Learned something new today

[bbfarm]

We were over at a neighbors house today. He bought a used Lennox and was having trouble with it staying burning.

It looked like the blower motors could use a good cleaning, but he had a repair guy on the way already.

Turned out to be a light sensor in the hopper that controls the auger output. Intresting. It was dirty and the window needed to be cleaned.

I Told him to buy a surge protector and install an oak.

 

[smwilliamson]

This is commonly called the photo-eye. It is the same technology that many oil burners use to detect fire. The good part is that it is almost an immediate reading which is great when you are talking about start up efficiency or when the unit is thermostatically operated, the downside...is requires a sight path and with a solid burning device which produces ash and soot and pellet hoppers which contain lots of dust, you can see where this would be problematic.

The way the control works is that the board is constantly sending a 5v signal to the photo eye solenoid. When the photovoltaic cell on the eye reads light is produces an electrical current which closes a relay in the solenoid thus completing the signal for operation.

Problem being is that if the cell of the solenoid fails by either dust, soot or heat, the stove could not only not start but completely shut down during operation. At least a thermodisc (which whitfield used) would commonly fail during a opening of the switch (if ever at all)

To those of you who want to revert...just connect the yellow wires that go to the solenoid to a 140 NO ceramic thermodisc on the exhaust motor housing and be done with it. There is still a port for that switch located on the housing which is covered with a metal plate.

If you want to replace your photo-eye and don't want to spend the $135 for the OEM Lennox part, feel free to type in the Honeywell serial on the solenoid in to Amazon.com and you find you can get them easy enough for about $10 bucks.

 

[chamas]

...140 NO ceramic thermodisc...

Do you have a helpful tip on where to obtain these as well? Thanks!

 

[bbfarm]

That's it...he called it a photo eye. I think ours is by the ignighter but our neighbors was in the hopper.

 

[smwilliamson]

yours may be behind the sirewall under the hopper. Hard to get to thats why Lennox relocated it into the hopper pointing down the feed chute. If yours is like this I would switch to the disc. There are no relocation kits out there that I know of and it would be a more difficult job