At 9am Atlantic time I filled my hopper to about 2 inches below the cover and made a mark. Tomorrow I will refill it and keep track of the number of full and partial bags. We are going to be about -5C on average. I am at the lowest heat setting on stove mode, with no room dist fan running. If anyone has some previous data or want to start a test me me that would be great.
P43 Starting 24 Hour Burn Test
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Question. Why do you not run the circulation fan?
When the stove gets hot enough the fan will turn on
so that it does not overheat. With the fan off other
than some convection heat the heat produced is just
sent up the chimney. For me, the purpose of burning
pellets is to heat my home.
Not just the astedices of watching a fire
When the stove gets hot enough the fan will turn on
so that it does not overheat. With the fan off other
than some convection heat the heat produced is just
sent up the chimney. For me, the purpose of burning
pellets is to heat my home.
Not just the astedices of watching a fire
My logic is that if I turn on the distribution fan, I will get more BTU's of heat from the stove and burn more pellets. If I don't run it, I won't be cooling down the ESP probe, and it will only burn enough pellets to make the "idle" probe temp. The stove is in the corner of my finished basement, and I have a separate fan near the stove blowing the air towards my open stairs. I get a nice 22C temperature so it's all about trying to use minimum pellets right now. I would be interested in knowing if others run this way?
Running the convection fan does not, could not, and can not cool the ESP
The convection fan pushes air through the heat exchanger and out into the room
The heat exchanger is located between the combustion fan and the firebox. The hot gases are passed by the heat exchanger
You are burning more pellets and getting less heat most of your BTUs are going up the chimney
![[Hearth.com] P43 Starting 24 Hour Burn Test](https://www.hearth.com/talk/attachments/1740161329856-webp.337031/ "[Hearth.com] P43 Starting 24 Hour Burn Test")
The convection fan pushes air through the heat exchanger and out into the room
The heat exchanger is located between the combustion fan and the firebox. The hot gases are passed by the heat exchanger
You are burning more pellets and getting less heat most of your BTUs are going up the chimney
You are 100% correct in how you describe the two different air circuits in a pellet stove. I didn't mean to imply that the ESP probe was in the convection air flow, only that the stove body (or the metal separating the two air circuits) would be cooled down if you run the convection fan. Would you agree to that? I believe that is the reason for a forced air circuit rather than a typical passive heat radiator (think of a woodstove with no blowers at all)
Seeing as the ESP is in the exhaust flow the rest of the stove could be ice-cold
The sense is heated by the fire . Pellet stoves are meant to have the heat removed by a convection fan
they have a heat exchanger for that purpose. Wood stoves are a steel box that gets hot and radiates its heat.
Pellet stoves are not designed for that kind of firing that's why they have an overheat sensor to shut them down on overheat
Which is just over 200
exhaust temp
The sense is heated by the fire . Pellet stoves are meant to have the heat removed by a convection fan
they have a heat exchanger for that purpose. Wood stoves are a steel box that gets hot and radiates its heat.
Pellet stoves are not designed for that kind of firing that's why they have an overheat sensor to shut them down on overheat
Which is just over 200
exhaust tempI have a p43 also, it would be a waste in my setup to run the stove as you are doing. If it works for you that is what is important. It does seem like a waste to just burn pellets and not allow the stove to move the heat it is producing.
Thanks I have an open mind, and don't hang on to beliefs too much. Right now I can't move the heat out of the basement, as I have no ductwork. I need the minimum BTU output, as it's already ay 22C. I could use thermostat mode, but that would transition from a hot stove to shutting off. The Harman is designed to run as a "Stove" using the ESP. At setting below 4 or 5, the Dist Fan is designed not to run.
bogieb
Minister of Fire
Have you tried using room temp mode? Then the stove would only fire when the room temp gets low enough, use the distribution fan to move heat out to the room, then shut down once the temp in the room is satisfied. You may find that you use less pellets that way.
I run my stoves in room temp mode most of the heating season. I also run them on cheap thermostats that are a bit away from the stove - my main floor thermostat is half way down the house and in a different room from the stove. That set up works better for heating the entire house the way I want it than the room temp probe on the stove. Only when it is super windy and in the teens (*F), or when it is calm and in single digits or lower (that is when my stove will start back up shortly after shutting down), do I change over to having either stove run constantly. I have an older house that is far from "tight", it is 2x4 construction so not much insulation can fit in the walls, nor is the exterior "wrapped".
