Will a Block Off Plate/Roxul Fix This...Help!!!!

[jscs.moore]

Okay...really need some advice here. I have a new Hampton HI300 insert installed in September 2015. I have a Center Hall Colonial just under 2,000Sq.ft with an fairly open floor plan & center stairwell, house is very well insulated & upgraded with new high efficiency windows throughout last year (barely notice heavy wind/rain unless I look out the window). I have a 28ft exterior chimney, Pre-insulated, 6" ovalized, SS liner, but no block off plate or insulation to speak of above the insert. Here's the problem...things were just fine with the insert in the months following the install when the temps have been moderate (40 to 50's). But now that we have been getting temps below freezing lately...it is taking almost two hours to get this insert up to crusing temps (around 450 to 500 degrees). Sent this blow by blow of last night's burn to the dealer today looking for some help on what the problem could be:

• 4:00Pm Outside temp about 23 degrees (heat pump on/house temp 70 degrees)
• 4:35PM Started Top/down initial fire, loaded fire box with bone dry kindling and bone dry splits, air intake wide open and blower off...flames burning very hot!
• 5:00PM Initial fire burning down to coaling phase, but Condor thermostat on the upper/middle part of door frame barely reading 200 degrees?
• 5:10PM Raked coals forward and loaded the firebox full (N/S) with with bone dry splits, checked with a moisture reader (all <18 moisture content)...Condor still barely at 200 d.
• 5:20PM Firebox burning really well, air intake wide open, blower still off...Condor barely reading 300 degrees (about 280).
• 5:35PM (1 hour after starting initial fire)...firebox is full of rolling flames, burning what appears to be a hot fire...Condor now reading about 350 degrees?
• 5:50PM Fire buring hotter, blower still off...Condor now reading about 375 degrees?
• 6:00PM Fire burning well, I'm starting to close air intake down a little, good secondary flames burning from baffles, glass completely clear...Condor just barely at 400 degrees?
• 6:15PM Fires is well established, good bed of coals established, very good secondy flames, air intake closed down to about half open...Condor now reading about 450 degrees?

Taking an hour and a half (sometimes 2 hours) to get the insert to crusing temp has been the norm since we have gotten into temps below freezing. I put the blower on any time BEFORE I reach 450...the firebox temp will start to drop off?? Problem is...I can't really start kicking good heat out into the living area with the blower until I get to crusing temp...which is taking the better part of two hours
So...am I just losing heat to the masonry & flu without a block off plate & Roxul, etc. Or is ther something else wrong here?? Would love some feedback!

 

[axeman628]

If you don't have a block off plate, get one. However, and I could be wrong about this, I don't think that would keep the stove that cool. AFAIK that would just allow heat from the room to escape.

28ft. Chimney and cold out could equal really strong draft. What about pipe temps? Are you sending a lot of your heat up the chimney?

 

[mellow]

So...am I just losing heat to the masonry & flu without a block off plate & Roxul

Buy an IR gun and measure the temps of the brick on the outside, that will let you know if you are losing heat to the outside.

See this thread: Finally got around to insulating my fireplace

 

[jscs.moore]

Buy an IR gun and measure the temps of the brick on the outside, that will let you know if you are losing heat to the outside.

See this thread: Finally got around to insulating my fireplace

Thanks for the thread...yeah, I'm really beginning to think now that the temps are getting into the 20's & teens lately, that I'm just losing a lot of heat through the masonry and up the flu without a block off plate! On the last 8 to 10 burn cycles I have made sure to use bone dry wood by checking all splits with a moisture reader (after hearing on this site so many times about wet wood causing problems I double check all wood I'm burning), I never see a whiff of smoke out of the chimney & the glass is always clear. The Hampton HI300 is rated to heat a house of my size (just under 2000sqft) and when the temps were moderate...it was amazing how well the insert worked. Now...I'm really getting concerned because when it gets cold I have the heat pump running the whole time I'm trying to get the insert to cruising temps. Even when I do get up to 450...it's very hard to get the insert close to 500?? I have reached 500 on the Condor thermostat only once when out of frustration I let bone dry wood burn wide open for about 3 hours! But I know that is NOT how your supposed to burn these inserts!

 

[jatoxico]

• 4:35PM Started Top/down initial fire, loaded fire box with bone dry kindling and bone dry splits, air intake wide open and blower off...flames burning very hot!

• 5:00PM Initial fire burning down to coaling phase, but Condor thermostat on the upper/middle part of door frame barely reading 200 degrees?

If your wood is dry as you say you're missing your chance to start turning the air down. If the fire is burning well you can start slowly lowering the air which should begin to raise your STT. Burning down a load to coal with the air open is a good way to heat the flue but not how to get the stove hot. I suspect the increased draft due to the cold is sucking all the heat up the flue much more than what you were used to in the first couple months.

