Fan speed - high or low?

[jophysx]

My Hampton hi300 insert has two blower speeds, high and low (naturally). Not clear to me what setting to use for maximum efficiency. On low, I think the firebox is going to stay nice and hot even at a low burn rate. But then I think I'm losing a bunch of heat out the chimney. On high blower speed, I feel like I am getting all the heat into the room, but I think I might be cooling off the firebox too much.

Anyone have any words of wisdom?

 

[kettensäge]

I run my 3 speed blower on low 99% of the time. The few times I use the middle speed was when there were sub zero temps outside and I was restarting a fire after work and wanted to quickly warm the house. After the fire got going and the house was warm I turned it down to low. The blower does remove heat so burn times are shortened.

Is there a baffle for the flue? If so, close it once the fire is established and surface temps are at 300 or so. With an insert there is no easy way to monitor flue and surface temps to the degree that standalone stove burners do.
Using the baffle will extend burn times and cause surface temps to rise and I'm guessing flue temps to drop just like a damper on a stove. I think the only way you would be losing a bunch of heat out the chimney is withoput a baffle or not using it. You do need to keep enough heat in the flue to avoid creosote build up.

Target a specific room temperature and try to stay as close to it as possible, for me it's 74.
Adjust your reload frequency and amount based on room temp. Work blower speed and usage into this as well.
This is the way I maximize efficiency.

For comparison my low speed is rated at 112 cfm and it will discharge air at about 100 to 150° colder than surface temps. Nice and toasty. Medium is around 144 cfm.
My insert is pre-epa, non cat.

 

[DanCorcoran]

I only use the blower when the cabin is really cold, essentially on startup. I wait until there is a really hot fire going, then turn blower on high. As cabin begins to warm up, I lower the fan speed, making sure not to let stove top or flue temp go below "normal" operating range. (This is a good reason to have both a stovetop and flue thermometer.) The only other time I use the blower is if the stove or flue temp has gone higher than I intended (into the "too hot" range). I immediately turn the blower on high and within minutes you can see the temperatures drop. It gives me a sense of security knowing that I have a second means of helping to control the stove temperatures (in addition to shutting down the air supply lever).

 

[pastera]

I have the same question with my HI200 (wish I could fit a 300) and will probably instrument it next season to get both stove and flue temperatures.

High will pull the most heat from the insert so in theory the most efficient. The problem is if you pull too much from the insert and loose a clean burn.

For now, I run the insert on low if I'm in the room with the stove and on high otherwise, adjusting the damper to compensate. The manual states not to fully close the damper with the blower on but does not specifiy a difference between high and low.

Without a reference, I look for a IR temp reading of 350° - 425° on the center of the door between the air ducts. A reading off the glass when running this way will show 750°-800° with no glowing parts in the firebox. If the glass hits over 825° then the front burn tube will start to go red. Running this way, I got about two cups of powdery soot/creosote from sweeping after 1 cord.

For the temperature readings off the glass - I know that they are bogus but they stand as a reference point that while completely inaccurate, they are very repeatable.

Aaron

 

[tfdchief]

For now, I run the insert on low if I’m in the room with the stove and on high otherwise, adjusting the damper to compensate. The manual states not to fully close the damper with the blower on but does not specifiy a difference between high and low.

So the HI200 has a damper? I have the H200 and it does not have a damper, nor do I remember any disccusion in the manual about when to use it relative to the fan speed. Or are you talking about the draft control? I have not had mine long enough to know for sure, but don't notice any apprciable loss of stove top temp when running the fan on high.

 

[Backwoods Savage]

I'm not totally certain on this but I think most inserts are meant to have the fan speed on low most of the time and to run on high speed for shorter periods of time.

 

[tfdchief]

I'm not totally certain on this but I think most inserts are meant to have the fan speed on low most of the time and to run on high speed for shorter periods of time.

Dennis, that sure is the case with my old buck, but I wondered if the new EPA inserts were different.

 

[Backwoods Savage]

It seems to me if the fan speed is on high you will feel more draft and that can be both good and bad. I doubt the newer inserts will be different from the old buck. But remember, the older the buck, the stiffer the horn.

 

[egclassic]

I've got the same insert(HI300). I keep the fan on low most of the time, for the reasons you described. On really cold nights, I'll run it on high for short periods of time with a very hot fire going, just to get some heat moving towards the back of the house.

 

[tfdchief]

It seems to me if the fan speed is on high you will feel more draft and that can be both good and bad. I doubt the newer inserts will be different from the old buck. But remember, the older the buck, the stiffer the horn.

That's a good one Dennis

 

[jophysx]

Without a reference, I look for a IR temp reading of 350° - 425° on the center of the door between the air ducts. A reading off the glass when running this way will show 750°-800° with no glowing parts in the firebox. If the glass hits over 825° then the front burn tube will start to go red. Running this way, I got about two cups of powdery soot/creosote from sweeping after 1 cord.

For the temperature readings off the glass - I know that they are bogus but they stand as a reference point that while completely inaccurate, they are very repeatable.

Aaron

Thanks for the reply. I run my insert very similar to what you describe. Almost always on low fan speed, and I use the IR readings taken on the glass as my primary means of monitoring (other than just looking). As you indicate, the IR temperature measurement on the glass may not be accurate, but it is repeatable and provides me a good benchmark. When I really want the heat, I try to run around 700-800F.

When I am up at those temperatures, however, is when I am most tempted to crank up the fan to high because it seems like the fire is throwing off soooo much heat. I want to match the rate of extraction with the rate of generation, and to me that implies turning up the fan.

