hello fellow techs i have a a/c system that has stumped me and would like to see what everyone else thinks. call: not cooling good in afternoon.
I have a 4 year old 4 ton trane 16seer 410-a heat pump that in the afternoon does not satisfy and has a 4 to 5 degree differance in set point, i have called trane and still awaiting a prognosis. this is my second day on this call so here are the details.
my first arrival 3:00pm (first day)
my pressures @ 143/463psig
ambient temp 104'F
delta t 19'F return temp 86'F supply temp 67'F
wet bulb 78.3
system shows symptoms of low charge due to high superheat and low subcool readings. condensor coil clean washed several times to make sure. decide to return in the morning to see what changes.
8:30am (second day) system maintaining
my pressures 121/344psig
ambient temp 93'F
delta t 19'F return temp 77'F supply temp 58'F
compressor amp draw 13.5 fan motor amp draw 0.9 fan is on high speed.
i decide to charge the system to get 10'F sc and drop my superheat and raise my subcooling at this point my main concern is my head pressure. i decide to return in the afternoon again to see my changes
3:00pm (second day)
my pressures are fluxuating between
154/520 and 149/500psig
my subcooling and superhead are also doing the same (but much better)
11-14'F sc - 13-16'F sh
discharge temp from motor 136'F
compressor amp draw 20.5 fan motor 1.0
the system is cooling a little better as you can tell from the superheat and subcool readings, but the head pressure is thru the roof and now my compressor is over amping. i thought maybe reversing valve could be leaking but common suction and suction is same only 5'F difference between c suction and @ evaporator. i dont believe it is the txv due to being able to maintain sh and sc plus when removing the bulb valve opens. also ajusted indoor motor and checked duct work (duck work is a issue but i dont believe it is THE issue) any advise would be much appreciated, oh and system is in cooling second stage