Insulation

[familyfarm42]

I have a Fisher Honey Bear with a 6" single wall stainless steel flex pipe installed connecting to a "boot" adapter. It works okay, a lot better than when I had it "slammed" in and no flue pipe connected. This season I want to make more improvements and I'm wondering how much of a difference I should expect when I add 1/2" insulation from Rockford Chimeny. My fireplace is oval 8"x17" and my flue pipe is about 11' from top of the fire box to the top of the pipe exiting the chimney. Do you think I will see a noticeable difference when I insulate?

 

[coaly]

It will stay cleaner if you run it the same as you did with no insulation. If you have a pipe damper or baffle, you can adjust them to keep more heat in the Insert instead of leaving so much out. If you have no flue damper, you are controlling what goes out as well as what comes in with the air intake damper.You can run it more closed with insulated flue and expect the same temperature results, theoretically using less wood. Insulating a flue makes a big difference and is well worth it.
The object is to have 250* flue gas temp at the top of chimney flue. More than that is waste, less will allow water vapor in flue from combustion to condense, allowing smoke particles to stick which forms creosote.
You can leave less heat out the stack with insulation while still keeping the same inner temp which relates to better draft with less heat loss.
Do you have a blower? That is the best way to make it more efficient, then add a baffle at the top of the firebox under outlet if it doesn't have one.
Does it have glass doors?

 

[familyfarm42]

It will stay cleaner if you run it the same as you did with no insulation. If you have a pipe damper or baffle, you can adjust them to keep more heat in the Insert instead of leaving so much out. If you have no flue damper, you are controlling what goes out as well as what comes in with the air intake damper.You can run it more closed with insulated flue and expect the same temperature results, theoretically using less wood. Insulating a flue makes a big difference and is well worth it.
The object is to have 250* flue gas temp at the top of chimney flue. More than that is waste, less will allow water vapor in flue from combustion to condense, allowing smoke particles to stick which forms creosote.
You can leave less heat out the stack with insulation while still keeping the same inner temp which relates to better draft with less heat loss.
Do you have a blower? That is the best way to make it more efficient, then add a baffle at the top of the firebox under outlet if it doesn't have one.
Does it have glass doors?

Hey Coaly, you’re the best! Yes it does have glass doors and I do not have a fan. There’s a lot of option, do you recommend electric or the ones that run off the heat itself?

 

[coaly]

The ones that run from heat are stove top to move radiant heat. They don't move much unless you have no power available and need that type. Then it should be an expensive sterling type engine type to move enough from a freestanding stove. You're extracting heat by convection;

You don't have a regular stove top. The heat you're trying to extract is from around the vent pipe leading from firebox to the outer shell that makes an air space around the firebox. This is convected heat, compared to radiated heat. It pushes the heat convected to air out around the rear of the Insert that would only drift out naturally and also radiate through outer shell to heat the masonry hearth behind it, radiating outside and upward through the chimney mass and roof. The blower brings the heat inside also removing the heat from the hottest parts, around the exhaust vent. Look under the front of ash fender (shelf) for a slot all the way across Insert. That slot is designed to blow air under firebox, up the back, and out the top slot, forward. There are optional ways to connect blowers if you have slots in the front face cover as well. It should move 225 CFM. They all push air out the top slotted vent where there should be an angled deflector to prevent rising heat from mantle.

A good thread showing blower types as well as homemade;
made-a-blower-for-my-fisher-insert.117672

 

[coaly]

With glass doors you have to be careful baffling too much. The baffle thread gives the advice you need. Most importantly is the area above baffle that the exhaust must move through, being the same square inch as the chimney flue. No smaller. Angle makes a difference on the open area you end up with over the baffle plate. Too flat is not good for any stove, but glass doors are more critical to keep clean from smoke particles, so adjust it so the smoke evacuates easily from firebox without contacting glass. The air wash across glass is designed to prevent this. Make sure you keep it open enough for good air flow across glass at all times. That is the simplest modification to increase output, efficiency and reduce smoke.

 

[familyfarm42]

With glass doors you have to be careful baffling too much. The baffle thread gives the advice you need. Most importantly is the area above baffle that the exhaust must move through, being the same square inch as the chimney flue. No smaller. Angle makes a difference on the open area you end up with over the baffle plate. Too flat is not good for any stove, but glass doors are more critical to keep clean from smoke particles, so adjust it so the smoke evacuates easily from firebox without contacting glass. The air wash across glass is designed to prevent this. Make sure you keep it open enough for good air flow across glass at all times. That is the simplest modification to increase output, efficiency and reduce smoke.

I installed a baffle last year based off your advice... and I have it on an angle. It seemed to help a bit. We just have a lot working against us with our setup. Fireplace is on an outside wall. House exterior walls are not insulated. There's a glass slider and a large window that the heat has to cross before it gets to the kitchen and living room. This year, adding the flue pipe insulation at a minimum I'm hoping helps. Looking at these blowers gets my mind running. Time is hard to come by, I wish somebody made one for a fisher! When I get home I'll look but I'm pretty sure I have the opening on the front bottom, below the ash catcher.

