P68 Maximum heat at maximum efficiency

[vranap]

I purchased a Harmon P68 a few weeks ago. For the past 13 years I have burned about 6 cord of wood in a large Fisher stove in my basement. I finished the basement off into a family room and installed the P68 in the wood stove's place (also the kids are almost out of the house and I did not want to lug 6 cord of dirty wood into the newly finished family room).

The house is large - about 3700 sq ft including the finished basement. I have 2 12"x12" holes at the opposite ends of the family room between the basement and first floor which fans in them to facilitate moving warm air up. The fans move a lot of air and I have them on dimmers so I can adjust volume at any time.

I bought the P68 because of the 65000 BTU output. My goal is to heat as much of the house as possible (obviously not all of it but I will keep the upstairs cooler) using the P68. It has been rather warm so I have not had time to fiddle with the P68. Anyone else trying to do something similar?

I need to figure out what settings to use to get the most heat out of the P68 (obviously when it actually gets cold this year) while still running the stove as efficiently as possible. The place I purchased the P68 told me to run the feed between 3 and 4 but I have a hard time believing that this setting will satisfy my needs.

Any thoughts?

Thanks!

 

[HarryBack]

The p68 (68,000 btu's/hr), is a point-source heater, meaning that it will be much warmer closer to the stove, and cooler further away. I also think 3700 square feet is a pretty ambitious area to heat with this unit, especially not knowing how well heat moves around the home, or how well your home holds heat. Im guessing if you are expecting to get much heat upstairs, your cellar family room might well be uncomfortably warm. That being said, you might comsider running the stove in Stove mode, on high, the feed setting at 3-4, and the temp dialed up as far as you deem necessary. Make sure you keep the unit clean as well. Good Luck!

 

[vranap]

Thanks for the reply. The p68 will definitely not heat the whole house (my previous wood stove would not either but with the air movement I created it worked pretty well). The fans I have are at the opposite end of the family room from the P68. The fans are designed to be put in 8" air duct to boost volume in a long run. They will push a lot of air (thus the dimmer switches for them). It should work well doing what I want (nice warm family room, cooler 1st floor and cooler yet 2nd floor for the bedrooms) once I figure out settings. Thanks again.

 

[smirnov3]

Stove Mode will make the unit perform more like a regular wood stove.

You can also use the Room temp mode, you will just have to set the temperature higher. For instance, in my house, I have an accentra insert downstais, and a closed off stair leading to the second floor (2000 sqft house). temp upstairs is 6-10 degrees cooler than on first floor, so I set the temp controller to 8 degrees warmer than I want the upstairs to be.

As to the feed rate knob: that only determines the MAXIMUM feed rate. I have mine set to 3, which is good enough except when the temperature drops to the teens. Then the stove can't keep up (ie stove runs at max, but temp in house drops.). I have it set up so that when this happens, my oil heat kicks in to bring the temp back up (that way, the pipes don't freeze)

With your set up - big house & lots of fans to suck the heat out of the stove room, I would set the feed rate high - 4-5. just make sure that you aren't pushing burning pellets into the ash pan

 

[elkimmeg]

Out of curisity I have to ask how safe you feel about cutting holes in you natural containment floors, that also act as an express way, should something go wrong in that basement,

what additional measures have you taken to protect and conain fire and smoke since you have blowers to accccellerate any possible incident Do you have fusable link dampers?

It is my understanding inorder to circulate air, equally important is a well designed return path.

What I getting at is many have tried exactly what you have done without the knowledge and thought process to provide safety and effeciency. Everbody make the mistake think in terms of moving heated air where removing cood air is more important. So now you have a blower but ttrying to pust heated warh air threw cooler floor level air Ttell me haw well that works without trying to remove the cool air first. I supose the blowers do bludgeon some penatration but that is counter productive to without a good return path.

Actually you have increased the negative pressure in that basement and also reduced you vollume of makeup combustion air. In the already compromised basement location.

Too boot you have drastically reduced your personal safety Containment provides additional time for safe exits in times when seconds count using a blower expodentially reduces that time

In A nice as possible way, I am trying to point out compromises have been made. Ones I would never submit my familly to. Stoves are area heaters if you want heat in the living area above then put the stove there.

