Monitor 441 Solenoid Damper #6406 AC-120V vs DC-110V

[guitargirl]

Hello,

A service tech told us that our damper solenoid assembly was on the blink. I was able to get the service manual, thanks to this forum! With it, my husband and I have learned much about our Monitor 441 heater that came with our house. We bought the part on ebay, advertised as part #6406. Once ours was apart, and we compared parts, it's clear our existing solenoid says AC and the replacement solenoid says DC. We are very reluctant to try this new part for fear of harming our heater. Does anyone have any comments about this? Thanks.

Here's our existing solenoid

And here's the new one we received

Although we didn't receive the box, this is what was pictured in the auction and box states part #6406

Thanks very much for any input.

[adnadeau]

The solenoid damper actually runs on DC in the first place. When I had my own combustion blower apart, I tried putting AC across the damper, and it wouldn't work. If you can read a schematic diagram, you will see that the AC voltage coming in from the wall plug is rectified into DC before it gets to the solenoid. The 110/120 voltage difference is not critical. It's sort of like referring to a 2-by-4; it's a nominal reference. It'll work fine.

I have to wonder why your existing solenoid "was not reliable". There's not much that can go wrong with one. The plunger might get dirty, but you can just wipe it clean. It's shouldn't be oiled; maybe just a little graphite. If you've been following the Monitor forum, you might have seen mention of an o-ring. If your blower is apart, you might find pieces of it inside the housing. Mine was all crumbled. It acts as a bumper when the solenoid plunger retracts. There's a shallow grove around the plunger that sort of keeps it in place.

[hawkins111]

I would like to know what the symptoms were that caused you to call a stove shop?

Tom

[guitargirl]

The solenoid damper actually runs on DC in the first place. When I had my own combustion blower apart, I tried putting AC across the damper, and it wouldn't work. If you can read a schematic diagram, you will see that the AC voltage coming in from the wall plug is rectified into DC before it gets to the solenoid. The 110/120 voltage difference is not critical. It's sort of like referring to a 2-by-4; it's a nominal reference. It'll work fine.

Thank you!

I have to wonder why your existing solenoid "was not reliable". There's not much that can go wrong with one. The plunger might get dirty, but you can just wipe it clean. It's shouldn't be oiled; maybe just a little graphite. If you've been following the Monitor forum, you might have seen mention of an o-ring. If your blower is apart, you might find pieces of it inside the housing. Mine was all crumbled. It acts as a bumper when the solenoid plunger retracts. There's a shallow grove around the plunger that sort of keeps it in place.

The old solenoid is missing the o-ring, and while it was working, but was hanging up a little. We had to smack the fan housing to get it to move and shift the yellow flame to blue. My husband says the old one wore a small groove on the plunger shaft, and also the hole the damper shaft fits in had become elongated from wear. He filed the hole round again, and smoothed the plunger, and it's almost as smooth as the new unit. We installed the new one, since it has the o-ring. We'll keep the other as a backup.

[guitargirl]

I would like to know what the symptoms were that caused you to call a stove shop?

Tom

It had a bad bearing and sounded like a jet engine. The fellow changed the bearing for us, showed us how the heater works and how to do basic servicing ourselves. He had the meter and showed us that the damper was taking a bit long to shift. He said sometimes they stick a little, but it might work in with time.

It became worse over time and we had some issues with soot in the chamber bridging the flame rod and shutting the unit down.

It's running well now, and hopefully it will continue into the spring. When it gets warm, it'll get a better going over.

[guitargirl]

Thank you for this forum and for the generosity of the readers. Wilmington Delaware, where we come from, isn't monitor country. This type of heater is all new to us. This forum has been a Godsend! Thank you!!!