Harman PC45 Efficiency Help Needed

chldofthe1truKG · Jan 15, 2014

Typically I run my stove in manual, room temp with a temp setting of close to max (7-8). As the temperature outside goes up and my house temperature goes up I turn my feed rate down. This allows me to achieve the desired house temperature of 71 degrees but I'm not sure how efficiently I burn pellets and if I am burning more as a result.

I have enough experience using it at this point to know what feed rate to set it at to achieve a house temp of 71 based on the temperature outside. e.g. 30 degrees = 1.5, 25 degrees = 2, 20 degrees = 2.5.

Could someone weigh in on my pellet burning efficiency or lack thereof and how I might improve it?

lbcynya · Jan 15, 2014

First, welcome to the Pellet Mill! Second, with all sincerity, why on earth did you buy a Harman? You are running your stove like a cord wood stove with a feeder nob instead of highly efficient, computer controlled, exhaust temp driven, state-of-the-art modern wood burning appliance. Read the link in my signature and come back with questions. We'll get you headed in the right direction.

chldofthe1truKG · Jan 15, 2014

lbcynya said:
First, welcome to the Pellet Mill! Second, with all sincerity, why on earth did you buy a Harman? You are running your stove like a cord wood stove with a feeder nob instead of highly efficient, computer controlled, exhaust temp driven, state-of-the-art modern wood burning appliance. Read the link in my signature and come back with questions. We'll get you headed in the right direction.

Thanks for the quick reply. Funny I read that and a couple other threads like it before I posted. I know enough to know I could be running it differently (better) but I've just learned on my own since I can't talk to Harman and the dealers around me know less than me about how the Harmans work at this point. My biggest question is what's a more efficient way to burn fuel while still achieving the desired temperatures? I am struggling to translate how the stove works technically with the best way to run it. There doesn't seem to be a cut and dried black and white answer to it but I am probably just not understanding. And probably my biggest misunderstanding is with the feed rate and how it relates to efficiency other than some comments about don't set it low. What's an alternative to how I am running it?

lbcynya · Jan 15, 2014

chldofthe1truKG said:
Thanks for the quick reply. Funny I read that and a couple other threads like it before I posted. I know enough to know I could be running it differently (better) but I've just learned on my own since I can't talk to Harman and the dealers around me know less than me about how the Harmans work at this point. My biggest question is what's a more efficient way to burn fuel while still achieving the desired temperatures? I am struggling to translate how the stove works technically with the best way to run it. There doesn't seem to be a cut and dried black and white answer to it but I am probably just not understanding. And probably my biggest misunderstanding is with the feed rate and how it relates to efficiency other than some comments about don't set it low. What's an alternative to how I am running it?

I understand. Sometimes we tend to overthink things when all the thinking has already been done for us.

Here's a simple, round number analogy:

Every house loses heat, let's say yours loses 16,000 BTU per hour at equilibrium.
Let's assume your pellets are 8,000 BTU per pound and your stove is 75% efficient (analogy, let's not turn this into an efficiency debate)...
That means you need to burn 21,000 BTU (2.6 lbs) per hour to maintain equilibrium.

You can fiddle with the knobs until the cows come home, but you have to burn 2.6 lbs per hour to keep the house temperature constant.

Here's the hard part, we don't exactly know at what point the stove is 75% efficient. It could be at low, medium or high burn. Only the stove mfg knows and, apparently, they don't share much of that with us folks. I tend to believe maximum efficiency is at higher burn rates.

Your method could be 60% efficient or 80% efficient...we just don't know.

What I do know, is your manual method cannot respond to external climate changes better than the computer in the stove you paid for. You'll overheat sometimes and under heat other times. Both are wasteful, IMO.

Get you room sensor calibrated as best you can, run in room temp manual during the dead of winter and room temp auto during the shoulder seasons, keep your stove fairly clean (or cleaner) and enjoy your investment which eventually pays you back!

Hope this helps. Surely there will be other opinions, go with what sits best with you, just don't wear out your feed rate knob!

PS - If you want to tinker, focus on keeping yourself busy by keeping the stove clean. I also believe the dirtier a stove gets, the less efficient it becomes.

