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Liquid line temperature fluctuation
When checking the subcooling on a R-22 system the liquid line temperature fluctuates from 94°- 105°. Does anyone know what could be causing this? I have tried searching Google but can not find anything on this
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Expansion valve metering,restricted drier,kink in copper somewhere. Need more data from ya so we can have a better idea on direction. When asking for help have the data posted in your post!
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Originally Posted by
Hurst11
Expansion valve metering,restricted drier,kink in copper somewhere. Need more data from ya so we can have a better idea on direction. When asking for help have the data posted in your post!
Thanks for the reply. I was checking the subcooling on the r-22 system. The line side pressure was 260psi and the temp clamp on the liquid line near the compressor was reading between 94°-105°. The air temp drop between the supply & return is about 19-20°.
What other information do you need?
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What type of metering device TXV or restrictor, is it split or package, if split how is line set run is evap above cond unit, how much.
If TXV and they start hunting you can get wide swings in liquid line temp.
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TXV or fixed?
Need subcooling, superheat and all line temps.
IDDB and ODDB temps
is the liquid pressure staying constant at 260 and just the liquid temp changing
Is the suction side stable or fluctuating as well
Filter dryer installed?
Are fans and blowers running at a constant speed
Sounds like possible restriction but more likely non-condensibles such as air, water, etc in system
Verify your equipment is working too on that temp clamp?
Need all the info you have to diagnose the the problem as every system is different and everything changes with indoor/outdoor conditions
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Originally Posted by
Shogun88888888
TXV or fixed?
Need subcooling, superheat and all line temps.
IDDB and ODDB temps
is the liquid pressure staying constant at 260 and just the liquid temp changing
Is the suction side stable or fluctuating as well
Filter dryer installed?
Are fans and blowers running at a constant speed
Sounds like possible restriction but more likely non-condensibles such as air, water, etc in system
Verify your equipment is working too on that temp clamp?
Need all the info you have to diagnose the the problem as every system is different and everything changes with indoor/outdoor conditions
Txv, no filter dryer installed, suction pressure steady, liquid pressure steady, fan constant speed
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What was your suction pressure and superheat doing during all this, how about compressor amps, was anything causing the load to change, how long had system been on-did it have time to stabilize, was there a trouble call of insufficient cooling or was this just an observation........? Food for thought. Hurst11 had a great idea, develop a list of data you need to record during your system check out. The road to learning is full of hard knocks😅
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I've seen something similar to that on a split system with an under sized liquid line.
I do a triple evac with nitro to remove non condensables.
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Post Likes - 1 Likes, 0 Dislikes
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Originally Posted by
BBeerme
I've seen something similar to that on a split system with an under sized liquid line.
Good tip
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I don't know - but let's talk about it anyway.
According to Mr. Newton actions are the result of force-pairs. As a refrigeration system is like a little closed universe - it seems that in order for the liquid line temperature to fluctuate - some other factor in the refrigeration system must also be fluctuating in order to cause the action which you are observing.
"fluctuates from 94º to 105º" over what period of time? A few seconds? A minute? An hour? A week?
Factors which would alter LL temp are ambient air (or water) temp, head pressure, discharge superheat, a metering device adjusting itself, excess pressure drop, air (or water) flow volume changing - that's all I can think of right now.
If would be real handy to know the following -
System application:
Refrigerant: R-22
Ambient temp:
Cond. leaving air (or water) temp:
Head press:
Suction press:
Liquid line press:
Discharge temp:
Cond. liquid line temp:
Metering device liquid line temp:
Evap. suction line temp:
Comp. suction line temp.
Subcooling: 94º to 105º
PHM
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Originally Posted by
Keith85
When checking the subcooling on a R-22 system the liquid line temperature fluctuates from 94°- 105°. Does anyone know what could be causing this? I have tried searching Google but can not find anything on this
PHM
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When faced with the choice between changing one's mind, and proving that there is no need to do so, most tend to get busy on the proof.
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PHM pretty well has it covered. Sub-cooling swings, then the suction superheat swings, then suction pressure swings. ..
Pumpdown test for non-condensables.
Measure sub-cooling at condensing unit & at the evaporator. if split unit.