Replacement flue damper for a Mizer M35BC-1

manolid

Hello all,

20 year old flue damper has stopped working. Sometimes it wont fully open preventing the boiler from firing and other times it wont fully close and starts making a ticking noise. When I manually fully open it the boiler fires up and when i manually close it the noise stops.

I'm guessing that the M35BC-1 has been discontinued as I cant find one anywhere. Someone suggested that I look for a Field Controls as a replacement. I'm not sure if the damper only can be replaced or if I need the damper and smoke pipe as a unit.

Pics attached. Pipe diameter is 6" and the damper is a 24V. If someone could please recommend a replacement it would be appreciated.

IMG_20261026_102733959_HDR.jpg

IMG_20261026_112938975.jpg

EBEBRATT-Ed

Johnson Damper.pdf

Maybe this.

manolid

https://forum.heatinghelp.com/discussion/comment/1907728#Comment_1907728

This looks like an exact replacement for the actuator. Where can I find one? I checked Amazon and SupplyHouse and neither has one.

Steamhead

ISTR the Johnson dampers are out of production. But they should use the same wiring harness connection as the Field, which is a 4-pin Molex connector. So the swap should be easy.

HVACNUT

Just because its a 4 pin molex, doesn't mean its the right 4 pin molex. Try crossing your boiler or specific aquastat to a Fields Controls GVD damper and see if there's a match. They also have kits with multiple molex connectors.

Is there not a switch on the motor to set with the damper manually open?

manolid

https://forum.heatinghelp.com/discussion/comment/1907753#Comment_1907753

No manual switch but I took the cover off and there are instructions printed on the board for emergency operation. Basically remove motor wire from terminal A and move wire to terminal B then turn flap to the open position.

Can you maybe recall who makes those multi molex kits?

Do you mean cross reference my boiler/aquastat to a GVD damper? Does Fields have a chart online somewhere?

EBEBRATT-Ed

@manolid

See the attached. You will probably have to find a supplier in your area that sells Field. You can do that on the Field web site

Field.pdf

manolid

https://forum.heatinghelp.com/discussion/comment/1907770#Comment_1907770

Thanks!