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Old 02-08-2009, 11:44 AM   #1
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Testing A/C system


What would be the lowest outdorr temp be in order to test my interior a/c systen without the coil freezing up? Is the 60's too low?

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Old 02-08-2009, 11:56 AM   #2
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Testing A/C system


Is it a split system with a outdoor condensor unit and indoor coil in a furnace/airhandler? I recommend a minimum of 70 deg F. You also need a good heat load in the house. If it is too cool then the compressor does not have a good load. To test it properly you need a good load to check the compression ratio and see if the compressor has any guts/capaacity.

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Old 02-08-2009, 12:01 PM   #3
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Testing A/C system


It's a split heat pump. The reason I'm asking is that I have had a lot of trouble with the system and it appears that the heat is working right. All I want to do is set the stat to cool and see how it operates, however, I believe that if the temps are too cool it will sense that and shut down the system.


So are you saying that I should wait till it is at least 70 o/d?
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Old 02-08-2009, 12:38 PM   #4
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Testing A/C system


It will run at 60 but won't tell a tech anything useful.
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Old 02-08-2009, 12:45 PM   #5
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Testing A/C system


Altough at 60, a ood tech can test a system.
A non tech, won't be able to tell if the cooling mode is working right or not.
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Old 02-08-2009, 01:51 PM   #6
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Testing A/C system


I turned the system on yesterday. It was around 65 o/d. I/d temp for the zone was 77. It blew really cold air, then the compressor shut down after about five minutes. The leds on the zone panel indicated that the low temp hit it's limit so it shut down to avoid freezing.

So are you guys saying that this shouldn't happen and I have a problem?
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Old 02-08-2009, 02:31 PM   #7
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Testing A/C system


What type of ongoing problems have you been having. What brand of zoning panel do you have. Do you have a barometric bypass damper?
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Old 02-08-2009, 04:44 PM   #8
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Testing A/C system


No, that is what should have happened.
Your zone panel did its job.
Te discharge air temp sensors got too cold. So the panel shut the A/C off so it wouldn't be damaged by liquid refrigerant.

If your panel hadn't done that, your compressor could have beed severly damaged.

If you want to run your A/C at such cold temps. You need a low ambient kit installed, and probably would need to have more then one zone calling.
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Old 02-08-2009, 04:45 PM   #9
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Testing A/C system


If you have one zone too hot when its 65 outside.
Set all your stats to fan on, and let the heat circ to the other areas.
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Old 02-08-2009, 06:46 PM   #10
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Testing A/C system


I understand that the system did what it should by shutting off. I donot normally want to run my system in this climate. All I'm asking is if the system is shutting off because it is not warm enough o/d, and not as a result of a malfunction.
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Old 02-08-2009, 07:48 PM   #11
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Testing A/C system


Quote:
Originally Posted by jeepgrady View Post
It's a split heat pump. The reason I'm asking is that I have had a lot of trouble with the system and it appears that the heat is working right. All I want to do is set the stat to cool and see how it operates, however, I believe that if the temps are too cool it will sense that and shut down the system.


So are you saying that I should wait till it is at least 70 o/d?
You say you had a lot of trouble. What type of trouble were you having?
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Old 02-08-2009, 07:58 PM   #12
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Testing A/C system


if it was the outside air knocking it off it would of never started,that was discharge air into the space off the furnace....if you need to run it in temps below 60F put a garbage can cover on top of the condenser with a BRICK holding it down and then move it just a bit to allow some air to discharge the condenser!
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Old 02-09-2009, 08:06 AM   #13
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Testing A/C system


It shut off because the outdoor temp was too low for it to maintain a high enough coil temp to operate safely.

So, its not a malfunction.
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Old 02-09-2009, 08:41 AM   #14
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Originally Posted by beenthere View Post
It shut off because the outdoor temp was too low for it to maintain a high enough coil temp to operate safely.

So, its not a malfunction.

Thak you. Finally someone understood my question. As usual, you've been a great help.

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