How to Read Ac Compressor Pressure Hihg and Low

Using Gauges for Troubleshooting

Gauge pressure is the first tool in Air-conditioning troubleshooting. The table below shows vii Judge Readouts that you may encounter. Use the Gauge Readout Tool separately or in combination with the table of Gauge Diagnostics for Air-conditioning troubleshooting.

Gauge Readout Tool

Normal Weather condition
Air in cooling system (insufficient suction)
Defective expansion valve
Excessive refrigerant
Moisture Intrusion
Refrigerant does non broadcast
Summary Tabular array of Guess Diagnostics

Normal Conditions

ane Atmosphere
Room Temperatures of thirty-38 C (86 - 96 F)
Engine speed of approx. 1500 rpm or about 75% of rated engine speed

Back to Height

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Air in cooling system (insufficient suction)

Pressure Range
Depression side: 36 to 50 psi
High side: 284 to 356 psi
Indications
Both pressures are Also HIGH
The low-side piping is not cold
Causes
Air in the system
Remedy
Evacuate the system
Replenish the refrigerant
Check the gauge readings
If prolonged operation with air in the organisation, the liquid tank must be replaced.

Dorsum to Height

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Defective expansion valve

Pressure level Range
Low side: xxx to 36 psi
High side: 313 to 327 psi
Indications
Both pressures are Likewise HIGH
Causes
Improper refrigerant charge
Defective expansion valve
Improper temperature sensor installation
Remedy
Verify refrigerant charge
Check temperature sensor installation and insulation
If the refrigerant charge is okay and the temperature sensor installation and insulation are right then replace the expansion valve.

Back to Height

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Excessive refrigerant

Pressure Range
Depression side: 36 to 43 psi
High side: 327+ psi
Indications
Both pressures are TOO High
Causes
Pressure increment due to excessive refrigerant
Insufficient condenser cooling
Remedy
Verify the refrigerant level
Clean the condenser
Check and arrange the fan belt and / or the condenser fan motors

Back to Meridian

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Moisture Intrusion

Pressure Range
Low side: eighteen to 28 psi
High side: 85 to 256 psi
Indications
Low pressure side alternates between a vacuum and normal pressure
Causes
Wet has frozen in the air conditioner system, clogging the expansion valve.
Remedy
Evacuate the organisation
Replace the receiver dryer
Recharge the arrangement

Back to Pinnacle

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Refrigerant does not circulate

Force per unit area Range
Depression side: 0 to -29.99 psi
High side: 71 to 85 psi
Indications
Low pressure side becomes a vacuum
High pressure as listed to a higher place
Frost or condensation on the front and rear pipage connections of the receiver dryer or expansion valve
Causes
Air-conditioning organization is blocked by contagion or ice
AC system is shut off by defective expansion valve or tempeerature sensor
Air conditioning line from evaporator to compressor has kink in the line
Remedy
Stop OPERATION IMMEDIATELY
Check for contamination or water ice
If wet is found then evacuate the system
If the expansion valve is defective then supercede it
Replace receiver dryer
Recharge with refrigerant to proper level
Repair any kinked hoses

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Summary Table of Gauge Diagnostics

 Low Force per unit area Side is TOO Loftier
The low pressure side unremarkably becomes likewise high when the loftier pressure side is too loftier.

Cause	Inspection	Remedy
Defective Thermoswitch	The magnetic clutch switch turns off before the outlet air temperature is sufficiently low.	Replace the thermoswitch
Poor Expansion Valve temperature sensor contact	The loftier and low force per unit area sides judge pressures equalize when the magnetic clutch is turned off (within a short time duration)	Replace Compressor
Expansion Valve opens as well far	Frost has adhered to the suction hose / piping	Install the temperature sensor confronting the low pressure pipe and comprehend with insulating record.
Clogged compressor suction filter	Compressor fitting is absurd but the depression pressure hose is not.	Remove and clean the filter.

Low Pressure Side is Too LOW

Cause	Inspection	Remedy
Insufficient Refrigerant	At that place is little temperature difference between the low and loftier pressure sides.	Repair any leaks and recharge the refrigerant to the correct levels.
Clogged liquid tank (receiver dryer, accumulator)	Considerable temperature departure between the inlet and outlet sides of the receiver dryer during operation. Also, tank may be frosted	Replace liquid tank (receiver dryer)
Clogged expansion valve	Expansion valve inlet side is frosted. Generally the depression side pressure is about vacuum.	Replace expansion valve.
Expansion valve temperature sensor gas leak (damaged capillary tube, etc..)	Expansion valve outlet side is chilled and depression pressure side is LOW.	Clean or replace expansion valve.
Chock-full or blocked pipage	Low pressure level readings subtract or a negative reading is shown. Indicates piping is clogged or blocked betwixt the evaporator curl and the compressor. A frost spot may indicate the point of blockage.	Clean or supervene upon piping.
Defective thermoswitch (cold command)	Evaporator is frozen showing ice along the confront of the coil, not merely frost on the manifolds of the gyre.	Adjust temperature sensing tube to a cooler part of the coil or supersede the thermoswitch.

Loftier Pressure Side is TOO HIGH

Crusade	Inspection	Remedy
Poor Condenser cooling	Muddy or clogged condenser fins, Cooling fans do not operate correctly.	Clean and / or repair the condenser cadre / fans.
Excessive refrigerant	Verify by estimate reading	Employ your refrigerant recovery equipment to capture excess refrigerant. Charge to the correct refrigerant levels.
Air in the system	Pressure is high on both loftier and low sides	Evacuate, vacuum and recharge with refrigerant.

High Pressure Side is TOO LOW

Crusade	Inspection	Remedy
Insufficient refrigerant	Lilliputian temperature divergence between the depression and high pressures.	Repair any leaks and recharge the refrigerant to the correct levels

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Source: https://www.perrinmfg.com/resources/gauge-diagnostics

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