Boiler wiring

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ADELECTRICWORKS

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New York
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Electric al contractor
Hi,
I have a situation, I don’t have an idea how to deal with it.
I received this from my GC, his plumber says electrician has to do it.

“One emergency switch is required to control all boilers.
Confirmation that spill switches are interlocked to boilers and HWH”

There are 6 HWH non electric, 6 boilers 120
Each boiler has its own shut off switch.
According to plumber. If 1 boiler or HWH has issue and shut off all the boiler/HWH should be off at once.
help me if this is what I should do it. If yes, then how?
Thank you
 
OK I was not sure how this was set up
Are the boilers and WH in one common mechanical room?
What is a spill switch?
If you need to turn of WH power this will be more complicated, as will require a 30 Amp 2 pole relay. Boiler power is 120 so thats somewhat easier
 
Thank you, all boiler and HWH are in same room. HWH are gas only,
All boilers are 120 each on dedicated circuits for each apartment. I toggle switch on each boiler and 1 for each at the door.
 
The simplest way to control multiple loads like that would be contactors held closed by an N.C switch.
 
ADELECTRICWORKS said:
Spill switch is for HWH I’d chimney use blocked it shut it off? It has some kind of low voltage wires
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LarryFine said:
The simplest way to control multiple loads like that would be contactors held closed by an N.C switch.
LarryFine said:
The simplest way to control multiple loads like that would be contactors held closed by an N.C switch.
Click to expand...
we can do this with contactor. Main point is if 1 boiler shut off for overheat or fire emergency all should be turn off.
Click to expand...

 
Also what about following
“Confirmation that spill switches are interlocked to boilers and HWH”
How can I setup a interlock for each hwh and boiler.
 
How funny. Heating hot water.
I remember that one from years ago.
The panel sch said: hot water heater.
The insp as a joke red tagged it.
The correction. Said; please re- lable to water heater.
We laughed at that one for months.

Sorry just brought back good old job site memories.
 
ADELECTRICWORKS said:
Thank you, all boiler and HWH are in same room. HWH are gas only,
All boilers are 120 each on dedicated circuits for each apartment. I toggle switch on each boiler and 1 for each at the door.
Click to expand...
Now it gets easier. can you get shunt trip breakers for each boiler? If the spill switch activates what does it turn off?
 
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The boilers should have control circuits and boards for what you need to accomplish.

I would review the manufacturers literature and look over the equipment. You could also reach out to the manufacturer's they will likely be willing to assist you. Did the plans have any drawing on this?
 
Probably good to do what LarryFine says in post#7. You could add any more safety N.C. swithes you need in series with each other.
 
Ken_S said:
The boilers should have control circuits and boards for what you need to accomplish.

I would review the manufacturers literature and look over the equipment. You could also reach out to the manufacturer's they will likely be willing to assist you. Did the plans have any drawing on this?
Click to expand...
Good point. There is likely an input on each boiler control board for an emergency shut down switch, wire inputs in series to one switch.
 
Thank you, it’s good I can make series for boilers.
What about following
“spill switches are interlocked to boilers and HWH”
 
Perhaps there is an input on boiler control card. Or if the spill switch has a NC contact, wire in series with boiler emergency shut down switch.
For the shut down switch, I would recommend a mushroom switch, push to trip, pull to reset. Less likely to get accidentally shut off. And the mushroom switch can have second set of contacts, wire as input to fire alarm for status
 
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Being separate meters and power supplies, putting the switches in series would not be good, because you would be interconnecting the different systems. Another problem is the control power if isolated relays are used. If you pull power from one of the apartments, and the tenant vacated, and utility cut, the whole system goes down. Is there a house panel? Power could be pulled from it, and dry contacts from each boiler in series to a contactor or relay with dry contacts to each boiler shutdown.
 
I SERIOUSLY doubt that any boiler manufacturer makes provisions for what you are wanting to do. No reason to. If you want an emergency shut off switch you kill power to the boiler. Simple.

Question is I don't know if such switches are allowed with gas heating equipment, other than the service switch next to each boiler, of course. If you smell gas, they don't want you turning switches off. Just get out and call 911!

The spill switches are quite another issue. These are thermal switches placed at the entrance of gas heating equipment draft hoods. If there is flame rollout caused by a blocked flue, wind or some other cause it will cut the gas supply. The problem here is that the spill switches are already wired to either the gas valve (in the case of the water heaters) or the boiler controls. So you can't use them.

Are there separate spill switches provided for your use?

-Hal
 
There is a ("slick" imo) way to do it.

At the emergency switch, control the power to a 40 VA class 2 transformer. The load side of the CL2 transformer, you can run a 2 wire CL2 cable and loop to each appliance. Being able to swap over to CL2 cable is what makes it slick.

The 2 wire CL2 cable at each appliance powers the 24 V coil of an ice cube relay, giving you NO contacts at each location. This fails safe off if the relay loses power for any reason, including damage. Heat controls usually fail on as I was taught. But the safety circuit would have to fail off.

At the heater, consult the manufacturer's wiring diagram and it will show were to place the NO contacts in series with the others. Sometimes you would interrupt control power to the fire eye burner control and not with the operating controls. Some larger burners with a 3 phase blower, the NO safety contact do go in series with the other operating and safety controls. Consult and wire per the appliance manufacturer's instructions.

The spill switch, I would look at if the switch is isolated to each appliance, or if it serves a header that some or all or the burners group to. If the spill switch is localized to only one burner each, wiring to the single appliance each should be OK (ask first).

If the spill switch serves the group flue gas header, likely the spill switch should disable all of the burners. So those NC contacts would go in series with the emergency switch, at the line side to the 40 VA CL2 transformer, to disable the burner group when triggered.
 
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