Harman P68 Stove Temp Mode question ...

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Frugalfreak

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Apr 6, 2011
34
Southcentral PA
... I've been trying out a few settings with my P68 and it almost seems that the Stove Mode uses much less pellets than the Room Mode ... has anyone (officially) compared the two as far as pellet usage goes. I understand the differences of how each works - looks like Room Mode is for those who don't want to mess with the settings as often and have confidence in the thermostat accuracy - that 70 really means 70.
This stove has been out for a awhile so there should be settings that are tried and true by now - by many users. Believe it or not I run mine on Stove Mode 1/1/low almost always after initial room 'warmup' and it keeps my home around 70 on a 45 degree day like today here in SC Pa and man it really seems to sip pellets. On colder days of course these settings may have to be tweaked and thus more pellet use.
 
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I guess it's as simple as being able to control the feed timing/BTU output thus allowing less pellets to be deposited/burnt ... just as long as it burns down to a fine ash and the fire stays going then I see no reason to not use the lowest settings possible to minimize pellet usage.
 
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Harman Tech for New England told a group of us at a Harman seminar that room temp is more efficient.
I look at it this way: If it is set for Stove Temp mode and the outside temp goes up, the room temp will gradually
rise, wasting pellets while you are at work. In Room Temp mode it will end up throttling the heat back.
This was our 3rd year with the P61 and run it in Room Temp mode 100%. Suggested feed rate is 4 which is the
max allowed not the target. (As I understand it)
My .02
 
lessoil said:
Harman Tech for New England told a group of us at a Harman seminar that room temp is more efficient.
I look at it this way: If it is set for Stove Temp mode and the outside temp goes up, the room temp will gradually
rise, wasting pellets while you are at work. In Room Temp mode it will end up throttling the heat back.
This was our 3rd year with the P61 and run it in Room Temp mode 100%. Suggested feed rate is 4 which is the
max allowed not the target. (As I understand it)
My .02

sounds basically right, Les
 
lessoil said:
Harman Tech for New England told a group of us at a Harman seminar that room temp is more efficient.
I look at it this way: If it is set for Stove Temp mode and the outside temp goes up, the room temp will gradually
rise, wasting pellets while you are at work. In Room Temp mode it will end up throttling the heat back.
This was our 3rd year with the P61 and run it in Room Temp mode 100%. Suggested feed rate is 4 which is the
max allowed not the target. (As I understand it)
My .02

I guess that kind of makes sense -but- the Room temp mode can't possibly throttle the temp back below 1/1/low setting of Stove Temp mode - unless it shuts the stove down and then restarts it as needed which puts more wear on the igniter and uses more electricity.
 
Depends on comfort and how your stove/piping tolerates burning on low-low. Even though you're sipping pellets, you might be creating a maintenance headache. Like most "burning appliances" they like to be run at higher temperatures, closer to their optimal efficiency ratings.

My XXV is on room temp and seems to be burning on low/low right now because the heat load is so little. I'm starting to see more build up at the base of the pot and the auger, so I'll likely switch to automatic on/off and see how it does.

Oh, and I've had my feed rate at 5 all winter. Why pay for ESP technology and not use it? Turning your feed rate way down is like putting a brick behind your gas pedal. Feed rate is only to prevent pellets from spilling over the edge, nothing else.
 
lbcynya said:
Depends on comfort and how your stove/piping tolerates burning on low-low. Even though you're sipping pellets, you might be creating a maintenance headache. Like most "burning appliances" they like to be run at higher temperatures, closer to their optimal efficiency ratings.

- I doubt there isn't enough heat being produced that will cause abnormal maintenance issues but I think this also depends on the type of stove and BTU rating. Stove pipe temp seems fine but I will likely only run it on lowest settings only when necessary. My guess is throughout normal PA winter temps I will have it set higher to maintain a 68-72 degree range in the house.

My XXV is on room temp and seems to be burning on low/low right now because the heat load is so little. I'm starting to see more build up at the base of the pot and the auger, so I'll likely switch to automatic on/off and see how it does.

- I have no extra buildup in the pot area - in fact the opposite I got more buildup in Room mode for some reason. The pellets are burning great, the wall temp is staying where it needs to be and less pellets are being used.

