Tank will not build pressure beyond 25 lbs. Just runs

check/ replace the non return valve in the line from the compressor heads to the tank

Hi, There are different posibilities. I would need more information. Was it always like that? Does the guage on the main tank and the guage on the regulator both not show more than 20psi? When the auto shut-off is triggered do you feel there is more than 20 psi in the tank?

Remove & check out the ---- Tank Check Valve

If that is good-- then the cylinder head comes off
next & you have a valve problem

If in the past your system can build-up pressure up to 40 psi even if the supply valve is open and water is being used in your house, then your pump impeller maybe already worn out that's why its pumping capacity was reduced.

check air tank drain valve located on bottom of tank, if it is not leaking try adjusting air pres regulator (large black knob close to air hose connection.) the knob when turned in will increase the tank air pressure, if knob wont turn check that lock ring on bottom of knob to make sure it is disengaged. also check for air leaks in all lines and connections

If your compressor keeps running and only builds to 25psi, I would suspect the reed valves, head gaskets or a leak. With the compressor running spray soapy water on all fittings, around the head area and tank components. If no leak is found, remove the air filter and feel for suction at the intake(make sure head is not too hot). If you feel good suction at first then suction is lost after reaching 25 psi, most likely reeds or gaskets (with bad reed valves, sometimes you will actually feel air blowing out of the intake). Good luck

Hi jdenney274...
Your regulator is not working properly...replace it
Please take time to rate me

150 lbs is the amount of pressure in the tank. When you connect a nail gun for instance you cannot nail everything at 150 lbs of pressure, it will blast through. The regulated pressure is at zero because you have the ability to regulate it by turn the know under or beside it to increase the output pressure to your desired amount. I was building a shelf last week and set my regulated to 80lbs with a brad and it blew through the panel and stuck in the floor. After you get to know your nail gun you will be able to regulate it between 60 and 80 depending on the type of wood. Panel - 50 lbs, Oak, 90 lbs, etc. Pleas remember to rate this solution high if it was helpful and explained it to your satisfaction.

Maurader1 an apprentice has this problem solved and is spot on. All these gurus and wiz need to stick to the basic and common sense. The first place your pump will give out after use or abuse is the gasket. All this garbage about defective reeds and defective pressure switch is a lot of nonesense if you first don't rule out the most common problem the head gasket. I'm cheap and this thing has paid for itself 10 time over. You can get a gasket kit for $7, but I fabricated a gasket out of the back of my notebook and sprayed some gasket spray and been working like a charm ever since.

Check the reset button on the motor to see if it tripped. The motor may be overheating. Some motors have an internal breaker and they have to cool off before they restart. Also check the pressure switch. Move the switch back and forth ( on and off ) and listen for a click. If it doesn't click with low to no air pressure then the switch is bad.