Going though wood...

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H

h8oil

New Member
Dec 21, 2016
9
NY
hi everyone, new poster and new wood stove insert owner.

I've been lurking the boards for a few weeks now and I tried to find the right answer but really haven't been able.

Here's my setup. I purchased a VC Merrimack about a month ago and trying my hardest to figure out the "right burn" for it. I have a 2000 sq ft 2 story colonial built in the earily 70's.

It's been around 30-40 degrees out and I'm getting 56-58 inside my home with all systems off.

I'm looking for advice on the following

When the stove is running what should the air temp from blower be in a range?

I'm seeing 150-250 max on all different speeds and at all different air levels it just seems odd that the firebox hits close to 1000+ but the surface temp from blower air is only 250.

When I do get the air temp that high I can only seem to get the temp
In the house no higher the 62. In the room it's max 68.

I was told by several people that the room should be blazing hot (80's). I'm just not seeing the hot temps that people are saying.

I've got dry wood (11% ) so I don't think it's a wood issue. Thoughts??

Also how fast should I be going though wood? I'm a 1/2 cord used in 4 weeks that seems really high....

Finally anyone have any real suggestions as to getting air out of the room and into other areas of the house? I'm going to be pulling down a wall which will open that room up more but not until spring.

I guess I'm just disappointed with this unit I really thought it would give be a healthy heat in the house and for the cost I'm just not happy. Any suggestions would be helpful!

Thanks!!!!
 
Exterior Fireplace? Is the liner insulated, as there a block off plate at the damper? I've known some applications where the product is working so hard to heat the 'cold sink' that can be some fireplaces, that there ends up being a lot less heat transmitted into the living space.
 
Hi There, it is an exterior wall fireplace chimney. When they installed it they did not install a block off plate where the fireplace damper was (they took the damper out). the Exterior is warm (using a surface "laser" temp reader). I've heard about block off plates from the forums here but I wasn't sure if the purpose of it was to keep heat in or to prevent cold hitting the unit.
 
Good forum name, I like it. You bit off a lot so will try to address some points.

Air temp from the blower is not terribly useful to help operate the unit. What's of more value is the stove top temperature. Not as easy to get as with a free standing unit but I measure my Jotul with a thermometer placed in the vent. Also have an IR.

You say firebox temp is 1000. Not sure what you mean there. If the stove or flue outlet is measuring 1000 you're way into overfire. I suspect you mean the fire itself which again is not very helpful as a reference point.

11% wood is low, actually if the reading is very accurate that's just below the equilibrium moisture content you can achieve in NY like for wood flooring. Makes me wonder how you took the reading. The proper way is to freshly split a room temp piece of firewood and take a measurement with probes stuck deep into the wood with the grain.

You should also be sure you're running the stove right. If you're trying to get max heat by leaving the primary air open then you're mostly defeating the purpose of the secondary burn. You should turn the air down is stages which will cause the stove temp to rise as long as you have good wood and draft.

If everything is running well you may be losing excessive heat up the chimney and need a block-off plate. You can read about those here as they've been discussed extensively.
 
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Hi Jatoxico,

I have a surface temp guage (the kind you put on a flue pipe of a regular wood stove and put that in the area where the forced hot air comes out of the unit. I also use a IR temp guage and they are close in temp (150 - 250 depending on the type of fire going).

I used my IR to measure the brick plates inside the firebox and it ranged from 800-1000 depending on where i fired it.

I will use your advice regarding measuring the moisture of the wood. I prob wasnt doing it right.

When installing a unit like this shouldn't a block-off plate be standard? For what I paid for the unit and install I would assume they would of :/
 
Put in an insulated block-off plate and if there is room, attach a sheet of roxul or micore board to the back of the fireplace. This will keep the convection jacket of the insert hotter meaning more heat will be delivered to the room than without it.
 
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Block off plates are rarely part of a typical install. Many installers and sellers don't even know what they are any that do know don't want to because they think it's a PITA and unnecessary. Most stuff a small amount of pink insulation at the top of the chimney by the cap and that's it.

But imagine a typical masonry fireplace. Without something to stop it, above the damper you have a large open space in the area of the smoke shelf then the column of the chimney itself. All sucking heat from the stove and liner. With an exterior chimney like mine it's an endless heat sink that steals heat and causes more creosote to form in the system.

I was heating pretty OK with what I had so it took me a couple years to get to mine but was still a big help. Depending on your setup it may worse. Post a pic or two and give some details like chimney length etc.

https://www.hearth.com/talk/threads/new-block-off-plate-and-insulation-for-jotul.123051/
 
Looks simple, but trying to remove a 500+ lb stove insert will be hard :/ I just dont get it. I do feel heat from the system. It actully feels hotter by the glass doors then it does air blowing out of the top of the unit.

What really concerns me is even though the air intake lever is all the way down I cant seem to get more then 2-4 hrs from a load of wood. Considering their lit claims 12 hr burn time and 55000 btu's. Sure seems like im getting 1/4 of that :(
 
Describe a typical load of wood in split diameter, length and quantity.

Also, what is the ceiling height in the stove room?
 
begreen said:
Describe a typical load of wood in split diameter, length and quantity.

