 model year.
 

John Canfield

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Ah-so. Mine is top return which is unobtanium, lucky me. Thanks for the clarification Chris! I've mentioned it previously but Winnebago's solution for a complete replacement of mine is roof airs. Or roof airs when and if the other version is an orphan. Hopefully parts will continue to be available for years to come, the capacitors should be available for a long time as they aren't unique.
 

Ray-IN

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Ah-so. Mine is top return which is unobtanium, lucky me. Thanks for the clarification Chris! I've mentioned it previously but Winnebago's solution for a complete replacement of mine is roof airs. Or roof airs when and if the other version is an orphan. Hopefully parts will continue to be available for years to come, the capacitors should be available for a long time as they aren't unique.
I understand replacement compressors are the same as my 6535.
 
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John Canfield

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Yes, in fact I had one compressor replaced a few months ago due to noise (really loud noise) it was making. Probably a broken suspension spring causing the guts to rattle against the shell.
 

DBarton02

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Update on this whole saga - :ROFLMAO:

Gave the portable AC Unit a run with a small trip we took with our boys to Michigan City this past weekend... and it did NOT Cool us off one bit! 10,000btu's on a floor unit, vented out the driver window, and we enjoyed 90 degree temps in the coach all weekend, but still had a BLAST!

At any rate - my success rate at finding a supplier with a new unit in stock fell flat on it's face with the supply and manufacturing issues - though I did expand my search a bit and was able to find a unit that was taken out of a salvaged coach ('05 model) 6535-871 with the side discharge.
It was tested for both cooling and heat, works as it should, has been paid for and set to be shipped (hopefully will receive it early next week for install!)

Seller confirmed left-side discharge of the vent, which is what I have. Only issue or worry I have is my current unit is the 6535A871, and this one is the 6535-871 - though by my reading so far, this shouldn't really have an effect on its functionality in the coach.

Here's hoping to have ACTUAL AC working by the 4th of July weekend!

Now I just need to flush out my water heater to get rid of the rotten egg smell we discovered after getting set up this weekend.

Previous seller didn't flush out from his earlier spring trips - so we've got a little more cleaning to do!
 

John Canfield

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I guess you gave up the idea of replacing the control board?

When you get the salvage unit, I would replace the caps and replace the fan bearing with a sealed version as Chris mentioned in this thread or the other one currently active. Run the unit on the ground and be sure it works well. Clean/flush the coils with coil cleaner.

Good idea to flush the water heater tank - that should be an annual event. There is a special wand about 12" long made for this or you can make your own out of 1/4" copper tube.
 

DBarton02

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Will do. Place I am purchasing it from did a full test to ensure proper heating and cooling, and are offering a 30 day guarantee. Gentleman I've been speaking with said they were going to replace all the capacitors as well.

Will be sure to go over it again and clean where needed.

To answer your first question - yes... I sort of gave up on the board replacement idea knowing I couldn't even get the 1st compressor to kick on even when bypassing the board. The more troubleshooting done lead me to the likely conclusion that there was more than one problem with this - and if I drop $200 on a new board, I still may be looking at another $700-$800 for a new compressor - and If I replaced one compressor, I might as well do the other one, which would put me up to close to $2,000.00 in total parts (before any factored time for labor).

Was less to purchase a tested unit and have it shipped.

Still a rookie with all this stuff, but I'll tell ya - this kind of stuff helps you learn quick!
 

Ray-IN

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I cannot answer your wiring question except to say, my #2 compressor would not run when we bought our MH, I found corroded terminals on the wires to the compressor. I cleaned them, reattached them and #2 compressor still runs fine today. I haven't had to mess with mine since 2013 so I've forgotten most of what I did.
BTW, here is the service parts list for your model: https://www.arvparts.com/coleman_mach_6535-671_parts.pdf
Blower fans, pillow bearings, compressors, etc are all aftermarket products if you need the links.
When you go to remove the unit this might be helpful: Basement A/C removal and repair by "Duner" of irv2.com
 

DBarton02

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Update to the saga - and man am I appreciative of all this information!

My tested salvage unit was delivered to me from AZ RV Salvage in Glendale, AZ on Friday.
My HVAC guy and I set aside today as the install date, and we got to work on it this AM. Following all the previous user instructions, we got the old unit out and new unit mounted up in testing position with little issue - though when connecting all power to it and running the initial test, compressor 1 did not kick on, though after the minute or so time gap, #2 fired up no issue and started blowing cold (HOORAY! - sort of).
After a few line tests, we discovered that COMP1 is completely grounded out, as it kept throwing the circuit on the generator when we'd do a direct test - further line testing show it completely out of whack (OHM readings) when adding everything up.
They claim to have tested it, but when the unit arrived, they had 2 jumper wires on the white and black lines for 120v circuit 1 and 2. HVAC guy said they wouldn't have tripped anything with the jumper on - as it should have been tested individually. As it stands, I've contacted the seller to lay out the issue and see what they'll be willing to do - as at this point, we either put in a new compressor and all is set to go, or we see if they have one in stock that has both functioning compressors and they verify to ship out to me in a swap.
SO - sort of back to square 1. At least at the moment, I get 70 degree air blowing off compressor 2, just not enough to really cool it down.

Double bonus - my tech will run through the unit we pulled out to see what can be done with it.

Getting there... little by little...

John Canfield - I kept seeing your trust but verify post flashing in my head as we were getting it set up
:)

Will update when I get a response from them.
 
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