takes lomg time to build pressure

by Brian
(MN)

Older Craftsman 3.5Hp 15 gallon model 919.153531 Flow valve leaks air and I replaced with a plug. This just takes pressure off cylinder for start up I assume. The unit builds full pressure to 120psi but takes alot longer. I'm guessing time for a cylinder and piston ring redo?? But looking at Sears web site parts are not available. Any options?


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Bill says.../b>

If by flow valve you mean unloader valve, check out the check valve page linked from VALVES. That is likely why your unloader valve leaks. Plugging it isn't the solution, as you are creating an overload on start up that isn't good for the compressor, or the supply circuit.

How is the intake? Is it pulling air in when it's running? You may have a valve issue, or you may have a gasket leak internally, and I would address these to make sure they weren't the cause before embarking on new rings or repairing a possibly damaged cylinder.

Your repair cost needs to be weighed against the cost of a new compressor. If Sears can't help, then check the REPAIRS page for a build it shop near you, or ask your local stores where they get their compressors repaired under warranty, and see these folks.

Cheers,

Bill

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Jan 30, 2012
status update
by: Brian

Finally got around to looking at this unit. All the reed valves look fine. My guess is it is a worn cylinder sleeve and rings. Sears does not carry parts. Is there a way to cross reference to DeVilbiss who was the original maker??

__________________

Good question. It were me, I'd ask Devilbiss directly.

www.devap.com



Dec 20, 2010
Followup
by: Brian

Well Sears calls it the Flow Valve DAC-140 part
#76 on their diagram. Small plug on cylinder head that blows air at startup until some pressure builds up. I think my cylinder got hot and melted the diaphragm in it. The plug was a temp fix to see if I could build pressure. The unit pulls in air and will build full pressure and shut off. Just takes a really long time. That is why I'm guessing wear on internal parts. I haven't pulled it apart to look yet. Have a small project to finish first. But with age of this unit and parts seemingly not available it may be time for a new one. Hard to find a new unit with adequate air capacity as this one with 8.5cfm @40psi and 6.8cfm @90psi. And running 120 volts. Any reccomendations? Thanks for the help.

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have a 33 gallon 220 volt craftsman dry compressor takes 25 minutes to build up what is the normal tme for it to build to 125 psi?

by Rich
(nc)

33 gallon 220 volt compressor takes 25 minutes to build up to 125 what is the normal time for this compressor

_____________________
Bill says...

Rich, I have never put a stop watch on a Craftsman air compressor as it builds pressure, yet I would think that at most, from 0 PSI in the air tank, maybe 2-3 minutes if there were no leaks?

So, take a look at the TROUBLESHOOTING page for the link "compressor will not build pressure" and have a look at those pages for some tips.

Cheers,

Bill

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