Oh, and I've had my feed rate at 5 all winter. Why pay for ESP technology and not use it? Turning your feed rate way down is like putting a brick behind your gas pedal. Feed rate is only to prevent pellets from spilling over the edge, nothing else.

- How many pellets/$$$ have you used? While I appreciate the brick comment - it will keep one from speeding and save gas/$$$. I agree the feed rate does prevent that -but- when set lower you can still hear that the stove isn't issuing them as fast and if there's no extra buildup and fire is steady then I see no harm here - but we'll see I guess. I doubt Harman would allow 'extreme' lows or highs to encourage extra maintenance/future issues.
 
in the long run, leaving the feed adjuster at 1 will cause operation problems....you will NOT necessarily burn more pellets by setting it to 4ish...which is where I recommend. I would explain, but, it leaves people to debate, and I'm just not up for debate right now. you can search through old posts, this has been discussed at length before. I would not try to mislead you...set it to 4is, leave it be, and the stove will be happy. Leave it at 1...I assure you, at some point, the stove will not like you, and shut down...incomplete combustion will be what it perceives.
 
Delta-T said:
in the long run, leaving the feed adjuster at 1 will cause operation problems....you will NOT necessarily burn more pellets by setting it to 4ish...which is where I recommend. I would explain, but, it leaves people to debate, and I'm just not up for debate right now. you can search through old posts, this has been discussed at length before. I would not try to mislead you...set it to 4is, leave it be, and the stove will be happy. Leave it at 1...I assure you, at some point, the stove will not like you, and shut down...incomplete combustion will be what it perceives.

During startup the first hour or so I run it at Stove temp 5/fan high and feed 3 - then back it down gradually to lower settings. 4 seems high to run it all the time -but- as you say it's open to debate (past and present) I wonder if anyone can jump in who has actually run the stove at lower number for a prolonged period to see the actual effect it has -or- if it's only speculation by posters here (no offence intended toward anyone because you may be right)
 
Frugalfreak said:
Delta-T said:
in the long run, leaving the feed adjuster at 1 will cause operation problems....you will NOT necessarily burn more pellets by setting it to 4ish...which is where I recommend. I would explain, but, it leaves people to debate, and I'm just not up for debate right now. you can search through old posts, this has been discussed at length before. I would not try to mislead you...set it to 4is, leave it be, and the stove will be happy. Leave it at 1...I assure you, at some point, the stove will not like you, and shut down...incomplete combustion will be what it perceives.

During startup the first hour or so I run it at Stove temp 5/fan high and feed 3 - then back it down gradually to lower settings. 4 seems high to run it all the time -but- as you say it's open to debate (past and present) I wonder if anyone can jump in who has actually run the stove at lower number for a prolonged period to see the actual effect it has -or- if it's only speculation by posters here (no offence intended toward anyone because you may be right)

I am not speculating...and I'm not offended. Have run,serviced these stoves for some time.
 
I'll stop here and only say that if that's true and running the stove at lower numbers means higher maintenance then running it in Room temp mode below say 70 would be a no-no ... because the flame and heat output stay lower just like in lower Stove temp modes. Why would Harman have settings that are lower if that's the case?
 
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you are confusing the different operations of the stove, I dont blame you, its sorta counter-intuitive...the "Feed Adjuster" does not tell the stove how many pellets to burn. It sets the maximum amount of time the auger is allowed to turn during a heat demand cycle. the knob with the temps and the 1-7 will dictate the output of the unit..feed adjuster is more like a choke on a throttle body...I have asked the "why" many times myself...with the diagnostic computer attached, tweaking the feed adjuster knob can allow a tech to see that everything is working as its supposed to..thats about the only reason I can figure that they put it on there.
 
