M55 insert temporarly responding to t-stat

[radiorental]

I have an enviro m55 insert with an ecobee wifi thermostat and it's been running fine all winter, been through 3 tons (first year using pellets)


The m55 has 3 modes and 5 heat settings (1 lowest, 5 hottest)
1) manual mode - run at the given heat setting (I usualy set to 3)
2) Auto high/low - heat at the given heat setting until the t-stat set point is reached, then run at heat setting 1 until more heat is called for.
3) Auto high/low/off - same as 2 except it will power down if no heat has been called for 30 minutes.

I usually run it on mode 2. In the last week it will respond to the t-stat calling for heat and then drop down to Heat setting 1 within 10 seconds.

If I re-trigger the t-stat (either power cycle or adjust the temp down then back up) the stove will run at the given heat setting for 10 seconds and then drop back down to heat setting 1.

If I run the stove on manual mode, it will happily run at any setting.

So, I've confirmed the t-stat is working, I hear the 24v relay doing it's job and the stove responding to it. I've confirmed the stove can run at any setting in manual mode. The problem is that the auto modes wont stay at heat setting 3 when the t-stat is calling for heat, it almost immediately drops back to heat setting 1 and the ambient temperature slowly drops. Any ideas?

thanks!

 

[vinny11950]

I would double check the t-stat. Check connections, wires, batteries (if you have any), and double check that none of the t-stat programs are out of whack.

Try the simple, obvious stuff first, the ones you can verify without pulling the stove out.

Then work your way in, maybe s-stat wires disconnected from stove, which it seems to have happened.

But I am not familiar with that t-stat.

 

[radiorental]

Just to follow up for anyone who hits the same weird issue; all is working now.

I pulled the stove out and vacuumed all the circuit boards, there was a small-to-moderate amount of dust build up. I also pulled and reinserted the ribbon cable in to the control board (but it seemed fine).

The stove is operating nominally now. I'm guessing that the dust was possibly causing some static and/or emf to interfere with the control circuitry.