Trane unit not cooling, mismatch?

[Panama]

Sure sounds like the installer screwed up. Warranty?

[jostheim]

Ahhh warranty... yes I do have one, but I don't know if I want to let the people who installed it back into my home.

First off the install was in November and took over a month for them to get right. The problem it turned out was that while installing the thermostat he had pulled to hard on the wire and frayed it which in turn shorted out a transfomrer. I was the one who finally debugged it by MAKING him bring a thermostat up to right beside the Air Handler, hooked it up directly and saw that then it worked (hence isolating the bad wire).

So long story short, the installers sucked. He once said to me that a digital thermostat wouldn't work because he didn't understand the "computer inside of it"...

Right now I am just appreciating everyone's help, because the more I know the better I can keep these guys in line (such as the guy today who may come back and tell me the units don't match and I need a new air handler).

Anybody on this list in the Washington, DC area, I could use a reccomendation...

James

[mark beiser]

Originally posted by jostheim
Check out A/C not cooling well
Found system pressures ok with press curv.
Sub cooling is high (overcharged)
Supper heat is high (undercharged)

Equipment may be mismatched Model #s
need to be checked.

Well, it can't be overcharged and undercharged, lol.
Since we don't know what subcooling and superheat readings he got, it is not really possible to tell what is going on.

Overcharging a TXV system can actually cause high superheat, and will definatly cause high subcooling.
For all we know, he could think the superheat is high, when in reality, it is normal.

The air handler has a built in TXV, maybe someone didn't realize it was there and tried to charge the system like it was fixed metering and badly overcharged the system trying to get the subcooling down. I find TXV equiped systems badly overcharged all the time because previous service people tried charging by superheat, then I guess just gave up and walked away when they couldn't get the superheat to go down.

[jostheim]

Just for my own edification,why would overcharge cause high superheat?

James

[ruud-man]

Yes, I would like to hear this one too.

Best regards....

[Panama]

Originally posted by jostheim
Just for my own edification,why would overcharge cause high superheat?

James

When the compressor is trying to pump liquid.

[ruud-man]

huh....where did the liquid come from?

[mark beiser]

Originally posted by jostheim
Just for my own edification,why would overcharge cause high superheat?

James

It is not oncommon on a TXV system to have higher than normal superheat at the outdoor unit when the system is badly overcharged.
I have found many TXV equiped systems that were so badly overcharged that the TXV was closing enough that the saturated temperature of the evaperator was near freezing. I have found at least 2 TXV equiped systems that the overcharge was causing the evaperator to freeze up.

It does seem strange to watch the vapor and liquid pressures go up, and the superheat and subcooling go down as you remove refrigerant from the system, but it happens.