Hydrovane Pressure Switch

[wilksy]

I have a Hydrovane 5 PURS which I have had from new, I have recently rebuilt the compressor with the correct maintainance kit and service kit and it produces air like it was new. However I have a problem with the pressure switch (which was a problem before I rebuilt it) it basically does not restart when the pressure drops.

It will start fine on the on/off switch but the only way I can get the compressor to restart is to operate the on/off switch which is a real pain.

The pressure switch is a Condor MDR4 ST11 which is no longer available, could any body help me with the problem or replacement part.

 

[Gary900r]

Is it single phase or 3 phase.
Is the motor running at the correct amperage. These pressure switches will stop the machine if its running and drawing too much current.

 

[piman]

Hello Gary,

"These pressure switches will stop the machine if its running and drawing too much current."

Are you sure, that sounds rather unusual?

I would have thought any generic pneumatic adjustable pressure switch will do the job. Motor overloads are normally in the control box?

Alec

 

[madkayaker]

on mine the overload is in the pressure switch and there is no control box.

 

[Gary900r]

To keep costs down Hydrovane used pressure switches with built in overloads and no control box as Madkayaker has. With a small box mounted on the side of the pressure switch they were also able to add a airend over temperature thermistor.
Recently they have changed to a control box with separate pressure switch.
The pressure switch needs to have a amp rating for the motor.

 

[madkayaker]

have you tried cleaning it. try contact cleaner (unplugged) it might just be junked up

 

[wilksy]

Thanks for the replies, the motor is a 1.1Kw single phase unit nothing has been changed except for the miriad of o rings, gaskets, filters and of course new 2000 oil. I have owned this unit from new since 1993.

When I tried it tonight it cut in when the pressure dropped but didn't do so the next time.

Silly question but to clean it do I just remove the top cover and spray the exposed conntactors?

I also have a Hydrovane HDD 2A Incandesiant Dryer but it seems to have seized up - is this unit easy to sort out or shall I just throw it away.

 

[Gary900r]

Occasionally part of the pressure switch wears slightly forming a ridge on a actuation pin. Try decreasing the cut out pressure slightly.
If you don't need the dryer bypass it they use between 15-20% of the compressors output. They are simple to work on but some parts are obsolete and others expensive.
The dryer would have been made by Domnick Hunter and rebadged by Hydrovane.