How to Avoid OverFiring an Insert??

jscs.moore · Dec 28, 2015

Okay Guys...I've been following the posts on this site for many months now and it seems to me the scariest ones have to do with overfiring scenarios. I had a Hampton HI300 installed in my 2,000 sq.ft. Center Hall Colonial in late October. I have an exterior chimney 28 ft chimney with a 6" ovalized, pre-insulated SS liner. I haven't been able to burn much due to the warm weather, but I have some questions regarding how to avoid overfiring the insert. Here are some points I picked up by reading other posts and you can let me know what you think.
Dont's:

Avoid putting a large load of new wood on to a deep, hot coal bed since this can rocket the stove temps upwards of 700 degrees very quickly, which will be hard to control?
Avoid loading up the firebox with lots of small, extremely dry splits which can also rocket stove temps too quickly?
Avoid burning Pine, lumber scraps and other wood that can rocket stove temps?
If you are dealing with an overfiring situation, shut down the air intake as far as it will go and turn the internal fan on high to cool the unit down?
I've read some posts about opening the door in a overfiring scenario, but wouldn't that be just adding a whole lot more air and compounding the problem?

Do's:

Use a stove stop thermometer to monitor temps?
Build the fire slowly at first to heat up the firebox...then load the firebox with large splits of seasoned hardwoods, packed tightly and slowly shut down the air intake after the fire is well established?
After building/establishing the fire...let the burn cycle run it's course over the period of 4 to 6hrs before adding more splits?
Let the coals burn down so you're not loading on to a deep, hot coal bed and rocketing the stove temp too quickly?

There are probably many more points to avoid overfiring a stove/insert but these seem to be the ones I can remember most clearly...just seems like a very scary scenario I'd like to avoid if at all possible. Any feedback would be appreciated

Retreadsme · Dec 28, 2015

jscs - you have read well. I have the brother/sister/uncle of the Hampton HI300 and they burn wood the same. The only advise I can give you other than what you have listed is to never load it and walk away to do something else before it starts burning well and the air is closed off some. A wide open throttle unattended will warm ya beyond desire! After a few full loads there may be a large bed of coals. I find that putting just 2 small splits in with WOT will burn down the coals while maintaining heat level.

Burn seasoned wood and you'll enjoy that insert.

jscs.moore · Dec 28, 2015

Retreadsme said:
jscs - you have read well. I have the brother/sister/uncle of the Hampton HI300 and they burn wood the same. The only advise I can give you other than what you have listed is to never load it and walk away to do something else before it starts burning well and the air is closed off some. A wide open throttle unattended will warm ya beyond desire! After a few full loads there may be a large bed of coals. I find that putting just 2 small splits in with WOT will burn down the coals while maintaining heat level.

Burn seasoned wood and you'll enjoy that insert.

Thanks for the feedback! Yeah, I guess the matter of the coal bed is tricky...cause inevitably you are going to end up with a large hot coal bed after a few burning cylces? I will give your recommendation of putting a few small spits on to help burn down the coals.

KB007 · Dec 28, 2015

Two things that help us are:

1) a thermometer with a high temp alarm. Have one of these with a magnetic sensor on the front of our I3100, set it to somewhere above where I normally damp down, so if I'm not paying attention, it will go off. Only pain is it will alarm once the secondaries get going, so basically any time it goes off, I turn it off until the next load.

2) a simple 30 min dial timer. When my wife is home and re-loads, she sets the timer for 20-25 minutes and when it goes off she knows it's time to go check.

jophysx · Dec 28, 2015

Although it may seem counterintuitive to open the door in an overfire situation, it works. The cooling effect of the flood of cool air far outweighs the slight increase in combustion. Open the door wide for several seconds then close, and repeat to bring the temperature down in a controlled fashion.

bjkjoseph · Dec 28, 2015

Putting fan on high helps a lot.

jscs.moore · Dec 28, 2015

[email protected] said:
Although it may seem counterintuitive to open the door in an overfire situation, it works. The cooling effect of the flood of cool air far outweighs the slight increase in combustion. Open the door wide for several seconds then close, and repeat to bring the temperature down in a controlled fashion.

Thanks Jim.od3...yes it does seem counterintuitive but if it works I will certainly use that technique to cool the firebox if needed...hopefully I'll never need to

rwhite · Dec 28, 2015

I approached (and maybe hit) overfire a few times on my insert. Air open and blower on high will usually bring it down pretty quick. I just monitor my wood to tell when to reload. Some of my pine is very dry and I usually don't reload until about 200 degrees. Some of the hard wood I'll reload around 300-350. Just getting to know how your setup burns is key.

Dmitry · Dec 28, 2015

bjkjoseph said:
Putting fan on high helps a lot.

