Merrimack heat output

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Joseymack

Member
Nov 9, 2010
22
Central ma
I purchased the Merrimack when it first came out. I like the stoves looks and all but I do not think the heat output is what it should be. I get some nice hot fires going but it seems I loose it all? Sometimes I open the dorrs and the heat finally gets in the room. The blower motor blow in heat but it seems weak and always has. The reason it is now a problem is I happened to be in a store with a tiny wood insert. The blower was on and the heat coming out was beautiful much more powerful than my expensive merrimack. What gives? Is it possible the guys crushed the vents during installation? or what should I check?
 
Is this in a masonry chimney on an outside wall? If so, it could be losing most of its heat to the masonry. This can often be remedied by putting in a damper sealing block off plate and if there is room, adding some mineral or ceramic insulation behind the insert.
 
Any new info on the heat output from the Merrimack. Mine seems to be lagging still. Seems there is barely enough flow to feel 6 inches away
 
Low quality BTU firewood with minimal seasoning will put out about 25% of the heat you expect, so we need to clear that up first.

That is scary, I almost purchased a Merrimack but a friend told me it would burn too hot and only burn 1/3 the amount of time as a blaze king.
 
Ricky I get great burn times, ovenight is not an issue for us as I can stir it up in the am and drop in some little peices. By the time the kids get up the damper system kicks in and it is fine. It does not get too hot for me. My problem is and has been that it seems the fan is not blowing hard enough. I am gonna get down there this week and finally clean it out good but is there some sort of damage that can be done when installing these things? I suspect there is a restriction or the fan just sucks.
 
Have you checked the blower fan location to make sure it is properly in place and not leaking air?

Can you describe the area the stove is in? What is its sq ftg and the ceiling height? How large is the house and how well insulated?
 
Whatever it is I hope its an easy fix. What type of firewood are you burning and what is its moisture content?
 
House is new and well insulated. Wood is well seasoned. Room is open and large with ceiling fans working. As I have said there just seems to be a lack of power from the fans. With them on full tilt sometimes I have to put my hand a few inches off the stove to feel the air. I sometime open the door and the heat which comes in is amazing and I will let that heat fill the room!!!!
Is there some type of plenum or tubing which could have been damaged during the install 3 years ago?
 
Please provide specifics for dimensions of the stove area and house size.

Have you checked to be sure that the blower assembly is properly seated?
 
Sorry to be pain in the a'', but are you burning willow, oak, pine? Just curious to know. When you place your hand six inches from the stove, do you feel a tremendous amount of heat radiating from it (in addition to the weak fan blowing) or do you feel only a slight amount of heat radiation.

Just to be clear, this has been a problem for 3 years or has this just started recently?
 
It has been a problem since it was installed in jan 2011. I am burning maple/oak seasoned at least 2 years. I have burned lots of wood previously so I am pretty sure it is well seasoned as I have a very sunny spot for that.
Again it burns well but it seems I am not getting the heat to blow out properly. It's almost as if it is trapped inside trying to break out. So i know i am losing alot through the chimney.

When feeling by the blower output NO It doesnt feel too hot
 
house is 2100 sq/ft and the stove is in the middle with an external mason chimney. The floor plan is open with the exception of the bedrooms and the ceilings are not cathedral... How can i test the airflow from the output to verify? Do i need a CFM meter?
 
First - do as Begreen suggested. Make sure the fan is in proper position and that the fan itself is functioning as it should and sealed as it should be. Make sure it is spinning (loose shaft screw could allow the shaft to spin but not the fan). Gotta get past step one, first.

Do you have any way to measure stove temps?
 
1. Do you have a damper sealing block off plate installed? https://www.hearth.com/talk/wiki/make-a-damper-sealing-block-off-plate/
2. Do you have a thermometer to read the insert's temperature? Where is it located and how hot does the insert get?
3. How full do you load the firebox? How much do you turn down the air control? Do you see flames in the top of the firebox?
4. Has the wood been split and stacked for seasoning? Did you measure the moisture content of the wood?
 
house is 2100 sq/ft and the stove is in the middle with an external mason chimney. The floor plan is open with the exception of the bedrooms and the ceilings are not cathedral... How can i test the airflow from the output to verify? Do i need a CFM meter?
Visual inspection. The blower assembly mates to a plenum duct that channels the air flow around the stove body. It should be correctly attached. Actually while down there do as Jags suggested. Remove the blower, clean it and make sure that the squirrel cage (blades) are tightly secured to the motor shaft. A loose screw would allow the shaft to spin faster than the blower squirrel cage, decreasing output. For frame of reference you might also want to visit your VC dealer and checkout the Merrimack fan output on a floor model. If it's notably greater, discuss with the dealer.
 
Thanks for the replies guys. I will do some checking tonight around the blower assembly. As a sidenote I just bought a Harmon p61a for the basement i have a mantown there and and additional 850sq/ft inlaw apartment down there with electric heat. I also have a large area down there and it gets too cold for the mantown in the winter. The merrimack is upstairs.... 2100sq/ft on each floor, basically a big open ranch style house. the lower level is a mirror of the upper. I love the merrimack but I cooked through 5 or 6 cords last year and I want to use the p61a to keep the basement warmer, not too hot, which in turn will keep my floors in my house warm so i can use the merrimack on a more leisurely scale. Coming in after work to cold trying to start a stove sucks....and kids home make the need for keeping the house moderately warm. I'll check back soon
 
I know a few posters have questioned the output of the blowers on their inserts but my princess blower wasn't all that strong and heated my space well. I had to get up pretty close to feel it, I don't think stronger is basically better.
I think with 2 stoves you'll notice a difference providing your fuel is good.
 
I got you weather guy but I spent good money on the Merrimack and I want it to work correctly, even if it has been almost the 4th burning season. 8^)
 
Kids don't need extra warmth. We couldn't have a wood stove in the house where our kids grew up. Thermostat was set to 68F day and 65F night in the winter. Everybody was healthy.
 
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