WaterFurnace Heat Pump Woes

[blabath]

I'm a little stumped.
I have a 2-ton Water Furnace Heat Pump in a school that is giving me a hard time.
Background... It appears as though someone has changed the compressor at some time in the past. The unit was installed in 1999.
Originally I had High head pressure (280 psi) and Lo suction (60 psi) in cooling mode with 60 degree water in loop and R-22. The filters are clean, as is the coil and the fan is blowing freely. I diagnosed as non-condensibles, possibly by shoddy workmanship of whoever changed the compressor.
Reclaimed the gas and evacuated to 400 microns. Recharged the unit with 63 oz. of R-22 (per the nameplate data) and turned it back on.
I'm still getting 280/60 in cooling mode and 280 hi pressure and less than 50 suction, at least until the unit shuts down on its lo pressure switch.

Possible reversing valve? I cycled it from heating to cooling several times hoping if it was a piece of crap in the valve it would work itself loose. No good!

Possible bad TXV. The only one I can find is attached to the bi-directional filter and seems to be the TXV for the indoor Coil. Since I cant find a second TXV on the water coil I must assume they are using a cap tube or orifice in heat mode.

What am I missing?
Thanks in advance for your help

[TMS134]

Sound like a slight restriction or TXV issue. With only 60 degree water and operating in cooling mode with the discharge at 280, the head pressure should be deffinately lower. Is there a filter drier? If so, check the temp differential across the drier. See if the TXV is adjustable.

[929rc51]

Sound like a slight restriction or TXV issue. With only 60 degree water and operating in cooling mode with the discharge at 280, the head pressure should be deffinately lower. Is there a filter drier? If so, check the temp differential across the drier. See if the TXV is adjustable.

+1. Take the TXV bulb off and hold it in your hand or put it in warm water and see if it changes anything. If not it is most likely bad if you are sure you have no other restrictions. What is your load in the space @ the time as well? And make sure you have enough water flow through the condenser.

[lwarren]

I would also very your Delta T on the water side. In cooling you should have a 9-12 deg. Delta T.

[bob_scheel]

I would also very your Delta T on the water side. In cooling you should have a 9-12 deg. Delta T.

If you do not have good water flow head pressure would be high, subcooling poor or non-existant, and that would lead to a starved TXV causing low suction. Could also be a limed up water side coil causing this. Check your subcooling and superheat.

[WF_Inc]

blabath,

Unfortunately, without being present at the unit, we are unable to determine what the issue might be. We have a commercial representative in your area. The name of the commercial representative is Capitol R & D, Inc. We would suggest contacting them at (515)273-5170 for further assistance in finding a resolution.

[TwincamDave]

Sounds like the water jacket is scaled up and not transferring heat like it should or water flow. Noncondensebles would give you gages moving up and down corresponding with when it's pumping refrigerant and then air/stuff. Let us know what you find.

[blabath]

I ordered a new TXV and filter from Capitol today. I'll probably put them in this weekend. Thanks to everyone that took time to help me out. I will definitely post my results.

[man from trane]

Not a TXV problem. That would give you lower head pressure if it were starving, higher suction pressure if it were flooding. Bob Scheel could be correct about condenser being scaled up. OR...what size is that new compressor? Could it be oversized? A 4 Ton comp on a 2 Ton condenser might give you those readings.

[jabeu]

is there a filter drier in the system?

[blabath]

:cheers:It might have been the TXV, it might have been the drier. I changed them both ( Easy to do as they are brazed together) and the unit is working just fine now.
Thanks to everyone for their help.

[man from trane]

Doesn't make sense unless it was overcharged. A restriction on the liquid side does not give high discharge pressure unless it's overcharged. Oh well, at least it's working!

[Pascone10]

Guys, we all know we dont have nearly enough info.
OP Your missing a ton of info.. Where is the rest of it? I hope your not trying to diagnose this unit with only pressures...

Water delta T
actual flow in GPM
air temp and delta T
Superheat
Subcooling
Compressor amps

This will get us in the ball park to help you. Without it the manufacturer will be your best friend as they sell you everything in that unit..:angel:

[blabath]

ManfromTrane,
A restriction in the txv would absolutely cause hi head, low suction pressure. Say a big chunk of dirt breaks loose and clogs the inlet screen. The hot gas would condense at a hi pressure, change to liquid, at a high pressure, and eventually see this bigass roadblock in the TXV. Meanwhile, back at the suction side of the pump, the compressor is sucking it's little mechanical heart out trying to draw the liquid through the restriction, to no avail, and the conditions I describe exist. Also, the exact same scenario if the filter was clogged.
After I removed the txv and drier (as one piece since they are brazed together) I scientifically blew through them and noticed quite a bit of restriction. Did the same to the new one just for reference and there was much less restriction. (Evacuated system to 400 microns before recharging to remove all remnants of my funky breath) In either case, at room temp, the valve should have been open all the way.
Also, it was not overcharged. I added nameplate factory-charge amount of R-22 as I stated above. The same conditions resulted after doing this. When I changed the TXV/Filter I used the same gas recovered from the unit and evrything was hunky-dory afterwards.
I'm pretty sure I made the proper diagnoses and repaired the unit properly.
Pascone,
I'm sorry I didn't give you all of the pertinent data ie. superheat, delta t, etc. I DID in my first post and when I spell checked it it erased my post. I was so distraught after typing it all over again that i accidently excuded it from my post.
Thanks again for everybody's help.

[TwincamDave]

"I added nameplate factory-charge amount of R-22 as I stated above. The same conditions resulted after doing this. "

So is it fixed or not?

[blabath]

TCD,
It is indeed fixed!

[TwincamDave]

Go Hawkeyes !!!