Taco vs Valemo end/signal switch.

bmw_airhead

I understand how the Taco switch works, closing the signal circuit with a micro switch once valve is open. I am replacing one of the Taco switches with a Valemo switch, which has 4 leads and something called an “end switch”. Can someone explain how that end switch functions to send the signal once valve is open? Thank You. 

EBEBRATT-Ed

Yor two red wires are the end switch, same thing as the micro switch. You need 2 wires to open the valve 1 of them is your common and 1 is the "hot" wire from your thermostat. Those connect to the two black wires

The two end switch wires (red wires) start the pump or boiler whatever the old valve used to start.

bmw_airhead

Thanks, got it! 

Joe Mattiello

sounds like you’re good? Yes, terminals 2, and 3 is isolated end switch to TT on boiler control. Simple closure of switch emulating T stat