Help with Rheem 3.5 Ton Heat Pump

[johnzo1995]

Two weeks ago, I installed a 3.5 Rheem R22 Heat Pump. Im having problems in which the unit is not cooling. The unit was factory charged for 15 feet of line. I added an additional ~1 lb for the extra lenght of line.

The unit does not cool very good at all, I'm getting only a delta T of 10 degrees arcoss the evaporator. The condensor came with a charging table on the inside cover. The pressures are right on. However the subcooling is ~25 degress. I didn't check superheat and the suction line was not cold at all. I'm thinking the TXV is faulty and is not metering the refrigerant correctly.

Another weird thing happend, since it was a heat pump I which it over to heat. I worked great for about 10 mintues, then the high side (low side in cooling) pressures went up very high and rapidly fluctuating between 350-400psi.

Every thing is brand new including the line set, installed to industry standards.

Sorry this is not in the pro forum, any suggestions would greatly be apreciated.

[Senior Tech]

Are you a pro in the hvac field? If so you need to apply for pro membership and post your questions in the proper forums.

[johnzo1995]

Yes, but I dont have the minium number of posts to meet the Pro forum requirements. I see other technical questions being answered is this forum, and so I tryed.

[beenthere]

Arguing with a mod is an automatic 2 post count deduct. :) J/K

Think traffic jam.

[shocka/c]

Were not allowed to answer or ask technical problems in here ? I have my own a/c bussiness guess I should sign up for the pro forum. I was just checking out some of the threads here and was going to try and help johnzo but I guess Im not allowed. I'm a new member guess I should read the rules before I go breaking any.

[amd]

Make sure that the blower speed is set correctly. Common sense->High airflow = low delta-t.

[beenthere]

I'm a new member guess I should read the rules before I go breaking any.


Kinda like reading the install instructions before installing a unit. :)

[johnzo1995]

The airflow is good, the fan is set at medium speed and total ESP is 0.40" W.C. I'm going to change the TXV.

[beenthere]

Big duct to move 1400 CFM at a TESP of .4"

[johnzo1995]

Yes the exisitng ducts in the attic are very big. The system moves air quite well. I'm still stumped on the cooling problem. I can't get the TXV for a week.

[beenthere]

Yea, at least 18" round, or minimum 20 x 12 for the return.

[accutrol]

If the evaporator coil suction line connection was overheated when soldered, it can damage the txv, causing it not to work properly. You may need to replace the txv valve. Nitrogen should always be used when soldereing. 1/2 of 1 psi is sufficient to keep carbon builup inside the lines. We as contractors need to be aware of the necessity to use nitrogen when soldering with the change from R-22 to R-410a. Also, liquid line filter driers are must.

[accutrol]

You might want to try heating the valve (carefully) and give it a good shot with a wooden mallet. This might free up the txv. Done it, it works sometimes.

[indianajones]

did you change the evap or just the cond.