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Low suction and head on 407c conversion
Helped change a air handler out last night due to a leaking coil so I'm not certain the unit didn't have pressure issues before, pulled vacuum down to 475 and held it there. Added about 14oz of POE oil, weighed in 7lbs of 407c inverted and started the unit up only to see the pressures we're about 39 psi and 103psi. Both the suction and the discharge line were cold. Does anyone have an idea what is going on?
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Originally Posted by
ctroxtell
Helped change a air handler out last night due to a leaking coil so I'm not certain the unit didn't have pressure issues before, pulled vacuum down to 475 and held it there. Added about 14oz of POE oil, weighed in 7lbs of 407c inverted and started the unit up only to see the pressures we're about 39 psi and 103psi. Both the suction and the discharge line were cold. Does anyone have an idea what is going on?
Do you any superheat or subcooling numbers?
Do you have what amps the compressor was pulling and its RLA?
TXV or fixed metering device?
Was a new filter drier installed?
Is it a straight AC or Heat pump?
What is the name plate refrigerant charge?
Did you remove all the compressor oil and add all new POE, or just add 14oz of extra POE oil on top of what was in the compressor?
What was the IDDB, IDWB, ODT?
What were the Return and Supply air temps?
What is the model number of the outdoor unit?
We are working blind here with only system pressures. Please paint a better picture of what you are dealing with so we may be able to provide the some insight into the issue you are having.
Instead of learning the tricks of the trade, learn the trade.
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Originally Posted by
rundawg
Do you any superheat or subcooling numbers?
Do you have what amps the compressor was pulling and its RLA?
TXV or fixed metering device?
Was a new filter drier installed?
Is it a straight AC or Heat pump?
What is the name plate refrigerant charge?
Did you remove all the compressor oil and add all new POE, or just add 14oz of extra POE oil on top of what was in the compressor?
What was the IDDB, IDWB, ODT?
What were the Return and Supply air temps?
What is the model number of the outdoor unit?
We are working blind here with only system pressures. Please paint a better picture of what you are dealing with so we may be able to provide the some insight into the issue you are having.
Didn't get a lot of information from it as it was late last night when we fired it up.
It's a Goodman heat pump, pistons inside and outside. Oil was added on top of what was currently still left in compressor (supply house sold the other tech some Super Change and told him that would convert the oil). Filter drier was changed out.
I'm almost curious as to if this system had more than just a previous leak problem.
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Originally Posted by
ctroxtell
Didn't get a lot of information from it as it was late last night when we fired it up.
Oil was added on top of what was currently still left in compressor (supply house sold the other tech some Super Change and told him that would convert the oil).
I'm not familiar with "Super Change".
14 oz of extra POE oil seems like a lot.
I'm really interested in what the refrigerant charge on the name plate says and how that compares to what you put in.
When you go back, try to get more information.
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The unit called for 122oz of R22.
I thought the same thing as far as the amount of oil. The other tech said it was supposed to get 2oz of POE oil per lb of refrigerant. I followed his word and now I'm trying to understand what or why the pressure issues are here.
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Originally Posted by
ctroxtell
The unit called for 122oz of R22.
I thought the same thing as far as the amount of oil. The other tech said it was supposed to get 2oz of POE oil per lb of refrigerant. I followed his word and now I'm trying to understand what or why the pressure issues are here.
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I would stop listening to him!
Do you have any #'s, make, model WAG?
10#'s is a lot.
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Originally Posted by
pecmsg
10#'s is a lot.
He put in 14 ounces ( 2oz x 7 lbs).
Still a lot in my book, unless there was oil all over the place when the leak was found.
14oz of oil on a 2 ton scroll compressor (ZR24K4PFV930) is about 1/3 to 1/2 of the total oil charge.
Instead of learning the tricks of the trade, learn the trade.
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It's a recip compressor I know that much.
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Originally Posted by
ctroxtell
It's a recip compressor I know that much.
Originally Posted by
ctroxtell
The other tech said it was supposed to get 2oz of POE oil per lb of refrigerant.
I would like to know where he came up with that recipe.
Recip. compressors held a little more oil, but even a 2 ton (CR24K7-PFV) only held 45 oz.
With that said, I don't think the additional oil is your primary issue, so it will be good to get some more numbers on the system when you get back.
Keep us posted.
Instead of learning the tricks of the trade, learn the trade.
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Well the compressor called for 43 oz of oil. The other tech just ended up purchasing a replacement outdoor unit and eating the cost (was one of his family members). He opted to do that then spend time trying to figure out what was broken. I'd of still liked to of known what was happening.
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What dryer did you change? The one inside the condenser or outside?
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Originally Posted by
KB Cool
What dryer did you change? The one inside the condenser or outside?
Unit only had the Emerson Biflow drier inside the unit, changed that one out.
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Originally Posted by
ctroxtell
I'd of still liked to of known what was happening.
Us too, but thanks for the update.
Side note: Please apply for "PRO" membership on this forum (it's free), and it will allow you access into the "PRO" forums where you will have access to a vast amount of knowledge in this industry.
We go into a significantly greater amount of troubleshooting detail, and provide manuals when needed.
Instead of learning the tricks of the trade, learn the trade.
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Originally Posted by
KB Cool
What dryer did you change? The one inside the condenser or outside?
This made me chuckle a bit haha
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Take ten minutes of pressures and temperatures?
Write them all down?
Spend five minutes analyzing them to see what the problem is?
Nahhhh; no time for that crap - just put a new unit in!
PHM
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Originally Posted by
ctroxtell
Well the compressor called for 43 oz of oil. The other tech just ended up purchasing a replacement outdoor unit and eating the cost (was one of his family members). He opted to do that then spend time trying to figure out what was broken. I'd of still liked to of known what was happening.
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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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Did you replace the piston in the AH with an R-22 piston?
What refrigerant was used in the new condensing unit?
PHM
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Originally Posted by
ctroxtell
Helped change a air handler out last night due to a leaking coil so I'm not certain the unit didn't have pressure issues before, pulled vacuum down to 475 and held it there. Added about 14oz of POE oil, weighed in 7lbs of 407c inverted and started the unit up only to see the pressures we're about 39 psi and 103psi. Both the suction and the discharge line were cold. Does anyone have an idea what is going on?
Sent from my Nexus 6 using Tapatalk
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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Originally Posted by
Poodle Head Mikey
Take ten minutes of pressures and temperatures?
Write them all down?
Spend five minutes analyzing them to see what the problem is?
Nahhhh; no time for that crap - just put a new unit in!
PHM
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Yeah, I was just helping him out...When it ran it was running about suction 39 psi over liquid of 101 psi. Thing was both liquid and suction lines were cold, liquid wasn't quite beer can cold like the suction was. Didn't grab temps since it was almost 11pm.
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He replaced the piston when he got the new condensing unit. When attempting to run 407c he had the old piston still in it.
The new condensing unit was a 410a charged unit.
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He sounds like he might be stupid. <g>
And just guessing about everything.
PHM
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Originally Posted by
ctroxtell
He replaced the piston when he got the new condensing unit. When attempting to run 407c he had the old piston still in it.
The new condensing unit was a 410a charged unit.
Sent from my Nexus 6 using Tapatalk
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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