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Thread: Checking numbers
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07-29-2012, 12:55 PM #27
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What are you readings now.
Originally Posted by daviddsims
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07-29-2012, 01:57 PM #28
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SP=82
DP=255
SL temp=65
LL temp=110
Still not completely happy with the results.
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07-29-2012, 02:17 PM #29
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8SC. Dirty coil maybe.
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07-29-2012, 02:27 PM #30
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Is this a heat pump? If so, measure the rise in temp of the lines across the reversing valve to make sure it is not leaking.
Where are you measuring the suction line temp? is this as close to the evap as possible. and measuring LL as close to condenser as possible?
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07-29-2012, 05:49 PM #31
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No it is not a heat pump. I measured superheat at the outdoor unit and subcooling at the outdoor unit.
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07-29-2012, 07:03 PM #32
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Superheat at the outdoor unit really doesn't tell you much. You should measure it as close to the evaporator as possible. Originally Posted by daviddsims
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07-29-2012, 07:35 PM #33
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Yep, there's quite a difference on mine. About a 6° rise in line temp from evap to compressor. Figuring in pressure drop that gives me about a 7° difference in SH. It's about 103° outside right now and my line set runs through the attic. Originally Posted by dijit
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07-29-2012, 08:03 PM #34
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Yeah I should have taken it at the evap as it does run through the attic and it is 103 here as well.
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07-29-2012, 08:13 PM #35
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Get in the habit of measuring SL and LL temperatures at condensing unit and at evaporator. It will reveal lineset problems.
Aircraft Mechanical Accessories Technician. The Air Force changed the job title to Air Craft Environmental Systems Technician. But I've decided I'll always be a Mech Acc.
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07-29-2012, 08:17 PM #36
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So what is the consensus on this unit? Even adding refrigerant having trouble getting to the 10 degree subcooling on this unit?
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07-29-2012, 08:23 PM #37
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You didn't add enough. Originally Posted by daviddsims
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07-29-2012, 08:24 PM #38
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What is the LL approach temperature? Liquid Line temperature - Ambient temperature if it is pushing 10 degrees may be a dirty condenser coil. If coil is clean it may be non condensables. Originally Posted by daviddsims
Aircraft Mechanical Accessories Technician. The Air Force changed the job title to Air Craft Environmental Systems Technician. But I've decided I'll always be a Mech Acc.
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07-29-2012, 08:28 PM #39
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The outdoor unit has superheat charging chart so I used my Fieldpiece HG3 to get a 12 target subcool. Tell me about LL temp - outdoor rule you referenced?
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