Thelin Gnome Pellet Stove Fan Keeps Running

[Ken1]

Have a Thelin Gnome Palour Stove. The fan never shuts off--even after 60 minutes of waiting. I replaced the T2 sensor, but the fan still runs. The voltage into the T2 sensor is 5v as it should be. The new T2 sensor is an open circuit when cold. Not sure what to do next.

Friend asked to take a look at it. I am not a pellet stove guru, but reasonably skilled at fixing stuff. Welcome suggestions.

One other misc. observation I made during my diag is in the Thelin repair manual (Figure 9), it says the voltage between D12 (Feed Motor Chip) and the GND should be 16.5v to 17.5v, but the measured voltage is 15v. Consequential?

 

[Whitenuckler]

Have a Thelin Gnome Palour Stove. The fan never shuts off--even after 60 minutes of waiting. I replaced the T2 sensor, but the fan still runs. The voltage into the T2 sensor is 5v as it should be. The new T2 sensor is an open circuit when cold. Not sure what to do next.

Friend asked to take a look at it. I am not a pellet stove guru, but reasonably skilled at fixing stuff. Welcome suggestions.

One other misc. observation I made during my diag is in the Thelin repair manual (Figure 9), it says the voltage between D12 (Feed Motor Chip) and the GND should be 16.5v to 17.5v, but the measured voltage is 15v. Consequential?

Most stoves have two "Fans". One is for combustion, and one is to blow hot air into the room. Which one keeps running?

https://thelinco.com/product/parlour-3000-pellet-stove/pdf/parlour-pellet-stove-owners-manual-th-ref-sls-234%202024-02-09.pdf?v=1.01

 

[Ken1]

There is only one fan on the Thelin Gnome pellet stoves. The single fan serves both purposes (i.e., combustion and circulation). I have the Owners and Repair Manuals. They don't appear to offer any insight as to root cause of the issue beyond replacing the T2 sensor, which I have already done.

 

[Whitenuckler]

There is only one fan on the Thelin Gnome pellet stoves. The single fan serves both purposes (i.e., combustion and circulation). I have the Owners and Repair Manuals. They don't appear to offer any insight as to root cause of the issue beyond replacing the T2 sensor, which I have already done.

OK - that is the first time I have ran into only one fan.
"16.5v to 17.5v, but the measured voltage is 15v. Consequential" Yes, on page 21, there are board voltage measurement points.
16.5 V minimum. Page 22 shows the transformer and rectifier. Check there.

The T1 and T2 sensors should returning some voltage as shown on page 21.

 

[Ken1]

OK - that is the first time I have ran into only one fan.
"16.5v to 17.5v, but the measured voltage is 15v. Consequential" Yes, on page 21, there are board voltage measurement points.
16.5 V minimum. Page 22 shows the transformer and rectifier. Check there.

The T1 and T2 sensors should returning some voltage as shown on page 21.

Regarding Thelin's single fan design, the way they work is one vertical motor with shaft on both ends. Motor is on the bottom of the unit in the center. The Upper end of the shaft has a small blade that provides combustion air. Lower end has a large blade that provides circulation air.

Thanks for pointing me back to transformer and rectifier. I checked the rectifier before, but on recheck, the voltage is a little high. Rectifier has 14vAC in and 12.9vDC out. Manual specifies 12.6vDC out. I'll just swap both those components out to eliminate a variable and hopefully get exactly 12.6vDC out.

By "return voltage", do you mean the 0.25 values by chips R29 and R33 (there are no stated units for the .25 numbers on page 21)? There is 5v at the sensor, which is the correct voltage.

Will post in a few weeks after I get the ordered parts. Thanks.

 

[Whitenuckler]

14vAC in and 12.9vDC out. Manual specifies 12.6vDC out

That is OK - it is not regulated. The 5V and page 21 voltages should be checked.
The 0.25 must be VDC, as the rest are voltage numbers, and that is all you can read with a meter when the board is hot.
Those sensors could be thermistors. Have you ohmed each of them and the new one?