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gone rayson 09-29-2012 11:52 PM

typical head pressure?
 
Hello everyone, I have installed ICM 333 head pressure control on new frigidaire window a/c 25000 btu. r410a. the control module has adjustable head pressure from 150 psi to about 500 psi. Everything is working fine, I set the head pressure adjustment to about 350 psi.Just wanted to confirm what typical head pressure would be on a hot day. thanks, Jeff

beenthere 09-30-2012 04:59 AM

350 is plenty high for a R410A system. Not sure why your running it that high.

gone rayson 09-30-2012 06:10 AM

Where do you think I should set it? thanks BEENTHERE.

beenthere 09-30-2012 06:17 AM

How high depends on application, as in if its being used for capacity reduction on a slightly over sized unit. or just as a low ambient control. Along with weather the motor is a sleeve bearing or ball baring motor.

290 is a good setting for units that you just want to operate in low outdoor ambient conditions.

Higher pressure settings( like the 350 your at now)can cause a lot of short cycling on sleeve bearing motors when the outdoor temp is below 80. its short cycling that can cause motor damage, along with too slow of a speed for the sleeve bearing trying to maintain that high head.

gone rayson 09-30-2012 10:52 AM

Ya, it's being used to cool 1200 sq ft room during cool months here in Ohio. I've also installed crankcase heater. The control module actually does not cycle, it slows fan rpm after hard start to maintain head pressure. So 290 psi it is. Thank you Beenthere. for your reply. Jeff.

gone rayson 10-05-2012 06:11 PM

o.k. The distributor called me back today, he has test pressures for units just like mine. typically on a 90 degree day the high side was 390 to 420 psi. the low side around 140.psi. Now my question is, do I try to maintain this pressure during cold weather?

beenthere 10-05-2012 06:37 PM

No, you don't need to simulate a 90 degree day.

gone rayson 10-05-2012 06:41 PM

O.K. so i will set for 290 psi. Thanks. Jeff.


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