Vermont Castings - Thermostat Flap Installation?

pftomo

New Member
Nov 25, 2020
3
NJ
I recently moved into a home with a Vermont Castings Wood Stove, a Defiant unit. Its been tough finding information but these forums have been very helpful. Part of the challenge is that the manuals I was finding discuss an air control handle when my unit has a thermostat flap.

So, the flap was broken, I bought replacement parts on Amazon that seem to fit well:
Amazon productAmazon product
There were no directions included with either and manual diagrams do not show enough detail. Now that I have the parts installed I am unsure if I need to cut the chain to fit directly so there is no slack or leave the full length. Since I believe the metal coil would expand when the stove heats, it makes sense to me that this action would extend the chain to drop the flap and decrease air flow to drop the heat and if this is correct, I would think the chain needs to not have so much slack on it. If there is someone who understands this setup I would greatly appreciate some help.

And if anyone can explain how the coil with the handle functions that would help as well. I was told by a friend that if I need to quickly extinguish the fire in case of an emergency then that flap should be closed quickly, and it looks like this would happen by unscrewing the handle to drop the flap, but I don't know if that handle piece attached to the coil is generally moved or adjusted to control the fire temperature, it screws in until it is tight but wouldn't rotate unless I unscrew it, dropping the flap. Thanks in advance!!

IMG_3286.JPG IMG_3287.JPG IMG_3288.JPG
 

Easy Livin’ 3000

Minister of Fire
Dec 23, 2015
2,868
SEPA
I recently moved into a home with a Vermont Castings Wood Stove, a Defiant unit. Its been tough finding information but these forums have been very helpful. Part of the challenge is that the manuals I was finding discuss an air control handle when my unit has a thermostat flap.

So, the flap was broken, I bought replacement parts on Amazon that seem to fit well:
Amazon productAmazon product
There were no directions included with either and manual diagrams do not show enough detail. Now that I have the parts installed I am unsure if I need to cut the chain to fit directly so there is no slack or leave the full length. Since I believe the metal coil would expand when the stove heats, it makes sense to me that this action would extend the chain to drop the flap and decrease air flow to drop the heat and if this is correct, I would think the chain needs to not have so much slack on it. If there is someone who understands this setup I would greatly appreciate some help.

And if anyone can explain how the coil with the handle functions that would help as well. I was told by a friend that if I need to quickly extinguish the fire in case of an emergency then that flap should be closed quickly, and it looks like this would happen by unscrewing the handle to drop the flap, but I don't know if that handle piece attached to the coil is generally moved or adjusted to control the fire temperature, it screws in until it is tight but wouldn't rotate unless I unscrew it, dropping the flap. Thanks in advance!!

View attachment 267714 View attachment 267715 View attachment 267716
This is hard to explain, but I'll try. I had the same exact problem a couple years ago.

The chain will need to be shortened, but I don't think you need to cut it. It's a ball chain, just select the right length and lock the correct ball into the slot.

Regarding the length, the lever pushes from side to side. The correct length of chain will allow the vent cover to just close completely, no more, and then lift it when the lever is pushed the other way.

The coil is the bimetallic thermostatic control. I believe it is supposed to shut the vent automatically when the stove gets hot. When you adjust it correctly, then push the lever so the vent is open when it's cold, it should close by itself when the stove gets hot.
 

fbelec

Minister of Fire
Nov 23, 2005
2,954
Massachusetts
also to add. make the adjustment with a magnetic thermostat on the cookplate it should be adjusted so that the handle is at 12 o'clock so that it is easy to move when it's hot. i can't tell from the picture if it is that way or not
 

pftomo

New Member
Nov 25, 2020
3
NJ
also to add. make the adjustment with a magnetic thermostat on the cookplate it should be adjusted so that the handle is at 12 o'clock so that it is easy to move when it's hot. i can't tell from the picture if it is that way or not
This is hard to explain, but I'll try. I had the same exact problem a couple years ago.

The chain will need to be shortened, but I don't think you need to cut it. It's a ball chain, just select the right length and lock the correct ball into the slot.

Regarding the length, the lever pushes from side to side. The correct length of chain will allow the vent cover to just close completely, no more, and then lift it when the lever is pushed the other way.

