AC not cooling enough


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Old 07-17-10, 08:44 PM
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AC not cooling enough

I have a slit system R22 air conditioning system thats not cooling properly. I have installed new air filter, have good airflow at registers. condensor fan and compressor are running have pretty warm air from condensor. checked evaporator coil for dirt. I have an A coil evaporator with airflow vertically up through it, have a fixed orifice metering device. incoming air to evaporator about 77 deg F, air coming out of evaporator 56 deg F, only at about 3/4 of the way up the coils on both sides, from top of coils to about 1/4 way down air is not cool about same as incoming air. on 95 deg day head pressure around 270 psig, suction pressure around 80 psig, suction line temp measured at outside line approx 4 in from service valve 70 deg F. Thanks in advance for any help.
 
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Old 07-19-10, 06:58 PM
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What is the indoor relative humidity?

Originally Posted by jrod40
I have a split system R22 air conditioning system that's not cooling properly. I have installed new air filter, have good airflow at registers. condensor fan and compressor are running have pretty warm air from condensor. checked evaporator coil for dirt.

I have an A coil evaporator with airflow vertically up through it, have a fixed orifice metering device. incoming air to evaporator about 77 deg F, air coming out of evaporator 56 deg F, only at about 3/4 of the way up the coils on both sides, from top of coils to about 1/4 way down air is not cool about same as incoming air.

On 95 deg day head pressure around 270 psig, suction pressure around 80 psig, suction line temp measured at outside line approx 4 in from service valve 70 deg F. Thanks in advance for any help.
This is very important.
What is the indoor relative humidity?


There appears to be a heavy load on the cooling coil.
At 270-psig that is around 122.5-F condensing temperature minus 95-F OAT is 27.5-F condenser temp-split. At around 50 or 60% indoor RH, that is considerably too high a split for a 10-SEER & higher condenser.

The Return-Air could be pulling hot air from the attic or garage...?

What's the temperature of the liquid line so we can also check the subcooling data.

Search: superheat & subcooling

Use both SH/SC to trouble shoot the system.

You also need to know the actual system's CFM airflow through the cooling coil & delivered to the rooms.
 
 

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