Hearthstone Phoenix Hot Temps should I add a damper?

[jnalexis]

Hi All!

This is my first season with my Hearthstone Phoenix (Hand me down from my father who never used it) and I’m having real issues getting long burn times/ stove top temps getting too high.

I reached out to another member a few weeks ago for some advice on getting longer more controlled burns and after implementing some new techniques I’m still getting way too hot of stove top temps.

Everytime I go to load up the stove onto some coals (stove top around 250-300 and flue 200-250), 3-4 medium/large splits of white oak (that’s my firebox filled up), all parallel not cross crossed, let a flame start, close up the door w/open air, let chimney get to about 300-325 and start cutting it back with lazy flames. Stove temps are usually not getting above 300-350 at this point. I keep lazy and small flames through this whole process. Eventually get the air control almost completely shut down, chimney around 300 but the stove will keep climbing 600+. I eventually end up opening the door flooding the firebox with cool air to get these temps down and basically waste wood. I’m sure if I just let it have its way I could see 650-700.

I’m not understanding what else I can do to keep these stove temps down and get longer burns. I’ve heard a damper on the chimney can help? I really have no idea any input would be really appreciated.

Thanks!!

 

[mark cline]

You need an in the flue thermometer, one that reads the internal flue temps. If your going with a magnetic flue thermometer, your real temperature is about 100F higher which equates to you turning down your draft way to late and too hot . 650F stove top temp is not that bad , your thermometer might be off ,get an infra red thermometer from Harbor Freight for less than 20$ and an in flue thermometer about 25$. Mix in some different wood with your oak .Oak burns hot especially when dry. Hope this helps.

 

[jnalexis]

Thanks @mark cline. I am using an IR thermometer but I’ll look into the influe thermometer.

Unfortunately oak is all I have right now but I’ll start keeping an eye out for more mixed wood for the future.

 

[Woody Stover]

You have to get the wood burning, but then try cutting the air back sooner to control the burn more. You'll have to look at the manual but you might not want to go much over 600 on a stone stove.
Describe your chimney setup, including total vertical height.

 

[mark cline]

This is the in flue thermometer I use . I usually run just into the orange and with my wood at 14% to 18% , burning 3 cord / winter , I sweep my chimney every 2 years.

 

[jnalexis]

@Woody Stover went to the hearthstone factory in November and actually asked them about that in person. They agreed they do not recommend running the stove at or above 600 degrees.

Chimney is 15’ vertical exterior. 4’ single wall interior to a 90 bend going outside.

 

[weatherguy]

Sounds like a damper would help you.

 

[Woody Stover]

[Chimney is 15’ vertical exterior. 4’ single wall interior to a 90 bend going outside.

That doesn't sound like it should be drafting real strong, and the fact that you can get lazy flames points in that direction. Try shutting the air down sooner, and use the search for terms like "longer burn" and the like. You'll find a lot here. I'm not versed in the operation of secondary-burn stoves, other than what I have read..

 

[Woody Stover]

I'm not sure how big the box is or what length of burn you can expect, but you should be able to find a way to run the stove a bit slower/cooler, even with White Oak. One thing, pack the splits as tightly together as you can..the less gaps between the splits, the slower it will burn.

 

[jnalexis]

@Woody Stover that was similar advice I got previously from begreen and it did slow my time of heating up but didn’t do much in the way of keeping me cooler. Stove still just kepts crawling it’s way up to 650+. I pretty much start shutting it down as soon as a strong flams is present (maybe 5-10 minutes after fresh wood is loaded up). Same result in a slower time to heat up but inevitably keeps crawling up.

Phoenix doesn’t seem to have a huge firebox so I know crazy long burns just probably aren’t possible, but it would be nice to not have to reload every 3-4 hours. Especially when everytime I load up a large, tightly packed firebox it shots to overfiring territory and need to flood the box with cold air to cool it down.

 

[Woody Stover]

Well, you could certainly try a pipe damper (or even two)...maybe that stove is just a very easy breather, even though your stack isn't too tall.

 

[jnalexis]

@Woody Stover interesting! Never heard of using two dampers. Thanks! Any rule of thumb or insight where on the stove pipe they (or just one) should be located? 12” up? 24” up from stove?

 

[mark cline]

Just reloaded the Mansfield about an hr ago. 2f outside with a 15 to 20 mph wind , house is at 66F. Reloaded with 5 large splits of 2 maple ,2 ash and 1 beech , reloaded onto a 3" bed of coals, let the air wide open until fluegard temp hit 450F. , cut the air down about 25%. I cut the air down to a slight bit more than totally closed , over the hr . Watching the flames , I have yellow and dark orange flames rolling above the wood and rolling down the glass door , all secondary burn at this point.
1 hr and 30 min into the burn , fluegard is at 400F stove top is at 500F measured with my IR gun in the middle of the stove top , hottest spot on the top.
Years ago ,I had the same problem with over heating (so I thought) ,at that time ,I only had the surface thermometer on the stove top and a magnetic surface thermometer on the flue pipe. This is when I put in a damper, 18" above the stove ,thinking the same as you are now. Then I got the Fluegard and an IR gun, come to find out that my magnetic thermometers were off by 100 to 150 degrees , so not over heating.
2 hrs into the burn, Fluegard is at 400F and stove top is at 500F. When I lean over the stove to check the stove top temp with the IR gun , I think holy crap this is too hot but its only at 500F. This stove replaced a Fisher Grandma Bear from 1979, which is now in my log cabin. The Fisher gets up to 800F to 900F ( IR temp) on a regular basis, but it doesn't seem as intensely hot as the Mansfield does , its a different type of heat .

 

[Rich L]

Thanks @mark cline. I am using an IR thermometer but I’ll look into the influe thermometer.

Unfortunately oak is all I have right now but I’ll start keeping an eye out for more mixed wood for the future.

Yes put in a in pipe damper.I have one on each stove and it gives me more heat times and control of the burn.My drafts are very strong.

 

[jnalexis]

Hey everyone just wanted to put a close on this thread. But I did add a damper and WOW what a game changer. I wouldnt say I starting getting insanely longer burn times but I definitely increased from needing to reload every 3-4 hours to still having really large hot coals at 5-6 house with easy reloading. Which before the stove would of been getting cool at that time.

The biggest thing the damper has helped with is controlling the fire. Since installing not once has the stove crept over 600 degrees. Even with a full box of smaller oak splits and possibly letting it go wide open a little longer than intended. I’ve been running the air control about 1/3 open, then start easy down the damper to about 2/3 open and the stove will literally cruise at 500-575 degrees for hours. I even have the ability to start shutting it down earlier and keep it around and under 400-450, if the house is warm enough already. I have never had that much control over the fire and it’s burn cycles.

Note: all of these temps are being read with my IR laser, not the stove top thermometer.

Just wanted to thank everyone again for their time and input.

 

[maple1]

Also remember that it is a lot hotter inside the pipe than whatever the measured surface temps are. New burners can get themselves into a lot of trouble trying to go just by pipe temps, especially if they just stick a cheap magnetic on there & put the coals to it.

Glad you got things sorted!

 

[vwmike]

I think most installs should have a pipe damper! You might not need it all the time but it sure is nice when you do. Modern stoves are amazing heaters but their lack of adjustability for different installs is a downfall.