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Possible TXV Probem fixed ?

Posted by scruffy12 (My Page) on
Tue, Apr 10, 12 at 20:51

Have a Lennox 2.5 ton and had a problem where between cooling cycles compressor would go into overload. Installed a hard start ( a good one with time dely etc. ) and sometimes with that it would not start on the first go around.

My neighbor down the street who is a well retired disabled HVAC guy ( 89 years old ) hooked up his gauges and found that the pressures were taking about 20 minutes to equalize. This problem was on going for about a month. Freon charge was good.
( I don't have the readings we took ).

He suspected a defective TXV valve so he had me take all he insulation off the TXV bulb and found it was not securely attached to the evaporator outlet line. On inspection there was a lot of green and white stuff on the bulb and line which lookied like heavy corrosion.

I cleaned it up with a fine sandpaper making the copper on both sides shiny. He then had me apply a small amount of heat sink compound to both surfaces and remounted the TXV bulb and insulated.

Now the problems seems to be fixed..what I need to know is if the bulb was not getting the proper temperature to regulate the flow of refrigerant would this effect the valve operation. His thinking is that it may have been flooding the compressor.

Now the cooling is fantastic as it seemed over the past few months it was not cooling as good as it always done. He said to leave the hard start in as it will do no harm.

Whats you opinion on this as its been cycling fine for the past 3 days here in warm Florida.


Follow-Up Postings:

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RE: Possible TXV Probem fixed ?

Sounds like you should hold on to him.


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RE: Possible TXV Probem fixed ?

"if the bulb was not getting the proper temperature to regulate the flow of refrigerant would this effect the valve operation."

The temperature is what makes the valve operate.

Wrong temp, bad performance.


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