Merrimack VC 3 seasons burning

[MI is Cold]

Hi, I'm from Michigan and will be burning with my Merrimack for my 4th season already. I have made several improvements to the insert.

#1 has been putting vinyl tubing underneath the fan motor to prevent it from vibrating like a jack hammer.
#2 splicing the thermostat sensor wires together to be able to turn the fan on and off whenever I want. 10 min after starting a good fire I have decent hot air that would be a shame to waste.
#3 bringing in fresh make-up air through the back of my fireplace masonary using metal pipes. They stay hidden as they go around the side and then through the the removable electric cord panel that can be removed effect to the unit. Nice to not have to use room air to combust. Hey, why heat it if you just blow half of it back up the chimney right?
#4 Insulated my 23 foot long 6 inch dia. flue with 1/2 chimney flue insulation for better draft. Two fires in and I'm not sure it make much of a difference.

Still have a couple problems:
Some smoke comes out when the doors are opened for loading. It is enough to bother me and and my wife. I can open the doors about 3-4 inches then the smoke starts to leak out. I was hoping that the flue insulation would have helped this problem out. Gasket at the top of the insert to the flue coupler seems good but maybe I need to redo the glass rope. This is my last ditch idea. I may think about a chimney top power vent for $1000 bucks. Any recommendations? Till then, I just wait till I have coals then I load.

I have about 2200 square feet to heat. I can heat the first floor to near 80, but the upstairs stays cool/cold. I'm looking at ways to distribut the heat more. Cutting vent holes in the ceiling to have a passage for the heat. Not sure about code or whether that would be annoying to have sound travel between floors. I run the furnace fan and it does an ok job circulating some heat but most of the heat stays near the ceiling of the room. A ceiling fan may work but it would look weird and our ceilings are low already.

I have had to replace the fan and door gaskets. Factor a $200 fan every 3 years into your payback for this unit. Seems the fan is a poor design. Hopefully you are a bit handy and can put the fan in yourself or it could get very expensive.

Good luck Merrimack owners. Let me know how you are doing out there. Especially with any smoke while loading logs to an established fire. If you do have smoke tell me more about it and your flue dimensions. No smoke, also tell me what your flue looks like.

 

[Jags]

A couple of thoughts. Smoke coming out the doors...
New gasket won't help this. Do you open your primary air for a minute or two before you open the door? Smoke is generally only present in large amounts prior to entering the coaling stage. Do you open the door prior to this stage? And why? Batch burning is considered the most efficient, and this doesn't require the door to be opened until adding fresh fuel to a coal bed.

There are rules for cutting in vent holes. Most manuals state that they need to be xx feet (usually around 10) from the appliance. Also look into fuse linkage types. They will close upon any "fire" event for safety.

 

[Grisu]

Hi, I'm from Michigan and will be burning with my Merrimack for my 4th season already. I have made several improvements to the insert.

#1 has been putting vinyl tubing underneath the fan motor to prevent it from vibrating like a jack hammer

Sure those don't get too hot? You are certainly violating minimum clearances to combustibles.

#2 splicing the thermostat sensor wires together to be able to turn the fan on and off whenever I want. 10 min after starting a good fire I have decent hot air that would be a shame to waste.

That would not go to waste or is your fireplace vented to the outside? It will just heat up the fireplace which will radiate it later into the room. The thermostat turns the blower on later to give the insert time to heat up for optimal combustion. By extracting heat too early from the insert, you will have more unburnt woodgases go up the chimney and thereby you are actually wasting heat.

#3 bringing in fresh make-up air through the back of my fireplace masonary using metal pipes. They stay hidden as they go around the side and then through the the removable electric cord panel that can be removed effect to the unit. Nice to not have to use room air to combust. Hey, why heat it if you just blow half of it back up the chimney right?
#4 Insulated my 23 foot long 6 inch dia. flue with 1/2 chimney flue insulation for better draft. Two fires in and I'm not sure it make much of a difference.

Nice improvements. You will see the difference with the liner when you clean the flue. It is also a safer installation.