 

[vranap]

Thanks elkimmeg

I have been experimenting with the feed rate. Right now I have it between 4 and 5 and the pellets are burned up about 1" prior to reaching the lip where they would fall into the ash pan.

 

[MrWinkey]

It depends on the pellets you are burning. I've been using my Harman P-68 to heat my house and depending on the brand of pellets I have my feed rate on 4-6. For my stove the higher the quality the lower feed settings seem to work good. My stove really has to burn some crummy pellets for it to get enough ash to push over into the burn pot. I found some pellet brands to have so many clinkers that it will sit on the air ports and then cause the fire to get lazy so I open the door and scrape them off into the ash pan.

I'm currently burning Eureka Brand pellets and they are a higher ash pellet so the stove gets set on 5.5 else it starts to build up hard clinkers and burns lazy. It will burn them and it doesnt clog the stove it just reduces the airflow because of the large clinkers that build up. The Home Depo brand Firemax or something of that nature did produce some ash but not the heavy clinkers and the stove still ran fine. I just tried some Blazer's from wowpellets.com I got at Fred & Myers untill the local plant gets back online and they seem to burn well. (Pellet plant is in next town over but going through a re-model so no cheap pellets.)

Mine is currently heating my 1900 sqf 1 level rancher w/ very high celings. 30ft high clear story above the stove and most other celings are 20 foot. This is also a very open floor plan so it heats most of the main living areas fine on stove temp mode. Bedrooms are down a hallway behind the stove and are slightly cooler. I usually setup a fan to blow the cool air out of the hallway and bedrooms. My house has a partial passive solar setup so if it's sunny the stove turns off during the day.

I would agree with Elk....if your going to duct air out of there have the proper setup for return air and proper fire precations taken also.

Your results may vary I've only been burning my stove for about 4 weeks now.

Good Luck!

 

[smirnov3]

I'm currently burning Eureka Brand pellets and they are a higher ash pellet so the stove gets set on 5.5 else it starts to build up hard clinkers and burns lazy. It will burn them and it doesnt clog the stove it just reduces the airflow because of the large clinkers that build up.


Your results may vary I've only been burning my stove for about 4 weeks now.

Good Luck!

What does the maximum feedrate have to do with clinker formation?

a lower quality pellet will require a higher feedrate if it doesn't have as much energy, but that's all, AFAIK.

 

[Andre B.]

What does the maximum feedrate have to do with clinker formation?

a lower quality pellet will require a higher feedrate if it doesn't have as much energy, but that's all, AFAIK.

Not all ash is the same. A lower quality pellet may in addition to leaving more ash, produce an ash melts at a lower temperature, and at higher feed rates it may be possible to reach that temp.

Sounds good anyway.

 

[GVA]

I'm currently burning Eureka Brand pellets and they are a higher ash pellet so the stove gets set on 5.5 else it starts to build up hard clinkers and burns lazy. It will burn them and it doesnt clog the stove it just reduces the airflow because of the large clinkers that build up.


Your results may vary I've only been burning my stove for about 4 weeks now.

Good Luck!

What does the maximum feedrate have to do with clinker formation?

a lower quality pellet will require a higher feedrate if it doesn't have as much energy, but that's all, AFAIK.

He may not realize YET what a Hard clinker is. The clinkers causing it to burn lazy sounds like the ash covering the holes in the burnpot, and not clinker related.....
Couldn't they have come up with a better name than clinker....... How about "that hard crap that looks like chunks of kingsford charcoal"....

Back to the pellets I was at HD this weekend and saw the pallets of fireside piled up, so hopeing that they would soon be having a sale I decided to try a couple of bags.
Bought 3 bags, That was enough for me...... I'm on the second bag now and the flame is very lazy looking and not stove related it's orangeish and looks like a TIKI torch inside a $3000 unit...... And to top that off the price......................... They STILL wan't $310 a ton for this :bug:
Pellet quality does matter but the premium on the bag is not equal for all brands, The color of these pellets are very dark brown..... This usually means they got alot of bark in the mix...... Premium is not supposed to have bark in the mix.... Well one good point here to these pellets NO CLINKERS.... I mean none..... 2 days...... Weird trade off for lower BTU value. It does have a heavy and kinda funky ash though..

