2015 a/c, low high-pressure

[sbagdon]

Trying to debug a 2015 a/c issue. a/c static pressure is about 65-70psi, and the compressor clutch activates. With the clutch active, low-pressure goes down to about 25-30psi, while high-pressure only goes up to about 125psi... expect high to go up to 150-175. Vents show ambient temp, with compressor running.

Any thoughts on why low would go to 25-30psi, yet high to only 125psi? Has the compressor gone bad, that it will attempt a vacuum on the low side, yet can't push out more on the high side.

Thx.

[mdmellott]

Sounds to me that you may simply be low on refrigerant and need a recharge. Low pressure side needs to be measured while running the a/c and recharged at the same time until it measures correctly. The high side will in turn increase in pressure as more refrigerant is added. Do not overcharge (measured on the low pressure side) or else the high pressure switch will cut off the compressor clutch function.

[sbagdon]

Tried to recharge... fresh 1lb bottle of R134, low pressure side, system running, dipped in hot water. No change in pressure after 5min. Will try again.

[mdmellott]

Dipped in hot water? Don't do that. The recharge bottle should be held upside down while filling the system so that liquid is delivered into the line. If held upright, the R134 bottle will expel vapor, the bottle will freeze, and so will the fill line hose. It should only take a minute or two to empty a bottle into the system. If held upright the vapor will freeze inside the fill hose and prevent proper filling. The fill line should have a pressure gauge attached to monitor the pressure while filling. Do not overcharge the low side pressure. The high side pressure will take care of itself so there is no need to monitor that unless the low side never gets up to proper pressure while recharging. It that is the case, you are probably looking a badly leaking system and need a service technician to evaluate the problem.