Room vs Stove temp mode

[PDawg]

I have a Harman XXV and I have benn running the stove in stove temp mode at night and room temp mode during the day. I keep the feed rate at 3 day and night. The other night I kept the stove in room temp mode vs stove temp mode with all other settings not changed. The following morning I noticed that I burnt significantly more pellets in room temp mode than I would have in stove temp mode. With the feed rate constant I would of thought that both modes would use the same amount of pellets over the same period of time. Does room temp mode override the feed rate if the stove needs more heat to keep the room at a constant temperature ? It now seems more economical to run the stove in stove temp mode.

 

[crausch]

How about the temperature? What temperature does your room stay over night on "stove temp" and what temperature did it stay at when run on "room temp"? Another factor is were the outside temps close each night for a fair comparison?

 

[lecomte38]

Basic answer is yes. In stove temp mode the temp adjuster knob is controlling the feed rate (inside numbers are about 5 seconds of auger run each) and the feed adjuster knob does nothing. In room temp mode the desired temp is selected with the same knob and the stove will eat as much pellets as needed to maintain the desired temp. In this mode the feed adjuster is setting the maximum feed so that if the stove goes into high rate to maintain room temps it will not overflow the pot.

I only run in stove temp mode now. Running on room temp I woke up one cold morning and founds the stove out because it had run out of pellets and I was burning a lot more pellets. I run on stove temp - 3 and burn a bag a day. My programmable oil heat kicks in at 6 am and 5 pm if needed for any extra heat.

 

[abrucerd]

Like others, I'm baffled by the intricacies between Stove Temp/Room Temp/Feed Rate. And like lecomte, I've begun strictly running my stove on stove temp as I feel I have more control and it's reliable.

My usually routine involves putting my Harman Advance on highest stove temp and feed rate settings (7 and 6, respectively) when I get home from work (the wife likes it warm when she gets home, and I like to keep the nagging to a minimum). When it's time for bed, I turn it down to about 3 and 3 (2 and 2 if it's relatively mild outside)... then I make any adjustments the next morning based on the days forecast.

I've found that during the weekend, when I run the stove at it's highest settings for longer periods, I go through one bag in about 12 hours. Not sure how much the pellet brand has to do with that... I'd be curious to see what others have found.

Cheers

 

[slheinlein]

I use both modes but find the room temp mode is good if you just want to set the house to a specific temperature and not worry about it. With stove temp, there is a little more maintenance involved since the house temperature will vary depending on the outside temperature. It seems that I don't turn the stove up enough and the house stays cold or I turn it up too much and it gets too hot. Stove temp requires me to keep an eye on it and I have other things to do during the day.

The past 30 days, I have been leaving mine almost exclusively on room temp mode but I am flying through the pellets. Burned 65 bags the past 32 days. I think I will try to put on stove temp mode at night since the stove is downstairs and everyone sleeps upstairs with central heat. I'll change the setting to room temp in the morning for the rest of day.

Hopefully, that will help decrease my pellet consumption.

 

[cac4]

"room temp" should be the most efficient way to run it...and that's what Harman says. I think the thing that makes it confusing is that there's a "feed adjuster" knob, and people equate that with "feed rate". its not the feed rate; its a feed limiter. it sets the maximum amount that can be fed; not the actual amount that will be fed.
If you're using fewer pellets on "stove temp" mode, you're getting less heat. You're not going to get the same amount of heat on less pellets. Its quite possible, (and probably very likely) that you're combination of settings in "stove temp" mode will send more heat up the chimney than into the room. In fact, they even describe how to do that very thing in the manual, so that you can enjoy a big fire without overheating the house. Big fire=big heat=big pellet consumption...if that heat isn't going into the room, its going up the chimney.
Even if an "ambiance fire" isn't your goal, the likelyhood that you'll be able to dial in the exact amount of heat output reuqired to maintain the temp in your house is slim. The weather is in a constant state of change; with the stove set at a fixed output (stove temp), the house is either going to steadily heat up, or steadily cool off. Room temp detects those changes and adjusts accordingly.

