Air compressor slow to build air pressure.

Most likely in tank check valve is leaking or belt is slipping. Belt tension easy to check, should not deflect with thumb pressure. Check valve should not let air escape out of tank. Easy to check. Run compressor till pressure builds to around 50 psi. Then unplug machine from power outlet. Listen for air leaking out of tank. In bad cases, air will actually leak out of intake filter. Replace check valve as needed. Good luck

All large air compressors are very noisy.

How long it takes to come up to pressure depends on the size of the compressor piston(s), how fast they are running and the size of the air tank attached to it. (and if the tank or hoses have leaks)
A 20 gallon tank could easily take 10 minutes to get all the way up to 120 psi. 120 is very high, and probably the limit for the compressor. Depending on what you're using it for, try dropping the setting to say 80-90psi.

It is not opening the bypass valve all the way see if there is a adjustment so that it pushes the valve open farther when it slows down.

Did you inspect lp and hp valves. I would take a close look at the HP valves first,typically bad Lp valves will cause it to build pressure very slowly.

have you turned up the regulator, the big black know by the output fitting

You may have to open andclose it a few times cuz it may have trash or be stuck

hi buddy can be the valves sticking try squirting oil in the air filter and get back to me

It sounds like it is not getting enough electricity.
Try plugging in to an outlet on its own circuit without an extension cord. make sure the circuit is rated for your air compressor. If it is on a circuit with other appliances, refrigerator, lights, ect. try shutting them all off before turning on the air compressor.


Good luck

sounds like the compressor is turning off cause of high pressure. check the coil that the exhaust hose connects to, if dirty clean it. if the fan is not blowing enough air threw the coil the unit will build up high side pressure and cut out, but will turn back on when pressure drops. if that dont help, maybe the fan motor is bad or needs taken apart and oiled.

sounds like you need a new check valve which should be somewhere between the compressor outlet piping,tubing,etc and the tank which prevents the air in tank to back feed to the compressor which would cause hard starting and could damage the motor easy way to check is when you shut off the compressor with some air in the tank if the check valve is bad it would continue to bleed air out out the unloader valve .the unloader valve on your unit is most likely part of the pressure switch when the unit shuts of it should only bleed down the pressure in the pump so it would make it easy to start when needed hope i didn't confuse you

compressor will not build pressure