Overhauling a differential compression tester?

[bruceh]

I have a really old compression tester that seems to need an overhaul. The pressure adjuster no longer adjusts.

Has anyone overhauled these? Is it rebuildable with some fresh O-rings or some generally available standard parts?

A google search has come up blank on overhaul instructions and/or kits. A new one from ATS is $140!

 

[cvairwerks]

Should be a simple diaphragm under the bonnet. As to whether you can get a replacement, that's a different story.

 

[Mark Curley]

Can you substitute another regulator for the defective one?

 

[bruceh]

Can you substitute another regulator for the defective one?

that was the part I was hoping to find a direct replacement for.
I will be taking it apart later to see what is inside and will report back.

 

[RV6_flyer]

The tester is nothing but an orifice made to a certain spec. TWO accurate gauges and the regulator are what I think are the most expensive parts. Any regulator should work. Typically the one supplied with the unit is small and that may be your hardest part to find a replacement for. IF the one you have does not work, I would think that it is worth taking it apart to see if you can find parts to fix it. O-Rings are pretty standard but a diaphragm may be difficult to source.

 

[BoydBirchler]

The tester is nothing but an orifice made to a certain spec. TWO accurate gauges and the regulator are what I think are the most expensive parts. Any regulator should work. Typically the one supplied with the unit is small and that may be your hardest part to find a replacement for. IF the one you have does not work, I would think that it is worth taking it apart to see if you can find parts to fix it. O-Rings are pretty standard but a diaphragm may be difficult to source.

I agree; any regulator will work, Harbor freight has a good selection of small regulators of conveinent sizes. Replaceing the regulator is likely the least hassel and expense.

 

[bruceh]

Just following up. I took apart the regulator, lubricated the 2 O-rings, and put it back together. Now the pressure adjuster works smoothly. Everything inside the regulator looked in great shape for being 30+ years old.

I pressurized my compressor, hooked it up and found that the gauge for the input pressure was way off at 80 psi (and all other values). I popped off the clear plastic cover for this gauge and found that the needle on the indicator was very sluggish and unresponsive. Looks like a new pressure gauge is needed and it will be back in service.

Disconnected from the compressor and it is indicating 12 psi.

Regulator disassembled.

Compressor at 80 psi, and 3 of 4 gauges also showing 80 psi.

Plastic cover off of the left gauge and moving the needle by hand shows that the gauge has probably failed.

Looks like replacement gauges are about $10.

 

[thinkn9a]

From the ATS website - an alternative that includes calibrations, and can be purchased separately from initial buy ( at least in the past)

5-Year Calibration Warranty entitles you to receive 5 annual calibrations of our 2E and 2EM Differential Pressure Testers at an effective cost of only $13.99 per calibration! Calibration warranty also covers replacement of defective components discovered during calibration.