Brand new P43 owner Feed Rate Dial question

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davidfieldsnwa

New Member
Jan 30, 2021
11
Northwest Arkansas
I have a new Harman P43 and it has both Room Temp and Stove Temp modes. When using Room Temp mode, does the Feed Rate dial do anything important? From what I understand, this is merely the maximum feed rate - and the stove in room temp is automatically varying the feed rate to satisfy its need for fuel to maintain the temp you set.

If that’s the case, why is the recommendation I find everywhere that this Feed Rate dial be set to 4 (sort of a medium setting) - why not set it the maximum (6+)? Seems like you should make the feed rate max in room temp mode so that it can have as much or as little fuel as it determines it needs?
Curious about your thoughts. Thanks You! I’m new to Pellet Stoves.

The context of this question is that I may have purchased too small of a stove for my 2200 sq ft home - an older one that is chopped up and not super open floor plan. My desire is to ensure that the stove has all the ability it needs to get to whatever temp I ask it to achieve. My probe is behind the stove taped to the hopper and poking out just above it. Believe my airflow is great and the flame can get very bright and aggressive.

Look forward to the pros on this forum's response! I'm really enjoying the stove. just want to be sure I'm getting the max out of it.
 

SciGuy

Feeling the Heat
Aug 17, 2007
310
Constableville, NY
David,

Welcome to the forum. Here's my quick take on your question.

There are times when a maximum feed governor makes a good deal of sense. Say you accidentally left the door to the house open and your P-43 tried to keep up with the heat demand cause by the cold air flowing into the house. Left to it's own devices it would run maxed out until it ran out of pellets or something not so happy happened to its innards. If you're running in room temperature mode and someone comes in from the cold outside the stove would immediately go to super high fire to warm the room right back up rather than bumping up to a more reasonable level to slightly less quickly warm the room up. Being able to set the maximum feed rate also allows one to set things up so that unburned or incompletely pellets are never pushed into the ash can as different brands of pellets vary in their burn rates. I'm sure there are other reasons too but those popped to mind the quickest.

Hugh
 
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rich2500

Minister of Fire
Nov 19, 2005
1,393
Berks County PA.
Hate to say it but you should have went with at least the P61 or better yet the P 68. Don't change anything now so all you can do is crack the P43 up when you have to.
 

Harman Lover 007

Minister of Fire
Welcome to the forum. Click on the link in my signature. You should find it very helpful.
 
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Tonyray

Minister of Fire
David,

Welcome to the forum. Here's my quick take on your question.

There are times when a maximum feed governor makes a good deal of sense. Say you accidentally left the door to the house open and your P-43 tried to keep up with the heat demand cause by the cold air flowing into the house. Left to it's own devices it would run maxed out until it ran out of pellets or something not so happy happened to its innards. If you're running in room temperature mode and someone comes in from the cold outside the stove would immediately go to super high fire to warm the room right back up rather than bumping up to a more reasonable level to slightly less quickly warm the room up. Being able to set the maximum feed rate also allows one to set things up so that unburned or incompletely pellets are never pushed into the ash can as different brands of pellets vary in their burn rates. I'm sure there are other reasons too but those popped to mind the quickest.

Hugh
7yrs running P61A and from exspirience i will say you at least have the probe in the exact place mine is and that works fine. Behind the stove doesnt get enough heat to throw off the probe specially if a corner install. My harman dealer suggested the P43 but i wanted to push heat up the stairs to 2nd floor bedrooms so went with P61A.. that said an open floor plan works best with pellet stoves which we have and in our case bigger is better. U might need to incorporate a box fan or 2 into your setup..or......go to the darkside and get the bigger P61 or 68 Beasts...
 
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davidfieldsnwa

New Member
Jan 30, 2021
11
Northwest Arkansas
Thanks everyone. My P43 seems to not heat our home completely when the temp gets into the teens. As someone mentioned, I’m living in Northwest Arkansas - so this kind of cold temps doesn’t happen all the time. The P43 is plenty for us much of the time, and heat definitely goes up to our second floor, but other times I want more heat output. I speculate that if I had purchased a P68, then I’d have more radiant heat and be able to be warmer when the temps get low. .

So I’ve got my feed rate at 4.5 and Im not seeing pellets go over the edge - just the normal fly ash. I’ll watch it to see if anything like that happens. The pellet bag says “premium” - so I think they’re Ok.

The stove is in our living room - so we like to keep it on low distribution fan - just so it isn’t so loud. I’m sure that doesn’t help - because increasing the distro fan would help circulate the air more.