having said that, I may be experimenting w/ stove temp over the next few days, as we sink into these record cold temps. Problem in my house is that my basement has been getting very cold without my furnace running. I found the magic in these magic pellets. the "magic" is that 1/3 of my house is 20 degrees colder than it was before. I didn't realize just how much "loss" there was in my fha ducts. I thought the ground temp was keeping my basement at 55-60 degrees; NO, it isn't. its the leaky heat ducts! In the single-digit weather we've already had, I saw the basement temp dip to 41F. I think that's about as cold as I dare have it. With the upcoming sub-zero temps, I'm thinking that I'd better run the furnace some, to keep the water pipes from freezing. But how much? I don't know. And how to set the thermostats so that they're not arguing with each other? I'm thinking maybe "stove temp" mode, on a medium to medium-high setting...whatever will keep the furnace thermostat (opposite end of the house, so its always a little cooler than the stove area) in the middle 60's...set furnace to 68. I could probably accomplish the same thing in "room temp"...we'll just have to try it and see.

 

[cac4]

WarminNH,
we cross-posted...
what size/age/efficiency is your house? I just checked, and today is day 52 of running my stove, and we just opened bag #55 thismorning. so...still close to 1 bag per day. 1500sqft of 1990's house, 6" walls, etc, so pretty tight/well insulated.

I think also, you may have hit on another source of "magic" in the magic pellet debate*, and that is that when running the stove at a steady rate, (as most stoves run), you're actually allowing your house to be cooler than you would consciously choose it to be. As the temp drops slowly, we don't notice it right away...especially if you're busy doing chores or what have you. "hours" might go by before you notice that "its chilly in here", and turn up the stove. During that time, you've "saved energy". Using a conventional central heating system, it notices slight temp drops, and reacts immediately.




*people so often reporting what seems to be "artificially low" pellet consumption, compared to fossil fuel consumption with their central heating systems, when a straight "btu to btu" comparison says that they should be consuming way more in pellets.

 

[tinkabranc]

I prefer to use the stove temp mode on my XXV during the season
and room temp mode for shoulder seasons. Not sure about pellets,
but it saves on the ignitor.

 

[wwburning]

I've also noticed that it seems like my Harman p61a-2 uses a little less in stove temp mode then in room temp mode. As far as a theory why that may be the case I have only one possibility. The amount of pellets used to re-start and heat up the stove when cold and get it up to a good temp to produce heat may be more then running it continuously at that good temp. Any ideas/opinions?

Chris

 

[slheinlein]

WarminNH,
we cross-posted...
what size/age/efficiency is your house? I just checked, and today is day 52 of running my stove, and we just opened bag #55 thismorning. so...still close to 1 bag per day. 1500sqft of 1990's house, 6" walls, etc, so pretty tight/well insulated.

I think also, you may have hit on another source of "magic" in the magic pellet debate*, and that is that when running the stove at a steady rate, (as most stoves run), you're actually allowing your house to be cooler than you would consciously choose it to be. As the temp drops slowly, we don't notice it right away...especially if you're busy doing chores or what have you. "hours" might go by before you notice that "its chilly in here", and turn up the stove. During that time, you've "saved energy". Using a conventional central heating system, it notices slight temp drops, and reacts immediately.

My home is 3400 square feet. We have 2 furnaces. The stove is on 1st floor and the furnace does not run at all - 100% heated by pellet stove. The second floor furnace stays on which is run on propane. Some of the heat from the pellet stove makes its way up so it does supplement it some.

I think you are right on the magic pellet debate. I am going to experiment some on stove temp mode and see if it makes any difference on pellets. I have a good base to compare from using the room mode.

 

[slheinlein]

I've also noticed that it seems like my Harman p61a-2 uses a little less in stove temp mode then in room temp mode. As far as a theory why that may be the case I have only one possibility. The amount of pellets used to re-start and heat up the stove when cold and get it up to a good temp to produce heat may be more then running it continuously at that good temp. Any ideas/opinions?