Sorry I guess I can't really say that definitively because that will depend on the temp outside and the area being heated ... even if the stove is set at 65 for example it may still yield a high flame/heat output for quite awhile depending on the circumstances - it is cool how the stove adjusts the flame/BTU output in an effort to keep the set temp maintained - if this system works well then it may very well be the most efficient way to go ... again there are debates on both sides (St vs Rm modes)
 
Delta-T said:
you are confusing the different operations of the stove, I dont blame you, its sorta counter-intuitive...the "Feed Adjuster" does not tell the stove how many pellets to burn. It sets the maximum amount of time the auger is allowed to turn during a heat demand cycle. the knob with the temps and the 1-7 will dictate the output of the unit..feed adjuster is more like a choke on a throttle body...I have asked the "why" many times myself...with the diagnostic computer attached, tweaking the feed adjuster knob can allow a tech to see that everything is working as its supposed to..thats about the only reason I can figure that they put it on there.

Ok I guess I am confused because I thought in Stove mode you could control the length of time between auger revolutions/pellet deposits - you are saying that's not the case - correct? It really sounds like it does effect both - but maybe it's not as much as I thought or in the way it seems at all. You would know better and I appreciate the info - it's very helpful.
 
This is a very touchy subject in my opinion. Everybody runs their stove differently. It all depends on the user and the application of the stove. Everyone like a slightly different temperature. Some people say stove temp uses less pellets and others say room temp uses less. I like to say, try running it in both modes at different settings to see what works better for the area you are trying to heat. I dont recommend one mode over the other, like I said it all depends on what you want the stove to do, find what works best for your application and stick with it.
 
CJ-SR4ever said:
This is a very touchy subject in my opinion. Everybody runs their stove differently. It all depends on the user and the application of the stove. Everyone like a slightly different temperature. Some people say stove temp uses less pellets and others say room temp uses less. I like to say, try running it in both modes at different settings to see what works better for the area you are trying to heat. I dont recommend one mode over the other, like I said it all depends on what you want the stove to do, find what works best for your application and stick with it.
While I agree I also don't run to run it in a way that may cause/make maintenance issues. I guess find where the stove burns most efficiently and is best for it and my wallet - in pellet usage, comfort and maintenance.
 
Frugalfreak said:
lessoil said:
Harman Tech for New England told a group of us at a Harman seminar that room temp is more efficient.
I look at it this way: If it is set for Stove Temp mode and the outside temp goes up, the room temp will gradually
rise, wasting pellets while you are at work. In Room Temp mode it will end up throttling the heat back.
This was our 3rd year with the P61 and run it in Room Temp mode 100%. Suggested feed rate is 4 which is the
max allowed not the target. (As I understand it)
My .02

I guess that kind of makes sense -but- the Room temp mode can't possibly throttle the temp back below 1/1/low setting of Stove Temp mode - unless it shuts the stove down and then restarts it as needed which puts more wear on the igniter and uses more electricity.

And it will eventually shut down if the temp in the room stays above the setpoint long enough. But during 90% (Guess) of the Winter,
it rarely shuts down completely. The circulation fan will run less often but the fire will continue to burn. It will come to life
quickly if a door is left open like when you bring in groceries. The design of the Harman does a great job keeping the
temperature right where you set it! I guess this is why we run in Room Temp mode. Basically the same as when a central
heat source is used. Not sure if it runs dirtier in this mode.(Combustion fan maintains same airflow 100% of the time)
I have emptied the ash pan 3 times so far since Oct. (Burn 24/7) Will have to empty one last time if Spring ever gets here!!
 
I use Room Temp. The stove has the incredible ability to maintain the room temp you set it at automatically, perfectly, exactly, flawlessly... why not use that feature?

Look at the variations in weather... 50's yesterday, 32 this morning. Full sun blasting in the windows; oh, wait... now it's overcast. Door just got opened 6 times. Cold front moves through while you're at work and temps drop 20 degrees with NW wind blowing 20-30, etc., etc.

Why would you want to have to constanly fiddle with the settings to compensate for all these variations?

Room Temp mode, Feed Rate 4, set it and forget it. Just add pellets as needed and scrape pot every 2 days. Full clean once a month.
 
