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BillyHvac, Journeyman HVAC Tech
Category: HVAC
Satisfied Customers: 22514
Experience:  Endorsed for unlimited heating, cooling, oil burners, boilers, refrigeration, hydronics
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I an Hvac system with low performance. Suction pressure is

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I an Hvac system with low performance. Suction pressure is 10 psi and 125 on the hi side. the suction line is iced over from the unit to the a-coil and the a-coil itself. please advise

You need to thaw the coil and then check pressures, but it sounds as though you are very undercharged.

Do you have refrigerant?

Customer: replied 4 years ago.

Thawing as we speak and I can get refrigerant on Monday. I have no idea how to measure a proper charge or how much oil to add if any. had a service out here two days ago and they said they added some and didn't want to add more because the pressures were to high, when I checked they seemed low.

Keep in mind there formulas for exact charging by superheat and/or subcooling but this is a tough venue to teach that.

The basic pressures for R22 on a 90 degree day...265 head and 75-80 suction depending on indoor temp.

The problem is a cold/frozen coil gives low reading because of ice, but with only 125 head pressure you are very low. There must be a significant leak needing repair.


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