High suction pressure
I am working on a split system...the problem is that the unit has a high suction pressure of 80 and the head pressure is 220, discharging 61 degree air and returning at 76 degrees. The unit does not have an expansion valve. What could be causing this problem? This is an air cool unit. Any help would be greatly appreciated.
Wow..many questions. What was your SH/SC readings? Was the area that this system serves very hot? There are a number of things that could cause this.........
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returning at 76??
what was your superheat?
try to give as much info as possible to help us help you when posting.
model and serial, tonnage, brand, SH SC. application (Resi,comm.)
Does The Condenser Have A Good Ventilation, Or It Is Too Hot?
I Think The Condenser Unit Does Not Work Well
Is this a resi/light commercial unit with fixed orfice metering device? If it is, you need to check the superheat. You'll also have to obtain the manufacturer's charging table. Tell us what you have and we can help you better.
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i take it we are talking about a hermetically sealed compressor.Generally they are capable of pumping at a ratio of 4 to 1.with a high suction and a low dishcharge pressure(be sure you are reading dishcharge pressure and not liquid pressure) it doesnt sound like your suction pressure is abnormal at 61 degrees dishcharge temp and your delta t looks ok ,the only thing i see is the low dishcharge pressure,but that is relative to ambient temp.
First things first.
Perform a compressor efficiency test. See if it will pump down, how far into a vacuum, and does it hold the pressure differential or equalize?
76* return, 80# suction, and 220# head don't add up. Is it a newer hi-efficiency condenser?
Could it be because it is a 2 ton unit on a 5000 square foot house.
What is the refrigerant? R-22 I would assume?
Of course what are the superheat and subcool readings?
What size is your indoor coil and what size is your outdoor coil? (I've had a recent experience with a high efficiency unit 3 ton outdoor and 5 ton indoor that causes higher than normal suction pressure readings).
What is your outdoor temperature at the time of these readings?
What is your db/wb humidity readings? Perhaps you are drawing out much more latent than sensible heat and thus the higher suction?
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is it a ductless unit?? if it is did you check the condensor for the txv??
Originally Posted by winbarro
observation is key..
80 + 15 = 95
220 + 15 = 235
2.5 to 1 compression ratio
Is your condenser and evaporator the same size? Is the evap. over sized?
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