Low Water Cut Off on Weil MclLain CGS Boiler

[rontram]

I am installing a Weil McLain CGS gas boiler. Does anyone know how to wire the power leads to an RB 24 low water cutoff? They need to go to the secondary side of the transformer. However, one of the output leads from the transformer is most likely grounded. But, which one? Thanks, Ron

[KField]

I think you will find the wiring diagram under the cover. I suspect that terminal #1 is 24 volts in. Terminal #2 is 24 volt common and terminal #3 is 24 volts out when the probe is wet. Use this for reference only, as I am not even sure which control you are using and just want to give you an idea how it is supposed to work.

Ken

[rontram]

Ken, I am using a McDonnell & Miller RB 24 low water cutoff. The wiring diagran only shows two secondary leads from the transformer, one red and one brown. None of them are numbered. The wiring diagram supplied with the control says to wire the power leads to the R and C terminals on the boiler transformer, but there is no letter or number designation anywhere to be found. Hummmmm?

[KField]

The common terminal will usually go right straight to the gas valve. The 24 volt hot terminal usually has a red wire connected to it and will be switched by all the 24 volt controls. I wish I could help more than that but if you look closely, I think you will find an R and a C on any 24 volt transformer with screw terminals. If it has wire leads, go with the color codes of Red for hot and white for common.

Ken