 

[familyfarm42]

The ones that run from heat are stove top to move radiant heat. They don't move much unless you have no power available and need that type. Then it should be an expensive sterling type engine type to move enough from a freestanding stove. You're extracting heat by convection;

You don't have a regular stove top. The heat you're trying to extract is from around the vent pipe leading from firebox to the outer shell that makes an air space around the firebox. This is convected heat, compared to radiated heat. It pushes the heat convected to air out around the rear of the Insert that would only drift out naturally and also radiate through outer shell to heat the masonry hearth behind it, radiating outside and upward through the chimney mass and roof. The blower brings the heat inside also removing the heat from the hottest parts, around the exhaust vent. Look under the front of ash fender (shelf) for a slot all the way across Insert. That slot is designed to blow air under firebox, up the back, and out the top slot, forward. There are optional ways to connect blowers if you have slots in the front face cover as well. It should move 225 CFM. They all push air out the top slotted vent where there should be an angled deflector to prevent rising heat from mantle.

A good thread showing blower types as well as homemade;
made-a-blower-for-my-fisher-insert.117672

This is a little below the CFM you suggested but any thoughts using this one?

https://www.acinfinity.com/componen...ith-speed-controller-4-inch/#product-warranty

 

[moresnow]

@coaly could a guy adapt this blower (link below) to the OP setup perhaps? I have used this one on shielded free standing stoves and been impressed. Price is right! Maybe mount 1 or2 adapted to fit the air convection slot under the ash lip? A thought. Assuming we are talking about a shielded unit?

Amazon product ASIN B07W96PRSW


@familyfarm42 have you considered using a small floor fan/fans located in the coldest rooms gently encouraging dense cool air towards the hot light air in the stove room? The cool air will easily displace the hot air which induces warm air circulation to the cold rooms. Just spit balling here

 

[coaly]

This is a little below the CFM you suggested but any thoughts using this one?

https://www.acinfinity.com/componen...ith-speed-controller-4-inch/#product-warranty

That is close, as long as you can duct it under or into a side vent intake without decreasing the square inch area of the outlet duct of the blower.

 

[coaly]

@coaly could a guy adapt this blower (link below) to the OP setup perhaps? I have used this one on shielded free standing stoves and been impressed. Price is right! Maybe mount 1 or2 adapted to fit the air convection slot under the ash lip? A thought. Assuming we are talking about a shielded unit?

Amazon product ASIN B07W96PRSW


@familyfarm42 have you considered using a small floor fan/fans located in the coldest rooms gently encouraging dense cool air towards the hot light air in the stove room? The cool air will easily displace the hot air which induces warm air circulation to the cold rooms. Just spit balling here

Any thing is better than nothing, but it takes a strong blower to push the air out of the top vent and move it across a room.
32 inches across bottom from front to back, 90* up back 22 inches, 90* forward 20 inches then across the room ! The air chamber goes all the way around the Insert. Figure about 1 1/2 inch air space all the way across the Insert is a lot of area.

Bottom intake under ash fender
Here you can see the air chamber around the rear.

 

[familyfarm42]

That is close, as long as you can duct it under or into a side vent intake without decreasing the square inch area of the outlet duct of the blower.

Okay sounds good. I'm going to give that blower a try. I can duct it as wide as the opening below the front glass doors and even if I'm just 1" thick on the duct that will be more square inch than the 4" blower outlet which is 16 square inches. I'm honestly just taking the dimensions to the local sheet metal shop and having them fab it up. I think the hardest part of the project will be making sure the fan is sealed into the ducting so that all the air is being pushed through the duct if that makes sense.

 

[familyfarm42]

@coaly could a guy adapt this blower (link below) to the OP setup perhaps? I have used this one on shielded free standing stoves and been impressed. Price is right! Maybe mount 1 or2 adapted to fit the air convection slot under the ash lip? A thought. Assuming we are talking about a shielded unit?

Amazon product ASIN B07W96PRSW


@familyfarm42 have you considered using a small floor fan/fans located in the coldest rooms gently encouraging dense cool air towards the hot light air in the stove room? The cool air will easily displace the hot air which induces warm air circulation to the cold rooms. Just spit balling here

Thanks for the links! I looked at this model and a few others but I'm trying to balance getting as many CFM as I can and still being quiet, I think that one is too small.

 

[coaly]

Leaks at joints; Duct tape. Not the fabric "fix all" type. Real metallic duct tape with UL label. Super sticky stuff made for duct work.

 

[familyfarm42]

I pulled the flue pipe back out and wrapped it with the 1/2" insulation blanket from rockford chimney. The job was not one I would wish on my worst enemy but I got it done! I used the furnace cement to help seal up the joint at the direct connect to my fire box but I'm ordering some high heat ducting tape to make that 100% air tight. I lit the first fire and the temperature climbed to the burn zone much much faster than it did last year without the insulation. I can definitely tell a difference and it seems much easier to keep in the burn zone. I have the baffle closed more and the air intake closed more, allowing me to burn slower. Very happy with it so far! Granted, it isn't a super cold night but it got us warmer than it did last year! Now i'm going to add one of those heat powered fans until I can build an electric fan to help blow the heat. Once again, thanks @coaly for all your help!

 

[coaly]

The colder the outside temp, the more difference you will experience since you will have a greater temperature differential equaling more draft. The stove will naturally burn hotter at the same settings. I built my masonry chimneys with oversize flues to allow an insulated flue liner. Saves lots of fuel.

 

[familyfarm42]

There has been a significant increase in heat. The insulation keeps the flu pipe hotter allowing the stove to push more heat out instead of having to heat up the flu pipe so much. It’s been extremely noticeable. The stove now can heat the house about 5 degrees more than it has the last 3 seasons without the insulation. Maybe it’s because the heat is more consistent, not fluctuating as much, but an obvious improvement is seen once we added insulation. ... everything else is the same, wood, outside tempt, etc.

Surely if you try to use less wood during the shift, you will see more change.
But in terms of heat, you will feel the same temperature.