Author Topic: Liquid line temp?  (Read 6965 times)


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Liquid line temp?
« on: June 22, 2007, 01:05:06 PM »
Is there a rule of thumb about the temperature of the liquid line (the smaller of the 2) that enter the compressor when the AC is running? For example - it should be ambient or a little above ambient?
I have a York split system.

What if your liquid line is hot to the touch and hot air is coming out of the outdoor unit fan.

Offline TECH X

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Re: Liquid line temp?
« Reply #1 on: June 22, 2007, 02:21:18 PM »
Yes it should be hotter then the ambient air.  A good rule of thumb, is your discharge saturation temperature should be aprroximately 30F higher then your ambient temperature.  If your ambient is 85F, I would expect a discharge saturation temperature of around 115F, which means your high side pressure for R-22 would be around 245PSIG.  That liquid line temperature subtracted from your discharge saturation temperature, is how you determine your subcooling.  You should be calculating your superheat as well.

You may need to clean your outside coil, it may be causing the higher then normal liquid line temp.
It is normal to have hot air discharging from the top of your outdoor unit.  That is where the transfer of hot air to cooler ambient air takes place, much like how the evaporator absorbs heat into the cooler indoor coil.

Offline acefurnacefixer

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Re: Liquid line temp?
« Reply #2 on: June 25, 2007, 04:33:22 PM »
Also when the cycle is at the beginning the tempature will be higher then at the end.

Offline Fitter597

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Re: Liquid line temp?
« Reply #3 on: August 04, 2007, 10:50:20 PM »
And if your liquid line temp is below outdoor air temp you could have a internal plugged condenser coil


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Re: Liquid line temp?
« Reply #4 on: August 30, 2007, 10:45:56 PM »
If its lower than outside temp its just overcharged. Bascially if its hot, shut the breaker to the unit off and slowly run your hose through the fins without bending them to clean the condenser coil out then you'll be fine, it should just feel warm, 20 or max 30 degrees warmer than outside air temp.

Offline ProTemp

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Re: Liquid line temp?
« Reply #5 on: October 21, 2007, 07:33:58 PM »
Sounds like a dirty condenser your amb air and your system pressures with sub-cooling and super-heat readings are? Also take an amp draw and compare it to the RLA rating plate. Delta T across the condenser coil will help you also. These are very important things to have prior to asking for help.....just my 2 cents 8..