Condor MDR2/11 Pressure switch leaking and adjustment

Condor MDR2 pressure switch

Condor MDR2 pressure switch

I have an older Fini Shuttle direct drive oil compressor.


I am getting leaking air at (5) in the photo, which I think is the pressure relief valve. It only leaks while it is pumping, once it eventually reaches pressure and shuts off, or if I manually shut it off, then it behaves normally and does not leak air.

Where should I look to resolve this? Does this have anything to do with the back flow preventer (2)? Also why is there 2 cut off adjustments (3 & 4)? I think (5) is the differential adjust. Thanks....
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Howdy, and thanks for including the photo.

To identify the parts and what they do, download this pdf:

http://www.condor-werke.de/pdf_files/14_montageanweisungen_leistungsdruckschalter_fuer_wechselstrom/mdr_2.pdf

I tend to agree that the air is leaking from the unloader valve. Typically, if the air leaks out of the unloader while the compressor is running, then it's the unloader valve itself that is at fault.

If air were bleeding out of the unloader valve with the compressor stopped then I would look to the tank check valve leaking (what you call back flow preventer) as the culprit.

Cheers,

Bill

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building pressure

by Norman Henry
(Olney Il. USA)

will pressure up to 35pounds, shut off for a short time and start up again

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Bill says...

Norman, it runs up to 35 PSI and stops for a short time, and then it starts again? When it's stopped, is air bleeding out? What starts it again?

My first thought based on what you've said is that your pressure switch is wonky, but to be sure, I need more details.

Please pull the plug, drain the tank to zero PSI, close the tank drain, and plug it in.

What happens? Please give me details.

Thanks,

Bill

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air compressor builts up to 145 psi and blows the pop off but doesn't cut off why?

by chris

i have change the cut off switch but did not help

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Bill says....

Chris, what is the cut out pressure level of your compressor when it's running normally? Assuming it is below 145 PSI, and the compressor is reaching that pressure level and blowing the PRV, then it pretty much has to be the pressure switch.

If, on the the other hand, the normal cut out pressure is, say, 150 PSI, then that would suggest to me that the PRV itself is at fault.

Cheers,

Bill

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Duplex acp compressor - two motors - one pressure switch?

by Bob
(Pa.)

Hi Bill, Great site. I just inherited a ACP cos 053DP3 duplex air compressor. I have replaced the 2-3 Phase motors with 2-110 volt 1/2 HP 1725 rpm motors. I want to wire up a single pressure switch so both motors run at the same time so it will keep up a higher cfm. Is this possible and how would I go about this? or would it be better to just add 2 separate pressure switches. Thank you for your time. Also is there anything else I would need? Bob
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Good question, Bob. I cannot recommend on this, and invite electrically oriented folks to do so.

Bill

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control valve or pressure switch?

the valve that controls air pressure in tank and regulates how much air pressure and controls max psi and psi kicks off and on at.






Bill answers...

Howdy...I don't see a question here, unless it is "what is the name of the valve" that does all you have noted.

It's not exactly a valve, though it may contain one.

What you are looking for is a pressure switch.

The pressure switch is just that, a switch that opens and closes electrical contacts based on the air pressure in the system.

When the pressure in the tank falls to the preset level, the switch will trip, and send power to the electric motor to begin compressing air.

When the pressure in the tank reaches the high pressure set point, the cut-out pressure, the switch trips off, cuts the power to the motor, and usually at the same time, opens the "unloader valve" to exhaust pressure from over the piston(s).

When replacing a pressure switch care must be taken to ensure, if the replacement switch is an adjustable one, to set the cut-in and cut-out pressures to the same settings as the old switch. That original switch was set to the optimal settings for that particular compressor.

Hope this helps.

Cheers,

Bill

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Compressor runs all the time, won't stop.

by Don
(Prince Albert Sk)

When I use my air compressor it runs all the time.






Bill answers...

Hi Don, hows things out in Sask?

I wish you'd included a bit more info, Don.

For example, when you say it runs all the time, does the pressure increase at all? Does the pressure in the tank continue rising until it blows off the pressure relief valve?

Or, is the compressor motor running, but it's not generating any pressure at all?

In order to offer some advice, I need to know a bit more. Thanks.

Bill

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