Central Pneumatic #47065 stops at 40 PSI?

by Sam
(Virginia)

I have a Central Pneumatic Vertical air compressor (Model # 47065-125PSI, 21 Gallon, 4.5 Peak HP). The compressor worked fine when it was purchased 3 years ago. Now, it will not build up to rated psi.

I put the valve control in the off position. I checked the oil to make sure it is adequate (on the specified red marker). I turn on the compressor to allow it to build up pressure. It takes about 15 minutes to reach 40 psi and stays there. The compressor never cuts off. I have let it run for a period of 30 minutes and no increase in pressure occurs.

After shutting off the compressor, the tank maintains a pressure of 40 psi (waited over 24 hours). I have not found any leaks ( I drained the tank using the valve underneath just for the hell of it - no changes).

Is it broken? Or , is there something quite simple I am missing. Clean the air filter? Adjustment?





Bill says...

Hi Sam. Yup, she's broken.

There are a bunch of reasons why your compressor won't build pressure, and topping that list are valves and gaskets.

Read the info on these pages.

Cheers,

Bill






Comments for
Central Pneumatic #47065 stops at 40 PSI?

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Oct 23, 2011
 complaint
by: AnonymouseEARL

I have same trouble with my model94667 it gos to 20 lbs and runs but wont pump up is this a piece of junk like to hear from some one from centeral pneumatic disapoited earl
Sep 25, 2011
 update
by: Anonymous

Sam, I have the exact same unit except it only ran for one summer. Now motor runs but won't fill past 40psi and Harbor Freight doesn't want to even offer any support because they stopped selling them. Did you ever solve your problem? Hate to toss the thing since the motors running!
Aug 28, 2011
 Your pressure valve is broken
by: Weirdnerd

Remove the four bolts on the piston head, remove the piston head carefully not to break the gasket, you will find there is an inverted "V" metal piece, remove it, (it has two Phillips head screws), under it there is a "flapper valve" made of thin spring steel, most likely that part is broken,and it will allow air to return to the piston, that part works as a "check valve" that prevents the air from the bottle to return into the piston. You can make a new "flapper valve" with a feeler gauge strip using an angle grinder and a #40 drill bit being very careful...That's what I did, make sure you hold the piece in a vise, and use gloves, safety glasses,or a full face grinding visor and thick clothing , steel shards can be very dangerous,and blood stains are hard to remove from clothing.

Once you have the "new" valve, reinstall it in reverse order as you disassembled it, make sure you tighten the bolts in a criss cross order, not to crush the gasket.
May 13, 2011
 parts
by: Anonymous

Good luck ordering parts, many of the gaskets are no longer available. Boggles the mind. If you are not comfortable making your own, then you're up the creek
Jan 21, 2011
 Call Harbor Freight Parts
by: Anonymous

If you are getting a good amount of air blowing out the intake you probably need the following from Harbor Freight Parts:

28153 03B 47065 GASKET $1.00
28727 04B 47065 VALVE SEAT $2.37
28471 05B 47065 GASKET $1.00

A fairly inexpensive repair if your are comfortable with doing it yourself.
Jan 20, 2011
 Broken Exhaust Valve
by: Anonymous

I have the same problem with A 40 PSI max. The exhaust valve is a horse shoe shaped reed valve that splits in the middle over time. I need a new valve plate and gasket set which I am in the process of ordering from HF.

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