If you turn the air down and the stove cools open it back up a bit. If you can't at all then the wood is suspect but unless your meter is messed up you should be OK.

As far as the block-off plate. How much it does for you depends on how badly the original job was done. It will improve performance for sure especially if you fill up the smoke shelf and place the plate as low as possible filling all the open space above.

 

[slayer7]

Hmmm...interesting scenario. Can you post some pics of your setup and in particular where you have the thermometer? For starters, I've never had any luck with those kind of thermometers and believe they are inherently inaccurate but placement is also a big factor as well. We want to know the temp at the top front of the insert and not of the air jacket either. Looking at a pic of your insert, it looks like it will be kind of difficult to find a good place to do this because of the surround. I would pick up an IR gun thermometer like someone else mentioned and try using that. I'm thinking the top of your insert is actually much hotter than your readings indicate according to how you are describing the fire's behavior but it's possible something else is amiss. The top of my Englander insert gets up to 5-600* from a cold start with dry wood, no kindling and a firestarter within about 20 minutes or so and by half an hour the air is shut down and it's cruising along belching heat for the rest of the burn cycle.

 

[jscs.moore]

Hmmm...interesting scenario. Can you post some pics of your setup and in particular where you have the thermometer? For starters, I've never had any luck with those kind of thermometers and believe they are inherently inaccurate but placement is also a big factor as well. We want to know the temp at the top front of the insert and not of the air jacket either. Looking at a pic of your insert, it looks like it will be kind of difficult to find a good place to do this because of the surround. I would pick up an IR gun thermometer like someone else mentioned and try using that. I'm thinking the top of your insert is actually much hotter than your readings indicate according to how you are describing the fire's behavior but it's possible something else is amiss. The top of my Englander insert gets up to 5-600* from a cold start with dry wood, no kindling and a firestarter within about 20 minutes or so and by half an hour the air is shut down and it's cruising along belching heat for the rest of the burn cycle.

Thanks for the feedback...I have explored the placement of the magnetic thermostat with the dealer and on this site several times. The dealer told me it should go in the middle top of the door frame, I've also seen many youtube vids of the HI300 with the thermometer placed in the same spot. However, I have moved it to other places on the door frame and the result is essentially the same? I agree that I will probably need to get an IR gun to get a better reading, but I don know that when the magnetic thermometer finally gets up to cruising temps (450) the insert seems to work beautifully with strong secondary flames and a lot heat coming out of the blower when I can finally turn it on.

I have also tried turning down the air intake earlier in the burn cycle several times and ultimately need to open it up again because the thermostat will start showing the firebox temp falling off? I do have a strong draft...I never have problem with starting a fire our smoldering fires, just seems to be getting the firebox temp to the cruising speed??

I don't know what the problem is and don't want to overplay the blocking plate remedy...but I do think I have to be losing heat into the masonry and up the flu at this point? I am waiting for the dealer to give some feedback on this?

 

[Nelson]

Just a data point. I have a PE Summit insert with no block off plate (project for early spring) in an outside wall fire place. I don't have any issues getting my stove up to temp in about 30 minutes. I'm not convinced that the block off plate is the issue. If it was, I don't think 10-20 degrees is going to make that much of a difference. If you were losing that much heat up the flue, it's going to happen regardless of outside temps. Has to be something else going on...

 

[NewHarmanOwner]

I can tell you from experience that I had the same issue with my Harman 300i insert sitting in a firebox without insulated block off plate and insulation behind it. I can get my insert temperature up to 5-600 degrees, but I'm barely heating more than 800 square feet of space. However, after I insulated the back with Roxul and top, the heat output has increased dramatically. Now I have hot air going up to my second level. Next project when I get this insert serviced, I think I'm going to wrap it with high temperature insulation around it and fill the empty space inside the firebox so there is almost no empty air pocket.

I definitely believe you will notice a huge difference once you insulate your insert.

Best of luck.

 

[NewHarmanOwner]

Also, if you lookat your current setup, all the cold air inside your chimney and your firebox is cooling your insert, and you insert heat is being siphon off by the bricks as well.

Lastly, check your firewood by splitting it and measure the freshly split face, but make sure the wood is inside for 24 hours because water crystallized when below freezing and throw off your reading.

 

[weatherguy]

If the woods dry the stove should still get up to temp, by chance have you checked your chimney cap to see if it's starting to get clogged? You should do the block off plate with some roxul above and insulate the brick too. Let us know if you figure it out.

 

[rwhite]

I can't understand how, after all the information that is out there that a few installers still don't use a block off plate. Without it you have 28ft of cold masonry you are trying to heat and that is keeping a cold pocket of air around your stove. Do the plate with the Roxul on top of it and I'll bet your situation improves greatly. You can do a 2 piece plate fairly easy. Just make a cardboard mock up and then transfer to some sheet metal.

