How to manually fire boiler for skimming?

jfleming

Homeowner here. We got vents installed and two boilers headers re-piped, now we're going to skim the boilers. The guys who installed it were able to fire the gas burner without using the thermostat, but I neglected to watch carefully as to how it was done.

Would like to figure this out without using the thermostat to fire the burner. We're doing this for another unit in the building, and would prefer not to have to access their thermostat to do the skimming.

mattmia2

Jumper t-t on the boiler. Simply put a jumper across the terminals the thermostat closes and control it with the disconnect switch.

ChrisJ

I found it easier just to turn the thermostat way up before I went down to the boiler, and then just use the shutoff switch to control it.

Now I use the Ecosteam, but that's another story.

EBEBRATT-Ed

@jfleming

a thermostat is just a switch like a light switch. find the two wires from the thermostat that start the boiler and jump across those terminals

EdTheHeaterMan

If you had a smart thermostat, all you need is the App to turn up the thermostat.

But seriously, if you follow @mattmia2's advise above you will get the necessary results. Being outside of the industry you may need that instruction translated. Here goes:

I believe your answer is right here. But it will take some deductive reasoning and you may get it wrong. If you feel up to the task, then try this.
I believe your thermostat is connected to the boiler by way of this white wire with 2 copper conductors enclosed therein. If you can remove the 2 wire nuts that make the conductors of the inner wires of the white wire to the inner conductor wires of the Red/Brownish wire indicated in the circle above, you can connect all 4 wire conductors, temporarily during the skimming exercise. That will operate the burner. You will need to place them back the way you found them in order to place the thermostat back in control of the burner. Use your cellphone camera app to take a picture before you take anything apart, so you can refer to it when you are completed.

heatdoc1

If its a newer thermostat I would disconnect the wires going to the thermostat and jumper the wires to the boiler.

EdTheHeaterMan

heatdoc1 said:

If its a newer thermostat I would disconnect the wires going to the thermostat and jumper the wires to the boiler.

I would do it with an older thermostat too!

But there is that question about "Middle Aged" Thermostats...

jfleming

EdTheHeaterMan said:

I believe your thermostat is connected to the boiler by way of this white wire with 2 copper conductors enclosed therein. If you can remove the 2 wire nuts that make the conductors of the inner wires of the white wire to the inner conductor wires of the Red/Brownish wire indicated in the circle above, you can connect all 4 wire conductors, temporarily during the skimming exercise. That will operate the burner.

This was it. I tested breaking one connection and verified that the thermostat no longer could operate the burner. Joining the leads coming off the boiler manually fired the burner, and I can control it with the shutoff switch.

Thanks!

Side note: Only one boiler has a shutoff switch, and the other one is wired up to the main breaker . Fortunately the messed up one is for our unit, so we don't have to disconnect the other guy.

mattmia2

You might want to add that switch to the other boiler. Technically code may allow it in some jurisdictions if it is in view of the panelboard and less than some distance away but in an emergency the switch would be a lot easier to find. Are you sure the boiler without the switch is a 24vac system and not a millivolt system?

j a_2

As far as a thermostat , keep it as simple as possible..
It a steam boiler and they like simple, lol

ChrisJ

j a_2 said:

As far as a thermostat , keep it as simple as possible.. It a steam boiler and they like simple, lol

That's funny I found forced air was least picky and steam to be the most picky though I'll bet in floor radiant is probably difficult too.