Still have a couple problems:
Some smoke comes out when the doors are opened for loading. It is enough to bother me and and my wife. I can open the doors about 3-4 inches then the smoke starts to leak out. I was hoping that the flue insulation would have helped this problem out. Gasket at the top of the insert to the flue coupler seems good but maybe I need to redo the glass rope. This is my last ditch idea. I may think about a chimney top power vent for $1000 bucks. Any recommendations? Till then, I just wait till I have coals then I load.

Are you opening the primary air fully for a few seconds before opening? Why opening it anyway before you have coals? Wait until you burnt down a load and then reload. Rake the coals forward, fill the firebox as much as possible leaving a small gap between the wood and the burn tubes in the top, wait until the wood is engulfed, close door and over the next 10 to 20 min reduce the air stepwise until you reach the final air setting. With good draft and dry wood the air can be closed to almost closed.

I have about 2200 square feet to heat. I can heat the first floor to near 80, but the upstairs stays cool/cold. I'm looking at ways to distribut the heat more. Cutting vent holes in the ceiling to have a passage for the heat. Not sure about code or whether that would be annoying to have sound travel between floors. I run the furnace fan and it does an ok job circulating some heat but most of the heat stays near the ceiling of the room. A ceiling fan may work but it would look weird and our ceilings are low already.

Try a small fan at the top of the stairs blowing cold air downwards towards the stove room. Warm air should flow up along the ceiling to make up for the moved air. You can also use little strips of tissue paper attached to the top of the doorways to follow the air movement. Before cutting holes in the floors/ceilings check your local fire code.

I have had to replace the fan and door gaskets. Factor a $200 fan every 3 years into your payback for this unit. Seems the fan is a poor design. Hopefully you are a bit handy and can put the fan in yourself or it could get very expensive.

Don't know anything about the fan of the Merrimack but replacement every 3 years sounds excessive. Sure you did not screw up the wiring when doing your modification (#2)?

 

[Charles1981]

If you leave the stove doors cracked for 10-15 seconds you should notice the flame and fire take off...or is there no significant change? This should temporarily cause a huge increase in draft up the chimney and allow you to open the doors without smoke spillage...or one would hope.

My stove is in the Basement. We have 2 registers cut into the floor above the stove. Not really code. The stove is also about 6 feet away from a spiral staircase with a ceiling fan above it. We have the ceiling fan push air down to the basement through the spiral staircase opening. There is a gigantic column of hot air that comes up those vents in the floor (put tissue paper over them and they get propelled upwards with force).

Can't really recommend cutting holes in the floor they way we have, but there are ways to install registers with firesheilding and all...we just haven't gotten there yet.

From our basement as long as it is above ~10-15F the basement is about 85 and the upstairs in ~70.

Another winter like last though and the basement is still about 85, but upstairs struggles to stay 65-66 at temperatures in the -15F range (-40 windchills), and with overnight burns we would wakeup to a house that was about 61-62 upstairs. Hopefully we don't have another of those winters.


edit: and as stated above before reloading and cracking door...the air control should be fully open for reloading.

 

[MI is Cold]

Wow! such quick and knowledgable thoughts. Let me elaborate on a couple things. The vinyl tube is about 1/2 inch of tube wedge under the motor on an otherwise non existant motor mount. VC literaly mounted it on a sheet of thin sheet metal that vibrates like a musical instrument. I don't see it as a fire risk because it is so small. I tried the glass rope but it did not have the bounce and damping the tube had. And believe me, this fan is a total weak link, the vibration is probably what killed my first one so quickly. But the soluton is easy and the stove is incredible otherwise, even with my smoke issue! I like the fan at the top of the stairs idea. I will check on ceiling vents after I check out some codes.

My typical procedure for adding wood to a mature fire would be to turn off the fan, move the lever all the way to the left, crack open the door for about 30 seconds. The fire picks up and a one can hear a nice rush of air being drawn up the flue. However, it never goes crazy like my friend’s old school Lope stove does. His starts to sound like a jet engine after 30 seconds, then it looks like a blast furnace. His would over fire in minutes if the doors were left open too long. I helped him put in his insert and insulated liner, and we share the same firewood source, so equal fuel. We used the same stuff to insulate my liner. I am scratching my head why he has such different results. Ok, so after it is going as fast as it can I can slowly open the doors and when I get to 3-4 inches there is a roll of smoke threatening to escape past the air rushing in.. I can either continue to open the door slowly and the smoke will come out or I can rapidly open and throw my log(s) in. Glad to hear that batch burning is an acceptable option, and the technique for raking coals forward. That would give me more space in the back to add my wood, and will become my standard procedure. My flue does make two bends going up, one bend toward the coupling, and then a curve to the right past the fireshelf, and his has just one gradual bend. His has a small firebox compaired to mine and I've heard there is a realtionship between the size of the firebox and the size of flue.

