turning off oil burner

bobbyjones

I want to prevent my oil boiler from firing while i run my oudoor wood furnace, but I want the circulating pump on the oil furncace to still function normally? I'm heating the boiler water with a flat plate hx. How do i best disconnect burner so it doesnt try to fire?
Thanks!

hot_rod

Automatically? Based on temperature? 

Typically when the wood boiler temperature drops to a determined temperature, maybe 150- 160, the oil boiler kicks on

If the wood boiler catches up, it drops off the oil

show a pic of how it is piped, how many pumps need to be running, what calls on the oil boiler?

I like a differential control for this application

bobbyjones

It’s just temporary while I resolve some issues with the oil furnace.

EdTheHeaterMan

B1 on the L8124 control is the power to the burner. You remove the wire from B1 and place it on an aquastat connected to the pipe that feeds the hot water from the wood stove boiler to the heating system. Then take another wire from that aquastat back to the B1 on the L8124 control. now you have an automatic control that will prevent the oil burner from operating when the wood stove water is hot. If the wood stove water temperature falls below the aquastat setting, the oil burner will be able to operate normally.
Grey wire was removed from the B1 terminal of the control and connected to white wire that goes to the aquastat

Your wire colors may vary. That is because electricity is color blind does not always follow the color code properly.

bobbyjones

Is there a way to do it that doesnt involve adding another aquastat? I dont need the oil to kick on in the event water temp gets too low from outdoor boiler.
Thanks!

EdTheHeaterMan

After looking closer at the photograph, it appears that you have a tankless coil in the boiler to make domestic hot water (DHW). In order to have the boiler maintain DHW temperature, the water in the boiler should be at least 150°. As long as the woodstove piping and woodstove circulator are set up to put heated water above 150° into the oil fired boiler, then the wiring in my previous post will work

EdTheHeaterMan

bobbyjones said:

Is there a way to do it that doesnt involve adding another aquastat? I dont need the oil to kick on in the event water temp gets too low from outdoor boiler.
Thanks!

The aquastat will be automatic. You can add a toggle switch and do it manually. Break the circuit between B1 and the wire to the oil burner.

EdTheHeaterMan

Does you oil boiler provide DHW?

bobbyjones

oil boiler has a tankless coil, but dont use it all the time.

EdTheHeaterMan

The boiler control is most likely a L8124 triple aquastat relay. This has a priority for DHW included in the circulator operation. The boiler circulator will not operate if the water temperature in the boiler drops below the low limit minimum setting. Since you want the boiler circulator to operate even if the oil burner is OFF, you may need to do some rewiring of that triple aquastat relay.

bobbyjones

Here’s the aqua stat wiring. 

EdTheHeaterMan

bobbyjones said:

Here’s the aqua stat wiring. 

No picture ???

Here is an explanation of how to convert the L8124 Aqua stat relay to operate as a cold start aqua stat relay. https://forum.heatinghelp.com/discussion/comment/1729767#Comment_1729767. I believe you want the first illustration where you do not need to remove the Blue wire. You just remove the Red and White wire from the Low Limit and wire nut them together. This makes the circulator operate when ever there is a call for heat from the thermostat regardless of the boiler temperature.

Mad Dog_2

Sounds like Ed has done this 1000 times!!  Some smart 🤓 Cookies 🍪 here, man.  Mad 🐕 Dog