Controlling A/C temps - Please read summary

[ijester]

I am running an A/C unit that I want to modify the thermostat to be able to work down to 0 Celsius.

Right now, on the coldest setting, it shuts the unit off at approx 20 c or so.

Any ideas?

 

[epsilon9090]

You might blow out your air conditioning doing something like that.

 

[ijester]

Ummmmm... NO. Doesn't work that way.

 

[Mday]

Originally posted by: ijester

I am running an A/C unit that I want to modify the thermostat to be able to work down to 0 Celsius.

Right now, on the coldest setting, it shuts the unit off at approx 20 c or so.

Any ideas?

buy a freezer. ACs don't go down to 0C.

 

[ijester]

OK, can you save the comments if you have no idea what you are talking about. What do you think a phase-change unit such as the prometia is? It is an air conditioner, in essence.

If I disconnect the thermostat completely, my ac unit will easily go below 0 celsius and quite a bit more.

 

[2Busy]

You could try jumping the contacts in the thermostat. That would make the compressor run all the time. But, the minute you have poor air flow across the condensor, because of dust, too tight of quarters, etc, expect everything to start icing over. Actually, you will need to dissipate alot of heat somewhere. You will be dumping a huge amount of heat back into the room that all of this equipment is in. Maybe duct it outside somehwere.

 

[ijester]

Yes, 2busy I understand all that.

The icing prob is exactly why I want to Control the unit with a thermostat, not just bypass it. I would want to be able to shut the compressor off just before the evap reaches freezing temps, and restart it after it warms up a little, etc.

And as far as the heat goes, it is not dumping that much new heat. Most of the heat coming from the condensor is the heat it removed from the air that was already there. The only new heat would be from whatever is produced by the compressor and fan of the unit.

 

[ijester]

I just experimented with the location of the temperature probe until I found one that works.

The stock location had the probe about 1/4" in front of the evap - with the dial at the coldest setting, this would turn off the unit at approx 20 degrees celsius. I moved the probe into the return air stream, about 2" away, and now at the coldest setting it shuts off when the air in front of the evap is approx. 10 degrees C.