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-   -   how cold should low pressure line be (http://www.diychatroom.com/f17/how-cold-should-low-pressure-line-148882/)

bob22 07-02-2012 06:29 AM

how cold should low pressure line be
 
I was weeding near my York condenser unit (YCJF42S41S1, not a heat pump) and felt the low pressure line (unit was running at the time). It wasn't very cold and no condensation (quite humid lately). House is keeping cool (set to 77* during day) in 98* weather but I'm wondering if freon charge might be off?
Condenser YP9C080C16MP with Aspen coil and thermal expansion valve.
Does the TXV "compensate" for off-pressure charge?

biggles 07-02-2012 06:48 AM

beer can cold:wink:...as long as that liquid line is filled from 3-4 rows up out on the condenser that is the state that the TXV looks for to operate(if you have it might be cap tubes).if the liquid level(charge) is low that liquid seal where the LL starts coming out of the condenser is changed seeing flashing and gas burps into the TXV....somewhat like a garden hose spray.so as the liquid is metered out into the evap the pressure drops as so does the temperature to give you 40F.typical evap is 18F drop on return air vs supply air taken at the air handler,with 10F rise on the air into and out of the condenser.sounds like it needs a tweek with questionable charges effecting the unit run time(longer) trying to make setpoint

bob22 07-03-2012 12:17 PM

I measured temp at a register close to the unit, 63*. Temp inside house set for 77* so I assume intake air would be close to that.
Do I have to measure within the duct work leading just out of the unit or is a register 10' away ok?

biggles 07-03-2012 12:43 PM

right on top of the A coil plenium box and at the filter on the return if you want to get that 18

bob22 07-03-2012 01:12 PM

Thanks; I see what holse I can find to poke in a thermometer.

biggles 07-03-2012 07:18 PM

nail and a hammer just above that A coil into the duct work

beenthere 07-04-2012 04:52 AM

Quote:

Originally Posted by biggles (Post 957226)
nail and a hammer just above that A coil into the duct work

Make sure your above the A coil.

plummen 07-04-2012 10:46 AM

Quote:

Originally Posted by beenthere (Post 957487)
Make sure your above the A coil.

:laughing::laughing::laughing::laughing::laughing: :thumbsup:


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