A/C unit

I just had the Coleman Mach control module replaced under warranty (5 years). The relay points weld closed on some units and they will not shut off.

You have R-22.

Ken

What Freon do I have in that unit 2001 model

Often short cycling is a result of improper A/C installation. Had this problem with my new 5'er. Not sure exactly what dealer redid but had something to do with improper airflow between the A/C return side and the outlet side. If it bleeds air between the two sides then short cycling is a result.

Campinghoss@51 wrote:
I read your problem as the compressor cycling on and off quickly. If it is doing that then in all probability it is a Freon problem. If it is cooling normally then you will need to check different components to determine the cause.

I did not read that it was short cycling. There can be other issues that will cause the short cycling other than low refrigerant charge which need to be checked out first.

Check the air filters, evaporator (indoor) coil is clean. Also check for air bypassing in the unit, check for a clean condenser coil. Also, the compressor or motor could be going bad.

See it the compressor is cycling off based on the thermostat or on the thermal overload on the side of the compressor. Check the motor amps as well.

To check for refrigerant charge you have to tap into the sealed system with a temporary valve. Then find a leak, remove the charge, install permanent Schrader valves, evacuate the system and finally recharge it.

The OP did not tell us the age of the A/C unit. If it over about 8 years old, I would just replace it before I dumped a bunch on money into the unit.

Ken

A restricted cap tube, dirty cond coil, dragging blower motor or bad comp motor can make the comp cycle on the overload. Craig

I read your problem as the compressor cycling on and off quickly. If it is doing that then in all probability it is a Freon problem. If it is cooling normally then you will need to check different components to determine the cause.

Campinghoss@51 wrote:
Sounds like you are low on Freon. The compressor cycling on and off is not good. If the fan is on auto it is not going to cut off until the temp is satisfied.

Least likely problem, but most often posted by the inexperienced.

To check the unit fro proper operation, set it to high speed and set the T'stat to keep the unit running. Using a good grade of thermometer, Get the reading for the air entering the unit. Then take a reading at the closest outlet to the unit. Do not use an infrared thermometer as it reads the temperature of the surface and not the air.

The leaving air should be 18 to 20 degF colder than the entering air if the unit is OK.

If this checks, you are not low on refrigerant.

You may have a stuck relay that starts the fan motor.

Ken

Yes fan is in auto.

Halmfamily wrote:
Do you have the thermosats fan selection set to auto? If the fan is set to on it will not cycle off with the compressor. Good luck

X2