New used Quadrafire 5100i

[LehighGuy]

I bought and installed a used Quadrafire 5100i in my fireplace with an interior masonary chimney a few days ago. The chimney has a 30' uninsulated liner, which I don't think would be as much of an issue for the interior chimney. The bricks are new; the ceiling ceramic board and carpet are not, but intact; the door is pretty tight (dollar bill test); the blower works, it is loud but it blows air, I don't have a point of reference to decide whether it is producing the air volume it is supposed or not. They had to take one brick out and cut the back plate of the damper to fit the liner through, and then put a lot of insulating ceramic fiber in there to insulate it; no sealing board, just the fabric stuffed all around the liner and the rest of the opening.

My burns have been pretty effortless to start, and get pretty hot pretty quickly. I measure heat at the top of the top plate, it gets to 700s and 800s degrees very quickly when I load it up with both airs on, while the front plate right above the door gets to 500s and sometime 600s. I shut the start up air and then go to half open main air, get the secondary burn without a problem, and for my overnights close it off all the way. No apparent problems there.

The blower is on and at high as soon as the unit reaches the 250 or so. It certainly blows hot air, and you can't stand directly in front of it for too long before feeling uncomfortable as in blowing a hairdryer directly in your face. I am not sure if it is producing enough hot air though, since I am not getting the temps in the room and the rest of the house as others have reported. The unit is in the family room, about 800 square feet, at the lower level of a split level 3000sqf house. It has windows on two sides, double pane with an additional storm layer. It gets to higher 60s when the insert works full force, much lower than I expected. That room is connected to the main floor, including kitchen, dining and sitting room, about 1000 sqf total, by a wide flight of 8 steps. At this level, the temp is 58 or so. At the bedrooms level I haven't noticed any measurable change in temperature compared with before I install this unit. Without it, shutting down my heatpump in similar days, those two floors would hover around 48 or so (20 outside overnight, if I turn the heat off before going to bed and let it cool down from 65 degrees). Another way of measuring the heat is if I build a fire and let it run for two hours, it brings me up from 55-56 to 58-59 at this main floor. Isn't this too little for this stove?

Also, if I maintain a fire 24/7, should the blower be on all the time? Is it designed for a continuous operation? Is it worth it to replace the ceramic boards and blanket in terms of the operation? I certainly appreciate any advice.

 

[begreen]

If the blanket and board are still intact I would not replace them. Try closing the startup air sooner. 800F is getting a bit too hot. The blower will help bring the top temp down about 100F and should be on when the insert is warmed up for best convection.

 

[Grisu]

The insert apparently gets plenty hot and with the air fully closed you are probably not losing much heat up the flue. Thus, the only reason your home does not get warm is that you are losing heat somewhere. Not having a proper block-off plate in there could be one possibility. Is the fireplace at an exterior wall? Maybe you loose heat out the back; insulating the fireplace may help: https://www.hearth.com/talk/threads/finally-got-around-to-insulating-my-fireplace.75755/
Otherwise, the heat loss of your home may be too much. What heat source did you use previously? How much fuel did you use in a cold month like January?

 

[LehighGuy]

Here are a few pictures of the liner connection, insulation, and the first fire.

 

[LehighGuy]

Thank you begreen, the 800s are momentary, not sustained through any length of time. Since I keep the fire going by adding fuel to a bed of coal, I don't keep the startup air on too long, a couple of minutes or so after I close the door.

Thank you grisu, the chimney is interior and pretty tall. Over 20 ft enclosed by the house, the top 8-10 is out. I have heatpump, with an electric backup and emergency heat that does not work anymore, so we opted for the insert as a solution for that zone. It works fine when it is not frigid outside, but without the backup heat the heatpump doesn't work and sometimes best left off. When this system worked, for a day like any of the past few days, it would be around 50 kwh for a 24 hour period (only to heat that zone, which is about 1800 sqf, up to 65 degrees).

 

[Grisu]

50 kWh of resistance heat are less than 200,000 BTUs; with heatpump it could be more, let's assume optimistically twice as much. Still, the 5100 should easily supply that amount of heat. Hoe often do you load the insert during the day?

The ceramic wool will not really stop the airflow up the chimney. A steel plate or similar may be required. Nevertheless, I am a bit at a loss why your home does not warm up more. With that low heating load and the stove essentially being as hot as it can be, you should see more of an effect. There is not by any chance a window open?

 

[LehighGuy]

Thanks Grisu, I try to keep the cruising temp at 450F at the top of the stove during the day. That requires 2 or 3 loads, not compketely packed, but pretty full. Overnight I pack it well to the ceiling and burn at low. By 7am, I still have burning coal, the stove top temp is around 200F at that time with the fan having blown all the time.

I wish a window was open! Would have been a much easier fix. How essential is the block-up plate? If I lay a row of firebricks to close the opening, will that work, or do I need to put an actual plate?

 

[fatcaaat]

Just as an experiment, burn it without the surround. My 5100i is quite impressive, check out my review and experiences on it in my thread. Blockoff plate is imperative or you are going to lose some heat up the chimney. Also, outside air on this thing is a near must. It really sucks up the air, so it is pulling it from the room and most likely letting all that cold air in from your windows, doors, cracks, etc. I had a significant improvement in heating with the OAK installed.