I run my stoves in room temp mode most of the heating season. I also run them on cheap thermostats that are a bit away from the stove - my main floor thermostat is half way down the house and in a different room from the stove. That set up works better for heating the entire house the way I want it than the room temp probe on the stove. Only when it is super windy and in the teens (*F), or when it is calm and in single digits or lower (that is when my stove will start back up shortly after shutting down), do I change over to having either stove run constantly. I have an older house that is far from "tight", it is 2x4 construction so not much insulation can fit in the walls, nor is the exterior "wrapped".
OK - I filled it back up. In total I just added half a bag(measured weight) and last night added a partial bag that I estimated at a third but I did not measure it(which I should have). I'm around a bag or 14.3 BTU/h which is much lower than the spec of 23,900 for the lowest input.
I will do it again, and this time have the scale out so I can measure actual pounds. Went down to -10C overnight. Room temp 22C.
With no fan on so at the outside 25% heated room 75% went out the exhaust
What a waste of resources but it is your money
What a waste of resources but it is your money
I did try it when the stove was new, but the fire size was too high for me, and of course depending on how you have the igniter switch set, it will go to idle (or the btu I run now), or shut off and restart. Right now in winter with my room I prefer to keep it running on low all the time. I do have a big raised fan next to the stove to blow the air away from the stove. I think once the days and nights are warmer I will let my basement heatpump run as it is very efficient as long as it is above 10C. When we had -15C forget it. The basement would go down to 14C with the heatpump set at 22C. That was using electricity and making no heat. When I went downstairs to watch TV, I had to have an electric heater running in front of me. That is when I said enough is enough. I always wanted a stove in case of a power outage. I looked at woodstoves and pellet stoves. The woodstove was a no go as I didn't want to deal with firewood and getting up to put wood on at night (I've had many wood stoves before). Being comfortable with the mechanical and electrical parts of the pellet stove, I went ahead and got it installed! I am really happy with it and it only draws 60W unless the feed motor is running. I have it running on a sine wave inverter fed by a battery which is fed from a battery charger. If the power goes out it will just keep running. If the house loses power, I will have no heat pump upstairs or electric heat, but then I will be cranking it up, and running the distribution fan and maybe the other room fan. I will have plenty on time to get my generator running.
Seeing as the ESP is in the exhaust flow the rest of the stove could be ice-cold
The sense is heated by the fire . Pellet stoves are meant to have the heat removed by a convection fan
they have a heat exchanger for that purpose. Wood stoves are a steel box that gets hot and radiates its heat.
Pellet stoves are not designed for that kind of firing that's why they have an overheat sensor to shut them down on overheat
Which is just over 200
The efficiency is lower for sure if you don't run the distribution fan, but my test is to try and find the minimum btu input (or bags of pellets) while in stove mode with constant burn.
I found some previous posts that discuss how the stove mode and ESP work.
"P38X2, where you might be missing something is in the fundamental design of the ESP; exhaust temp drives Harman Stoves. Whether you have the fan on Hi or Low, the target EXHAUST temp is what the stove will strive to achieve/maintain. Fan on Hi will strip more heat, forcing the stove to feed MORE pellets to maintain ESP temp, but room temp will be achieved QUICKER. Fan on Low will strip less heat, forcing the stove to feed LESS pellets to maintain ESP temp, but target temp will be achieved SLOWER. So, basically, they offset. At what point the lines intersect on a graph is the devil in the details, probably somewhere in the +/- 5% off center range. We'll never know...
As I've said before, if we focus on efficiency and pellet consumption, we'll make ourselves nuts. The goal is comfort and resulting savings whether you believe comfortable is 78 degrees or 65 degrees or somewhere in between. Fan on Hi might be what's necessary to achieve your ideal of comfort based on the heat loss of your house or the rooms you need to heat at the other end of the house. Fan on Low will give more even temps in closer proximity to the stove."
"Higher blower speed extracts more heat from the firebox but makes more noise. You’ll send more heat out the vent pipe with a low distribution blower speed. If you’re using the stove in “stove mode” you will burn more pellets per hour at a specific stove setting when using a higher distribution blower speed as the vented gasses will need more heat added to warm up the ESP."
I found some previous posts that discuss how the stove mode and ESP work.
