It cycles on and off for the first five minutes or so. (IPS!) Napoleon

[tubbster]

Alright, got the Napoleon Bayfield installed and running.
For the first five minutes or so, the pilot flame walks away from the sense rod, and it cycles off. Then she begins snapping her sparks, and the cycle starts all over again. Run time would be maybe 10 or 15 seconds. Seemed worse when I cranked it up on high. The pilot light never went away totally, just walked up an inch or so. When the ips closes its valve, it then disappears.
The flames were blue of course. After 5 or maybe a few more minutes, it runs great at any flame level. After 10 or 15 minutes, proper looking blue - mostly yellow flame, and steady.

1) Just the nature of the beast?
2) Safe?
3) Should I maybe try to adjust the sense rod so as to put it more "in the line of fire"?
4) Do nothing?

Now that it has been running for an hour or so, I can see where I am gonna like the thing!

 

[PaulRicklefs]

Is it Nat Gas or propane? I would certainly check the supply pressure to start with. Should be between 10-11" w.c. for propane and 6-7" w.c. for natural gas. I suspect too much input pressure would explain the pilot issue as well as the long time for it so sustain a flame. Once the metal in the system warms up it will be able to withstand the extra velocity created by excess pressure.

Other than that I would suspect too much air but then your pilot shouldn't be adjustable.

It certainly is not normal for your system to operate like that.

Let me know what you find out!

 

[tubbster]

Nat Gas.
I was thinking it was a drafting problem. The flue collar is mounted at a 45* angle, and I used the supplied 45* elbow, and vented straight out the block wall in a raised ranch lower level.
It is an approved venting configuration. The stove just ran three hours great, just getting it going is a little iffy.

When the draft is not optimal, wont the flame start to rise off the normal position?

 

[PaulRicklefs]

Well initially I was thinking draft but normally you would get less draft from a cold start than too much. Flame lifting is usually caused by too much air in the mix or too much gas pressure. But as pilots are often not air adjustable it lead me to too much gas pressure.

Failing that I would certainly look at your venting configuration. Is it a direct vent system or natural draft? If it draws air from the outside and returns it back outside at the same location it is direct vent and the system should be balanced. If it's drawing air from inside the house and sending it out the vent system it is a natural draft type then it could certainly cause a vent/draft issue. If your vent exits a side of the house that is subject to low pressures such as the side of the house facing away from the wind you will experience too much draft. OR vice versa if you have bathroom fans or some other type of air exhange going on that would mess with the balance. Natural draft appliances that vent the side of the house shouldn't be installed this way as all sorts of draft issues will appear. If this is your install setup I would suspect something like this is going on. I know where I come from if I installed it in that manner my gas inspector would write me up.

Give me a hint at your vent config and we can figure this out..

 

[R&D Guy]

Yeah it sounds like your not getting enough draft to me. Really blue transparent "Ghosting" flames are a sign of poor draft. Venting straight out the back is one of the more challenging config's too as it doesn't do much to promote draft. Did the manual talk about having a 1/4" rise per foot on horizontal runs? If so do you have that? I'd be surprised if it didn't.

Do not bend the sensing rod.

Sounds to me like you don't have enough air, then once the appliance gets warm and a good draft is established, it starts burning right.

Couple things to check:
- The unit should have a exhaust restrictor. Make sure it is per the manual (likely wide open).
- Same for an intake restrictor if it has one.
- If you can still take the cap off, look into the pipe and see if the flue is misaligned where the sections meet.
- Do you have a lot of kibbles (ember chunks) over the burner and or air slots? If so remove them and try buring the unit.

Something you can try that should help is to put the pilot in continuous pilot mode. Might be worded as "Standing Pilot" in the manual. You should have this option and it will allow you to run the pilot 24-7 which helps insure a draft is already established.

 

[R&D Guy]

Paul, I found the manual to his stove here:

(broken link removed to http://napoleonfireplaces.com/Tech/installation_manuals/GDS25.pdf)

It's a direct vent with a IPI valve system.

tubbster - page 9 talks about that minimum rise per foot for horizontal runs. Looks like max horizontal run straight off the back of the stove is 24". Are you longer than that?
Look at page 18 for the restrictor position. I believe you want fully open.
I don't see anything in the manual about a continuous pilot mode. You might want to see if the ignition module has a pilot switch on it. You might also want to call Napoleon.

 

[tubbster]

The throttle plate/ restriction is fully open. The total length of the vent not including the 45* elbow is 18". It even pitches up about an 1" or so over that run.
I fear that there is not much to be done. I just hope that it is not too unsafe to run like that. After four minutes (timed it this morning) it runs great. I am very hesitant to hook up a thermostat however. I feel like I have to be there until it goes steady state.

I now see why there are very few units (all less than 18K input except for this one) that vent straight out as this one does.

I'll be calling Napoleon next.

Surprise surprise. No number to be found. Hope they reply in a timely manner to my question on their website contact form!

 

[tubbster]

Also, no ability to set a standing pilot. I think that may help by creating an established mass flow. Oh well.

 

[tubbster]

Well, took it all apart, and found the exhaust is completely sealed to the flue collar. Not leaking there.

I could get it to operate PERFECTLY with a 2 foot section of 4" stove pipe stuck in the end and pointing up where the wall terminal should be. Napoleon was not much help, the guy said it was either obstructed (no), not sealed (no) or not an approved set up (no). Also, was told to contact the dealer. (internet ordered). In not so many words, I am on my own. He did tell me he did not consider it unsafe with the gas valve cycling on and off.

I'm not a big fan of Napoleon or this design right now.

 

[R&D Guy]

The other thing I'd try is to restrict it a bit. There is plenty to be lost in translation when we talk about these issues in a chat board verses being there and seeing it for yourself. That's where you might want to call a local dealer. I'd also consider a snorkel if one is approved for your unit.

