NORMAL????....OR NO....???

Paul S_3 · June 2011

HEY GUYS. I HAVE A PROBLEM WITH A 4 TON TRANE RESIDENTIALSPLIT A/C SYSTEM. THE COMPLAINT IS HOUSE COOLS TO SET TEMPATURE ON A NORMAL 75F-80F DAY DESPITE VERY HIGH HUMIDITY LEVELS. THE CUSTOMER STATES THAT ON A VERY HOT DAY THE SYSTEM RUNS ALL THE TIME WITH HIGH ELECTRICAL BILLS, AND THE HOME IS VERY HUMID. SO MY QUESTION IS WHY IS THIS SYSTEM NOT REMOVING HUMIDITY. TODAY THE AMBIENT TEMP WAS 78F BUT NOT THAT HUMID . THIS IS A R-22 UNIT 4 TON, WITH A TXV. TEMP SPLIT IS 15F EVAP AND CONDENSOR COILS ARE BOTH VERY CLEAN. HEAD PRESSURE IS AT 250PSI AND SUCTION PRESSURE 72PSI COMPRESSOR RLA ON NAMEPLATE IS 22 AMPS COMPRESSOR RUNNING AT 21 AMPS. SYSTEM HAS NO SUPERHEAT AND SUBCOOL IS 37F (112F-75F=37F). COULD THIS BE OVERCHARGED CAN AN OVERCHARGED UNIT CAUSE A LOW TEMP SPLIT , BEFORE I LEFTI SWITCHED FAN SPEED FROM HIGH TO MEDIUM HIGH AND GOT THE SPLIT TO 19F. WILL RETURN IN A COUPLE OF DAYS . AND HOW COME THE LIQUID LINE WASNT HOT AT ALL (TO TOUCH) AND WHEN I WAS RECOVERING REFRIGERANT COULDNT GET SUBCOOL DOWN. PLEASE HELP;;!!!! GUYS I KNOW ITS ALOT OF WRITING BUT 4 OTHER COMPANIES WERE THERE BEFORE ME AND NO FIXED PROBLEM

James Day_2 · June 2011

Xpansion Valve

Could the Expansion Valve be faulty. Try removing the sensing bulb and putting it in warm water. See if you get any reaction from that. If it is unresponsive you might have a stuck txv.

Paul S_3 · June 2011

thanks

ok i will do that tomorrow but what about the temp split changing is that a result of slowing the fan speed down??

don_9 · June 2011

Decrease capacity

Being your subcooling is so high your condenser is stack with refrigerant and in your case now has decrease the capacity of the condenser and its ability to transfer heat.

So I would recover the freon and get that subcooling down to about 12 to 15 and then see if my txv start mainting superheat.

And yes temp drop is a fuction of airflow and humidity.

The reason the bills or so high is bc the comp is being over work due to the compressor is being ask to do what it not design to do and that is pump liquid.Its a vapor compression system not design to pump liquid.that comp not going to last long being hit with liquid like its doing.

Techman · June 2011

...OR NOT...???

What Seer?How big of a house? How old is the system?Is this the original comp/cond unit? Remove lots of freon until you get some activity in the liquid line just before it enters the AHU. Take readings and start thinking all over again,again!

Paul S_3 · June 2011

Still...

I recovered all refrigerant evacuated and recharged. My temp split went up to, 18f but my head pressure is really high 275psi at 76f ambient temp my suction is at 55 psi with still no superheat I have a really high subcool 40f and the liquid line is not warm at all all coils are clean.it is a 13 seer trane condensing unit original seems like the evaporator coil has been changed It is a 4 ton system and this is a piston type metering device not a txv I will go back tomorrow to check out again but if the home is still humid should I be checking the orifice size in the evaporator??? Stuck???...inefficient compressor??

Techman · June 2011

or not

In the 1st post the suction press was 72psi = 42*f , so with "no superheat " the suction line at the comp was also the same 42* ? the last post the suct press was 55*f = 30*f and the frosted suction line at the comp was a balmy 30*f also?Pull out freon until you get a little activity at the metreing device and record your readings.Add just a little more freon and record the readings again .Do not let the subooling go over 12*. What are the readings w/ a full liquid line and 12* SC.?

Paul S_3 · June 2011

weird....?

after i recovered all the freon and evacuated the system i finally fixed the humidity problem in the house but like i said before all coils are spotless but the pressures are way off 40f of subcool and no superheat head pressure is close to 300psi and suction around 55psi. when i recover more refigerant to get subcool down and superheat up the suction pressure drops and so does my tempature split. so i left system as is but i will return tomorrow to recheck. (system has piston type metering device ) and how come my liquid line is so cool when the head pressure is so high???and how come i cannot get a proper superheat and sucooling reading???and how come the humidity level dropped dramatically in the home after i recovered evacuated and recharged??? its like the problem is fixed but weird readings.......

Techman · June 2011

Head Pressure

Paul , I think the hiside press at 78* ambient is about 205-220 ,depending, and w/ a 300psig head the air into the cond coil was 100* or so , 95-92 w/ a higher seer unit. If you had a temp split ,you had superheat, I think.

NORMAL????....OR NO....???

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