URGENT: Weil Mclain Wiring

Sep 21, 2006 5 Replies

We have an old Weil-Mclain Steam boiler at our business and we want to add a new thermostat and have no idea which of the two wires go to which connection. Weil-Mclain does not assist owners....only contractors....even for a simple question.



Model is L EC-75-PL (or I)



Two wires....red and white....but not sure if these are the actual colors since wire is generally red and white by default.



The new digital thermostat has several different color combinations and I just want to be careful.



TIA, Steve


Your model will also have to have the reset switch jumpered or else taped down permantly in order to use the modern thermosat.

If your digital thermostat has batteries, connect one wire to R, the other to W1. If your digital thermostat doesnt have batteries, you'll need at least 3 wires for it to operate. Take it back and get a digital with batteries.

Thanks for the assist.

  1. Anymore explanation on the jumper or wire....I am quite technically inclined.
  2. I know no contractor would ask this question...as such it would have been simple for the mfg. to answer.
  3. Thanks for the wiring assist.

I assure you that I am competent, but have never owned a steam boiler...nor want to.

  1. Jumper from RH to RC is irrelevant in this case. Leave it in, or remove the RH to RC jumper. Makes no difference.
  2. Yep.
  3. Y'welcome.

What is the make/model of the new stat, or do you maybe have a link for an on-line manual?

-zero

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