 

[MrWinkey]

Hard crap that looks like a burnt up porus sponge that is like a rock.....that's what I call a clinker.....It covers up the air jets on the front of the burn pot and causes the flame to go all lazy and yellow. On the harman if I turn up the feed rate it pushes that junk off the end of the burn pot. Plus usually thoes pellets are not really high BTU and sometimes need the feed rate turned up.

One of the pellet types I tried had more ash but hardly any clinkers. It was ligher ash and did not seem to make the flame quality suffer and would just get pushed off the end of the burn pot. The Firemaster ones I got from Home Depo were not bad. They were OK. They did have some ash but not the Hard Clinker deposits the Eureka pellets left. I didnt notice the yellow burn but the stove did chew through alot of them pretty fast.

I agree with the premium pellets varying ALOT.

The best brand was from Canada called Armstrong. (broken link removed) They were also like 215 per Metric ton....Ouch!

Anyways.....your results may vary.

 

[GVA]

If a clinker forms that high up on the burnpot so as to cover the holes Then you have a problem hh:

 

[MrWinkey]

I will get out the Cam later tonight and try to post a picture of what is going on then.

Possibly this thread has been hijacked!

 

[iceman]

I'm currently burning Eureka Brand pellets and they are a higher ash pellet so the stove gets set on 5.5 else it starts to build up hard clinkers and burns lazy. It will burn them and it doesnt clog the stove it just reduces the airflow because of the large clinkers that build up.


Your results may vary I've only been burning my stove for about 4 weeks now.

Good Luck!

What does the maximum feedrate have to do with clinker formation?

a lower quality pellet will require a higher feedrate if it doesn't have as much energy, but that's all, AFAIK.

He may not realize YET what a Hard clinker is. The clinkers causing it to burn lazy sounds like the ash covering the holes in the burnpot, and not clinker related.....
Couldn't they have come up with a better name than clinker....... How about "that hard crap that looks like chunks of kingsford charcoal"....

Back to the pellets I was at HD this weekend and saw the pallets of fireside piled up, so hopeing that they would soon be having a sale I decided to try a couple of bags.
Bought 3 bags, That was enough for me...... I'm on the second bag now and the flame is very lazy looking and not stove related it's orangeish and looks like a TIKI torch inside a $3000 unit...... And to top that off the price......................... They STILL wan't $310 a ton for this :bug:
Pellet quality does matter but the premium on the bag is not equal for all brands, The color of these pellets are very dark brown..... This usually means they got alot of bark in the mix...... Premium is not supposed to have bark in the mix.... Well one good point here to these pellets NO CLINKERS.... I mean none..... 2 days...... Weird trade off for lower BTU value. It does have a heavy and kinda funky ash though..

what hd are you at? over here in western mass they 249 a ton or a couple bucks less

 

[GVA]

I know everybody else has pellet prices that average $50 bucks less than here even HD is hopping on the bandwagon.... That store was in Danvers......
I don't buy my pellets locally, If I travel even 20 miles The prices are much, much, much better. And a much better quality.

 

[iceman]

I know everybody else has pellet prices that average $50 bucks less than here even HD is hopping on the bandwagon.... That store was in Danvers......
I don't buy my pellets locally, If I travel even 20 miles The prices are much, much, much better. And a much better quality.

check these prices you might want to drive
(broken link removed)

 

[GVA]

I know everybody else has pellet prices that average $50 bucks less than here even HD is hopping on the bandwagon.... That store was in Danvers......
I don't buy my pellets locally, If I travel even 20 miles The prices are much, much, much better. And a much better quality.

check these prices you might want to drive
(broken link removed)

Those are the same prices just north of me ie: the 20 miles.
It's a local thing I think, These are the gougers ruining the market, they seem to refuse to drop below $300.
Prices are cheaper the farther west you go (towards the pacific) I am about as far east as you can get, maybe I should move inland :grrr:
The HD's here are just adjusting towards the local market just like they do with plants and everything else in the garden dept.
The owner of the company I work for said that I could store pellets at work in the warehouse, if I wanted.......... WOOOHOOO, can't wait for the spring time sales... Could probably store about 50 ton in the available racks, but could never afford it, but maybe I could cut out the middleman and get a full truck load and save even more..... :cheese: Nah still couldn't afford it.