Also, what is the ceiling height in the stove room?
Click to expand...
Hey There, I load the box up with 5-6 pieces of wood about 18 inches long 3-5 inches deep. i put the air control all the way up untill i see a good flame from the wood i just loaded at around 11am. by 5am the wood is gone and the top layer of coals is dark the fan is sometimes on but a few times it was off. i open the door to put more wood in it and the firebox is still warm but not "hot" i turn the coals and they brighten up a little.

My ceilings are 8 feet high. It's a typical living room 20 by 18 with a 6 foot wide doorway. i put a door fan that blows out and the ceiling fan on low blowing in reverse.

right now the blower is pumping out 150 temp. and the room temp is 67...

I dunno to me it just seems like it's not producing anything good. I felt the brick around the stove and it's warm (not hot) and the brick above the mantle is not hot at all. outside it's warm but nothing to crazy hot...
 
Half a cord in a month isn't bad. You can do the block off plate without removing the insert, not sure if the block off plate will be enough but it should be done regardless
 
h8oil said:
Hey There, I load the box up with 5-6 pieces of wood about 18 inches long 3-5 inches deep. i put the air control all the way up untill i see a good flame from the wood i just loaded at around 11am. by 5am the wood is gone and the top layer of coals is dark the fan is sometimes on but a few times it was off. i open the door to put more wood in it and the firebox is still warm but not "hot" i turn the coals and they brighten up a little.

My ceilings are 8 feet high. It's a typical living room 20 by 18 with a 6 foot wide doorway. i put a door fan that blows out and the ceiling fan on low blowing in reverse.

right now the blower is pumping out 150 temp. and the room temp is 67...

I dunno to me it just seems like it's not producing anything good. I felt the brick around the stove and it's warm (not hot) and the brick above the mantle is not hot at all. outside it's warm but nothing to crazy hot...
Click to expand...
OK, high ceilings are not the issue, had to check to cross it off the list. Another consideration would be the species of wood, It could be the firebox is underloaded. That's about half the amount of wood I put in our 3.0 cu ft firebox. Typically our stove is loaded with 9-11 splits, but out splits are typically thicker, in the 5-7" range. The Merrimack has a wide firebox. 18" wood will leave a good sized gap on the sides. Maybe try loading it with a bit more wood and load the splits to one side then fill in the 4" side gap full of shorter splits if you have some.

Also, how far closed do you have the air control when the fire is burning well?
 
Last edited:
begreen said:
Also, how far closed do you have the air control when the fire is burning well?
Click to expand...

Ok I did a test tonight. the stove was working with a coal layer. I loaded it with as much as i could fit in it. there was gaps but nothing more then a few inches if that from back to front. (around 10 pieces). I opened the air up 1/2 way till i saw it catch.

at 8pm the air was blowing 3/4 speed on the fan, 150. it dropped down to 100 after i put the wood in.
at 8:30 the flames were healthy, i then decided to close the air down all the way. (to the right on this stove).
at 10pm (2 hrs in) 1/2 the wood looks like it's done. i still have alot of wood in the stove and i still have flame.. The Surface temp of the stove (right next to the glass is about 225 and the air blowing out is 200 degrees.


I'm actully shocked it's burning so warm with the lever all the way down.

Avg temp in the house is still 62. room temp is 68
 
That's progress. It takes a long time to warm up the interior of a house due the mass of it's contents, the walls, floors and furniture. Most stoves will burn best with the air closed or close to it once the fire is burning well. Are you seeing good secondary combustion?
 
I see a flame and it's burning near the top part of the stove kinda like it's floating and curiling. I'm assuming that's what you mean? I was under the impression secondary burn was just a way to burn off the smoke...
 
E="h8oil, post: 2134845, member: 54343"]I see a flame and it's burning near the top part of the stove kinda like it's floating and curiling. I'm assuming that's what you mean? I was under the impression secondary burn was just a way to burn off the smoke...[/QUOTE]
h8oil said:
I see a flame and it's burning near the top part of the stove kinda like it's floating and curiling. I'm assuming that's what you mean? I was under the impression secondary burn was just a way to burn off the smoke...
Click to expand...
Whree
 
[QUOTEin ny "h8oil, post: 2134845, member: 54343"]I see a flame and it's burning near the top part of the stove kinda like it's floating and curiling. I'm assuming that's what you mean? I was under the impression secondary burn was just a way to burn off the smoke...[/QUOTE]
Where in ny are u located I can come by and show u how to burn in that thing
 
h8oil said:
The Surface temp of the stove (right next to the glass is about 225
Click to expand...

I see the Merrimack has a start up air feature. Are you using it and is it functioning properly? Try to get a stove top reading from the vent a few inches back from the front of the stove. 225 stove top is low, real low. Makes me suspicious that you're either getting a very false reading or you're not getting the air set right and sending all the heat right up the flue.

Possibly the baffle system is not seated correctly? Did you ever remeasure your wood moisture?
 
