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Discussion Starter · #1 · (Edited)
Low pressure is too low (icing suction line). First image is showing pressures with the system running. Second image the system is off after +/- 4 minutes. I am suspecting a constraint on the TXV. Please confirm:)


I need more info about this TXV.



EVAP MODEL: C23-51FC-1
 

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Discussion Starter · #3 ·

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Discussion Starter · #5 ·
I removed sensing bulb but temperature and pressure have not changed. I'm trying to find the TXV replacement. I can't find online.

Condenser: 12ACB48-3P
Evap:C23-51FC-1
 

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Usually there is a 5 digit part # on the sticker or valve itself like "97F56". You need that number to give them and they will match it or cross reference it to the new part# and valve. May need a magnifying glass and to look REAL closely to find it.
 

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Discussion Starter · #8 ·
I found online 26K35. I'll check next week.......Yuri, any input about what I said bad TXV?

why the pressure is different when the system is not running?
 

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That digital manifold can do SH and SC. Use its features.
 

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Yep. You need to completely defrost it and start all over. If a TX valve fails and it is rare with the old ones it will pump down when it starts. Ie: suction pressure should drop quickly while discharge is rising above what is normal (that depends on OAT and load). Need to monitor that at startup. I hate digital gauges and can't tell what you got for readings there. Dial ones and a PT chart is my method. Too much info overload with fancy gadgets is not for me. I like to see the needle move/pulsate/fluctuate and can get a feel for what the compressor is doing. Hard to teach an old dog new tricks.:yes:

The first time you get a load of "blue leak lock" or some other crap a guy put in schraeder valves to seal them and it wrecks those fancy gauges you may see why I avoid them.
 

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Discussion Starter · #12 ·

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Discussion Starter · #13 ·
Coil still frozen?

No

JJ no need to special order a txv,just pick one up at a local supply house. The only time you need an OEM one is if it's still in warranty
So I just need to know the Ton?
 

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It may be a LOT easier for you if you get the OEM one. Should have the same dimensions and fit w/o any alterations. Most of the new Lennox units have special teflon gaskets/o-rings etc so unless that one uses straight flare fittings I would recommend OEM parts until you get a few yrs experience under your belt. Same thing with motors and cond fan motors. Once you understand wiring REAL well then you can use generic parts confidently is my advice.
 

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Discussion Starter · #15 ·
Yep. You need to completely defrost it and start all over. If a TX valve fails and it is rare with the old ones it will pump down when it starts. Ie: suction pressure should drop quickly while discharge is rising above what is normal (that depends on OAT and load). Need to monitor that at startup. I hate digital gauges and can't tell what you got for readings there. Dial ones and a PT chart is my method. Too much info overload with fancy gadgets is not for me. I like to see the needle move/pulsate/fluctuate and can get a feel for what the compressor is doing. Hard to teach an old dog new tricks.:yes:

The first time you get a load of "blue leak lock" or some other crap a guy put in schraeder valves to seal them and it wrecks those fancy gauges you may see why I avoid them.
The suction pressure change from 50psig ( not running ) to 12psig ( running )
 

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Use your old school PT chart. If it is 72 deg F outside tell me what the pressures on your gauges should be when it is not running.

Not sure what they teach you in school but probably nothing "real" useful when it comes to working with flare nuts etc. When you go to tighten them you put some refrigeration oil on the threads, tighten to seat the flare, loosen slightly, re-tighten more and repeat once more to work in the flare and seat it properly.

Not questioning Marty but in general it will be easier for you to use OEM parts and not get stuck with some odd fitting combo when working on other units.
 

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If there's ice on the coil then the standing pressure will be below freezing temp. Once it thaws out then the pressure will be normal.
 

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I wuz hoping he would interpret that. Most newbies just don't know what a PT chart is telling them or how it works in real life. At least mine don't.:no:
 

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Discussion Starter · #20 ·
Use your old school PT chart. If it is 72 deg F outside tell me what the pressures on your gauges should be when it is not running.

Not sure what they teach you in school but probably nothing "real" useful when it comes to working with flare nuts etc. When you go to tighten them you put some refrigeration oil on the threads, tighten to seat the flare, loosen slightly, re-tighten more and repeat once more to work in the flare and seat it properly.

Not questioning Marty but in general it will be easier for you to use OEM parts and not get stuck with some odd fitting combo when working on other units.
125PSIG.....outsite temp was 87F. I don't understand the difference in pressures when the system was not working ...... It would have to show + /-160psig
 
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