Pro-Source 2HP compressor will not build pressure beyond 25psi

by Neil Berman
(Lexington,MA, USA)

Pro-Source 2HP Air Compressor Parts diagram

Pro-Source 2HP Air Compressor Parts diagram

I have a 2HP Pro-Source compressor with a 13 gallon tank, distributed by Big Lots Stores. I've had it for about 4 years, looks pristine, only use it for inflating tires and blowing out my sprinkler system every fall.


This past fall the pressure will not rise past 25psi and the motor would keep running.

After shutting the motor I listened for any air leak sounds -- no hissing and pressure guage showed pressure maintained for over 2 hours, so probably not a leak. Admittedly, I let the oil level get too low, then added 10W30 automotive oil to bring it up to level.

Would that alone cause the problem? After reading many of the posts on your website, I decided to check the reed valves. I removed the head and found the valve plate. I was not aware of any gasket material (but leak-down after shut-off was so slow that I don't think that would explain pressure not building.) The reed valves were not what I expected to see. I expected flexible strips that could "flap" over the ports. Instead I found very rigid "fingers" that could no-way ever close over the ports. ??? were those fingers just limiters and did the flaps maybe vaporize from the extreme heat of running it with low/improper oil and that's why I saw no flexible flaps? I get the impression that the flaps are of a guage similar to Coke can material.


My other question is --- How do I know if it's the reed valves failing or lack of sufficient piston compression for my failure to build pressure?


I USED THE HARBOR FREIGHT SITE BECAUSE IT LOOKED MOST LIKE THE PRODUCT I HAVE. SORRY IF I POSTED ON THE WRONG SITE. I TRUST YOU CAN MOVE IT IF YOU NEED TO. Thanks in advance for any help. Neil Berman
neillex@verizon.net

Comments for Pro-Source 2HP compressor will not build pressure beyond 25psi

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Jan 05, 2015
valve failure?
by: Doug in s.d.ca

From your description, it sounds like the valve(s).

Could also (additionally) be the rings.

Did you happen to take pix of it while it was torn down?

Are you saying the diagram is for an HFT machine?

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