Lennox KGA060S running hot and high head pressure
Anyone ever have an issue with a Allied(Lennox) running hot with high head pressure? 400PSI He'd and 135 suction. On a 80F day. Need to clean condenser monthly and have burnt through a compressor. Triple vacuumed, with clean gas. It seems to not be able to reject enough heat as liquid pipe temp is 110F. Also attached is some pics of piping in unit. Something seems off with the liquid line manifold piping. Might be by passing part of condenser?
Comments
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Chemically cleaned condenser?
Condenser fan motor amperage and RLA?
Need to follow the condenser piping to know0 -
2 amps on fan 2.4 RLA. Condenser chemically cleaned many times, also split Condenser to clean in between.
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that’s not a condenser that can be split!
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Plugged condenser coil? A thermal image would be insightful.
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what's happening with the evaporator? is it getting cold? how much is getting cold? if i'm thinking about this right, if nothing is restricted it should be flooding liquid back to the compressor at 135 psig suction
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what are the liquid and suction line temps?
i assume this is r410? 400 psig liquid line is only about 115 f0 -
R-410A 135PSIG = 47*F
the high suction will lead to high head.Theres a lot of information missing.
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lower the suction you’ll lower the head!
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Discharge feeding the bottom of the coil and liquid out the top seems odd. Or maybe I am missing something.
You need to check air flow across the evap in and out evap temps. superheat and sub cooling.
Sound like it could be possibly overcharged or the equipment is too small for the load. Check compressor amps to see how hard the compressor is working.
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I will send in some more info, my main question is should the liquid line not be piped into the liquid manifold instead of from the condenser? Like how the discharge is piped? I actually measured the liquid manifold and its almost 10F cooler than the line feeding the TXV. That just does not make sense to me. When I remove gas, my SH gets too high and my head is still over 400psi. Never seen that before
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that’s up th the manufacture. Are mistakes made, yes but rarely.
As your suction goes up so does the head. Lower your fan speed ( measure static before and after) and I think you’ll see the head come down.How did you split that coil?
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The top of that coil is a subcooling circuit. You should be all liquid when you hit those ten passes at the top of the coil, and the outlet temperature should be less than the inlet temperature. Not sure what to make of your temps. Approach is 30°, which is really high, but subcooling is 6°, which might be a touch low.
Superheat? Entering & leaving air temps? Does she make water?
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Can you try bringing the bulb from the TXV out of the air handler into free air and see if there's any change in pressures?
Is there a liquid line drier? Can you measure pipe temperature before and after the drier? More than a degree or two is a problem.
What does the evaporator coil look like?
I don't see a problem with how the condenser is piped. If I see correctly, it leaves the compressor and goes right into the condenser. Leaves the condenser (Red hose) as liquid to the TXV.
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You have to take lid off and corner supports, then clip tie wraps and carefully separate. Hard to clean and need two guys
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I dunno. Just seems odd that the discharge gas goes in the bottom of the condenser and liquid out of the top. Guess it doesn't matter
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can’t say I’ve seen a 2 pass coil that splits!
3 or 4 deep yes.
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I've done it. There's two tube sheets on the far side, it's split down the middle.
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How much gas did you put in? Should be 12lbs 8oz.
The condenser piping is correct.
The suction pressure is in the ballpark.
The condenser pressure is to high.
Verify correct charge,
Verify airflow across evaporator, (static pressure, belt tension, ect)
Verify economizer is functioning properly and remains closed while taking readings.
Verify OEM part#s / specs on condenser fan motor and fan blade,
Check for restricted metering device.
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