Trane 5ton XR12 troubleshooting


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Old 10-03-13, 05:46 AM
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Trane 5ton XR12 troubleshooting

Hello everyone. Could use some help on a strange issue. I have a trane xr12 heat pump. It works fine most of the time. Usually around 8:30 pm a few times a week, I notice the house temp a few degrees above the set temp. I go outside to see the fan running, ice on suction line, and bubbles in the site glass. I checked the a coil, and it was not frozen. I have changed filters and ran my hand across the a coil checking if its clean. It seems to be. I also for grins replaced my stat.

To clear the issue, I turn the unit to fan only for about 15 minutes.

After the ice is gone, pressure while running was 60 and 185 while outside ambient temp was about 70. Led light on board blinks once a second. And there are NO bubbles in site glass. Unit seems to work fine again for a couple days.

This is killing my electric bill. Any help would be appreciated.
 
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Old 10-03-13, 06:23 AM
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clean the coils first if it still does it call a tech to check pressure.
 
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Old 10-03-13, 10:57 AM
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Could use some help on a strange issue. I have a trane xr12 heat pump. It works fine most of the time. Usually around 8:30 pm a few times a week, I notice the house temp a few degrees above the set temp. I go outside to see the fan running, ice on suction line, and bubbles in the site glass. I checked the a coil, and it was not frozen. I have changed filters and ran my hand across the a coil checking if its clean.
Due to the lower outdoor temps, an insufficient amount of refrigerant is being fed to the indoor coil; low pressures & temps are dropping the refrigerant system below the freezing point.

There could be a problem with a heating-check-ball in the TXV not completely closing, or the cooling-check-ball not opening fully. If not TXVs with ball-check-valves, it would be the gate-check-valves malfunctioning...

Also, a restriction in a liquid line filter-drier could reduce the liquid flow to the indoor coil enough to drop the liquid flow sufficient to cause the icing problem & bubbles in the sight glass.

The strainer screen prior to entry to the cooling TXV or other metering device could be partially plugged.

The core problem appears to be that a 'sufficient amount' of liquid refrigerant is NOT being fed to the indoor cooling coil...with an orifice metering device the head pressure could possibly be too low to sufficiently feed enough liquid to the indoor coil. Could be a combination of factors...
 
 

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