Worked for me every time when needed to bring temp down.
As of opening the door to cool it down I wouldn't risk it before trying everything else if you have catalytic stove. I think cat may be at risk of thermal shock because of all the cold air rushing in.

crater22 · Dec 29, 2015

Dmitry said:
Worked for me every time when needed to bring temp down.
As of opening the door to cool it down I wouldn't risk it before trying everything else if you have catalytic stove. I think cat may be at risk of thermal shock because of all the cold air rushing in.

I believe I had read here that for a overfire with a cat, after trying everything else, just open the bypass instead of opening the door.

Dmitry · Dec 29, 2015

crater22 said:
I believe I had read here that for a overfire with a cat, after trying everything else, just open the bypass instead of opening the door.

WOW, It does make a LOT of sense. You are absolutely right. All the overfiring gasses would go straight to the chimney instead of heating up the insert trough cat combustion.

markam · Dec 30, 2015

jscs.moore said:
Okay Guys...I've been following the posts on this site for many months now and it seems to me the scariest ones have to do with overfiring scenarios. I had a Hampton HI300 installed in my 2,000 sq.ft. Center Hall Colonial in late October. I have an exterior chimney 28 ft chimney with a 6" ovalized, pre-insulated SS liner. I haven't been able to burn much due to the warm weather, but I have some questions regarding how to avoid overfiring the insert. Here are some points I picked up by reading other posts and you can let me know what you think.
Dont's:

Avoid putting a large load of new wood on to a deep, hot coal bed since this can rocket the stove temps upwards of 700 degrees very quickly, which will be hard to control?

Avoid loading up the firebox with lots of small, extremely dry splits which can also rocket stove temps too quickly?

Avoid burning Pine, lumber scraps and other wood that can rocket stove temps?

If you are dealing with an overfiring situation, shut down the air intake as far as it will go and turn the internal fan on high to cool the unit down?

I've read some posts about opening the door in a overfiring scenario, but wouldn't that be just adding a whole lot more air and compounding the problem?

Do's:

Use a stove stop thermometer to monitor temps?

Build the fire slowly at first to heat up the firebox...then load the firebox with large splits of seasoned hardwoods, packed tightly and slowly shut down the air intake after the fire is well established?

After building/establishing the fire...let the burn cycle run it's course over the period of 4 to 6hrs before adding more splits?

Let the coals burn down so you're not loading on to a deep, hot coal bed and rocketing the stove temp too quickly?

There are probably many more points to avoid overfiring a stove/insert but these seem to be the ones I can remember most clearly...just seems like a very scary scenario I'd like to avoid if at all possible. Any feedback would be appreciated

Don't worry too much. I have had my hampton for 11 years now. It is a tank. i have had nothing go wrong in all that time, burning 3-4 cords a year. It looks and acts brand new.

MourningWood · Jan 3, 2016

I guess this is a good place to ask about over fire. I have the hampton hi300 as well. I have had it since August didn't take me long to figure out something was wrong with it. This is when I got into a scary situation. I filled the unit up on light coals. Before long it took off with air all the way closed the temp kept rising got over 800 degrees F. I don't know if this is considered over firing but I scared the crap out of me that I couldn't control the fire. Come to find out through research here the unit was damaged in shipping or defective. The door on my brand new unit wouldn't seal. They tried everything then replaced the unit in early December. I used it just last week a couple time getting 5-6 burn time and filling the unit with wood to the bricks. Temperatures topping out 650ish. I felt comfortable. Saturday I made a small fire to heat up the stove and get it ready. Couple splits and kindling to get the stove warm and up to temp. Burning down the coals and raked them to the front. Loaded the stove full around 11am with the hopes of getting through afternoon with the burn. When the fire was established I backed the air down slowly. I had it completely closed off and my fire was raging and the unit kept getting hotter and hotter. The temp with an ir gun in the center of the glass was 830 degree F. If I read the top between air gap it was well over 700 degrees but was definently lower than the glass but not much. It was scaring me had fire extinguisher in hand. When it hit 750 I turned fan on high when it hit 800 I started opening and closing door in a control fashion. Over fire is a large fear of mine after my first issue with the damaged unit. I would like to know what you guys think. How hot is too hot? I read a post in this forum that said his unit gets to 700 on the glass and then it starts falling and this was normal for him. This seems high to me. I was told normal burning should be 300-600 degree F. When is it considered over firing? Like which temp. What temp will the unit start being damage? Even at temps in the 800 degree range the metal in the unit and the top between air gap wasn't glowing.

jatoxico · Jan 3, 2016

MourningWood said:
When is it considered over firing? Like which temp. What temp will the unit start being damage? Even at temps in the 800 degree range the metal in the unit and the top between air gap wasn't glowing.

I don't think you can shoot the glass and get an accurate reading. Stove top and flue collar are hottest for me. With a full load climbing I crank the fan before it starts peaking.