I think a picture will be worth a thousand words with the fresh make-up tubes.
And I will get back with those if you are interested. But let me explain these in more detail. First I took a 1 inch masonary drill to the back of my fireplace with the insert removed. I put two through holes in on the bottom right and left. I inserted ¾ black pipe into those holes and then connected flexable copper gasline pipe to the black pipe. The Merrimack is interesting because there are two always open inlet holes in the front right and left bottom. There is no air regulating device on these holes. There is a ready made space to bend the copper tube up and into the unit. Then I bent the copper inside the unit up to where the holes are. The negative pressure of the house and the draw of the fireplace easily pull outside air in. While I had a fire going I tested the draw with a smoldering leaf that I got real smoky. I saw the smoke get drawn down the tubes. It was cool I have to admit. Then I went into the house and tried to see if I could smell any burning leaf smell. Nope. All the smoke must have been drawn into the unit. That was exciting. Also exciting was that the tubes are totally hidden by the surround. It was seamless. I don’t recommend putting holes through your masonary, because it basically destroys the chimney ever going back to an open face fireplace, but I’m never going back.

 

[Nick Mystic]

You mention that you've been burning for several seasons now, so I'm wondering if you've had this smoke problem from the very start, or has it gotten worse over time? The reason I ask is because whenever someone has smoke coming out the stoves door when they open it to add wood the first thing to check is a clogged rain cap. The screens in the caps are the first thing to get gunked up with creosote and even a small build up is enough to slow the draft and cause the smoke problem you've described. Good Luck.

 

[Jags]

I second Nick's suggestion. Also, if you have not, inspect the liner and sweep as needed.

 

[MI is Cold]

Man I wish it was that easy! Just cleaning the cap. I have a really nice stainless cap that has a somewhat restrictive design. I will post a picture of it. I also have a totally open 3 leg cheapo cap from TSC. I may put that on and see if there is a difference. Think there will be? BTW, I swept everything in August, prior to the flue insulation install and it is pristine.

 

[MI is Cold]

Update: With the insulation, fresh air makeup and my special stash of extra dry cherry I fully loaded my box. The fire became so strong that I had to fully dampen my air lever to prevent the box from overfiring! That I couldn’t do last year. I was all the way down on my air lever and the reburns were going absolutely nuts. The top by the reburns was a ball of fire like I’ve never gotten before. The heat coming out was almost overpowering. This is my third year burning, and I burn about 14 face cords a year. So not too shabby. I’ve never gotten a fire so hot, let alone having the air setting all the way to the right. The box was finally doing what it was advertised to do (and perhaps more…) by having a massive reburn at the top. Now I can see how it could heat 2000 square feet. It is cool that I can get the box as hot as I want with the limit being the temperature of melting cast iron. I will have to be more careful of where the air is set at since I don’t want to burn down the house!

That being said, when the fire started to die down after 5 hours and I wanted to add more wood, I carefully went through my adding wood procedure, having to wear welding gloves this time. Wisps of smoke and a strong odor of smoke of entered our living room. Maybe some smoke is inevitable? Is there anybody in lower Michigan, preferably close to East Lansing, reading this that has this insert and it doesn’t smoke? If so I’d like to see yours in action. I will even bring you a load of my special dry cherry for your time. Just send me a private message and I will contact you. Thanks!
Brian

 

[Joseymack]

Where did you buy the replacement fan 30004669 for $200. I just ordered a new one for almost $500 bucks!

 

[MI is Cold]

(broken link removed to http://www.stove-parts-unlimited.com/mobile/Product.aspx?id=44430)
I'm not sure if I got it from this exact website but I just googled it again and this popped up under $200. I would return the $500 one. You got totally ripped off. Sorry to hear about that. Did you purchase it through a local brick and mortar dealer? I understand they would have to be more expensive than the Internet, but shame on them.