Chris

No doubt that the starting up of the stove is very inefficient. Not only the amount of pellets to get it started but the time it takes to get to full operating temperature.

 

[PDawg]

If in room mode you keep the ignitor swith to manual the stove will not go out. It will drop down to a lower setting but it will not go out. This save on the ignitor as well.

 

[Sawduster]

"room temp" should be the most efficient way to run it...and that's what Harman says. I think the thing that makes it confusing is that there's a "feed adjuster" knob, and people equate that with "feed rate". its not the feed rate; its a feed limiter. it sets the maximum amount that can be fed; not the actual amount that will be fed.
If you're using fewer pellets on "stove temp" mode, you're getting less heat. You're not going to get the same amount of heat on less pellets. Its quite possible, (and probably very likely) that you're combination of settings in "stove temp" mode will send more heat up the chimney than into the room. In fact, they even describe how to do that very thing in the manual, so that you can enjoy a big fire without overheating the house. Big fire=big heat=big pellet consumption...if that heat isn't going into the room, its going up the chimney.
Even if an "ambiance fire" isn't your goal, the likelyhood that you'll be able to dial in the exact amount of heat output reuqired to maintain the temp in your house is slim. The weather is in a constant state of change; with the stove set at a fixed output (stove temp), the house is either going to steadily heat up, or steadily cool off. Room temp detects those changes and adjusts accordingly.

having said that, I may be experimenting w/ stove temp over the next few days, as we sink into these record cold temps. Problem in my house is that my basement has been getting very cold without my furnace running. I found the magic in these magic pellets. the "magic" is that 1/3 of my house is 20 degrees colder than it was before. I didn't realize just how much "loss" there was in my fha ducts. I thought the ground temp was keeping my basement at 55-60 degrees; NO, it isn't. its the leaky heat ducts! In the single-digit weather we've already had, I saw the basement temp dip to 41F. I think that's about as cold as I dare have it. With the upcoming sub-zero temps, I'm thinking that I'd better run the furnace some, to keep the water pipes from freezing. But how much? I don't know. And how to set the thermostats so that they're not arguing with each other? I'm thinking maybe "stove temp" mode, on a medium to medium-high setting...whatever will keep the furnace thermostat (opposite end of the house, so its always a little cooler than the stove area) in the middle 60's...set furnace to 68. I could probably accomplish the same thing in "room temp"...we'll just have to try it and see.

Your experience mirrors mine exactly. Here is what I do to make sure that my basement water pipes don't freeze. I keep the stove in room temperature mode and run the stove on manual rather than auto. I then set my programable thermostat at 85 degrees (it is in the same room as the harmon) to operate the oil furnace and come on twice per day for 30 minutes. By running in manual and keeping the T-stat set so high, it insures two things: One the furnace will come on and run for 30 minutes (this warms the basement to 50 degrees both times that it comes on; Two the pellet stove will not shut off and quickly maintains temp after the furnace shuts off. Works for me.

 

[cac4]

But...doesn't that make your house 85 degrees? isn't that a bit uncomfortable? or does it not actually get that hot, because you've limited the run time to 30 minutes?

 

[Sawduster]

No it does not make the whole house 85 degrees - it makes the room the stove is in 85 degrees. That room generally is at 78 - 80 to keep the rest of the house where I want it - 68 degrees upstairs and in the living room with the rest of the house around 72-75. Also, when I run the furnace up to 85, I am either not at home and at work, or sleeping and don't notice it upstairs.

 

[investor7952]

When in room temp and temp is in the teens how often does the room the stove is in get above 74-75? If dial is set just above 75 it is just like running in stove mode.With either setting stove or room the stove will hit a max temp output and room will hit a max temp.

 

[investor7952]

I prefer to use the stove temp mode on my XXV during the season
and room temp mode for shoulder seasons. Not sure about pellets,
but it saves on the ignitor.

What stove setting do you use?