If the flue collar's not glowing I think you can ride it out. At 750 I'm likely to stay in the room at the ready but it's still safe. I think your on it by looking for glowing metal. Prevention wise, as a wise hearth member told me, use bigger splits!

KB007 · Jan 4, 2016

The important question in my mind is where are you guys getting your temp reading. The Hampton, like many inserts, including my Regency I3100, are essentially a box inside a box, with an air space between the 2 boxes. The stove top and most of the front cast iron is the outside box, and will read colder than the actual firebox temps, so you get a deceptive reading anywhere on the outer box. When you get a high reading on the outer surface, it really means the inner box is even hotter.

You've got 3 basic choices to read the temp correctly:
1) use a stove pipe probe sensor and wire it out to a thermometer or similar reader. This is probably the most accurate, but is often not easy to get in to drill for the probe in the pipe for an insert
2) find a spot ion the inner box to place your magnetic or sensor and use that reading
3) find a spot on the outer box and read it there, but adjust your expectations based on whatever differential you have between the 2 boxes.

On the I3100, I use #3, in that I have a calibrated magnetic thermometer on the front of the firebox, just above the door, which is still technically the inner box, but a little cooler than what would be the stove top temp. Using this, I then know the delta to what it would be based on previous readings and then adjust my turn down temperature to suit. e.g. if the magnetic is reading 550F, I know the stove top and/or flue temp is ready (and that much higher) and I also know the stove is ready to start shutting down the main air. I calibrated the magnetic using an IR gun as they are often quite a way off.

As a backup I also have a screw type sensor on my stove pipe connector and a magnetic sensor on the other side of the stove front to ensure I'm getting good consistent readings. I bought the thermometers/sensors from http://www.auberins.com/index.php?main_page=product_info&cPath=17&products_id=292
Only reason I have 2 of them is I bought the screw type one first, then decided I wanted a magnetic sensor for the front.

99% of the time I just use the magnetic dial thermometer as I know it's now accurate and easy to see the temps.

Bottom line, with an insert you've got to be careful where you get your temp readings from and adjust as necessary.

jscs.moore · Jan 4, 2016

KB007 said:
The important question in my mind is where are you guys getting your temp reading. The Hampton, like many inserts, including my Regency I3100, are essentially a box inside a box, with an air space between the 2 boxes. The stove top and most of the front cast iron is the outside box, and will read colder than the actual firebox temps, so you get a deceptive reading anywhere on the outer box. When you get a high reading on the outer surface, it really means the inner box is even hotter.

You've got 3 basic choices to read the temp correctly:
1) use a stove pipe probe sensor and wire it out to a thermometer or similar reader. This is probably the most accurate, but is often not easy to get in to drill for the probe in the pipe for an insert
2) find a spot ion the inner box to place your magnetic or sensor and use that reading
3) find a spot on the outer box and read it there, but adjust your expectations based on whatever differential you have between the 2 boxes.

On the I3100, I use #3, in that I have a calibrated magnetic thermometer on the front of the firebox, just above the door, which is still technically the inner box, but a little cooler than what would be the stove top temp. Using this, I then know the delta to what it would be based on previous readings and then adjust my turn down temperature to suit. e.g. if the magnetic is reading 550F, I know the stove top and/or flue temp is ready (and that much higher) and I also know the stove is ready to start shutting down the main air. I calibrated the magnetic using an IR gun as they are often quite a way off.

As a backup I also have a screw type sensor on my stove pipe connector and a magnetic sensor on the other side of the stove front to ensure I'm getting good consistent readings. I bought the thermometers/sensors from http://www.auberins.com/index.php?main_page=product_info&cPath=17&products_id=292
Only reason I have 2 of them is I bought the screw type one first, then decided I wanted a magnetic sensor for the front.

99% of the time I just use the magnetic dial thermometer as I know it's now accurate and easy to see the temps.

Bottom line, with an insert you've got to be careful where you get your temp readings from and adjust as necessary.

Thanks for the feedback! Yeah, I'm beginning to wonder if I'm getting accurate temp readings? I have a Condor magnetic dial thermometer and I put it in the upper, middle part of the door, exactly in the middle right above the glass (dealer said it should go there). Funny thing is, the insert seems to be working fine and heating the house well...but I can get the Condor to read much above 425 to 450. In fact, 450 is the highest I've have been able to get and was I turned the blower (on low) it starts to slowly drop again. Yesterday, for the first time I (based on advice from Hampton users on this site) I used the top down method to start the fire and then made sure to load North/South to get to cruising temp. The insert appears to be working great...as it was kicking out good heat (downstairs about 72 with no heat pump on) and I was getting nice secondary combustion in the firebox after closing down the air intake to about 70% closed. But it's confounding with the Condor reading because I don't seem to have the problem of the insert overfiring...I seem to have the problem of not getting the firebox upward of 500 or more? Of course, that's if the Condor thermometer is really giving me accurate temps. Because when I open the door it feels really, really hot and if I didn't have the Condor reading at 400 to 425 I would think the firebox was running at 550 or so? By the way, yesterday I checked all my wood with a moisture reader and every split I put in was less than 20% moisture reading. No visible smoke from the chimney and glass perfectly clear and clean the whole burn? So again...I beginning to wonder if I'm getting accurate readings from the middle top of the door? The only thing I haven't quiet done is pack the firebox to the gills yet...still a newbie and still a little shy of overfiring, but right now I don't seem to have that problem!