If you have 1" of rise for an 18" run and you only needed 3/8" then it could be that its drafting too much at start up. Since it runs fine with a little vertical on it I really doubt it has too much draft, but the other thing that happens when the stove warms up is that the pipe warms up too and sometimes it slows the combustion air down as the air gets preheated. I'm not familiar with your appliance so I can only shoot from the hip at this point.

Do the flames look transparent, blue and lazy (little movement), or do they look wind blown and hyper??

 

[tubbster]

I think the term is ghosting?
They seem to become detached, there is definitely not a lot of wind in there (don't think there is any). From what I have read online and looking at manuals of other units, it seems under drafted until completely warmed up.
There is one jet in the forward right that seems indicative of what is going on in the pilot jet. It just seems to start to become detached, and at then the valve closes, and the cycle repeats itself.

The one time I started it cold with a temporary 2 foot extension in place of the vent cap, it worked perfectly. I am thinking of somehow modifying the vent cap to make a snorkel extension out of it. It will affect the view out the window maybe, but I don't like gas shutting on and off so much in the confined space. I would love to hear of other peoples experience with the same stove and vent setup. Napoleon seemed to think there is something dreadfully wrong with my install, and I maintain there is not. I have an engineering degree and and aircraft mechanics license, not the dumbest rock under the sun.

Been running on low now for a few hours, and it's beautiful.

 

[R&D Guy]

Do NOT Modify the cap!! You can create a very dangerous situation in windy conditions.

Try taking the logs out and see if it burns better at start up.

 

[tubbster]

Thanks. No cap modification of any kind then.

Logs out, I'll see what happens. I'll have to wait till Friday so I can get a cold start.

 

[R&D Guy]

OK, and what about the embers? Do you have any on the burner or covering any air slots?

 

[tubbster]

No embers. The manifold for the base of the unit (where all the jets are) is made out of the same ceramic stuff that glows. Really only two logs - plus the back drop log which is held up in the back. It really is not part of the game.

 

[R&D Guy]

Well I could be wrong, but the rear log looks like it blocks air flow. Obviously this isn't how you'd want to operate the appliance all the time, but if it was removed and it burns better at start up then it would help confirm a lack of air flow.

 

[tubbster]

How profound of an affect will Outside Air Temperature have on this whole thing?

Most of my futzing has been at around 60 -70 degrees. When it's cold, will there be significant change in its operation? Like maybe the way it's supposed to work?

 

[tubbster]

Now I would not do it, but I could call in a gas guy who knew his gas.....

Would adjusting the venturi do anything?

Sure seems to run great after 15 minutes or so, here are pics on high and low, after running an hour or so.

 

[PaulRicklefs]

Have you checked gas pressure yet?

 

[tubbster]

Do NOT Modify the cap!! You can create a very dangerous situation in windy conditions.

Try taking the logs out and see if it burns better at start up.

Logs out = no difference, except the front row of burners took longer to ignite, which made me pretty nervous.

I tried closing down the restrictor plat on the top of the unit, no difference.

I have a pro coming later. Hopefully he can get to the bottom of it, check gas pressure, etc. All my other gas appliances in the house seem fine with the pressure.

 

[R&D Guy]

That's a beautiful fire you have there! Could be the flsh if you used one, but looks like the air shutter could be closed down a tad to give you more yellow flames. Great looking fire though.

 

[PaulRicklefs]

Do NOT Modify the cap!! You can create a very dangerous situation in windy conditions.


I have a pro coming later. Hopefully he can get to the bottom of it, check gas pressure, etc. All my other gas appliances in the house seem fine with the pressure.

On a nat gas system each appliance has a small regulator that takes the 7" (1/2 psi) line pressure and reduces it down to usually 3.5" (1/4 psi) manifold pressure. If your manifold pressure isn't set right or bypassed (like propane systems) you can get a funny pilot light as well as burner issues due to excess pressure.

I hope your pro can get you fixed up.

 

[tubbster]

Well, my gas pro has called in sick for the last couple days.
Not willing to sit there, I fooled around some more. (Emphasis on fool?)
The hearth pad which I made for the stove was originally 1 1/8" taller than you see it now. I let the table saw have it, and trimmed it down, lowering the stove by that amount. Then I cut out the hole in my inboard wall to let the exhaust pipe come down the same amount. The exhaust on the outside stays at the same altitude. Now, the exhaust is more positively pitched up. That may have helped some. I also took some thick aluminum foil and made a block off plate at the bottom of the pilot assembly to stabilize the flame a little more. Between the two, it now goes from cold to hot cycle on LOW without any cutouts, at least the one time I tried it so far. ON high, it will still cut out once in a while. But hey an improvement. I do no like the idea of modifying anything like this, and may take the foil out.

A couple more pics. The first is the install, and you now can see I will have some trim work around the wall thimble because I now lowered it.
The other pic is a pic of the gas jet on the front left corner. It is my canary in the mine so to speak. When I see that one start to lift off I know to keep an eye on the pilot area, because chances are it is starting to lift off also. This pic was with the flame set at max high, and maybe a couple minutes into the start cycle. Flames on a stove are hard to photograph!

 

[R&D Guy]

Sounds like you're making some progress. I bet your gas pro does the same thing with the pilot shield.

 

[tubbster]

It still will not start correctly on high.
I guess if it never gets completely corrected I can live with it on low.
(Not that I should have to!)
Here is a pic of it starting on high, about one minute into the start.
It will cycle only a few times, not consistently like it did before, so it is improved. But there is now about 2" of lift over the 18" exhaust.
You can see the flame lifting/walking off pretty well here, and when it is doing it there, the pilot/sense rod flame is 'puttin on da boots also.