Liquid line temperature.

[romaurie]

A 4.H.P. Belcor split-system had the evaporator changed to Electra some time ago.The capillary (correctly sized) is on the condensing unit.The temperature of the returning liquid on a 20 foot run in 3/8" tube is neither hot nor cold, but the returning suction is "sweating" and at 78PSI with a head pressure of 300PSI at 45 Degrees C ambient. Normally you get a good "feel" for how a system is performing by the temperature of the suction and liquid lines.I have seen this a couple of times in the past but don't understand what causes it.There is no capillary tube in the evaporator.
After changing the compressor and capillary the operating pressures are the same as is the temperature but the compressor does not cut out on klixon intermittently now even in the afternoon when ambient temperature peaks.

[nike123]

Check your airflow (measure it).
If you getting bigger diameter line colder than smaller one, you have restriction in evaporator or on bigger line. Maybe line is kinked somewhere or insulation particle is entered in pipe while it is hauled.
Smaller diameter line should be at evaporation saturation temperature and bigger one should be at temperature of superheated vapor refrigerant.
How did you charged your unit? By weight or other method?
Could you measure both pipe temperatures and suction pressure?

[chemi-cool]

Hi romaurie,

I have a thought, at such high ambient, not all the refrigerant condenses and some times you get vapour at the capillary inlet.

This can cause the difrences in temp that you feel.

And for our readers, Belkor is a local AC manufacturer.