Reversing valve or what?

[klokmiloco]

Hey guys I have a system that's driving me crazy I have what you could call perfect pressures but only 72 degrees suction line temp. Unit pumps down with no problem ,no ristrictions. So I'm already at a new txv and new compressor and same problem. Unit still under warranty. Only thing I can think is reversing valve bleeding ! It's not noisy or stuck

[FixItRight]

If the reversing valve is bleeding by then your suction will get warmer after the valve and the hot gas will get cooler after the valve. Do you have that or did you check.

[klokmiloco]

About 5 degree difference on suction didn't check hot gas side. But if I manually revese from cool to heat and wait a bit and reverse it again it starts to cool for about 10 seconds but once it stabilizes back to cooling it won't drop from 72 average suction line temp

[FixItRight]

what is perfect pressures and what is your superheat and subcooling?

[klokmiloco]

Subcoolig at 12 low side 79/80 ( 84 inside house). High side 245/250 , evaporator coil gets completely wet when panels on a/h is opened to check coil behavior. (no signs or behavior of restrictions )

[hvacrmedic]

If the reversing valve is bleeding by then your suction will get warmer after the valve and the hot gas will get cooler after the valve. Do you have that or did you check.

The delta between hot gas in and hot gas out will not increase.

[klokmiloco]

Gonna tackle it again tomorrow to see what is temp difference at R V on hot gas , thanks
If I run itin heat the out door coil suction one won't get cold. There for its same behavior for indoor and outdoor coil. It's a Trane heat pump.

[hvacrmedic]

Subcoolig at 12 low side 79/80 ( 84 inside house). High side 245/250 , evaporator coil gets completely wet when panels on a/h is opened to check coil behavior. (no signs or behavior of restrictions )

Measure suction line temp at the evaporator outlet. The TXV controls superheat at that point, not at the compressor inlet.

[hvacrmedic]

Gonna tackle it again tomorrow to see what is temp difference at R V on hot gas , thanks
If I run itin heat the out door coil suction one won't get cold. There for its same behavior for indoor and outdoor coil. It's a Trane heat pump.

You'll be spinning your wheels. It's only the temp rise on the cold lines in and out that you need to measure. Bypassing will not cause a temperature difference across the hot lines in and out. If you pour a beer into a lake, does the can fill up with lake water? Thats an analogy. In any case, it isn't the reversing valve. When a reversing valve is bypassing suction pressure runs higher than normal. Your suction pressure is normal.

[beenthere]

Was the LLFD changed out when any of the other parts were changed?

This is R22?

[klokmiloco]

Yeah r22 new filter drier new txv new compressor , same behavior with both coil if reversed from heat to cool condenser coil won't cool in heating and evap coil in cool. No ristrictions

[heresjohnnyb]

Wow. judging by your first post sir. You should call trane tech support before you replace anymore parts. Make sure your check valves are seating properly and hopefully you changed the dryer. Why again was the compressor changed:gah:

[klokmiloco]

Old compressor every once in a while would trip breaker on start up, new compressor works excellent

[TACKERDOWN]

So its warranty and your not sure if it was like this before you worked on it ? How about some air temps, dry/ wet and if its new you should have a charge chart. Some conditions are going to give you a high super heat what's you Target subcool , what's you temp split on the coil?

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[klokmiloco]

10 degrees sub cooling and I'm at 12 ( bumped it a bit to see if anything change) temp difference is 13 to 14 across coil (return to supply)

[Saturatedpsi]

It's not the compressor, not the reversing valve and you tried a new TXV. Try running the subcooling up 3 or 4 more degrees. If that doesn't do anything, slow the blower, or restrict the airflow some and see what happens.

[gravity]

what is your superheat? sounds like everything is working normal. a bleeding reversing valve in cooling would create a high discharge superheat. what is your discharge superheat?

from over here you could have return air being drawn in from attic which is causing high superheat or too much airflow. could also have a restriction in your suction line.

[beenthere]

I'd put a tap on the compressor discharge line, and I be I would see what w wrong then.

[jhef83]

Did you check supply air temp at furnace or look at the stat? I'm with the guy who said you might be pulling attic air. If that's not it you might pull the bulb on the TXV and see if that changes your superheat. Trane has had a lot of TXV failures.

[jhef83]

80# suction with a 72 line temp would be 24 degree superheat. Your not that far off. Did you leave it running? might look better after the house cools off.

[gravity]

the valves rarely go bad. its 99% of the time the powerhead. Most of the time its not the valve at all its the filter drier restricted which acts like a bad txv.

[klokmiloco]

Changed reversing valve today and pressures still the same but gradually started to cool very slowly took house 2.5 hrs to drop 6 degrees . Improvement but weird on how suction temp started high and took a while to get sweat back on line. Gonna do a recheck tomorrow am

[klokmiloco]

Changed rv valve and filter drier today. Some improvent at last

[jhef83]

Changed reversing valve today and pressures still the same but gradually started to cool very slowly took house 2.5 hrs to drop 6 degrees . Improvement but weird on how suction temp started high and took a while to get sweat back on line. Gonna do a recheck tomorrow am

6 degrees in 2 1/2 hours is actually pretty good. You just may not be able to maintain proper superheat till you get some heat out of the house.

[Saturatedpsi]

Changed reversing valve today and pressures still the same but gradually started to cool very slowly

Thank goodness. You were running out of parts to swap.;)

[TACKERDOWN]

Thank goodness. You were running out of parts to swap.;)

Now that was funny.
I'm curious if you're indoor coil was aluminum. They seem to have a longer balance time when indoor temps are high.

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[klokmiloco]

Copper coil Trane. Went back to recheck and suction temp is 64 pressures are 78 240. House cooled down to 76 still 64 is not right after running for a day. There's no return air from attic ( drawing hot air) duct all good

[beenthere]

Put a tap on the compressor discharge line.

[HVAC_HUSKER]

get temp reading on each side of liquid drier any more than 2 degress replace. get temp reading across rv valve any more than 2 degrees differrence replace.

[XcelTech]

Did you check your return to make sure it isn't getting air from a none cooled space. You might have a system working correctly but you keep pulling in warm air.

[TACKERDOWN]

is 76 degrees all the cooler the house would get or is that what the temperature is set at . is your sub cool at target temp. yet. your worring about superheat when your conditions may not allow you to get it , return air temp. & humidity. it was said before the txv is trying to maintain superheat at the coil what is your super heat at the coil.

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[heresjohnnyb]

I see that nobody saw my post about the check valves. Also trane units already have a port on the discharge before the reversing valve. If you have a check valve bleeding it will bypass refrigerant. The check valve in the outdoor unit is hard to see because it is copper. It has arrows on it tho. The indoor unit may have one built into the expansion valve. If it is external then you will see it in the piping.Also check each distributer in the indoor and outdoor coils to ensure that you do not have a restriction there. What are the model #of your equipment.This would be great help. If you have anything higher than 15 seer then you may have other issues.I hope your equipment is matched from trane.:putergreet: