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Air conditioner blowing hot then cold

My front roof air conditioner has started blowing cold air for 5 minutes then blowing hot air (as if it switched to heat pump) then back to cold.  It cycles back and forth about every 2-3 minutes. The rear airconditioner works fine so we swapped the circuit boards but that mad no difference. Has anyone else run into this? 

2003 U320
Jim churchill
2003 U320 40'
2016 Jeep Wrangler

Jim

Re: Air conditioner blowing hot then cold

Reply #1 –
Quote from: Skillagalee –
My front roof air conditioner has started blowing cold air for 5 minutes then blowing hot air (as if it switched to heat pump) then back to cold.  It cycles back and forth about every 2-3 minutes. The rear airconditioner works fine so we swapped the circuit boards but that mad no difference. Has anyone else run into this? 

2003 U320
Jim churchill
You have a reversing solenoid valve that changes unit from ac to heat pump. Coil often becomes weak and need replacing. Remove cover and you will see it. Only solenoid on unit. Coil is $15 or so.
Jim C.
coachfree, previous 1997, 1999, 2000, and 2003 Foretravels.

Re: Air conditioner blowing hot then cold

Reply #2 –
that can also be caused by the connectors that come from the thermostat and go up to the top board. You might try by unplugging the connector and cleaning with some contact cleaner. That is what I found was wrong with ours.
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins

Re: Air conditioner blowing hot then cold

Reply #3 –
Is the solenoid on the circuit board or by the compressor?
2003 U320 40'
2016 Jeep Wrangler

Jim

Re: Air conditioner blowing hot then cold

Reply #4 –
It is by the compressor.
previous 1984 35 ft ORED 250 HP 3208 Cat       
previous 1998 40 ft U295 CAI 325 hp Cummins
previous 2003 40 Ft u320 build #6140 450 Cummins M11.                                                         
1999 Mazda Miata
Ron, Nancy, Tipper the cat, Max The dog
1997 U 270 36 ft build number 5174 8.3 Cummins

Re: Air conditioner blowing hot then cold

Reply #5 –
Quote from: Skillagalee –
Is the solenoid on the circuit board or by the compressor?

It is on maybe a 3/8 inch freon line under the cover on your top unit.. Coil has two wires coming from it. The square [or sometimes round thing on top] is the coil. It is held onto the valve by a clip on top.
This is basically what it looks like. Most AC shops, or electrical supply places will have just the coil. Air, Oil and Water Solenoid Valves - Grainger Industrial Supply
Take you old one with you to match up.
Jim C.
coachfree, previous 1997, 1999, 2000, and 2003 Foretravels.