Surface mount junction box/transformer on boiler jacket?

Dave_61

We have a Burnham V-74T boiler. I need to add a 24v transformer to power a wifi thermostat. Is it ok to attach primary leads of transformer to L1and L2 of oil burner ignition control? Also, is it ok to screw the junction box to the outside jacket on side of boiler? Thanks very much. Dave

delta T

What is the xfmr going to be for?

Dave_61

It will be powering a wifi thermostat

Jamie Hall

I wouldn't think it would be a problem to screw the junction box to the boiler jacket, assuming the screws don't hit something inside.

However, one of the two primary (120 volt) leads must, no options, be wired as a neutral, which means it must lead, with no switches or fuses, to the neutral in your fuse or circuit breaker box. The other side is hot, and should go through a switch -- though that is optional -- and then a properly rated fuse or circuit breaker. It could be on the same circuit as the oil burner, but I'd rather see it branch off that circuit on its own feed rather than Macgyvering it onto the burner control -- even if that is an properly fused, neutraled and switched connection.

ChrisJ

Dave said:

It will be powering a wifi thermostat

Does the thermostat allow you to power it from a separate source than what it is controlling? Most do not.
The Honeywell Prestige I just installed does, but it's the only one I've seen so far that does.

Dave_61

I'm not sure. It is an Ecobee 4.

EBEBRATT-Ed

Yes you can connect it to the oil burner primary hot and neutral connections. I am assuming the oil burner has a switch witch will kill the power to both the primary and to the new transformer.

Yes you can mount the junction box on the boiler jacket use 1/2 or 3/4 inch screws

HVACNUT

> @EBEBRATT-Ed said:
> Yes you can connect it to the oil burner primary hot and neutral connections.
>
>
>> Ed, I'm assuming you meant L1, L2 on the aquastat, not the primary. The primary only gets power through B1 on a call from the aquastat.
>
>
>> @Dave, don't mount anything on the right side of the jacket as that is an access panel for cleaning.

Dave_61

Thanks guys. I'd definitely use short screws. I wasn't sure if outside of boiler would get too hot.

Dave_61

EBEBRATT-Ed said:

Yes you can connect it to the oil burner primary hot and neutral connections. I am assuming the oil burner has a switch witch will kill the power to both the primary and to the new transformer.

The oil burner ignition controller is Honeywell R8184. It has a kill switch.

HVACNUT

> @Dave said:
> The oil burner ignition controller is Honeywell R8184. It has a kill switch.
>
>
>> You CANNOT wire it into the R8184.
Read my post above.

Dave_61

I didn't see an aquastat on the boiler. It is a steam boiler. I will look again.

HVACNUT

> @Dave said:
> I didn't see an aquastat on the boiler. It is a steam boiler. I will look again.
>
>
>> Aha! Then I owe @EBEBRATT-Ed an apology.
You can wire it into your R8184. It does (should) have constant 115v.
The burner circuit will close at TT.
Sorry Ed.
>
>> But keep in mind, it doesn't have a kill switch. That black lever is only to manually put the primary into safety. It will not interrupt 115v coming in on the black wire.

Dave_61

There is a switch at top of stairs to turn off boiler. I thought that is what you meant by kill switch.

HVACNUT

> @Dave said:
> There is a switch at top of stairs to turn off boiler. I thought that is what you meant by kill switch.
>
>
>> ok. Emergency switch at the top of the stairs. The way you worded it, it sounded like you meant a kill switch on the R8184.
>
> Fire up the Ecobee! Done yet? Lol.
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