Moved to Tech to Tech residential
I am working on a two stage heat pump with a varable speed air handler.
The system runs about 1.5 deg S/C and about 2 deg S/H The delta T is 22 deg. A capacity check shows systems is operation at 122% of publish Capacity. Adding refregerant does not change the S/C much at all.
My question is how is this possable? low subcooling and low S/H
This is a matched system, and all test equiment was checked for accuarcy.
Moved to Tech to Tech residential
Is the compressor and evap motor at 100% ?
What kind of airflow to your air handler?
You've got multiple problems, I think.
Please provide all of the readings that you took on the unit along with model and serial and maybe we can see a problem.
25HNB624 with an FE4ANF003 Air Handler.
90 deg ODBD Pressures 298/138# liquid line@ service valve 93deg vapor @ service valve 52 deg.
air flow @ 700 CFM +/- 20 cfm
RA 76 deg db 67 Deg wb
SA 54 deg db 52 Deg wb
Compressor @ 60% of fla air flow @ 700cfm
You may have a flooded everything due to a gross overcharge. Start by recovering all the refrigerant from the system. The start with a fresh charge to factory specs and see where things are at that point.
If YOU want change, YOU have to first change.
If you are waiting for the 'other guy' to change first, just remember, you're the 'other guy's' other guy. To continue to expect real change when you keep acting the same way as always, is folly. Won't happen. Real change will only happen when a majority of the people change the way they vote!
The Refrigerant charge was recovred and weight back in @ factory specs added 5 lbs more. and removed 10lbs. still little change is s/c
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2 Tim 3:16-17
RSES CMS, HVAC Electrical Specialist
Member, IAEI
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Where, exactly, are you measuring the liquid line pressure and temperature?
Where, in relationship to the liquid drier?
I'm guessing it's metered by a txv? Could the txv be causing the issue?
As did I with three different instruments A cooper digital. Field Piece digital. And my old standby yellow jacket and fluke temperature probes. Nothing makes sense. How can a evap show flooded and the condenser be starved?
Txv stuck open
TXV problem
I rather do nothing and be happy than to do something and not be happy
Read the book on that cond. Unit. I know with some Carriers, they have to be running in high capacity or you'll get funny pressure reading. Also check if the indoor blower is running in high speed.
Sounds like more air flow is needed to me.
As iron sharpens iron so one man sharpens another Proverbs 27:17 NIV84
TXV Problem, Airflow is good at 700 CFM for a 2 ton. Newer systems call 350 CFM better dehumidification. Seems stuck open.
I believe your compressor is still in first stage. IIRC there's a five minute delay from signal sent to compressor engage in addition to the delays in some thermostats. I've seen those same pressure/temp/sh/sc conditions on a carrier two stage system that would not engage full capacity.