The coil is the bimetallic thermostatic control. I believe it is supposed to shut the vent automatically when the stove gets hot. When you adjust it correctly, then push the lever so the vent is open when it's cold, it should close by itself when the stove gets hot.
Thanks SOOO much for the help, I was able to install the chain with the extra slack still there for future adjustments. The only problem is that the thermostat door has no effect on air flow to the inside. I have to keep the side door cracked to allow air flow in otherwise the fire starts to die out. I had this problem when I first moved in and started using the stove so I cleaned out behind the thermostat door and the back of the stove on the inside by blowing compressed air into each hole to clear any clogs. I was hoping this would open up air flow through the thermostat door but it didn't work. I guess the next step might be to remove the back inside panel to get access and clean more thoroughly. I think I read about this unit having a catalytic converter, can those go bad and maybe affect air flow? I appreciate the help!!
 

fbelec

Minister of Fire
Nov 23, 2005
2,954
Massachusetts
if your catalytic was bad then as long as you don't engage it the stove will burn. with your thermometer on the cook plate and a cold stove the back primary air flap should be wide open. get a fire going and bring the stove up to 500 and then close the flap by moving the handle and leave it open about a quarter of a inch. if you can't get the stove up to that temp open the side door and listen for a hiss. if you hear a hiss the wood is not dry enough and use that wood next year or the year after. if you continue to use hissing wood you'll build creosote in your chimney for a chimney fire. with that stove it's easy to build creosote take it from my experience. i had a beauty my first year.
 

pftomo

New Member
Nov 25, 2020
3
NJ
if your catalytic was bad then as long as you don't engage it the stove will burn. with your thermometer on the cook plate and a cold stove the back primary air flap should be wide open. get a fire going and bring the stove up to 500 and then close the flap by moving the handle and leave it open about a quarter of a inch. if you can't get the stove up to that temp open the side door and listen for a hiss. if you hear a hiss the wood is not dry enough and use that wood next year or the year after. if you continue to use hissing wood you'll build creosote in your chimney for a chimney fire. with that stove it's easy to build creosote take it from my experience. i had a beauty my first year.
Thanks for the info, so far I have tried to use the back flap to control air flow with the damper open and closed (closed to engage catalytic convertor) but the fire begins to go out as soon as the side door is closed, as if there is no air flow from the thermostat door either way. So I have to keep the side door cracked a little and everything runs fine.

I am able to get the stove up to around 300-350, not sure if I have it over 400 yet. That is with the thermostat on the pipe, but I think it is a double walled pipe so it may be giving a lower reading? It does take some time to get it there, maybe 30 minutes and needs constant feeding to stay there and I get frequent drops to around 275 at which point I throw an extra log or two on.
When letting it die out and it is down to hot coals I put a scoop of Rutland Creosote Remover on and close all the openings. But I don't run it daily so hopefully that will minimize each winter's buildup? I have also been checking the moisture level and it is around 15% or so.
 

fbelec

Minister of Fire
Nov 23, 2005
2,954
Massachusetts
you need to figure out if the pipe is double wall or single. if it is single wall you are not hot enough for the cat to run. if you are keeping the cat disengaged and its running 350 to 400 on double wall pipe that should be hot enough to maintain a fire with no problems. if you can't keep the fire going at 400 on the pipe and need the door open your wood is not dry enough. when you have taken a moisture reading where are you putting the meter?
 

Easy Livin’ 3000

Minister of Fire
Dec 23, 2015
2,868
SEPA
Thanks for the info, so far I have tried to use the back flap to control air flow with the damper open and closed (closed to engage catalytic convertor) but the fire begins to go out as soon as the side door is closed, as if there is no air flow from the thermostat door either way. So I have to keep the side door cracked a little and everything runs fine.

I am able to get the stove up to around 300-350, not sure if I have it over 400 yet. That is with the thermostat on the pipe, but I think it is a double walled pipe so it may be giving a lower reading? It does take some time to get it there, maybe 30 minutes and needs constant feeding to stay there and I get frequent drops to around 275 at which point I throw an extra log or two on.
When letting it die out and it is down to hot coals I put a scoop of Rutland Creosote Remover on and close all the openings. But I don't run it daily so hopefully that will minimize each winter's buildup? I have also been checking the moisture level and it is around 15% or so.
I don't believe your wood is dry enough. Find some construction scrap that hasn't been in the rain, and isn't pressure treated. 2x4s work great. Build a fire with them, and see what happens.

If you are reading 15%, you either live in the desert, or the meter isn't accurate, or you aren't making an accurate reading on room temp freshly split wood correctly.

Wet wood is the cause of your problem almost every time, and it takes a shift in mindset for folks to come to terms with it.

The chances that your air intake is completely blocked are extremely small. Figure out where that is and blow air through it to rule that out.
 
  • Like
Reactions: fbelec