thermostat trick to get hard starting AC going


  #1  
Old 07-31-12, 08:22 PM
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thermostat trick to get hard starting AC going

I tried to start our split 4 ton Ac but it would not start...the compressor was just replaced.

So this is the only way I could get it to fire up.

1- Turn off thermostate keep Auto function on

2-Tunn temperature to 20 degrees above room temp

3-Wait 10 minuites

4- Turn back to on postion

5-Now adjust temperatue to 10 degrees below room temp

Unit fired uop ans runs great

I tried all kinds of start stop setting waiting 10 minutes between start attemps but nothing would work
 
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Old 08-01-12, 04:20 AM
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if it was just replaced then call the contractor back and dont touch anyhing.
 
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Old 08-01-12, 10:41 AM
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Well at 100F outside air temp I get 59F out of the register nearest to the evaporator ( 4 feet)
The condenser temp rise is about 20F.

Sooo this seems ok.


If the evaporator never made sounds ( from the liquid inlet line) then why dose it do it after a new compressor>?
 
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Old 08-01-12, 01:13 PM
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If the evaporator never made sounds ( from the liquid inlet line) then why dose it do it after a new compressor>?

Read more: http://www.doityourself.com/forum/ai...#ixzz22KMPGgBL
Tech didn't pull a good vacuum or improper charge.
 
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Old 08-03-12, 09:02 PM
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Thanks for info on charging

I have 2 3 1/2 ton 30 year old units the older unit runs with no sounds but as I posted the one with a brand new compressor seems to :

1-about 8 to 10 F hotter at the evaporator inlet that the older units

2- making evaporator gurgling sounds that the older unit does not make


if the new compressor unit was low on charge would not the low pressure cutout stop the unit from running at all.

The unit with a new compressor will run non stop for about 10 to 12 hours at 105 F air outtdoor temp then it will stop. but not to restart

When it stop I have to set the thermostate to the off postion and set the temp to 20 dgrees above room temp wait 10 minuted then turn to the on postion and dial in 10 degreea below room tmep.

Nothi else will get to to run even if a turn to off and wait up to 20 minutes.

the thermo high temp ) overload ) does not trip
 
  #6  
Old 08-03-12, 09:32 PM
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Your ten minute waiting system doesn't really make sense. Your saying if you wait ten minutes its OK, but twenty minutes its not? That really is the strangest thing I've heard in a while. Obviously there is problem. It needs to be checked out before it gets worse.
 
 

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