"P38X2, where you might be missing something is in the fundamental design of the ESP; exhaust temp drives Harman Stoves. Whether you have the fan on Hi or Low, the target EXHAUST temp is what the stove will strive to achieve/maintain. Fan on Hi will strip more heat, forcing the stove to feed MORE pellets to maintain ESP temp, but room temp will be achieved QUICKER. Fan on Low will strip less heat, forcing the stove to feed LESS pellets to maintain ESP temp, but target temp will be achieved SLOWER. So, basically, they offset. At what point the lines intersect on a graph is the devil in the details, probably somewhere in the +/- 5% off center range. We'll never know...
As I've said before, if we focus on efficiency and pellet consumption, we'll make ourselves nuts. The goal is comfort and resulting savings whether you believe comfortable is 78 degrees or 65 degrees or somewhere in between. Fan on Hi might be what's necessary to achieve your ideal of comfort based on the heat loss of your house or the rooms you need to heat at the other end of the house. Fan on Low will give more even temps in closer proximity to the stove."
"Higher blower speed extracts more heat from the firebox but makes more noise. You’ll send more heat out the vent pipe with a low distribution blower speed. If you’re using the stove in “stove mode” you will burn more pellets per hour at a specific stove setting when using a higher distribution blower speed as the vented gasses will need more heat added to warm up the ESP."
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Adding a blower to a pellet stove can typically increase its efficiency by 10-20% by ensuring better air circulation and heat distribution throughout the room, allowing more of the generated heat to be utilized instead of simply rising upwards from the stove.
I could write a long article on running low mode with my PC45. I took extensive logs of settings and conditions and various temperatures around my house to know: 1) how to run in low mode and supplement my NG furnace; and 2) how to run in high mode as a standalone heating system in my house. Two winters of data gave me the settings for my home.
In low mode I use room temp mode set low and keep the distribution fan running at a slow speed. 24 hrs on a bag is possible. You can throttle the feed rate by turning its control knob down low if you want. Carbon does build up in my burn pot if I go too low though. I monitor one point of the outside firebox temp and found when it is at 300F I am optimal. That point on my 45 is the left side, top corner near the door. It’s only a relative temperature but at one point you use it to tune the burn.
I recommend reading your hopper levels using a measurement. I have installed adhesive backed measuring tapes on the inside of the hopper for accurate measurements.
![[Hearth.com] P43 Starting 24 Hour Burn Test](https://www.hearth.com/talk/attachments/img_4961-webp.337103/ "[Hearth.com] P43 Starting 24 Hour Burn Test")
In low mode I use room temp mode set low and keep the distribution fan running at a slow speed. 24 hrs on a bag is possible. You can throttle the feed rate by turning its control knob down low if you want. Carbon does build up in my burn pot if I go too low though. I monitor one point of the outside firebox temp and found when it is at 300F I am optimal. That point on my 45 is the left side, top corner near the door. It’s only a relative temperature but at one point you use it to tune the burn.
I recommend reading your hopper levels using a measurement. I have installed adhesive backed measuring tapes on the inside of the hopper for accurate measurements.
What i have learned in 5 years of running my stove, stop worrying on how many pellets you are using set it and forget it. I tried to conserve pellets to save a few $$ and in all honestly when all was said and done i would only maybe save a 1/2 to a bag. Now i just set it and forget and run the house a little hotter and im good with that.
The only really way you are going to determine usage is weigh the pellets before and after fill. Using a tape measure or i think i used 1/2 bag method can have huge differences in your calculations. The only way the stove is going to be as efficient as possible is run it how it was designed with the blowers running. As stated several times without the blower running its just going out the exhaust.
The only really way you are going to determine usage is weigh the pellets before and after fill. Using a tape measure or i think i used 1/2 bag method can have huge differences in your calculations. The only way the stove is going to be as efficient as possible is run it how it was designed with the blowers running. As stated several times without the blower running its just going out the exhaust.
And just as a heads up, running your stove on low constantly will build up some creosote and black sludge…I run mine on stove temp 4 and 4 once a week for about an hour to burn any of that out.
That it is all going out the exhaust is not true. Any wood or pellet stove gives up heat to the room in only two ways. Radiant Heat and convection. If you add an internal fan you will get more heat by convection, maybe up to 20% more efficient than no fan. If you are inputting a set amount BTU fuel then you would actually cool the stove down by doing this and there would be less radiant heat. Me I love the feeling of the radiant heat, and I have another big fan next to the stove to aid the convection and blow the hot air across the room. Works great.