mass_burner · Jan 4, 2016

OP, why so preoccupied with over firing? Your #1 don't seems to be common practice for me. Putting a load of dry splits on a bed of red coals is a definite "do".

jscs.moore · Jan 4, 2016

mass_burner said:
OP, why so preoccupied with over firing? Your #1 don't seems to be common practice for me. Putting a load of dry splits on a bed of red coals is a definite "do".

Yes..I'm beginning to think I am too pre-occupied with not placing a full load on splits on a hot coal bed because (according to my Condor stove top thermometer) I haven't been able to get my insert reading over 450?? But as I noted earlier...I haven't really packed the firebox full (North/South) to the gills just yet, because I've been fearful of overfiring. I guess the next step will be to pack it full on a bed of hot coals and see how high the temps go? P.S. I have noticed much better burns loading N/S...yesterday I had the best secondaries I've ever seen since burning this insert...beautiful rolling bluish yellow flames coming off the baffles for a few hours or more. Really nice to see...but again, no temps from the Condor over 425?

MourningWood · Jan 4, 2016

I measure in between the air gap on the top of the insert. This is the inner box top. The glass is just easier to get a quick reading from. I will try different measuring styles. But I am still curious inner box temperatures what is too hot? Is 800 to hot is 1000 too hot. I know the sweat spot is 300-600 according to my dealer. But when starting and getting everything going. If I get the fire going and it is in the mid 500s and back it down when the secondary kick in strong is when my temps sky rocket sometimes. This is when I got temps around 830 from glass. And high 700 measuring top between air gap. All though the glass might not be the best spot to get a reading it is consistent in that it is about 75-100 degree hotter than the top in between air gap. I don't know if it gets to the point of over firing or if I am just getting a good burn. I am less worried about it after reading some of the replies but I would like a rule of thumb.

Stove pipe thermostats. Do they getting inserted into the liner? As in they are taking a reading of the gases and temperatures inside or the metal temp outside? If inside temps is this a higher number? My dealer said that 300-600 degrees on the outside means the fire inside is 600-1200.

I guess I really just want to know the limits. Normal burning. Max normal burn before is settles in. Top of the comfortable range. Unconfortable range and danger of damaging or unwanted fires.

Guy I work with has one with a cat in and has a probe that reads it. He says he usually gets 800-1300 which seems okay if that is the temp of gasses and internal.

Deano31 · Jan 4, 2016

After a bunch of research I found the best place for the magnetic thermomiter is on the door if the hi300 on the center post of it it is set so it clears the stove top and don't hit it when I open the door I have been doing this for about 4 years now and have the best readings in this spot

cableman · Jan 5, 2016

I wouldnt worry too much, load it up and just pay attention to it. I rake coals forward stick 1 split e/w and maybe 7-8 n/s on top, gets to over 700 on the collar and drops from there.
I have a stove top therm inside left corner where air blows out and ir gun i shoot on collar.

etiger2007 · Jan 5, 2016

Just a couple things from my experience with an over fire, I too ended up having a defective unit that was replaced by my manufacture , one night i loaded up my stove more than usual and before i knew it my stove top therm was pegged at 900 , i remembered reading on here to open the door to cool things down and in my sitiuation it made it worse to the point my ss line was glowing about two ft above the insert, scared the hell out of me. I ended up closing the air and putting a box fan on hi blowing directly on the stove to cool it down. I have never had an over fire with the new unit but if it does get out of control im going to throw cold ashes on the fire to smother it.

How hot is too hot: I called my manufacture and per their recommendation I can hit 800 without it being a problem anything over that is not recommended. My new stove likes to cruise at around 700 with the blower on low. Good luck and again this is just my situation.

MourningWood · Jan 6, 2016

Thanks for you thoughts. Thank you for etiger2007 for giving a number. It is around where I was thinking but I just wanted another persons thoughts. I tried contacting Hampton but it is next to impossible to get the manufacturer they just forward you to nearest dealer. Who doesn't have anything to say

begreen · Jan 6, 2016

To avoid overfiring don't load the stove full of kindling, thin splits, or super dry wood like construction cutoffs or pallet wood. Use them for starting the fire and maybe mixed in with cord wood if it's not fully seasoned.

How to Avoid OverFiring an Insert??

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