Mostly I just resist the urge. Get the fire cruising along, keep the fan on low, and try to go do something other than obsess about my new toy.

 

[pastera]

For now, I run the insert on low if I’m in the room with the stove and on high otherwise, adjusting the damper to compensate. The manual states not to fully close the damper with the blower on but does not specifiy a difference between high and low.

So the HI200 has a damper? I have the H200 and it does not have a damper, nor do I remember any disccusion in the manual about when to use it relative to the fan speed. Or are you talking about the draft control? I have not had mine long enough to know for sure, but don't notice any apprciable loss of stove top temp when running the fan on high.

Damper or draft control - same function different name

The object is to control air flow through the fire box - neither control the draft (negative pressure developed by the chimney)

a draft control device installed in the exhaust side (damper) reduces negative pressure in the firebox by restricting flow out of the firebox but does nothing to restrict input

a draft control device installed in the intake side (draft control) increases negative pressure in the firebox by restricting flow into the firebox but does not restrict exhaust

By only controlling air flow by restricting input air, the firebox is ensured to be at negative pressure at all times insuring that any problems with firebox sealing do not lead to an exhaust leak within the home. Also, the secondary burn systems on these stoves require an unrestricted exhaust to work correctly.

As far as running the fan on high - there is a definite difference in the stove temp between low and high fan under otherwise similar conditions. To reach the same temperature on the door, I need to open the damper about a 1/4" - 3/8" with the fan on high versus low.

Aaron

 

[pastera]

Without a reference, I look for a IR temp reading of 350° - 425° on the center of the door between the air ducts. A reading off the glass when running this way will show 750°-800° with no glowing parts in the firebox. If the glass hits over 825° then the front burn tube will start to go red. Running this way, I got about two cups of powdery soot/creosote from sweeping after 1 cord.

For the temperature readings off the glass - I know that they are bogus but they stand as a reference point that while completely inaccurate, they are very repeatable.

Aaron

Thanks for the reply. I run my insert very similar to what you describe. Almost always on low fan speed, and I use the IR readings taken on the glass as my primary means of monitoring (other than just looking). As you indicate, the IR temperature measurement on the glass may not be accurate, but it is repeatable and provides me a good benchmark. When I really want the heat, I try to run around 700-800F.

When I am up at those temperatures, however, is when I am most tempted to crank up the fan to high because it seems like the fire is throwing off soooo much heat. I want to match the rate of extraction with the rate of generation, and to me that implies turning up the fan.

Mostly I just resist the urge. Get the fire cruising along, keep the fan on low, and try to go do something other than obsess about my new toy.

If you run the stove on high, the firebox will cool down forcing you to open the damper to compensate, so if you need the heat crank it up (but not until it glows)

I run the fan on high most times as I am trying to heat a 2800+ SF area with a tiny insert (it does as long as I am there to feed it). Only when the family is in the same room as the stove do I turn it on low and that is only to reduce noise. You need to run the stove hard to push a cord of wood through a 1.4 CF stove in 5 weeks - this is with two startups on weekdays (morning and return form work).

Aaron

 

[tfdchief]

For now, I run the insert on low if I’m in the room with the stove and on high otherwise, adjusting the damper to compensate. The manual states not to fully close the damper with the blower on but does not specifiy a difference between high and low.

So the HI200 has a damper? I have the H200 and it does not have a damper, nor do I remember any disccusion in the manual about when to use it relative to the fan speed. Or are you talking about the draft control? I have not had mine long enough to know for sure, but don't notice any apprciable loss of stove top temp when running the fan on high.

Damper or draft control - same function different name

The object is to control air flow through the fire box - neither control the draft (negative pressure developed by the chimney)

a draft control device installed in the exhaust side (damper) reduces negative pressure in the firebox by restricting flow out of the firebox but does nothing to restrict input

a draft control device installed in the intake side (draft control) increases negative pressure in the firebox by restricting flow into the firebox but does not restrict exhaust

By only controlling air flow by restricting input air, the firebox is ensured to be at negative pressure at all times insuring that any problems with firebox sealing do not lead to an exhaust leak within the home. Also, the secondary burn systems on these stoves require an unrestricted exhaust to work correctly.

As far as running the fan on high - there is a definite difference in the stove temp between low and high fan under otherwise similar conditions. To reach the same temperature on the door, I need to open the damper about a 1/4" - 3/8" with the fan on high versus low.

Aaron

I understand the difference and the function, just wanted to know if the HI200 actually had a damper? Sounds like it does not. Thanks

 

[DanCorcoran]

Aaron,

"If you run the stove on high, the firebox will cool down..."

I think you meant "run the fan on high", no?

 

[zknowlto]

I've owned the I1200 for two seasons now. I've found that the insert performs better when the fan is on the low setting. Specifically, the burn times are considerably longer and I find myself having to fiddle with the air intake less. If I've been outside shoveling snow or something and want a blast of heat, I'll put it on high for a few minutes while I stand in front of the insert. Otherwise, once the room is up to temperature, I notice very little difference in heat output between the high/low settings.

 

[maverick06]

mh stove isnt in the room i am in so i am not concerned about noise. I run my blower on full power all the time. It removed most heat from the stove, which is what you want to heat the house! Of course, you might want to let it get up to temp first.

But this is advice for an insert, where you get very little radiative heat. For a standalone, its all different.

 

[burleymike]

Having an insert I have to use the blower to get much heat. When we don't need a ton of heat I can run it on low but if I really need some serious heat I put the blower on high. I have noticed the stove top temp will be over 100° higher with the blower on low.