Repair a Taco zone valve?

Old 01-17-17, 07:15 AM
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Repair a Taco zone valve?

A Taco 571-2 zone valve power head isn't working reliably on our hydronic system.

When the thermostat calls for heat the zone valve opens but it wont send the signal to the circulator relay to start the circulator.

Yes, the wiring is correct. I took the power head apart- it's pretty easy. The zone valve has a wax motor and 2 switches. The first switch (like a reed switch) is beside the conical plunger and opens when the plunger is extended to open the zone valve. The 2nd switch (made by Cherry) is mounted on the zone valve frame and turns on the circulator (through the circ. relay). It's wired to terminals 2 & 3 of a 3 wire zone valve.

The problem, I think, is that the 2nd switch has failed. Now, given that the switch probably costs about 10 cents.....does anyone have any experience fixing this sort of thing?

$82 power head is very expensive. There's got to be some way to fix this.
Old 01-17-17, 11:23 AM
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I don't believe Taco offers that switch as a replacement item.
There should be a part number on the Cherry switch.
Post all the numbers you see on it and I can link you to a parts retailer.
Old 01-17-17, 02:28 PM
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A few years ago I had a similar problem on a Honeywell zone valve. Found a replacement switch from an electronics supply (Mouser?) that was identical. Original was riveted on, I had to do some creative mounting, but it has worked fine ever since. I left the ZV opened manually while I found the part and did the repair, so I had some heat. I got a couple of spare switches when I ordered, but haven't need them (yet). Good luck, Steve

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