2011 GT/CS · Jan 15, 2014

I have a Harman P43. Set your feed to 4 as per the manual, read the sticky at top on how to run your Harman. I run my fan on hi, to get the heat out of the stove and into the room. When it's cold I run the igniter in manual, it goes into a low burn, when it's warmer out I put it to auto and let it start and stop. Your best bet is to try this, just let the stove do what you paid the money for it to do. I basically feed mine pellets and keep it clean. Set it and forget about the knobs. Good luck, welcome to the forum and keep us posted.

chldofthe1truKG · Jan 15, 2014

lbcynya said:
I understand. Sometimes we tend to overthink things when all the thinking has already been done for us.

Here's a simple, round number analogy:

Every house loses heat, let's say yours loses 16,000 BTU per hour at equilibrium.
Let's assume your pellets are 8,000 BTU per pound and your stove is 75% efficient (analogy, let's not turn this into an efficiency debate)...
That means you need to burn 21,000 BTU (2.6 lbs) per hour to maintain equilibrium.

You can fiddle with the knobs until the cows come home, but you have to burn 2.6 lbs per hour to keep the house temperature constant.

Here's the hard part, we don't exactly know at what point the stove is 75% efficient. It could be at low, medium or high burn. Only the stove mfg knows and, apparently, they don't share much of that with us folks. I tend to believe maximum efficiency is at higher burn rates.

Your method could be 60% efficient or 80% efficient...we just don't know.

What I do know, is your manual method cannot respond to external climate changes better than the computer in the stove you paid for. You'll overheat sometimes and under heat other times. Both are wasteful, IMO.

Get you room sensor calibrated as best you can, run in room temp manual during the dead of winter and room temp auto during the shoulder seasons, keep your stove fairly clean (or cleaner) and enjoy your investment which eventually pays you back!

Hope this helps. Surely there will be other opinions, go with what sits best with you, just don't wear out your feed rate knob!

PS - If you want to tinker, focus on keeping yourself busy by keeping the stove clean. I also believe the dirtier a stove gets, the less efficient it becomes.

This is helpful and gets me closer to solving scenario #1 which is what to do when the temperature fluctuates besides messing with the feed rate.

And yes I do overheat and underheat and always try to err on the side of overheating as it's easier to maintain warmth than it is to create it. And yes I keep my stove as clean as possible and clean it often depending on how much fuel I am burning through.

For scenario #2 which is what to do when it's 15 degrees or colder and I just want to produce max heat. Typically I dump the room temperature sensor in the cold air return and take it out of the equation running it again on feed rate of 3, manual, room temp. Should I run it in stove mode instead? Should I worry about the temp setting on the stove?

Bioburner · Jan 15, 2014

If your feeding it some corn you will want to set the feed rate lower. Great stove and easy to clean with the removable burn tray. Second year using them. Remember to keep the ESP clean or it will start to feed extra.

lbcynya · Jan 15, 2014

chldofthe1truKG said:
This is helpful and gets me closer to solving scenario #1 which is what to do when the temperature fluctuates besides messing with the feed rate.

And yes I do overheat and underheat and always try to err on the side of overheating as it's easier to maintain warmth than it is to create it. And yes I keep my stove as clean as possible and clean it often depending on how much fuel I am burning through.

For scenario #2 which is what to do when it's 15 degrees or colder and I just want to produce max heat. Typically I dump the room temperature sensor in the cold air return and take it out of the equation running it again on feed rate of 3, manual, room temp. Should I run it in stove mode instead? Should I worry about the temp setting on the stove?

Scenario 2 sounds like the "space heater conundrum"... When it get's cold out, your stove room is fine, but other rooms start to suffer, no? If so, then consider a wireless thermostat (my second link in my sig) to place the thermostat in a "go between" location so as not to completely overheat the stove room, but also not to allow the other rooms to cool off too much. You could simply turn the temp knob up to 80 to accomplish the same thing, but the wireless thermostat is a good compromise that doesn't require knob adjustment, just a few key presses to turn up or down...and its programmable as well.

If you follow the proceedure on determining proper feed rate, that in room temp auto/manual, the stove will drive as hard as necessary to satisfy the call for heat.

turbosporsche · Jan 15, 2014

Set it on feed 4 room temp on 70 and blower speed on high. Then walk away.

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Harman PC45 Efficiency Help Needed

chldofthe1truKG

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lbcynya

Feeling the Heat

chldofthe1truKG

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lbcynya

Feeling the Heat

2011 GT/CS

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chldofthe1truKG

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Bioburner

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lbcynya

Feeling the Heat

turbosporsche

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