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So why not just burn a wood stove? They are by design, made for exactly what you are doing. Don't care what pellet stove you have they were not designed to run continues without a convection blower operating. And to add it is easier to move cold air to the stove than hot air away from it
Many reasons why I didn't go with a wood stove. However one reason that is important is that I don't think I could control the BTU input. If the stove produced more heat than I could use, I'd have to close it's vents and choke it. With a pellet stove you can control the heat.
Yes, you are 100% correct re pellet stoves are designed to run their EPA CSA tests with the convection blower running. I looked at my stoves EPA test results (on the website) and they don't have any tests for not running the fan. My specs are: LHV 82.7%, HHV 76.7%.
So since I don't know any stove designers to ask about efficiency with no fan , I looked up a pellet stove with no fans:
"This manual describes the installation and operation of the USSC, GW1949 wood heater. This heater meets the 2020 U.S. Environmental Protection Agency's crib wood emission limits for wood heaters sold after May 15, 2020. Under specific test conditions this heater has been shown to deliver heat at rates ranging from 12,706 to 27,220 Btu/hr and 0.8 g/hr and 70% efficiency."
As you can see, convection and radiant heat can produce some pretty good heat. ie 70%
Thanks for the suggestion re: moving cold air. I was wondering (and have a post) if I should blow hot air upstairs. Maybe I should try moving cold air (say from my upstairs bedroom) down to the stove area?
Yes, you are 100% correct re pellet stoves are designed to run their EPA CSA tests with the convection blower running. I looked at my stoves EPA test results (on the website) and they don't have any tests for not running the fan. My specs are: LHV 82.7%, HHV 76.7%.
So since I don't know any stove designers to ask about efficiency with no fan , I looked up a pellet stove with no fans:
"This manual describes the installation and operation of the USSC, GW1949 wood heater. This heater meets the 2020 U.S. Environmental Protection Agency's crib wood emission limits for wood heaters sold after May 15, 2020. Under specific test conditions this heater has been shown to deliver heat at rates ranging from 12,706 to 27,220 Btu/hr and 0.8 g/hr and 70% efficiency."
As you can see, convection and radiant heat can produce some pretty good heat. ie 70%
Thanks for the suggestion re: moving cold air. I was wondering (and have a post) if I should blow hot air upstairs. Maybe I should try moving cold air (say from my upstairs bedroom) down to the stove area?
Golfeur
Burning Hunk
I don't know if this can happen but I think that if the stove is operated without a fan even if the setting is at minimum I think it can have enough heat to cause the heat exchanger to warp by the expansion of the metal and possibly crack in the welds
From the notes:
Stove temp - 100% driven the the ESP (temperature probe in stove exhaust flow). Temp dial corresponds to a fixed ESP temperature. For simplicity, let's assume a setting of 3 = 300 degrees ESP temp. The stove will ramp feed up/down to always be as close to 300 degrees as possible. In stove temp the stove doesn't care what the room temp is, only the ESP temp. The room might be 60 or 90 degrees doesn't matter, all it cares about is maintaining an ESP temp of 300.The stove will not shut off in stove temp regardless of whether the igniter switch is set to auto or manual. Stove temp, switch to manual - I call this fireplace mode. Distribution fan will not turn on unless the temp knob is set to 5 or higher. This is designed to give a nice fire, but not a ton of heat in the room. Most goes up the chimney. Stove temp, switch to auto - distribution fan operates normally to push heat into the room, regardless of stove or room temperature. There is a caveat to this, if you have your room temp set to 1 (very low) then the distribution blower might shut off because the ESP temperature is below the lowest setting allowed for the distribution blower to run.
Basically the way I understand it, the ESP probe will prevent damage. If you have a smaller flame (less BTU) then the stove is designed to run without a dist blower. My control board and feeder work perfectly, so I just always have a nice"warm" stove. The only time I had a problem like what you describe is when I hooked up my OAK and was playing around with the comb fan speed. Tomake a long story short I ended up with either freezing air or not enough air and then the stove really fired up! (I turned the dist fan on)
Update and end of test. Just turned it up to 4 and turned the distribution blower on low. As recommended by a member, I need to run it hot every once and awhile. BTW creosote does not condense below 121C or 250F
Added 38.4 Pounds total to fill to mark at 9am all weighed
I recorded some temperatures. Bottom middle of RHS of stove = 104C 219F Vent Pipe Outside vertical run eye level 52C 125F
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