Basement AC won't turn on

[Deucenut]

Hello. I have a 2005 Winnebago Journey 39K. Today I went over to my coach to do some monthly maintenance and charge up the batteries(its at a storage location that doesn't have plug-in's) So I started the generator and it ran fine. To put a load on the generator as well as exercise the basement AC systems, I went to turn it on. The inside temp of the coach was 58, so I pushed the button to "COOL" and lowered the "Set" temp to about 40 thinking that would be enough of a difference to get the AC to come on. I waited about 5 minutes and it never came on. So I pushed the button to furnace and ran it for 10 mins. Then I ran it on Electric Heat for 10 mins. No problems there. By now the temp inside the coach was 68. So I switched it back to cool(after the furnace had shut off on its own). I lowered the temp and waited for another 5 mins. Nothing happened. Then I switched the Fan switch to On from Auto. It started to blow coolish air from the vents, but it I don't think the AC came on as I didn't see a change in the number of amps being drawn on the EMS readout.

Anyone have any suggestions? Am I doing something wrong or do you think it has just quit on me? Thanks

[glenda1908]

We had this happen once in our 08 Vectra, only it's the heat that wouldn't cut on. I called our tech in a panic cause I thought we would have to spend the weekend wrapped in blankets. He had me turn on the air let it run, turn it off then turn on the heat. I had to do it a couple of times before it kicked on. He said if it hasn't been used in a while...and it hadn't....the ?? I forget the name, sticks and you have to switch it back and forth to get it to come on. Not sure this will help you, but it worked for us Good Luck.

[DancinCampers]

If nothing came on in the cool mode I would first look at tstat. When switching to cool I would whiggle the switch a couple of times to ensure good contact. Then listen for the tstat to click. If it clicks you might have a bad relay on the pc board.

[Deucenut]

Originally Posted by DancinCampers

If nothing came on in the cool mode I would first look at tstat. When switching to cool I would whiggle the switch a couple of times to ensure good contact. Then listen for the tstat to click. If it clicks you might have a bad relay on the pc board.

Yes I did hear the Tstat click. Twice actually. But still nothing happened.

[DancinCampers]

Sounds like tstat is closing contacts for 1st and 2nd stage cooling.

If your comfortable with using a meter, 1st click should show +12vdc on yellow wire, 2nd click should show +12vdc on orange wire, on lifeline from tstat. -12vdc I believe is on blue wire.

If you are getting voltage there, then move to basement pc board to check there.

I have pubs available for my previous unit and can email them if you PM your email.

[mel s]

Air conditioner compressors don't like cold temps.
I would never expect an air conditioner to operate if it is only 58 degrees.
They are designed to cool the air when it's to HOT, they're not made run to when it's COLD.
My 2 cents

[ChasA]

What Mel said X2.

[ChasA]

Cannot wait until it's warm enough to actually use the air conditioner.

[Deucenut]

Originally Posted by mel stuplich

Air conditioner compressors don't like cold temps.
I would never expect an air conditioner to operate if it is only 58 degrees.
They are designed to cool the air when it's to HOT, they're not made run to when it's COLD.
My 2 cents

Ok I'm sorry, but this is the silliest thing I have ever heard. I have turned on the AC in my vehicle in the winter to exercise it and it worked fine. I was just with my father, who was exercising both roof top AC units in his motorhome and they worked quite well. Blew very cold air. To say it won't come on because it isn't warm enough? These things have seals in them etc that shouldn't be allowed to sit and not get used for long extended times(6 months etc) Anyway, I guess I am going to have to take it to the dealer to have it looked at. The last thing I want is for the warm season to come and then my motorhome is laid up at the dealership waiting for parts/getting repairs done and we can't go camping. Thanks everyone.

[Catch14me]

On an RV I previously had we had the same type of problem with the roof AC/heat pump and it was a reversing valve or solenoid that was responsible. On the roof unit it was not an expensive or difficult part to replace. Please let us know what you find out when you take yours in for repair.

