180 psi at Suction line - Carrier 4T Heat Pump

[davefr]

My old Carrier heat pump seems to be operating sub optimally.

Suction Line - 180 psi
Liquid line - 200 psi
Temp of suction line at condenser unit - 180 degrees
Temp of liquid line at condenser unit - 70 degrees
Temp rise from cold air return to closest indoor register - 15 degrees. (it's been closer to 20 degrees in the past)
Outdoor ambient 50 degrees

The operational chart from Carrier suggests Liquid should be approx. 240 psi and Suction should be about 60 psi given these temps.

What would cause my Suction pressure to be so high and yet the unit still produces about 15 degrees heat rise? (leaky reversing valve????)

Could a slightly low refrigerent charge cause this?

[white6294]

sounds like u have your blue hose in the wrong spot, try the service port closest to the reversing vale for a correct suction reading.

[tn a/c man]

I agree with white you have your low side on the wrong port.Sounds like it is a little low on freon.You should have a good company come out to perform the work.You will need many tools to determin if your system is undercharged.Your pressures will only get you close.

[davefr]

Yep, your were both right. I was connected to the fitting at the suction line. (where it exits the condenser) It looks like Carrier calls it the "Suction Service Port".

Apparently the "real" suction valve is between the accumulator and compressor. It reads 40 psi.

It look like my charge is a tad low at 40/200. Carrier claims it should be 60/240. I guess I better call sometime to look at it.



[Edited by davefr on 11-05-2006 at 02:56 PM]

[emcoasthvacr]

I hope it isn't the compressor suction valve -- our valves go bad when we get old; leaking reversing valve could also be the culprit.

Other things to check include, indoor & outdoor expansion valves stuck open, loose thermal bulb on your expansion valve, leaking check valves, etc.



Originally posted by davefr
My old Carrier heat pump seems to be operating sub optimally.

Suction Line - 180 psi
Liquid line - 200 psi
Temp of suction line at condenser unit - 180 degrees
Temp of liquid line at condenser unit - 70 degrees
Temp rise from cold air return to closest indoor register - 15 degrees. (it's been closer to 20 degrees in the past)
Outdoor ambient 50 degrees

The operational chart from Carrier suggests Liquid should be approx. 240 psi and Suction should be about 60 psi given these temps.

What would cause my Suction pressure to be so high and yet the unit still produces about 15 degrees heat rise? (leaky reversing valve????)

Could a slightly low refrigerent charge cause this?