Boiler emergency shutdown

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Crabcakes&football

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I need to install 2 emergency push buttons for a boiler. 99% for my time is in residential so this is all new to me. Was wondering if I could get someone's input how to go about doing this.
 
They have a disconnect switch already there amd want to add 2 e-stops. So ill have the 2 e-stops in series with 12 awg stranded wire. Then do I need to hit a relay that kills the power?
 
Thedudeabides said:
They have a disconnect switch already there amd want to add 2 e-stops. So ill have the 2 e-stops in series with 12 awg stranded wire. Then do I need to hit a relay that kills the power?
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Depends on the load you are interrupting. And the designs desires. If the switch contacts are rated for the load (amperage and motor, etc) the you don't "need" a contactor.
 
However, if the boiler has a controller with a low voltage class 2 transformer, it might be easier to install a relay and class II wiring.
 
If the boiler control panel doesn't have a place to connect estop buttons, then you will probably have to add some method to disconnect the power. A shunt trip breaker would be one common method.
 
I don't know anything about residential boilers.

Larger commercial fire tube boilers have safety circuits to shut the boiler down. Those are primary low water, secondary low water, primary high pressure, secondary high pressure, high and low gas pressure, lack of air pressure, and flame failure. Wiring in series with any of them would safely stop the boiler. How to do it would depend on what the AHJ wants and rather you want to boiler to start automatically after the E-stop is reset or if you want to have to manually reset the boiler also.

My boiler inspector wanted one. But he is just an insurance agent and has no power to enforce his wishes. We elected not to do it and all was fine. So you may have options.

One thing I would not do is kill all incoming power. You want the boiler to shut down in the proper orderly fashion. Depending on what you are looking to accomplish you might need something extra (2 pole switch or contactor) to disable the feed water pump as that is a separate circuit routed through a boiler control.

There are a lot of ways an electrician can make a boiler stop. I advise it be done in the way a boiler manufacture specs.
 
If it's a small residentail boiler (burner) as you describe, I would consider the class 2 TT terminals on the fireeye as an operating control only and would not consider it for safety shutdown. I would loop the 20 Amp power feed through all of the safety shutdwon switches, firematic ...

A large boiler burner with a 3 phase blower on the burner, as described in the post above, the safety and operating controls all loop in series to two terminals (In the burner control cabinet) typically 3 and 4.

In either case you would have to read and follow the manufacturer's installation documents where this will be instructed, how to. Should be clear on the residential burner instructions.

On the commercial type with multiple accessories, gas train, combustion air, flue draft fans, all those pieces are just that, seperate pieces each with their own instructions, but now no whole assembly diagram or instructions, no sequence of operation for the assembly. In that case you have to piece together your own assembled package wiring diagram, sequence of operation. It's easy to get instructions for the individual pieces, but I've never seen one with instructions for the enitre assembled package.
 
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