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Rick, HVAC Supervisor
Category: HVAC
Satisfied Customers: 19102
Experience:  40+ yrs. experience as a licensed oil & gas technician.
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I bought a Weil-McLain CGM-6 series 8 boiler from a guy in

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I bought a Weil-McLain CGM-6 series 8 boiler from a guy in the paper. He said it had all parts but did not have a flame sensor. Long story short, I had to buy a rebuild kit and got the Y8610U by Honeywell. So....I have a question - on page 14 the install manual shows a schematic of the control board/spark box and it shows the 24V junction and the 24V GND junction going to each side of what I THINK is the transformer. (One side of the thermostat is connected to the 24V terminal). The schematic shows the limit controller either on the 24V side or the what I think is the 110V side of the transformer. My question is: Is the 3 rectangular box symbol that the 24V & 24V GND wires to to a simple symbol for the transformer or is it something else? I can't imagine what else it could be....

Also, I'm wondering how the water pump gets it's on/off signals....? I assume the signals come from the control relay plug in (mounted next to the transformer which came with the boiler). I see on the boiler schematic that the circ pump is wired to position CR3 while CR1 is 110v. But I don't know what activates the Control Relay (CR)...can you help me?

thanks, XXXXX XXXXX dark
Welcome to Just Answer,

Yes, that symbol is a transformer that supplies the low voltage to the control.

The pump is controlled by the relay. The relay is triggered by your thermostat if you only have 1 zone or the end switch in your zone valves if you have multiple zones and use zone valves for zone control. If you use multiple pumps for zone control then you need a relay for each zone.
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