i have a napoleon nps40 pellet stove that i bought in june 08.  a couple weeks ago the power went out and when the power came back on, the stove’s exhaust fan comes on automatically and will not stop and the stove ignitor will not get hot. could this be caused by a faulty sensor or switch, and if so how do i test to find out which one it is.

Was the stove plugged into a surge protector?  You might try unplugging the stove for 15 minutes and replugging it in.  This may allow the circuit board to reset.  Worth a try.

Bkins

no surge protector

we have had it unplugged for days and the fan starts as soon as you plug the unit in

It might be the proof of fire switch?? Unplug the stove and disconnect it. Then plug the stove back in. Worth a shot?

it has low limit switch 140 degree , over-ride switch 160 degree , ignition switch 120 degree and high limit switchh 200 degree

which one should i try

ignition switch 120 degree should be similar to a proof of fire.

I may have to download the manual or service guide to be of any help. There may also be another way to reset the board? IDK must research.

thanks will try so if i disconnect that switch, the fan should not run, correct.  the switch is saying that there is a fire when infact there is not.

bones1123 - 11 April 2010 08:19 PM

thanks will try so if i disconnect that switch, the fan should not run, correct.  the switch is saying that there is a fire when infact there is not.

That’s what I am guessing. Happens to the breckwells all the time. Flukes the board into thinking it has a fire to early.

Here’s what I get from the manual. Pretty vague!

The heater will not
turn off

- Disconnect one of the brown wires from the exhaust temperature sensor and if the unit continues to
operate, contact your local dealer for service.
- Compare the wiring diagram to the start control module and the connections to the 140°F (60°C)
temperature sensor. Check the connections.
- Remove one of the brown wires from the 140°F (60°C) temperature sensor. The heater should be shut
down right away as long as the start button was not pressed within 15 minutes of this test. If the heater
shuts down within 15 minutes, replace the 140°F (60°C) sensor. If the heater does not shut down in 15
minutes, test the switch.
- The heater must be cold to test the switch. Pull the plug, then plug the heater back in. If the heater fails
to start, replace the switch.

I didn’t see any other means to reset the board. If the switch is good. Sounds like something took a hit in the power surge event. Maybe someone has a service manual with some more info?

Unplug one lead from the 160 switch (purple wire) and start it up, if the convection fan does not come on, the switch is bad. To test the igniter, unplug the leads that go to the igniter and directly power it. You can also run a Ohms test from a multi-meter. If there is conductivity, chances are it works. The leads to the igniter are orange and brown. the brown wire is in line with the Low Limit switch (proof of fire). Your LL switch may be bad too. Limit switches can short out during power surges. LL switch is Normally closed and opens with heat at 120. Take it out and heat it with a lighter and listen for it to “ping”. If you hear the ping test it for conductivity. Blow on it and wait to hear it ping back, then test it again.

as soon as i plug the stove in the exhaust (combustion) fan comes on.  never did before

bones1123 - 14 April 2010 07:56 PM

as soon as i plug the stove in the exhaust (combustion) fan comes on.  never did before

uh oh. sounds like a control board. I presume you haven’t been swapping leads around and just got something mixed up?

bones1123 - 11 April 2010 07:34 PM

i have a napoleon nps40 pellet stove that i bought in june 08.  a couple weeks ago the power went out and when the power came back on, the stove’s exhaust fan comes on automatically and will not stop and the stove ignitor will not get hot. could this be caused by a faulty sensor or switch, and if so how do i test to find out which one it is.

did you unplug it and hit the reset button?

Once again, this is the reason we mention over & over about putting a GOOD surge protector on the stove. Not saying 100% that the board got fried, but they are still MUCH cheaper than a control board to replace.

where the original poster go?

Most likely hasn’t run the stove since April and may not be back if problem is solved.

still not working   i have had a tech here for 5 hours and still nothing

the tech had checked all switches (all good)  reset button fine,  unplug wires and still the fan runs, the only way to turn it off is to disconnect the power supply to the fan itself.  he has tried everything he knows.

Its the board. You have a triac that has stuck closed and runs the fans. Cheap part but tough to change. Better to swap out the board than tinker with board components.

Man I need to start repairing these control boards. 3 so far and the season hasn’t started yet.

is the the 2 blue blocks that are one the control panel sides?

Napoleons are not the everday stove. Could you post some photo’s of the control board and surroundings. The blue blocks could be relays or timers?? IDK(off to download the manual and wiring harness).

If the blue blocks are relays one could be stuck. Otherwise the Triacs are soldered to the main control board.

here the pics

The blue blocks are timers. That is very similar to an older Enviro EF3. Hopefully hearhtools checks in. I know very little about the older stoves. I thought it was a new digital board.

About what year is this stove? Maybe send hearthtools a PM.

we bought it brand new 2 years ago