[Hikerdogs]

Originally Posted by mel stuplich

Air conditioner compressors don't like cold temps.
I would never expect an air conditioner to operate if it is only 58 degrees.
They are designed to cool the air when it's to HOT, they're not made run to when it's COLD.
My 2 cents

The basement air/heat pump uses the same compressors for both heat and cooling. It should be able to provide heat down to approx. 37*F. The only difference between heat and cooling on this system is the way the refrigerant runs through the system.

Here's an over simplified explaination of how the system works as I understand it:

When in the cooling mode the compressors take low pressure gas returning from the (evaporator) coils inside the coach and turns it into a high pressure gas. (Compressing the gas also causes it tobecome heated) The hot high pressure gas then passes through the outside (condenser) coils and is condensed into a high pressure liquid.

The high pressure liquid continues through the system to an orifice/expansion tube. At this point the high pressure liquid is changed back into a low pressure gas. As the refrigerant expands back to a gaseous state it cools rapidly. The cooled gas then completes the cycle by passing through the evaporator coils inside the coach. Fans blow across the cooled coils cooling the air that enters the passengers comparment.

The only difference between the heat and cooling mode is the direction the refrigerant runs through the system. When in the heat mode a switching valve changes the direction of flow making the inside coils become the condenser and the outside coils become the evaporator. Since the inside coils now are filled with compressed and heated refrigerant air blown over them by the fans now heats the interior of the coach.

The reason the heat portion of the system only works down to about 37* is that the cooler outside coils frost over at about that temperature. Once that happens refrigerant flow is restricted and the system rapidly looses it's efficiency.

[Deucenut]

So I got my motorhome back from the dealership and they tell me the AC won't work if it is too cold outside. This still doesn't make sense to me as my dads's rooftop AC works no matter what the temperature outside is. Sooooo...Can anyone tell me what the temperature outside needs to be for the AC to work?

[94-Newmar]

I do know that AC units specifically designed to run in subzero temps such as in Data Centers, Cell tower stations, etc have a bit different setup to keep the head pressures in the system up, slower condensor fan speeds, etc etc. Generally though, anything above freezing is still ok in most systems. It is plausible the manufacturer of your unit is preventing compressor startup in low ambient temps. I think a call to the manufacturer of the AC unit is in order to clarify it for you.

[DancinCampers]

I would check the indoor coil thermistor. You could jumper it on the control board.

If it is good, check the tstat pigtail.

[Deucenut]

So today it was a little warmer outside. Temp inside the coach said 57. So I decided I would try the AC. Turned the thermostat down to 54, flicked the switch and it turned on. I was surprised, but thankful. After a 10 second delay it sounded like a click and something else turned on. Would that be the second compressor? Either way, I'm just happy it's working.

[Kingixolib]

Yesterday I turned on my Coleman basement model air conditioner........nuttin' happened.......except that the indoor fan would run...no compressors, no outdoor fan. In december we went to Disney and everything worked properly.

Went online and printed a maintenance manual for the Coleman 6535A671 unit. Started trouble shooting and found that the green light on the PCB was blinking rapidly which indicates that there is no power to circuit 1 or a thermister is open. I jumped T14 and T15 and bingo...everything works beautifully. T14 and T15 are connected to a thermister that controls the outside fan in the unit so that the air conditioner can't come on if it is too cold outside. This particular thermister is located deep inside the heat pump/airconditioner cabinet which requires removal of the unit to replace the scoundrel. Expensive and labor intensive . Thermisters have been a PIA for me and I am wondering.......now that I have T14 and T15 jumpered and my unit is working well........why do I need that thermister?

[David K]

Originally Posted by Deucenut

So today it was a little warmer outside. Temp inside the coach said 57. So I decided I would try the AC. Turned the thermostat down to 54, flicked the switch and it turned on. I was surprised, but thankful. After a 10 second delay it sounded like a click and something else turned on. Would that be the second compressor? Either way, I'm just happy it's working.

The second "turn on" was indeed the 2nd compressor starting up. This delay is normal.

[Deucenut]

Originally Posted by David K

The second "turn on" was indeed the 2nd compressor starting up. This delay is normal.

Good to know....thank you for the information. I was thinking it was the second compressor but just wanted confirmation.