two compressors together

[koch68]

I hooked two of the same size compressors together for more air storage but I just have low pressure coming out of the lline. There is a line coning from each compressor to a tee then to a air dryer mounted to the bench with a fitting. No pressure regulator. Please help

[sargentrs]

They're fighting against each other? Most compressors have a 1way check valve going into the tank so the air in the tank won't fight back against the air from the compressor feed.

[averagef250]

Compressors have a check valve between the pump discharge and tank to prevent the exhaust valve from holding tank pressure when not running.

There's nothing wrong what the OP describes. Compressors with multiple pumps are commonplace, they're called duplex compressors and the pumps are staged into lead and lag modes, with roles being transferable so the run time can be broken up between pumps/motors. Sounds like some basic troubleshooting needs to happen (like pressure gauges to show what's happening or remove the drier and see what happens).

[koch68]

So what I have been doing is running one at a time off and on. So both tanks get filled. But your saying if I run one compressor and not the other the check valve won't let it fill the other tank? Do I need to run them at different psi?

[Cipher43]

Have you checked the dryer you are using? we had one cut the air pressure down when it was plugged so i would check the pressure before the dryer to see if you have it there. Also how big are your feed lines to the dryer? if both tanks have a gauge telling you how much air is in them let all the air out of both and turn on one compressor and see if both tanks fill to the max pressure they normally do because if they do you must have a different problem than the tanks being full.