AC problem

[PamfromVA]

Roof top coleman AC/heat pump is blowing out hot air instead of cold. Are there a series of troubleshooting procedures that we could use to figure out what needs to be replaced? Unfoturnately neither of us know anything about AC's.

thanks,

[PamfromVA]

We bought the new AC and husband is installing it this morning. I was under the impression that when you ordered an A/C, it was bought in two pieces: the outside unit and the inside unit. We needed to replace the outside unit which is what I ordered. My husband discovered that the new unit was missing the circuit board. Here is a picture of the old unit and the space where he removed the old board to put inside the new outside unit:




I guess we will find out shortly whether it was the circuit board or freon leak.

If it is the circuit board I want to know why that isn't part of the outside unit.

[RedG]

Bob Landry wrote:
It still hasn't been determined if it is actually low on refrigerant, but at this point, you are probably better off to simply replace the unit and move on.

I agree, it will probably be cheaper to buy a new unit than keep paying "Mr. Fixit" to try to figure out what's wrong and then fix it.

[Bob_Landry]

The "new" freon is R410A. It does run at higher pressures, but it can be weighed in just like R22. The difference is that he would have to sweat in a second service valve which isn't that big a deal and because it's a blended refrigerant, it has to be charged as a liquid on the high side and he probably doesn't have a clue how to do that. It still hasn't been determined if it is actually low on refrigerant, but at this point, you are probably better off to simply replace the unit and move on.

[PamfromVA]

I heard back from Coleman. The AC is 2-1/2 years old. Coleman said that if it had failed within 2 years, they would have covered the replacement. Since it is 6 months past warrenty then the failure was caused by vibration and not covered. Our AC guy said since this unit has the new type freon he is not comfortable with putting in a valve for recharging. I guess the new style freon operates under a higher pressure than the old. I'm going to call a RV place today to see what they recommend - recharging or replacing.

[Bob_Landry]

Ok, then in order to tell if charge is correct without tapping into the unit. the only way to tell is to measure current draw. The symptoms are saying it's a bad compressor. They can run without doing anything and an amp measurement or tapping into the system is the way to tell. At this point, why not. If it has a leak, you'll have to fix it anyway so you fix the hole made by the piercing valve at the same time. Same with changing out a compressor, if you are a DIY,you have to do some brazing anyway. If it has lost it's charge, or if the compressor is bad, either way will put you close to the cost of a new unit. If it's less than five years old and only has a leak, then it's probably economically feasible to fix it. if it's older than that or if the compressor is in fact defective, then a replacement makes more sense that repairing it. My point was, unless you have the tools to diagnose it and know how to use them, any assumption about the problem is just that, an assumption and an unfounded one.

[PamfromVA]

Ok folks...the technician is my husband. He does not have gauge to check amp draw from the compressor but we can tell you that whether it is on heat pump or ac it blows ambient air temperature. While on ac, he unplugged one of the wires going to the reversing valve and we still had ambient air temperature. The compressor is running.

[loggenrock]

I have had a similar issue with my DuoTherm AC/Heatpump. Problem was the switch on the thermostat, NOT the unit itself. You might want to try spraying some electrical contact cleaner into the switch mechanism that changes from AC to Heat Pump and running the switch between those 2 settings to clean any contacts. Just make sure all power is OFF when you do this! Something else to check is do you have COLD air coming out of the AC unit OUTSIDE, which is what would happen in the Heat Pump mode... If you have a roof top unit this isn't too convenient, requiring a ladder, but if you get heat inside and cold outside, the unit compressor and charge are OK, it has something to do with the reversing valve (hence cleaning the switch...). Good luck! ST

[enblethen]

I was just thinking that the compressor was not operating.

[Bob_Landry]

What procedure did you use to determine that it needed freon? Correct charge can be verified by measuring the amp draw of the compressor, so if a "tech" just listened to it and made that diagnosis, Wrong!!
These are sealed systems. There is no place for a leak to occur short of an area of copper tubing rubbing against something on the chassis and rubbing a hole in it. These units only take 24 oz of freon, so with any leak at all, you'll lose all of the charge. If it's actually blowing warm/ hot air and not the trailer ambient temperature air, then charge is OK. You have what sounds like a reversing valve problem, either a sticking reversing valve, a shorted reversing valve solenoid(not common) or a defective circuit board that is keeping it switched in the on condition.
Unplug one of the wires going to the reversing valve and see if it blows cold air.

Emblethen, the "compressor capacitor" which BTW, there are two, does not have anything to do with determining if the unit blows hot or cold air, however, that is almost always a response to any AC problem posted here.

[PamfromVA]

After troubleshooting today we have determined that it needs freon. Very disappointing on a unit that is barely 2-1/2 years old. Any one have any luck getting coleman to replace their unit?

[PamfromVA]

I did not hear compressor Tues night because it had been running all day before I noticed the problem. I will turn it back on tonight when it cools off some.

[Cobra21]

When you turn it on do you hear the hum of the compressor? You should hear it a few seconds after turning unit on. It
it is not running make sure thermostat is turned cold enough to make it run. If it is running and no cold air, could be that refrigerant leaked out.

[enblethen]

It is possible that the AC compressor capacitor has failed.
Here is site that has some information.
RV comfort

[AirZone]

When the unit is running, switch from heating to cooling on the t-stat and see if you hear a swooshing sound from the reversing valve. If you don't then the valve or the relay supplying power to the vale is defective.
Gives you somewhere to start.