Technotrans beta.c

I was called into look at the Technotrans beta.c unit that cools water for our Manroland sheet fed press. I was told that the water temps were too high and that they had reset the high pressure switch on the compressor, but were not sure if it had helped. I went outside to make sure that the condenser fan was working like it should, which it was. The compressor was cycling on and off over, maybe a 30-40 min period (not short cycling). I put the refrigeration gauges on and checked the pressure. The pressure was well below the limit of the high pressure cutoff switch.

Time to call the tech.
I call Technotrans and explain the problem. The tech wants the serial number so as I am looking for it, opening doors, I see another compressor. He says, yes the smaller compressor on the left is the one that cools the chill water. I pushed the red reset button, and what do you know, it comes on and starts cooling the water. The tech tells me that I should check the pressure  on this one as well. If the pressure is in the 250-270 range then there is an oriface that needs to be cleaned. I measured the pressure and it was in the 200 psi range which is good.

This is the compressor that was tripped, and the on that controls the chill water

To the left of the brass 90 degree elbow is the orafice that would have needed cleaning.

So, call that tech, it is what they are there for. I wanted to get all the information about the problem before calling, but I was getting information about the wrong compressor.

Calibrating a pneumatic thermostat

Pneumatic thermostat

Tools needed: thermometer, Allen wrench tool, and needle pressure 

gauge

Use the Allen wrench tool to remove the cover. Turn clockwise to  turn the screw into the  base allowing the cover to slip over the head of the screw.

Adjust the temperature so that the edge of the black dial is lined up with the measured temperature. This one is set  just below 76 degrees.

Push pressure gauge into the hole as shown. Insert Allen tool into adjustment screw. Adjust until the gauge reads 9 psi. Be careful, adjust slowly, it is also sensitive to the heat from your hand.

You can also adjust the temperature reading on the front display, so that it will better reflect                                                   the actual temperature of the room.