I was told this winter, by a large Harman dealer, that Harman issued a new policy on feed rate settings, they now say to set feed at 5.AS far as this debate on stove/room settings I am a stove guy, especially in the dead of winter. I would rather keep use of my igniter to a minimum seeing that that part is off warranty for me. In spring I still set it on stove, low fan and 1 I just have to scrape carbon build up more often than in winter.
 
noelp68 said:
I was told this winter, by a large Harman dealer, that Harman issued a new policy on feed rate settings, they now say to set feed at 5.AS far as this debate on stove/room settings I am a stove guy, especially in the dead of winter. I would rather keep use of my igniter to a minimum seeing that that part is off warranty for me. In spring I still set it on stove, low fan and 1 I just have to scrape carbon build up more often than in winter.

Yup, in the dead of winter even in room temp my stove runs pretty much constantly anyway. I found that in colder temps, say below 20 or 25*, the stove uses less pellets and heats the house better in stove temp. Now that its warmer out I have been using it in room temp...
 
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Bigjim13 said:
noelp68 said:
I was told this winter, by a large Harman dealer, that Harman issued a new policy on feed rate settings, they now say to set feed at 5.AS far as this debate on stove/room settings I am a stove guy, especially in the dead of winter. I would rather keep use of my igniter to a minimum seeing that that part is off warranty for me. In spring I still set it on stove, low fan and 1 I just have to scrape carbon build up more often than in winter.

Yup, in the dead of winter even in room temp my stove runs pretty much constantly anyway. I found that in colder temps, say below 20 or 25*, the stove uses less pellets and heats the house better in stove temp. Now that its warmer out I have been using it in room temp...

X2......agree 100% with Jim
 
Bigjim13 said:
noelp68 said:
I was told this winter, by a large Harman dealer, that Harman issued a new policy on feed rate settings, they now say to set feed at 5.AS far as this debate on stove/room settings I am a stove guy, especially in the dead of winter. I would rather keep use of my igniter to a minimum seeing that that part is off warranty for me. In spring I still set it on stove, low fan and 1 I just have to scrape carbon build up more often than in winter.

Yup, in the dead of winter even in room temp my stove runs pretty much constantly anyway. I found that in colder temps, say below 20 or 25*, the stove uses less pellets and heats the house better in stove temp. Now that its warmer out I have been using it in room temp...

The question is why does it use less pellets in Stove Mode? - if both would make the stove run constantly anyhow - it must have something to do with the settings.
 
Frugalfreak said:
Bigjim13 said:
noelp68 said:
I was told this winter, by a large Harman dealer, that Harman issued a new policy on feed rate settings, they now say to set feed at 5.AS far as this debate on stove/room settings I am a stove guy, especially in the dead of winter. I would rather keep use of my igniter to a minimum seeing that that part is off warranty for me. In spring I still set it on stove, low fan and 1 I just have to scrape carbon build up more often than in winter.

Yup, in the dead of winter even in room temp my stove runs pretty much constantly anyway. I found that in colder temps, say below 20 or 25*, the stove uses less pellets and heats the house better in stove temp. Now that its warmer out I have been using it in room temp...

The question is why does it use less pellets in Stove Mode? - if both would make the stove run constantly anyhow - it must have something to do with the settings.

likely because its a constant burn.....once the exhaust gas gets to temperature, there is very little "up and down" of regulation, whereas, in Room Temp mode, the stove is constantly adjusting itself to the changing room temps.
 
For what its worth, the last week or so has been pretty warm-days in the mid to upper 40s and nights not much below 30. The last 2 nights it went down to 20 and 24* and I left my stove on room temp when going to bed. Both nights I went through nearly a full bag of NEWP pellets. My thought on it is this: in room temp the room the stove is in and other rooms get cooler, the stove kicks on to heat it up to a point and then cycles down. The room the stove is in and other rooms get cooler so the stove kicks up again and gets it up to a certain point. When the stove cools down I think it takes more pellets to heat it back up to a certain point rather than just keeping it on a certain point the whole time.

***Keep in mind, this is just my observation and I have no technical stuff to back it up. So each night I check to see what the low temp is supposed to be and judge whether or not I need room or stove temp. I'd rather burn a few more pellets than have the wife kick me awake to go turn the stove up cuz she's cold!!!***
 
Bigjim13 said:
... I'd rather burn a few more pellets than have the wife kick me awake to go turn the stove up cuz she's cold!!!***

You need to invest in a full suit of armor, then you can both turn the stove off at night and sleep safely ;-).
 
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