I have noticed - if I’ll keep my room temp on high temp, and the distribution fan on low - the air that does come out is very nice and hot! However, it doesn’t take the hot air to all the adjoining rooms.

Appreciate the thoughts.
 

SciGuy

Feeling the Heat
Aug 17, 2007
310
Constableville, NY
So I’ve got my feed rate at 4.5 and Im not seeing pellets go over the edge - just the normal fly ash. I’ll watch it to see if anything like that happens. The pellet bag says “premium” - so I think they’re Ok.

The stove is in our living room - so we like to keep it on low distribution fan - just so it isn’t so loud. I’m sure that doesn’t help - because increasing the distro fan would help circulate the air more.

Appreciate the thoughts.

David,

Your P43 ought to be able to burn a bit over 3 bags per day run at full capacity. As you’ve imagined, the stove will pump out the heat more effectively with the distribution blower set to a higher output. The sound is aggravating but really makes a substantial difference in effective distribution as well as efficiency. I’m not sure that a P68 would radiate all that much mo than your P43. How many bags per day are you burning now?

Hugh
 
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Tonyray

Minister of Fire
David,

Your P43 ought to be able to burn a bit over 3 bags per day run at full capacity. As you’ve imagined, the stove will pump out the heat more effectively with the distribution blower set to a higher output. The sound is aggravating but really makes a substantial difference in effective distribution as well as efficiency. I’m not sure that a P68 would radiate all that much mo than your P43. How many bags per day are you burning now?

Hugh
P68 is a beast! Just might...
 

davidfieldsnwa

New Member
Jan 30, 2021
11
Northwest Arkansas
I’m definitely not burning close to 3 per day. Maybe a bit over a bag per day when I run it hard for the whole day. I”ve only used room temp but I definitely push the thermostat high. Over 80.

I have a wall mounted thermostat for our conventional Hvac about 35 foot from the stove directly across from the stove - when it is cold I can’t get it to get over 70 degrees.

Maybe I need to use stove temp? Surprised this thing could do over 3/day. What am I missing? We do have pretty high ceilings - 100 year old house but had lots of TLC - new wall insulation and windows.
 

Tonyray

Minister of Fire
I’m definitely not burning close to 3 per day. Maybe a bit over a bag per day when I run it hard for the whole day. I”ve only used room temp but I definitely push the thermostat high. Over 80.

I have a wall mounted thermostat for our conventional Hvac about 35 foot from the stove directly across from the stove - when it is cold I can’t get it to get over 70 degrees.

Maybe I need to use stove temp? Surprised this thing could do over 3/day. What am I missing? We do have pretty high ceilings - 100 year old house but had lots of TLC - new wall insulation and windows.
Stove temp will deff use more pellets but it will be a steady non stop distribution blower until u run out of pellets..no on and off like room mode..you should eventually achieve well over 70 degrees...
 
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Harman Lover 007

Minister of Fire
If he doesn’t turn his distribution blower to high he’s not going to achieve what he’s trying to do....
 
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davidfieldsnwa

New Member
Jan 30, 2021
11
Northwest Arkansas
Message received! Distribution fan going higher!

Last question though - does the stove have the same power in max room temp + high temp as it does in max stove temp + high stove numeric setting? I believe the answer is likely to be yes - but just checking.

I do understand that stove temp will not vary the output whereas room temp will if it has hit target temp. However, if my house is cold bc stove has been on low or even off and I want the quickest path to a warm house - I want to know if i need to put the stove in a stove temp mode for that - or if just raising the target temp in room temp mode does the same thing.
 

Dataman

Minister of Fire
Sep 10, 2018
1,012
Newport, Wa
Box fan will help a lot, even on low. I have 2 of them pointing down hallway. Both have Filter on Front to help with dust in house (Humidifiers). Run my Harmon XXV on high fan speed. I adverage about 1 bag per day. In the day when it's above 32f I run my heat pump. On days I can't I use 2 bags. 74f in hallway. Stove is in Room Temp on Manual.
 

Harman Lover 007

Minister of Fire
Message received! Distribution fan going higher!

Last question though - does the stove have the same power in max room temp + high temp as it does in max stove temp + high stove numeric setting? I believe the answer is likely to be yes - but just checking.

I do understand that stove temp will not vary the output whereas room temp will if it has hit target temp. However, if my house is cold bc stove has been on low or even off and I want the quickest path to a warm house - I want to know if i need to put the stove in a stove temp mode for that - or if just raising the target temp in room temp mode does the same thing.
Either one will achieve the same goal. You’ll be happier with Room Temp in my opinion. Bring your feed rate down a bit to 3.5 or 4, otherwise you might spill some pellets over the edge when the stove ramps up from a cold start. Hang in there....
 