As for the blower, i run my blower 24/7 on high whenever the thing is burning. Been like that for 3 seasons, no issues...just clean out the ratcage every now and then with a vac.

I'm at a loss for you. If I run mine on high it will certainly eat a lot of wood, but it actually roasts me out. I am at a point where I can sustain a temp anywhere from about 350-650 on that front plate and glass. It will run hotter still if I want it to, but this is where the best range is...I prefer it around 500-550.

 

[mellow]

With 30 foot you might have an overdraft issue sucking heat up the chimney, I would keep an eye on that, you might have to block one of your secondary air inlets, but I would get to know the stove first before doing this.

With the air fully closed (it will still be open on EPA stoves) do you still see quite a bit of flame action and higher heat levels?

 

[LehighGuy]

Fatcaaat: as I mentioned earlier, I get the high temps pretty easily, and depending on how much air I let in and how full I pack the box, it can be sustained, no problem. The difference between the temp reading right above the door and on the top plate is some times a lot, as much 200-300 degrees. The front rarely goes above 650, I don't let it run higher, but the top gets up to 850 or so pretty easily. Once the surge is over, the top settles at 500-600 and the front at 350-500. I put a series of wireless thermometers in different floors, the room that has the stove is at 73-75 when it is running hot (800 sqf), but the floor that is 8 steps above and 1000 sqf gets to only 63-64 at the most. I'll read your tread, thanks for referring me.

Mellow: they sealed the top of the chimney, it is not wide open. Did you mean sucking up air through the 6in liner, or the surround space in chimney? The former is pretty impossible I would think. When I close down the intake air the flames go away almost immediately, I am left with only bright coals and tertiary burn. The ceramic blanket may need to be changed as it is not as evenly and nicely laid over the board, I have ordered one and will change it when it arrives. That may have an effect on the quaternary burn and the smoke, but aside that I feel the burn is normal and the stove is doing its job. It burns a lot of wood, but I don't see anything abnormal there. I just never thought the block off plate and OAK could have such an impact, especially since I am pretty sure the house is fairly well insulated since it heats up without much efforts with the electric/heatpump heat.

Is there an easier, albeit less efficient, alternative to the blockoff plate? Something that could be placed at the damper opening without necessarily hard-attaching it. Fire bricks at the damper, or something else?

 

[Grisu]

When I close down the intake air the flames go away almost immediately, I am left with only bright coals and tertiary burn.

What do you mean by "tertiary burn"? When you close the air do you still see flames in the top of the firebox seemingly coming from the burn tubes? Or are there hardly any flames at all? How long do the stovetop temps stay above 600 F?

Any airtight, non-combustible material that's ok with the elevated temps in there will work as block-off plate. It is totally up to your imagination and DIY skills how to keep it there.

 

[LehighGuy]

Grisu, QF calls the wood and coal burning as primary, the burning air that cleans the window secondary, the gases burning at the tubes tertiary, and the gases burning above the blanket quaternary; I was going with that terminology. See this:

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I get good burns at the tubes, and depending on how packed the box it, how hot the stove has run, and the size of my wood, it stays like that for 2 hours, sometime a bit longer on a full load over a hot burning bed.

I have actually started doing something new recently, with a lot of success: I fill the box, but don't stuff anything in it, so it is not very packed. The tertiary (or secondary if you prefer it; burn at the tubes) develops and the smaller splits coalify. About an hour into the burn, I open the door, push the existing fuel to the back of the box which at this point is possible since some of the pieces break and make room, and then I add an 18" piece of round unsplitted wood (about 10" diameter). The rest of the fuel is NS, this last piece is EW. Close the door, let the air in for a couple of minutes to allow for the burns to develop, and then close it down. The tertiary lasts for an extra 2 hours after that, since this new piece starts contributing gases immediately and for a long time.

Stovetop plate maintains 600+ for as long as the tertiary is going on, and then drops to high 400s when I am left with lots of coals. The reading above the door goes down more and faster, is in the 400s during the first phase and goes down to 300s and even high 200s after that.

Also thanks for the comment about blockoff. I was going to put a row of bricks and firewool in the location of the damper. Right now there is just firewool stuffed in.

 

[mellow]

My point is with an EPA stove even though you close the primary air lever you still have secondary air going into the stove. If you still had quite a bit of flame action with the primary closed that usually means your draft is pretty high (they test these things on 15 foot liners), you're almost double that so in theory your draft could be double what the stove was tested for leading to hotter faster burns with more of the heat being sucked up the liner.

 

[LehighGuy]

mellow, yes that makes sense, thank you for pointing it out. So this is the logic: Double the chimney --> double the pressure difference from the top of the chimney to the stove --> double draft. The numbers may not be all linear for obvious reasons (for example, the air pressure inside the house is not necessarily that of the lowest point in the house since it is not open air, etc.) but it definitely makes sense to have more draft. I don't have flames, or at least a lot of them, if I close down the primary air. If the fire is not too hot, that would in fact kill it completely. For a well made fire, closing the primary air doesn't kill all the flames, but immediately reduces them significantly, and in a few minutes I am left with basically almost no flames. My burn rate is also not too different than what others have reported here (for example fatcaat in his review of the unit).