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Hot transformer

Boston_2 Member Posts: 107
I have a 3 zone hot water system controlled by an older argo 3 zone switch. Today the Taco fuel mizer started acting funny by rapid fire relay action when the thermostat called for heat (it's been running fine for several months). I disconnected the fuel mizer and everything went back to normal; however, I did notice that the transformer on the 3 zone switch was hot, not hot enough to smoke, but enough that it started to burn my finger. Is that normal and I didn't notice before? The only change I made was adding new Vision pro thermostats about a month ago? Are they drawing more power? Any thoughts on why the fuel mizer went crazy? I am most worried about the temp of the transformer.


  • SWEI
    SWEI Member Posts: 7,356
    WiFi-enabled stats consume several VA apiece. Measure the current in the transformer secondary and consider adding another just to power the stats. Be sure to keep both grounds tied together and do not use separate hots for any of the safety string.