SciGuy

Feeling the Heat
Aug 17, 2007
310
Constableville, NY
I’m definitely not burning close to 3 per day. Maybe a bit over a bag per day when I run it hard for the whole day. I”ve only used room temp but I definitely push the thermostat high. Over 80.

A bag of typical pellets contains something on the order of 8500 X 40 = 340,000 BTUs. Divide that by 24 hours in a day yields 14,166 input BTUs per hour in a stove rated at 43,000 input BTUs per hour so a bag per day is only running at ~ 33% of maximum usage. If the heat isn't getting out of your living room and it's warming up to the temperature you've got the thermostat set to then the stove will ramp down compared to what it might run on maximum stove temp mode. Then again your living room will begin to resemble a sauna. You need to push the heat other places to increase the output of the stove when run in room temp mode.

Hugh
 
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Tonyray

Minister of Fire
Yes. Open floor plan is best setup for pellet stoves . With broken up rooms going forward some improv is needed lest your melt in the stove room. Redesign the house or fans will do it..
 
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mtnbiker727

Burning Hunk
Mar 11, 2019
179
PA
I have a basement install, which is not preferred, but we opened up all the floor vents and I have a fan on top of the pellet hopper blowing at the open stairwell and fans in the stairwell blowing up. When I stand at the top of the stairs I can feel the cold air falling on my feet as the warm air goes up by my head. You need to get the cold air back to the stove as bad as you need to get the warm air away from it. Think about your floor plan and see if there's anything you can change about airflow back to the room the stove is in.

Also: Is your igniter set to auto? If so, the stove will get hot until it satisfies the need, then it will idle down and completely shut off. I read on here, and proved it to myself, that set to disabled, the stove will get hot and stay hot, throwing off more ambient heat like an old fashioned wood stove.
 

davidfieldsnwa

New Member
Jan 30, 2021
11
Northwest Arkansas
Interesting on that last about the igniter. I know the manual setting will prevent the stove from totally shutting off after it meets the heat condition - but I was unaware that it would prevent it from varying heat at all. So it essentially puts the unit into stove temp mode even though its set to room temp?
 

SciGuy

Feeling the Heat
Aug 17, 2007
310
Constableville, NY
Interesting on that last about the igniter. I know the manual setting will prevent the stove from totally shutting off after it meets the heat condition - but I was unaware that it would prevent it from varying heat at all. So it essentially puts the unit into stove temp mode even though its set to room temp?
It just feeds the very minimum amount of pellets to keep the fire alive between calls for heat from the thermostat i.e. keeps a minimum "live fire". So if your igniter is dead or you're worried about the minimal KWs it might consume you still can still run in room temperature mode.
 
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Tonyray

Minister of Fire
The thing about room manual( switch down) at least on my harman P61A, it seems like the sweet spot is set at 75.. any lower and the blower shuts of for longer periods of time which i dont want.. not that 75 degree set will be as hot as stove mode continuous but the blower will stay on longer before it stops and goes into few pellets here and there maint mode..
 
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mtnbiker727

Burning Hunk
Mar 11, 2019
179
PA
Interesting on that last about the igniter. I know the manual setting will prevent the stove from totally shutting off after it meets the heat condition - but I was unaware that it would prevent it from varying heat at all. So it essentially puts the unit into stove temp mode even though its set to room temp?

When you read the brochure about Harman stoves, it says the stove can keep the temperature of your room within 1 degree. What they don't tell you is that Room Temp - Disabled is how the stove achieves that. The fan will kick on and off and the pellet feed will increase as needed to maintain the temperature setting.
 

SciGuy

Feeling the Heat
Aug 17, 2007
310
Constableville, NY
When you read the brochure about Harman stoves, it says the stove can keep the temperature of your room within 1 degree. What they don't tell you is that Room Temp - Disabled is how the stove achieves that. The fan will kick on and off and the pellet feed will increase as needed to maintain the temperature setting.

My P-43 seems to do a pretty good job maintaining temp with very close to 1*F in Room Temp mode with auto ignition on. It does cycle a good deal in the process. I believe the location of one's temperature sensing wire is essential in the success of maintaining an even temperature.
 
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Tonyray

Minister of Fire
My P-43 seems to do a pretty good job maintaining temp with very close to 1*F in Room Temp mode with auto ignition on. It does cycle a good deal in the process. I believe the location of one's temperature sensing wire is essential in the success of maintaining an even temperature.
mine is taped to the back of the hopper just peaking out above the hopper lid..
does good job in room auto as heat doesn't get back there to prematurely affect the probe too soon.