Tools, Sharpening and Power Machinery - Regulator problem on compressor

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dc-in-md
03-28-05, 12:01 PM
:wall:

Good afternoon.

I have problem with a small twin-tank portable compressor. I can not regulate the output pressure. I thougt it had a bad pressure regulator so I changed out the old unit with a new unit. (THE PROBLEM is) I still can not regulate the air pressure. Instead of keeping the tank pressure at 135psi and the output 70 psi ... it bleeds down the pressure in the main tank to 70.


I know how it is supposed to work: I just can not figure out why this sucker will not work like I know it should. Any ideas what's up????

I even tried installing a second pressure regulator from another compressor and it did the same thing.

HELP!! :wall: Thanks!


GregH
03-29-05, 01:56 AM
dc-in-md,

What does the output side of the regulator go to when the pressure is turned up.
Also, why does the compressor not start when the pressure drops.

To be clear though, you are talking about an electric compressor, right?

dc-in-md
03-29-05, 08:08 PM
When I adjust the regulator pressure down it bleeds off out of a port in the regulator. If I set the regulator say for 40 PSI the main tank pressure will bleed off until the compressor kicks on and runs up to the cut off point. It will keep cycling like that. AND... yes it is an electric. :confused:


GregH
03-29-05, 08:31 PM
dc-in-md,

There might be two things going on here.

When you back off the pressure regulator and say the compressor comes on at 70 psi, the pressure switch might not be set correctly.
A normal differential would be about 30 psi or so.
If the control opens to stop the motor at 135 psi like you said it is, it should close at around 100 psi to start the motor again.

The problem of the regulator bleeding off the pressure sounds like a damaged diaphram in the regulator.
If the regulator pressure is lowered, it is normal for the air that is within the reg to bleed off, but only the air is within the regulator body itself.

Are you absolutely sure the regulator is connected correctly.
I have had regulators where the fittings were in a cross arrangement and you had to pay close attention to which tap was which.

dc-in-md
03-30-05, 08:12 AM
Thanks so much for your help.

Well as far as I know I installed it in correctly. It's a Ingersoll Rand, regulator and gauge. Parts numbers 37992849 regulator and 56279383 gauge. It was recommended for single stage compressors up to 135psi. Regulator is the mini type with 1/4" ports. It is laid out in a standard pattern with 1 port on each side. I have it setup with air supply going in on one side and exiting on the opposite side. I would have to go back and look but as I recall the gauge ports are not 1/4" so I don't think I have them installed wrong.

GregH
03-30-05, 12:26 PM
dc-in-md,

Most guages have a flow through configuration, maybe check the direction of flow.
If not a ruptured diapram, then another reason the relief will vent is if the input pressure is above the guage's operating range.
Check the guage on the compressor to make sure you are not unknowingly operating at 250 psi! :eek:

What I would first do though is remove the regulator and make sure the compressor is cycling at between 100 psi and 125 or so.

One problem at a time and the compressor pressure must be the first thing you fix.
There should be a diagram under the cover for the pressure switch that will tell you which screw is which.
If you need any more info we will need the make model of the compressor and pressure switch.