# Napoleon NPS40 Ignition Switch Fix



## smwilliamson (Jun 28, 2011)

The NPS40 is one of those stoves where a simple oversight in the maintenance can lead to very devastating results. It all has to do with the ignition off switch. This switch is located under the auger motor on the back of the exhaust port that leads off of the refractory over to the combustion motor. The mounting for this switch is inset into the exhaust; there is a hole cut out in the steel for it to seat into. If the exhaust gets too hot, your igniter switch can melt.

The ignition swithci s NOT thermally protected (not ceramic) but is located in an insert mount in the exhaust path. Let's understand why...

The igniter switch is "open on rise", which is backwards from a proof of fire switch, such as the thermally protected switch locate inset on the exhaust of the combustion blower on the same unit. Why is that switch ceramic? Cause the exhaust is hot ya'll! Dugh? And. That switch is made for an inline draft blower to detect proof of fire on rise.Why is the ignition switch plastic...? Cause it is made to be a fan controlleror other such for HVAC purposes. A switch repurposed, whitch oddly enough, most pellet stove parts are...repurposed controls and motors. When you dive into it...you'll find that many parts are the same, just used diffedrently.

The igntion switch is normally closed. When the unit is started there needs to be current flowing to the igniter, however as long as there is heat, the current needs to be shut off. This is done by the L120-10 ignition switch. AT 120Â°F  in exhaust temp the power to the igniter is cut off via this switch and will remain off until the unit has cooled to 10Â°F  below 120Â°F ...so at 110Â°F  degrees the ingition switch snaps back closed to ready for the next use.

The proof of fire on this unit is a F140-20 switch, so at 140Â°F  in exhaust temp the unit then send power to the timer boxes to maintain operation. When the fire goes out and cools to 20Â°F below 140Â°F power to the unit is turned off. The ignition switch will still be open at this time because it is waiting for the temp to get to 110Â°F, but at that time there is no power so the unit sits dormant waiting for the rocker switch to be pressed again.

So here is the problem....

Many folks neglect to keep the convection motor clean or maintain enough air flow to efficient remove excess heat from the exhaust. If the unit is running effiecint, the temp is the exhaust should not exceed 300Â°F  and therefor the ignition switch will be spared.

If the ignition switch fails the igniter will stay on the whole time the unit is running and this will burn out the igniter. Check the ignitor resistance when installing a new ignition switch. The proper resistance through
the ignitor should be 30Î© to 50Î© +/- 3Î©

If the igniter fails and shorts it may also short out the on-off timer box. this is the blue box under the convection blower with the two leads going to it. The auger timer box is the other blue box with more leads attached.

To test whether the on-off timer box is bad simply plug the unit in. If the combustion blower turns on without turning the unit on or fails to turn on when the heat knob is turned on, you may have a bad timing box or other problems.

This whole cataclysmic event can be averted by simply making sure that the ignition switch does not fail.

Here is my fix. To preserve factory equipment you need to keep the convection motor clean. To prevent this in the future you need to make the switch a surface mount.

The ignition switch needs to be removed from the inset and the hole covered to a install the switch to a surface mount. To do this I mount in a switch face from the broken switch (separate the metal plate from the plastic switch) and silicone it in the mounting hole or cover the hole with a piece of stainless plate. Then install a surface mount bracket to hold the switch off of the surface.







Mounting bracket part number in Grainger Catalog, #2E853    $4.86
New Ignition switch part number in Grainger Catalog, #2FBT6 $5.98

A fix for under $11.00

Or wait and pay big time.

New Napoleon Igniter Switch - $29.99
Igniter - $87.99
Igniter gasket - $5.00
On-Off Timer Box - $115.00

Total - $237.97

I saw this problem yesterday and see it about 12 times a year.

Fun stuff.


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## save$ (Jul 14, 2011)

I hadn't seen it.  I do not go on the forum daily as I did during the heating season.   I'll need to read that one over a few times to grasp most of what you are saying.  Looks like it goes back to the warnings about keeping a clean stove.  So far, I have been trying to do this.  I have really enjoyed pellet heat, esp. the $ saved.  Don't mind the work so much as I don't have much else to do during the winter.   I'm going to cut and paste your note so I can refer to it.  (I have to keep things in their place these days, or I forget about them)   Thanks for the advice.  When I go back into it for another cleaning, I'll start looking around so I can be oriented to what your warning is.   I'm all for preventing a problem.   This will be my 4th burning season with pellets, all with the same stove.   In the past,  I had many years of wood burning.  My son now uses that same stove I had for many years.


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## smwilliamson (Jul 14, 2011)

save$ said:
			
		

> I hadn't seen it.  I do not go on the forum daily as I did during the heating season.   I'll need to read that one over a few times to grasp most of what you are saying.  Looks like it goes back to the warnings about keeping a clean stove.  So far, I have been trying to do this.  I have really enjoyed pellet heat, esp. the $ saved.  Don't mind the work so much as I don't have much else to do during the winter.   I'm going to cut and paste your note so I can refer to it.  (I have to keep things in their place these days, or I forget about them)   Thanks for the advice.  When I go back into it for another cleaning, I'll start looking around so I can be oriented to what your warning is.   I'm all for preventing a problem.   This will be my 4th burning season with pellets, all with the same stove.   In the past,  I had many years of wood burning.  My son now uses that same stove I had for many years.



simple fix that will SAVE $...very appropriate.