'Black' coals can be an indicator of less than optimal wood. As jatoxico said, measure the cut side on a fresh split. Also, cut the fan back and let the stove really heat up. Our VC Montpelier's are measuring 350 on the arch of the door. That Merrimack should crank! If I had the room, I'd pick one up myself [emoji16] Good luck
 
h8oil said:
hi everyone, new poster and new wood stove insert owner.

I've been lurking the boards for a few weeks now and I tried to find the right answer but really haven't been able.

Here's my setup. I purchased a VC Merrimack about a month ago and trying my hardest to figure out the "right burn" for it. I have a 2000 sq ft 2 story colonial built in the earily 70's.

It's been around 30-40 degrees out and I'm getting 56-58 inside my home with all systems off.

I'm looking for advice on the following

When the stove is running what should the air temp from blower be in a range?

I'm seeing 150-250 max on all different speeds and at all different air levels it just seems odd that the firebox hits close to 1000+ but the surface temp from blower air is only 250.

When I do get the air temp that high I can only seem to get the temp
In the house no higher the 62. In the room it's max 68.

I was told by several people that the room should be blazing hot (80's). I'm just not seeing the hot temps that people are saying.

I've got dry wood (11% ) so I don't think it's a wood issue. Thoughts??

Also how fast should I be going though wood? I'm a 1/2 cord used in 4 weeks that seems really high....

Finally anyone have any real suggestions as to getting air out of the room and into other areas of the house? I'm going to be pulling down a wall which will open that room up more but not until spring.

I guess I'm just disappointed with this unit I really thought it would give be a healthy heat in the house and for the cost I'm just not happy. Any suggestions would be helpful!

Thanks!!!!
Click to expand...
Definitely get the block off plate! I have a 2000sq ft Center Hall Colonial and had my Hampton HI300 installed in September of 2015. I asked the dealer about a block off plate at the time of install and he dismissed it outright. All was fine until it started getting into the low 30s and below. After a lot of frustrated posts on this site looking for advice on why I couldn't get the insert & main living area hot enough...I concluded that I was just losing a lot of heat to 28ft of cold exterior masonry! So this September I had the dealer install a block off plate at my expense and the difference is night and day. I have no trouble getting the insert up to cruising temps of 550 to 575 and keeping main downstairs living area at around 73 to 74/upstairs bedrooms at around 70.

I'll concede that I also have better wood this season as well, which also makes a big difference. I get beautiful secondaries coming off the baffles and it's a wonderful thing to watch:) I believe the VC Merrimack is a pretty good size insert (I think bigger then my 2.3cubic ft firebox) so you should really be able to get your main living area toasty warm very easily. Good luck...I would get a block off plate and an insulated liner if you don't have one.
 
the dealer told me that because i have a external masonry chimney that I cannot and should not insulate the liner. that it will overheat the unit and void any warranty .

I heard of the block off plate but I cant seem to figure out a way to get the decorative surround off to see whats behind the stove. I purchased a new IR temp meter and the surface temp of the glass and the iron around the glass is in the range of 400-600 depending on how much the fire is going. the heat surface temp where the air is blowing out of is 250-300 but it just seems like it's not hot enough.. i dunno. I was hoping someone with the same insert could compare against what i've got.

I got a new moisture meter and the "fresh cut" split wood is around 18-21% the precut wood i got that was seasoned hovers around 15-18..


I did buy a pack of envi blocks (envi-8) and that really got the stove hot when i put them in. (i laid out 2 north south and 1 east west).

the bricks above the insert hover around 100 - 200 degrees.

The room im in hovers around 68-70 (not 78 like ive been told it should be). But Im sure I could get it that hot if i slammed a ton of wood though it. but do i really want to burn though wood just to get it 78?

I also purchased one of those corner fans that push air out of the room but i'm not sure if it's doing much if at all.


a
 
h8oil said:
the dealer told me that because i have a external masonry chimney that I cannot and should not insulate the liner.
Click to expand...

I'd say these dealers are too funny except the crap they're shoveling has effects that are anything but funny and could actually end up hurting someone.
 
Your dealer is 100% wrong about insulating the liner. Having an exterior masonry chimney is more reason, not less to have an insulated liner. Saying that an insulated liner will void your warranty sounds like a desperate attempt to get you to drop the idea of insulation. Call your stove manufacturer and ask them yourself about their warranty in regards to using an insulated liner.

I'll put it this way, if your exterior masonry chimney doesn't have 1" of clearance to combustibles its entire length than him installing a non-insulated liner is a not to code installation, whether he or anyone else signed themselves off on it.

Best practices for an exterior masonry chimney are block off plate and insulation stuffed above it and in the smoke chamber as well as a full insulated liner.

Take that IR gun and take some readings on the outside of your chimney to see what sort of heat you're losing through lack of insulation.
 
Also why would they use an adjustable type liner the entire length. they left some extra at my home and i was surprised to see that. My thought would be it's harder to clean with a brush and would collect more creosote. wouldn't smooth pipe going up be better?

The Dealer stated that because I don't have a prefab chimney that the installation is just not needed and the VC states you cannot install one.

I am just really disappointing After spending A LOT of money in what amounts to nothing more then a glorified fireplace. At this point the more I read these forums, the more I feel I got scammed :(
 
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