Modern draft inducer control on 40 y/o furnace

[spuldup]

Installed a (hopefully) better draft inducer control on the old Brunco WC190. Rather than monitoring the thermostat temperature, this uses the flue temperature to regulate draft. There is a thermocouple probe mounted in the stack which the controller monitors, and turns on the draft inducer based on a preset temperature. The hope is to regulate flue temperature high enough to stop creosote buildup. The round red thing is a klaxon siren that actuates when the alarm temperature is sensed. Loud AF.

I used an Inkbird controller to replace the old 24V transformer and relay. They were always hot to the touch. Now everything is 120V.

Old:

New:

Still keeping it a bit old school, on/off control of the inducer, disabled PID for now.

I love these connectors

Wired up:

It works:

Before zip ties went on the TC cable:

 

[rgerber]

This is really interesting. I just picked up a Brunco 190 this morning and was searching the internet for best practices before I installed it in the house. This seems like a great idea. I'm not experienced with these furnaces. Could you share the paramaters you are using for your high/low and temp for the alarm? I need to do some research on the digital monitor you are using as I have never used one of those either, but looks great.

 

[spuldup]

@rgerber Glad to meet another Brunco owner. They seem to be a regional brand of furnace from Ohio. Yours looks to be a twin to mine.


I would recommend replacing the inducer with a modern PSC one if it has not been done. Much quieter and uses less electricity.
Make sure you use 8" venting. Ours began with 6" and it was not adequate. The manual is avaliable online for no cost. If you have coal avaliable, that burns very well in the furnace because the air is split 50/50 above and below the grates. Wood burning efficiency is no where near a modern furnace, but it will get the job done. As our sole heating source last year we burned about 10 cords in a 2800sqft house, and about a ton of coal. The coal makes great heat but a ton of ash, and it stinks up the whole outside around your house (some folks actually like the smell, though...).

The alarm runs off the factory bimetal switch that controls the main blower. Low setpoint turns on the blower, and the higher setpoint triggers the alarm.

I plan to set the draft inducer controller at 300-350F. May go a bit higher depending on how I have the air damper settings.

 

[spuldup]

We ran the furnace for the first time last night with the new control. It works excellent! The heat is much more steady and the fire burns just above creosote zone when the controller is set at 200F. It seems low, but this morning I saw all the old creosote from last year had flaked down.