What causes high pressure on AC system?
Piston ring blow-by and reed valve leakage can also cause high suction pressures from re-circulation of refrigerant. This is also a cause of low refrigerant flow rate. The condenser will also see a reduced heat load to reject from the decreased mass flow rate of refrigerant being circulated through it.
Can you overcharge AC system?
If the AC system is overcharged, the change from liquid to gas cannot happen, so the compressor starts producing liquid coolant instead of gas. It now has to work extremely hard to pump the excess coolant through the lines. Others who do not have this system end up with a broken compressor over time.
Will low refrigerant cause high head pressure?
The excess refrigerant will accumulate in the condenser, causing high subcooling and high head pressures. If a TXV receiver system is restricted in the liquid line, most of the refrigerant will accumulate in the receiver, with a bit in the condenser. This will cause low subcooling and low head pressure.
Can a restriction cause high head pressure?
Many technicians believe that when any part of the system’s high side is restricted or plugged, head pressures will elevate. This is simply not the case, especially on a TXV/receiver system. A restricted liquid line will starve the evaporator of refrigerant, causing low evaporator pressures.
What should my high side pressure be?
Actual readings will vary according to ambient temperature. The low-side should be near 30 PSI at 90 degrees Fahrenheit or less. Pressure that is too much lower or higher shows there is a problem. On a properly working system, high-side pressure will be about twice the ambient temperature, plus 50 PSI.
What causes high pressure cutout?
The most common cause of a refrigerant high-pressure switch tripping in the wintertime is lack of airflow across the indoor coil. One of the signs of lack of airflow is a high temperature split across the indoor coil. Inspect the filter, not just if it is dirty but restrictive.
How do you reset an AC high pressure switch?
A manual-reset high-pressure switch needs to have an operator manually press a reset button in order to restart the compressor. They are also available with either an adjustable cut-out setting that could be adjusted by a technician, or fixed settings, which cannot be adjusted by a technician.
How does the high pressure switch protect the compressor?
A high pressure switch (HPS) and a low pressure switch (LPS) are protective devices for the compressor and refrigeration circuit. The high pressure switch monitors the system for an inoperative outdoor motor, and/or a dirty/restricted condenser (outdoor) coil. Some switches are reset only from inside the HVAC unit.
Where is the high pressure switch located?
The high-side switch is located on the smaller of the two air conditioning lines close to the radiator on the passenger side of the vehicle. The low-side switch will be located on the largest diameter air conditioning line or on the side of the accumulator (round container) on the passenger side firewall.