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## shy-ky (Sep 27, 2011)

I got the parts and I am ready to try this. My switch has cooked right off of the metal insert. Could I leave the insert in place and put the surface mount over it?


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## smwilliamson (Sep 27, 2011)

shy-ky said:
			
		

> I got the parts and I am ready to try this. My switch has cooked right off of the metal insert. Could I leave the insert in place and put the surface mount over it?



yes, I'd seal it in w/ RTV though


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## shy-ky (Sep 29, 2011)

One more question. The mounting holes for the bracket are further out than the original mounting holes. Do you drill new holes to mount, or do you do something else. Thanks for all your help.


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## smwilliamson (Jan 7, 2013)

Drill one hole and use one old hole from old switch


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## EJW1 (Sep 15, 2013)

The switch is out of stock at Grainger. Do you know of any other places to check? Thanks


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## EJW1 (Sep 15, 2013)

Should have looked around Grainger a little longer Would this switch work? It seems to be the same in every way. Thanks

http://www.grainger.com/Grainger/Snap-Disc-Control-6UDY9?BaseItem=2FBT6


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## smwilliamson (Sep 15, 2013)

EJW1 said:


> Should have looked around Grainger a little longer Would this switch work? It seems to be the same in every way. Thanks
> 
> http://www.grainger.com/Grainger/Snap-Disc-Control-6UDY9?BaseItem=2FBT6


Yes


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## EJW1 (Sep 16, 2013)

Thank You!


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## Don2222 (Sep 16, 2013)

Hello

Instead of using the "air stream" mount ignition snap disc with a bracket that must be sealed with RTV very carefully to fill  the gap, I would prefer to use a "surface mount" snap disk such as the Selco SES-120 "open on rise". The same mounting holes can be used. Then all you have to do is screw it down with a smaller amount of RTV and not worry about the pressure of the exhaust gasses pushing the RTV out of the gap created by the bracket and failing and leaking exhaust gasses into the room!

Looks like the ignition switch is 120 Deg F not 140 Deg F. So the switch would open at 120 Deg F instead of 140 Deg F and the ignitor would last even longer.  
http://www.stove-parts-unlimited.com/Napoleon-NPS40-and-NPI40-Ignition-Switch-120F-p/w660-0054.htm

Also if you really want to protect your house from the ignitor dying and creating a dead short in the house wiring, a simple 5 amp glass inline fuse on the one of the ignitor wires is similar to what other stoves have. When the ignitor dies, the fuse blows and then you can still light the stove manually.
http://www.homedepot.com/p/30-Amp-Glass-Tube-Fuse-Fuseholder-12-BP-HMK-RP/203298931
Take out the 30 amp fuse and put a 5 amp in. That is all you need.

Just my 2 cents.

Do you have a pic of one of your 12 melted ignition switches?
No pic it did not happen.

When I work with Ardisam on their stoves, they always insist on sending defective parts back to their engineer for a full failure analysis. Every stove company should have that policy!


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## smwilliamson (Sep 16, 2013)

Don, you ought to perform the mod sometime. Anyone can scan the internet for parts and make hypothetical suggestions. The selco switch you are suggesting is the same kind of switch that leads to the problem. The stove isn't going to take out the guys wiring in the house either. Your missing a key part to the mod which is to seal the hole off before mounting the plate.


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## smwilliamson (Sep 17, 2013)

You seal the hole with the metal cap from the old switch.


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## jtakeman (Sep 17, 2013)

Who's got the popcorn?


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## Jags (Sep 17, 2013)

Keep things in control fellas.  This is an informative post, and I hope we can keep it that way.


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## Don2222 (Sep 17, 2013)

smwilliamson said:


> You seal the hole with the metal cap from the old switch.


show us some pics?


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## smwilliamson (Sep 17, 2013)

Funny, I was at a guys house today with the mod I did 3 years ago...couldn't snap a pic cause I left my phone at a lumber yard during lunch...


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## WoodPorn (Sep 19, 2013)

My money's on Scott
......Any takers?


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## jtakeman (Sep 19, 2013)

WoodPorn said:


> My money's on Scott
> ......Any takers?


I got some cash on don, He's a scraper and scots a bit skinny. Don gets a hold of em its all over!


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## WoodPorn (Sep 19, 2013)

jtakeman said:


> I got some cash on don, He's a scraper and scots a bit skinny. Don gets a hold of em its all over!


Yeah but Scott's wirey!


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## EastMtn (Sep 19, 2013)

jtakeman said:


> I got some cash on don, He's a scraper and scots a bit skinny. Don gets a hold of em its all over!


I see the makings of a hit reality TV series. Move over Duck Dynasty and Honey Boo Boo, beginning this fall:
Pellet Pig Place.​I'll call Bravo and A&E and pitch the idea.


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