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High side pressure going up and down from 300 to 400. No exspansion valves on unit. What's going on ?

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Possible over charge or air flow problems through condenser

Posted on Jul 13, 2009


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2005 vw jetta why won't my high side high pressure go down

I assume you are talking about your a.c unit, if so the high side pressure takes a while to go down after turning a c off, it its too high it is either overcharged or there is a restriction

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How to pump down there are not contractor

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Since this a not the auto or truck area you might want to repost this there.

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Poor air compression

I would guess from the info supplied that the pressure switch is shutting it down at 125. Most piston type compressor only pump a max. of 175 unless it is a special high pressure unit. Also it may be shutting down on high amps, high temp etc.However with all that said Piston units are positive displacement, meanning that it should pump until something gives. Start your unit, close the discharge air valve and see what it pumps up to. May have to adjust pressure switch to get over 125. If unit runs and runs and just will not go over 125, you probably have a valve going bad. Do you have a safety lifting. if so another indication of a bad valve.

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Where is the low pressure schrader valve for the air conditioning

Usually mounted on the larger copper line going into the condenser on split systems right next to the high side (smaller copper line). On window units their is usually no valve to access. you must add a saddle valve or bicycle valve to the low pressure side. (Larger copper)

Sep 27, 2011 | Heating & Cooling

1 Answer

Yesterday my ariston boiler made a loud noise and water burst out from the boiler what can be the problem?

The pressure built up in the boiler and the relief (safety) valve released some water to relieve the pressure...
Either the exspansion tank is bad or the fill valve is leaking by...
This causes excess pressure to build in the boiler...


Aug 27, 2010 | Heating & Cooling

1 Answer

High pressure side too high.

Either the unit is over charged, the exspansion device is clogged, or the condensaer fan is not running need to figure out which of these things could be causeing your high head problem..

Here is a tip about trouble shooting your air conditioner...

Air Conditioner Trouble -Review the Possibilities


Aug 14, 2010 | Heating & Cooling

1 Answer

I hook my gauges to the condensing unit on the A/c I'am working on. The problem I am trying to solve is: High side pressure is going up and down from 300 to 400 every 10 seconds. This system dose not have...

Im thinking you might be over charged...too much will pop off on high head if over 400...other wise no airflow through the condenser will cause this

Jul 13, 2009 | Heating & Cooling

1 Answer

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Check the exspansion valve its part of the evaperator on that car for being clogged.

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Ac not working Dodge ram 2500 diesel

compressor is shot ,replace it and dryer orfice tube or exspansion valve

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