Convection blower slow to come on and off - Quadrafire Classic Bay 1200 FS

Burrn

New Member
Oct 10, 2019
2
49404
My stove (year 2000) calls for heat, ignites, drops pellets, and then lags to turn convection blower on (15+ minutes). Once it reaches temp, the convection blower lags to shut off... 30+ minutes after exhaust blower does. It's super noisy on startup too- grinding metallic noise, but that fades off after the fins spin for a while.. when it is blowing air, it pumps it out like crazy.

Could my control box be getting delayed temperature read from thermocouple somehow? The feed motor seems to come on timely.
The problem is my convection blower is late for the party, super loud at times, and then stays partying too long after the fire goes out
This was not an issue last season prior to a thorough cleaning and maintenance

Here is my thought pattern. Looking for some help from a seasoned quad vet:

Thermocouple- tested with voltmeter and is OK I believe, the end is a little frayed, but snap discs are opening and closing, which means control box is getting a read on temps correct??
Thermocouple cover- new- just replaced
Snap discs 1 and 2- these can't be the issue right? Feed motor and fans coming on and off...
Firepot gasket- new- just replaced
Ash pan- gasket seems OK, securely latched
Door Gasket - not perfect (rope is frayed in spots) but passes the dollar bill test

Heat exchanger tubes all thoroughly cleaned recently, exhaust path is clear and the stove purrs with vacuum, so I don't think any air flow issues. Any ideas?
 

StockHR

New Member
Jul 12, 2019
30
Vermont
I had the same problem when my stove was new. It would startup, drop pellets and burn for about 15 minutes before the convection fan would come on and blow heat. I would get plenty of heat but than once the thermostat told the stove to shut off, the convection blower would run for upwards of 45 minutes before it would shut off. Actually cool sir was being blown in prior to it shutting off. my Snap discs 1 was a 110 - 20 meaning turn on at 110 degrees and off at 90 degrees. Not even close. The firebox was close to 150/160 before it turned on and about 70 degrees before I would hear the snap and it would turn off. I put in a new Snap discs 1 and it has worked as expected ever since. I'm now thinking of changing it to a 110 - 10 to have it shut down sooner yet. Anyway most snap discs are cheap, and might be an easy fix just to put in a new one.
 

Burrn

New Member
Oct 10, 2019
2
49404
I guess I figured if the snap disc would open and close, then the issue would have to be something else telling it what temperature it was. In other words I thought a snap disc either works or doesn't work, but can't work poorly.

Which is why I was thinking maybe it could be something to do with my thermocouple or control box..

I saw on another thread a few people using this snap disc from Grainger:


You can adjust the temps to what your preference is... I might give that one a try and see if it makes a difference
 

StockHR

New Member
Jul 12, 2019
30
Vermont
Looks like a good switch. Can't hurt to try it. Let me know how it works out.
 

Overfireinthehole

Minister of Fire
May 5, 2017
701
Miller MO
The thermocouple has no effect on the convection blower. If the motor is noisy you might pull it and blow it out with an air compressor and oil the bearings with 3 in 1. If it’s really noisy, you might replace it. Snap switches can take longer to open and close with age, but you might double check that snap 1 is touching the side of the stove but not tight. If your convinced that there is something else going on, watch your snap and listen for it to close and open and see if the motor is kicking on with the switches changes. The snap switch is literally just completing the circuit that the room blower is on.