Sparks visible through fan vent? VC Montpelier

[denney]

Hello!

Our Vermont Castings Montpelier unit has been noticeably more smokey last season and now beginning this season. This is after there's a good fire already going...not necessarily a drafting issue at startup.

Today, with the room lighting low, I noticed embers in the vent area of the stove. They were certainly on their way 'up' but I'm wondering if this visibility could be contributing to the smokey air coming from the blower?

I tried to take some photos and put arrows where I saw the embers. It is a very small gap. There are some pretty harsh shadows from the camera strobe.

Another thing I need to investigate is the seal between the door and the unit...perhaps the latch needs adjusted.

Might anyone else offer any suggestions?

The unit was purchased in December of 2010 and has been in service since March of 2011. So we're beginning our 3rd year of Winter use. We live in central Fort Collins, CO.
The insert vents through a 6" stainless flex liner, which is run about 20' through an existing clay/masonry chimney. There's a cap at the top which seals the masonry chimney, making it an enclosed space.

Thanks!

 

[glennm]

I have the same insert and occasionally I smell a faint hint of smoke as we'll. I have a fire going right now and I don't see anything where your arrows are. I changed my gasket last year. I find that little pieces of wood and small coals get on the ash lip and if someone doesn't clean them off they will get crushed by the gasket when you close the door and damage the gasket. I also had to adjust my door, it wasn't closing correctly and with the design of the casting it damaged the gasket as well.

 

[denney]

Thank you for the reply! It may take me until the weekend but I'll investigate the door seal first.

That seems more likely than getting a smoke smell from where I put arrows. (I'd have to think the velocity of the hot fire draft would discourage smoke to escape out through such a tiny area.)
While this is the first time I've noticed embers like that...it's not to say it hasn't always been like that from the start.

 

[KaptJaq]

Hi Denney, welcome to the forums...

The first problem I see, in the first picture, is the coil of wire in front of the fan intake on the lower right side of the stove. That wire should be laying straight and out of the way outside the stove.

There is occasionally a small amount of smoke out of the fan vents when there is not enough draft. This should stop as soon as the stove warms up, within a few minutes of starting.

Are the embers actually inside the end of the fan vent? If so then there are several causes of "embers" in that area of the vent. The first is burning lint from dirty fans. Have you cleaned the fan unit? The area that your arrows point at is the actual top of the fire box, just forward of the outlet. In my stove it is the hottest point on the stove. If fan lint is blown there it can ignite. With the wire coil in front of the fan inlet you may have some accumulated dust balls breaking loose.

Since that is the top of the firebox it is also subjected to the most heat. Have you pushed the stove hard? I would take off the baffle and inspect the inside top of the stove to make sure everything is intact. Use a bright light to check the seams, etc...

KaptJaq

EDIT/ps: If the fan wire is coiled because you do not use the fan you might want to remove the entire fan unit. It is an easy process and will allow more natural convection through the stove.
To remove the fan first remove the two large screws that hold the cast iron access door assembly. (Blue circles below) After the door assembly is removed there are one or two screws on either end of the fan assembly, remove them (red arrows) (newer units have 2 on each end). Slide the fan assembly out. If you had only two screws holding the fan assembly in place then there will be two screws holding the snapdisk to the bottom of the firebox, remove them and remove the snapdisk. Replace the cast iron access door assembly.


(Click for larger image)

 

[denney]

Hi KaptJaq, thank you for the welcome!

I hadn't given the fan much thought...it does have some of the vibration others have mentioned but there are certain speeds that minimize that. It's been like that since day1, I just figured "that's the way it is".
The fan is hooked up and kicks on after 30 minutes or so...seems it can depend on how cold the hearth is.
The outlet was installed in the enclosed space, near the rear/bottom of the old/original firebox. I suspect the installer didn't need much additional length so he left the excess coiled up in the unit?
I hadn't considered that the extra cord would be blocking the incoming airflow but I see how that'd be possible.

I've never removed the fan assembly, nor cleaned it; sounds like something I should do. The user manual doesn't really describe this (save for the exploded parts diagram)
I appreciate the removal tips.

In your experience with the montpelier unit, have you had to replace more than the door seal? The user manual mentions the seal around the glass as well as "firebox parts" (not sure what parts they're specifically talking about).
I just did the 'dollar bill test' on the door seal...there was still some 'grab' or resistance but not a whole lot. So I don't know if the door seal is to blame. I suppose I could adjust it a small amount tighter and see if that makes a difference?

Could the placement/orientation of the fiber-baffle on top of the secondary air tubes make any difference? There's a little bit of slop in that it can be slid forward or backward in the unit.

 

[KaptJaq]

The baffle should be all the way to the back of the stove. Probably a better place for the wire is outside the box, along side near the outlet. VC surrounds lift off and should give you access to move the wire.

I don't see how a poor door seal would give you hot embers in the convection vents. It would give you a hard to control stove.

Have you checked to see if the seam between the front and top casting is still sealed? If the stove is pushed hard the top does expand and contract. This movement does affect that seam. When the stove is cold remove the front secondary air tube (one carter pin) and slide the baffle out of the stove (it is fragile so don't force or drop it). Put a bright light inside the stove near the top front and see if any light escapes to the top of the stove. Also put the light up the flue outlet to see if the liner is still solidly attached to the stove.

Have you cleaned the flue and cap? Any buildup restricting the exhaust gases? A clogged flue or cap will cause a stove to smoke into the house.

KaptJaq

 

[denney]

Hi KaptJaq!

I spent some maintenance time with the stove this weekend.
I slid it out a few inches and removed the surround. After a test fire tonight, I'm fairly confident the culprit was found!
When I cleaned the 6" liner last year, I didn't pull the stove out; just removed the cap on the chimney, the baffle from the insert and brushed from the top down.
I removed a smallish size pile of buildup from inside the insert. I figured the job was done.
But here's the thing; the original chimney isn't spotless. I think when I bang around with the brush on the 6" liner, it bumps against the original chimney and knocks old junk down on top of the insert!
I think this 'junk' is what was smoldering when my insert would get hot...and even sending off the occasional spark/ember.

So from now on, I know I'll need to pull the insert out a bit during cleaning so I can wipe off the top of the insert afterwards. Or better yet, insert some cardboard while I brush to catch the junk from the old chimney so that it doesn't fall on the insert.

The fire tonight is much more pleasant...no smoldering odor!

I also tried the light test you mentioned...thank you; that seems to check out 'ok'.

 

[begreen]

It's seriously important to have the chimney very clean before lining. Was this done?