Yes...they installed my HI300 into an exterior masonry chimney (28ft)/insulated line...but were adamant that a block off plate wasn't needed. All was well in mild temps (40's/50's) as the insert kept the whole house really toasty (about 74/75 downstairs and 70/71 upstairs). However, once we really got into the cold snap this season when the temps started getting below freezing and into the teens...it was taking me about 90 minutes to get the insert to cruising temps (450 to 500) and the firebox temps would start falling off much more quickly...house would starting cooling down quickly and the heat pump would start kicking on?? I made sure to use only kiln dried wood checked with a moisture reader or 3 year seasoned wood provided by a neighbor and I still had the problem? Now I will concede that I am a newbie to all of this, but after seeing such a stark difference in performance between mild temps & frigid temps...I believe I have to be losing heat to 28ft of exterior masonry? The only other factor could be that the HI300 is undersized for my home, but Estates said it was the right size (my house is approximately 1950sqft and very well insulated with brand new high efficiency vinyl windows installed last year). So in the end, I'm going to have them install the block off plate and be done with it...I just wish and had the foresight to insist on it at the time of install when I was told it wasn't needed.
Yes, I recently did a continuous burn thru last weekends polar vortex and with wind chills it was -10 at times. I want to be fair and say up front that I love the HI300 and when I get it up to cruising temps (500 to 550) it kicks out some serious heat when I have the blower on (yes we did get the blower). However, it can take 60 to 90 minutes in really cold temps to get the unit to cruising temps and I have made sure to only burn bone dry wood (mostly using kiln dried now as my cord wood isn't seasoned enough yet). I should note however, that in moderate temps 35 to 40 the HI300 heats our house really well...I can keep the whole downstairs where the insert is located at 75 easily, and the upstairs around 70/71. But when the outside temps really drop below freezing, I notice it takes a lot longer to get up to cruising temps (this after packing it full N/S loading) and notice the firebox will start to cool much more quickly. Since I have a 28ft exterior chimney and no block off plate or insulation in the smoke chamber...I have come to the conclusion that I have to be losing heat into the masonry. I hope I'm not wrong...but I definitely don't think the HI300 is too small for a 1,950 sq.ft Center Hall Colonial. I just think a simple block off plate and Roxul will keep most of the heat coming back into the living area and not up the flu and into the masonry. But I love the HI300 so far and have every confidence this will be resolved with the block off plate and Roxul.
The dealer I got my unit from sells crown brick. Similar to bio brick I think They told me a lot of their customer only burn them and they deliver in bulk. It almost seemed as if they were trying to get me on their band wagon for a returning income every year. I can't say if or if not it voids the warrenty or not as I am not sure but I wouldn't know why a dealer would talk highly about it if they did.
You can use bio bricks. In fact , in your case I would advise to use biobricks. This way you going to learn how your stove should work with dry wood. Just don't overload it with bricks, they burn hot as moisture is low. You can mix them with your wood to improve your moisture content.
