Stumped!

[Jogalloway]

Help!! 2.5 Ton Goodman Heat Pump, when unit first turns on in cool, the suction psi is between 35-45psi, head pressure is between 125-150psi. These pressures hold steady at those psi's for 15-25 mins then both pressures slowly start rising and steady off at 70-75 low and 250-270 high depending on conditions. Problem is if pressures do not start rising fast enough sometimes unit will start freezing at evaporator. Unit does not freeze all the time just sometimes very infrequent. The air filter is clean, evaporator is clean, condensor is clean and evap. fan is running good on high speed. Could I have a restriction at the orifice, but usually the circumstances are the reverse of what i am finding. Any thoughts would be appreciated. The compressor was replaced in April 08 and has been running good up until about a week ago.

[Evolutionizer]

Are you sure the indoor fan is coming on when pressure reagings are low?

[Jogalloway]

Yeah, indoor fan comes on every time.

[I_bend_metal]

Superheat?
Subcooling?

Just because your fan in on high doesn't mean it's right. Have you tested staic pressure to determine CFM?

Sounds like a charge issue to me but without more information, hard to tell.

[Jogalloway]

How do you test staic pressure?

[I_bend_metal]

Jog.....don't take this the wrong way but if you have to ask, you may need to call a service professional out to evaluate your system. If you are a professional, get your post count up to 15 and apply for professional status on this site. There is a wealth of information on here, including step by step procedures for testing static pressure.

We are not allowed to give out DIY advise on the open forums of this site but once you are professional, we can talk shop all day and night.

I can tell you this....we test static pressure to get the amount of CFM a blower is moving. If you follow the 400 CFM per ton rule then your indoor blower should be moving as close to 1000cfm as you can get. After that is verified, then you can begin adjusting your refrigerant charge using superheat and subcooling measurements.

[Jogalloway]

O.K. thanks for the heads up. I am not a pro. just a maintenance tech at a n apartment complex, only been in the hvac/maintenace field about a year so this is really the first unit i have had that has given me a problem I couldnt figure out and my superiors think it is a bad compressor but i am not sure and dont want to just changing out parts if you no what i mean!

[beenthere]

Was it the compressor that was changed out in April, or the condenser.

What are the chances that someone has added gas to get the vapor pressure up.

[skwsproul]

O.K. thanks for the heads up. I am not a pro. just a maintenance tech at a n apartment complex, only been in the hvac/maintenace field about a year so this is really the first unit i have had that has given me a problem I couldnt figure out and my superiors think it is a bad compressor but i am not sure and dont want to just changing out parts if you no what i mean!

Still get your post count up and apply for pro status if you get it you will get all kinds of really good info from all of these great techs. Being a rookie does not mean that you are not a pro, it is defined by the way you approach problems and asking questions before making mistakes is the first step in the pro-direction. Good Luck

[diverdan]

You either have an air flow issue or a leak that needs to be repaired, assuming an R22 system.

Best thing to do is to get a good evaluation from a reputable company and pay them to fix the problem. Easy as pie. Find a company tha guarantees their work the first time and let them figure it out.

[skwsproul]

You either have an air flow issue or a leak that needs to be repaired, assuming an R22 system.

Best thing to do is to get a good evaluation from a reputable company and pay them to fix the problem. Easy as pie. Find a company tha guarantees their work the first time and let them figure it out.

It is amazing that you are able to diagnose that with so little information. Uh hire a company to do your job for you, brilliant why did I not think of that. You need to be careful not to lead a person in the wrong direction, it can be very costly to both the customer and the contractor. Not trying to be mean but try to get all of the info before you take blind stabs at the problem, it is kind of like defrosting a freezer with an ice pick.

[diverdan]

Your criticism of my diagnosis reflects an unsound technical background.

[Gunslinger]

if it's a TXV system, could be a plugged equalizer.