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  1. #1
    Join Date
    Feb 2010
    Location
    Seattle, Wa
    Posts
    6

    Indoor coil freezing up

    split system - r22 with fixed meetering device carrier condenser and goodman gas furnace 100k btu. This is an old unit in one of the our fire stations. pre inspection, after unit was thawed showed clean filter - we change them out quarterly, clean indoor and outdoor coils, airflow good on both coils, voltage and amps good. Low side was 40 psi and high 190 but due to quickly freezing up I din't have a chance to check the superheat and subcooling. I recovered the refrigerant, nitro pressure tested it with no leaks. Although they looked clean, I cleaned both coils, orfice for the fixed meetering device (screen look debris free) and replaced the filter drier. Pressure tested again all good. evuacated the system and charged the system. Had a hard time getting all 7lbs back in the system. Suct pressure was good 65-70 psi, super heat 12 subcooling in the 40s Discharge was 290 and raising quick. vsp was 45deg and lst was 110 deg. Any ideas would be much appreciated.

  2. #2
    Join Date
    Aug 2001
    Location
    Mechanicsville, Virginia
    Posts
    1,398
    Quote Originally Posted by osci View Post
    split system - r22 with fixed meetering device carrier condenser and goodman gas furnace 100k btu. This is an old unit in one of the our fire stations. pre inspection, after unit was thawed showed clean filter - we change them out quarterly, clean indoor and outdoor coils, airflow good on both coils, voltage and amps good. Low side was 40 psi and high 190 but due to quickly freezing up I din't have a chance to check the superheat and subcooling. I recovered the refrigerant, nitro pressure tested it with no leaks. Although they looked clean, I cleaned both coils, orfice for the fixed meetering device (screen look debris free) and replaced the filter drier. Pressure tested again all good. evuacated the system and charged the system. Had a hard time getting all 7lbs back in the system. Suct pressure was good 65-70 psi, super heat 12 subcooling in the 40s Discharge was 290 and raising quick. vsp was 45deg and lst was 110 deg. Any ideas would be much appreciated.

    Your stated pressures, superheat and subcooling values don't jive with your stated saturation temperatures.

    Recover refrigerant until you get some stability with your pressures and temps, then repost your measurements. Include ambient, indoor dry and wet bulb as well.
    "If perfection is your goal, you may end up with good enough, what might you end up with when good enough is your goal?"
    efficientcomfort.net

  3. #3
    Join Date
    Feb 2010
    Location
    Seattle, Wa
    Posts
    6
    will do thanks

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