Zone valve

WilliamGripp

Came across a Johnson zone valve today that is stuck in closed position. No wires to it just a 1/4inch copper line. I assume it operates on pressure or vacuum from the copper tube. Tried to research on line but could not find anything. Any idea where I can look to get more info? Also could not find any numbers on the valve, just the name Johnson.
Bill Gripp
Gripp Plumbing and Heating

JUGHNE

My best guess would be that it is a pneumatic-air control system. The little I am familiar with them is they are mostly fail safe.....lose the air and everything opens up to max heat position. Air pressure will keep them closed or modulate them to needed positions.
With the normally open valve, if you have air pressure on the tube, (depending upon the pressure there) it is closing it or modulating the valve, if you remove the air it would open unless physically stuck shut.

If pneumatic there would be an air compressor and control panel somewhere in the building. These can be very sophisticated in design. Pneumatic controls was and still is a trade within itself. In their day these controls could modulate devices before the electronic devices were capable of doing it reliably.

Just to mention an observation, our 1977 hospital has fairly involved pneumatic controls installed new with the building.
The additions with rooftop/hvac/zones have probably had the first 2 generations of electrical controls changed out because of failure and unreliability. The original pneumatic still does the steam heating/hot water and chilled water. They have an "old guy" who comes out for maintenance and repairs.

RJ_4

I can help with pneumatic control questions, worked with them for years and was a pneumatic control U.A. instructor.