Weil McLain Boiler Wiring


Old 12-11-18, 08:01 PM
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Weil McLain Boiler Wiring

I have a Weil McLain HE Series 3 boiler that I would like to rewire the T Stats and circulating pumps The existing setup that the boiler has is 2 circulating pumps each controlled by individual T-Stats The boiler is currently wired to run hot So with the boiler turned on the boiler runs until the temperature set at the aquastat ( 180 Degrees) is reached I would like to rewire this so the boiler only will come on when one or both of the T Stats are calling for heat. The existing T stats are wired to individual relays activating the pumps when heat is called for. The existing T Stats are the older mercury bulb type The control relay at the boiler has the T Stat terminals G & Y jumper together Would like some input on the best way to accomplish this I thought to maybe wire the T Stats in parallel but have read that is not a good idea Any help would be greatly appreciated
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Old 12-12-18, 04:53 AM
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Hi, how do you plan on maintaining your deomestic HW? If you parallel the Tstatís you wonít have any control of your space temperature.
What is it you are trying to accomplish?
Old 12-12-18, 10:45 AM
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The W.M. HE Series is a gas boiler so you do not have a tankless coil installed and there is no reason to maintain boiler temp. year round and should only run on a call for heat or hot water if you have an indirect hot water heater.

When you say your running hot do you mean that your boiler maintains that 180 deg. no matter if anything is calling or not?

Your boiler only comes packaged with a high limit control because there is no tankless coil, so it should only run on a call from the stats, either heat or indirect H.W. tank if you have one.

As Geo asked, what are you trying to accomplish. Are you saying that even in the summer when there is no demand for heat your boiler is maintaining that 180 deg. If so you have a wiring or control problem somewhere.

Could you be more specific in what you are looking to do.

Hope this helps a little.
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