Attending a call for the goodman ac.it was 1.5 ton unit with 1800 sq ft house.found lk at the service valve cap.after fixing the unit and charging 3 lb of r 22 got this reading.low side 90/high 160 psi.superheat 10 .subcooling was only 2'outdoor air temp was 85.
Model GSC130181AE.SERIAL 0704641810
Temp diff across coil 13 f.
Wet bulb 66 in return 56 in the supply
Factory chg was 5 lb.
Any thoughts
what coil was being used? tx valve or orifice style?
Was the fixed orifice.i didn't chk the size of the orifice though.
Those are some strange readings! I would expect the superheat to be much higher. Your suction line temperature was 64F and your liquid line temperature was 85F?
Was the unit empty when you got there? You only added 3lbs of R22, and that could explain the low discharge pressure. The system might be undercharged. Has the furnace fan been replaced? Lowering the fan speed might increase your 13F drop and lower the suction pressure.
I don't think Goodman units have a side access panel that you can use to access the compressor. A quick test would be to stop the AC and grab the suction line right at the compressor, and if it gets hot it could mean the compressor valves are leaking internally and bypassing hot gas.
If the compressor can only be accessed by removing the top of the AC, I would perform a pump down test.
Start the AC and close the high side service valve. Once the suction pressure drops to 10 psig, stop the AC. It's normal for the suction pressure to increase slowly, but if it increases over 12-15 psig/min you can be sure the compressor is leaking internally.
All your readings point to an inefficient compressor, except that it normally causes a high superheat.
They probably should have purchased a 2 ton AC for a 1800 sq ft house in Toronto.
And be careful quoting a Goodman compressor replacement job. The last one I did was upgraded to a scroll compressor. I had to remove a muffler and completely modify the copper lines inside the unit. And of course the wholesaler didn't ship me the new wiring harness. A simple compressor replacement turned into a real nightmare!
The unit had some pressure like I got low 40/high 80 at the start .Than after I started to add the R 22.I stopped adding bcoz I was getting 10 degree of superheat.Also I tried to alter the fan speed but nothing helped.I think I will run the test for the compressor and see if I get the call back from the customer.
Thx for your inputs