Caleffi Z-One valves.

ChasMan

Is there supposed to be a resistor on these somewhere? I have five of these, two had failed end switches and were replaced with the newer reed / magnet. I'm still surprised that the other three microswitches are working. Well, no not really I am being sarcastic. I replaced the Burgess switches with Honeywell switches so instead of a cheap knockoff you get real wiping with real silver so they are ok. But I read somewhere that the reed switch heads should have come with a resistor to limit current through the end switch. My heads did not come with a resistor. Does anyone know if it is needed and what value it should be?

hot_rod

If you are using a Caleffi Z-one with the reed switch type end switch, the resistor is built (molded in ) to the switch now. It has been for several years.

We also eliminated the need for a resistor when using power stealing t-stats.

Read the directions on other brands of relay boxes, some still require you add a resistor to "shed" away that voltage with power stealing stats wired with two wire.

ChasMan

Thanks again. I bought these five just before the switchover, I had two go within a month so I bought two new heads with reed switches and I put new microswitches in the other heads. Not one problem in the last 10 years so I will just let sleeping dogs lie for now. I'm not using power stealing stats just a zone control. I Like these valves a lot. Just wish I could get the label upside right but you have been hearing that for years I am sure.