 

[TedyOH]

With bone dry wood and a strong drafting chimney as you say, only having the air shut down half way after 2 hours and 15 minutes would seem to be the issue, should be closed 80% or more at this point. Possibly you got into a lower BTU wood from your wood pile? Sometimes stoves just "stall" at a temperature for a while, mine did last night for an hour.

 

[jscs.moore]

I can't understand how, after all the information that is out there that a few installers still don't use a block off plate. Without it you have 28ft of cold masonry you are trying to heat and that is keeping a cold pocket of air around your stove. Do the plate with the Roxul on top of it and I'll bet your situation improves greatly. You can do a 2 piece plate fairly easy. Just make a cardboard mock up and then transfer to some sheet metal.

Thank you! Yes...I really think you have hit the nail on the head. I the insert is trying to heat 28ft of cold masonry, compounded probably 10 fold when it gets into the teens or single digit temps outside! My next step WILL be to get a block off plate and Roxul insulation to see if that solves the problem. Obviously taking this step can't hurt because even if the block off plate does not fully remedy the situation...it certainly can't hurt.
My problem is...I'm waiting for a response from the dealer but I'm not hopeful he will see a block off plate & insulation as a solution because he was dismissive of the block off when I questioned him about it just before the install. I'd prefere to have the block off plate professionally installed because I'm not terribly handy...and pulling out the insert and taking this on myself is not something I can do right now. In the end, I don't have the years of wood burning experience of many of the posters on this site...but simple logic tells me I must be losing heat to 28ft of masonry!

 

[mellow]

Like I mentioned before, get an IR gun and prove it to yourself.

 

[jscs.moore]

Like I mentioned before, get an IR gun and prove it to yourself.

Absolutely...I am going to pick up an IR gun this weekend! Thanks for you feedback again, it's very helpful! I'm determined to get this fixed. I've invested just under $5,000 on the Hampton HI300 including the install...and everyone on this site who has one has basically said it is a kick ass insert that should throw out a lot of heat! I wish I had just insisted on the block off plate at the time of install...my mistake I guess

 

[mellow]

Good fodder for a drinking story...

 

[jscs.moore]

Like I mentioned before, get an IR gun and prove it to yourself.

Thanks again Mellow. Just so I'm clear...to get a baseline reading point the IR gun on the outside chimney masonry right about where the insert to get the "cold" temp reading. Then after getting the insert burning at around crusing temp...go outside and point the IR gun to the same place on the chimney to get a "warm" reading? By the way...I was looking at your chimney pics, how tall is it? Looks to be about the same as mine...28ft?

 

[mellow]

Yea, about 28 ft. You can also get a baseline from measuring the side of the chimney like I did where it should be the ambient outside temp.

 

[rwhite]

FYI...My cheap Harbor Freight IR ($19 on sale) gun works very well and tracks my stove top thermometer pretty consistent.

 

[begreen]

I let bone dry wood burn wide open for about 3 hours! But I know that is NOT how your supposed to burn these inserts!

Don't do that. Running wide open can allow too much air into the fire and inhibit good secondary combustion. The stove will often get much hotter when closing down the air due to more complete secondary combustion. Close the air down at least 50% or more once the fire is burning vigorously.

 

[jscs.moore]

Don't do that. Running wide open can allow too much air into the fire and inhibit good secondary combustion. The stove will often get much hotter when closing down the air due to more complete secondary combustion. Close the air down at least 50% or more once the fire is burning vigorously.

Thanks Begreen...I did that one time and definitely won't do it again as I realize this is not good for the insert. Just frustrated why it takes so long to get to cruising temps. I'm hoping a block off plate and insulation will resolve this...based on feedback I've received on this site, an hour and half to two hours to get to cruising temps way too long. Most say they can get their stoves/inserts to 500 degrees within 20 minutes!

 

[gzecc]

I think its the wood.

 

[jscs.moore]

I think its the wood.

Yes...I was waiting for someone to let me know the is just the wood? Fact is...I've read this so many times on this site that I've become paranoid about not putting anything in the insert that isn't split open and double checked with a moisture reader on the fresh split! I have been using a combination of Kiln dried wood (split open and double checked readings) and 4 year seasoned wood from a neighbor who was king enough to help me out (also double checked with a moisture reader...all wood burned has been <20%...most around 15%! After repeatedly going thru burn cycles from a cold start and watching it take 90 to 120 minutes to get the thermostat on the insert to cruising temps...I am convinced either the magnetic thermostat is completely wrong or I'm just loosing heat into the masonry & flu. I bet you if I went out and got a pile of lumber scraps & pallets...burned them and reported the same problem, someone on this site is going to tell me..."it's the wood." Sorry, just frustrated!

 

[kennyp2339]

Take advantage of the warm day today to pull the insert and install the insulation & block off plate, temps are going to take a dive on Sunday night.