Older Automag Zone Valves

Tom M.

Went to a house that had Automag zone valves. There were two control panels on the wall that had standard 4" electrical boxes mounted over the top half and the bottom half had three large terminals labeled R,W and B. These terminals were a square of copper with what appeared to be 6 or 8 1/4" sheet metal screws to connect to. There were transformers on the 4" boxes. From what I could tell, the valves are normally open. The transformers were putting out about 30V but there was a small square black plastic unit with four white wires coming out that reduced the voltage to about 12V at the three large terminals below. If I had to guess, I'd say this was done in the 60's.

The call was for too much heat and I found an automotive style 2Amp fuse at one of the transformers that was popped so things seem OK for now. The reason I would like to know more is that there are 9 thermostats in the house and there are two zones with pumps and of the seven returns, only two valves in the boiler room. So there must be five of these valves throughout the house. Re-zoning would be costly and I'm sure I'll get more calls before that gets done. Any information would be appreciated.
Thank you.

Unknown

Automag Zone Valves

If I remember those valves run on DC voltage, the small square black plastic unit may be a rectifier to change AC to DC. I have some info somewhere on these I will look for it tomorrow and get back to you.

zibob

Automag zone Valves

Automag black piece with 4 wires is a rectafier, to change voltage to DC, they use electro-magnetic valve head made of wound wire to keep there valves powered close. You should be able to find them or possible a local supplier on the web. Most of the valve are rated for 14' of circulator head pressure, and may be sensitive dirt build up under their seats. The system seems to be a great idea with just a simple wire electro-magnet, the only problem we found is they are sensive to junk in you system. The valve does not have alot of power to over come a dirt in them.

Dana

These zone valves power shut. If there is a power failure they simply open. In the days of millivolt boilers, they would open on a power failure and the boiler would run with the millivolt gas valve and the theory was you would heat by convection. Most systems I see with automags have been changed since the original installation and just don't work this way anymore. The thermostat is wired like a cooling zone so that on a temp. rise, the thermostat closes, (makes), and powers the valve shut. If its a simple T-87, you have to mount it to a cooling sub base. Auto Mag is still in business I believe. You can still get the rectifiers and other parts. The building I took care of with these valves, (200 units), we slowly converted to regular taco zone valves. The boilers were all electronic and wouldn't run without power anyway. If your going to service this system the way it is you should have spare parts on hand, there not easy to come by in a pinch.

Tom M.

Thank You

These explanations make sense. I was thinking that the black thing was some sort of balast like in a flourescent light. I do remember seeing a note on the control panel saying that different numbers of valves could be powered depending on whether they were 9', 14' or 25' valves. Apparently, they close against the flow. I did clean out the one she complained the most about and when I purged the system, I dumped a can of Silver King #5 in. The fuse hasn't blown again as far as I know. Thanks again.