How efficient is the Harmon Room Temp Sensor Mode?

[jzinckgra]

As stated in another thread, I am thinking of buying an Enviro Empress, but looking at the ability of the Harmons to automatically control feed rate/combustion based on room temp sensor probe. Unlike the Empress , whereby I was planning on attached a std. T-Stat to basically program the stove to come on/off (2x/day) I am wondering if my room temp, based on the outside temp will fluctuate greatly. Anotherwords, I set the feedrate to say 50% and it's ~20 degrees out all day and the room temp is 68F. Now the next day, outdoor temp is 10F, but indoor temp is 64F. So unless I I turn up the feedrate and guess as to what the pellet feed should be for any given day, my room temp might either be too cold or too warm.

I really like the Empress, but am wondering how much more efficient are the Harmons in automatically adjusting feedrate and therefore maintaining solid room temp regardless of outdoor temp? Does it really control roomtemp as advertised?

 

[cac4]

yeah, it does control the room temp, as advertised.

The feed rate on the Harmans is not "fixed", like others. Its always automatic. Its a maximum setting...i.e. "no more than x". That just keeps the feed rate from over-filling the burn pot...but the computer decides on exactly how many seconds in any given minute to turn the auger and feed pellets.

I set mine between 70-73 (there's no tick-mark for 71 and 72), and my digital thermometer across the room stays steady all day, only varying by a couple of tenths of a degree. The stove adjusts itself to the actual heat load on the house, and as such, I can use the flame height as an outdoor thermometer, of sorts. if the flame is high, "it must be getting cold and/or windy out". It only kicks way down low if someone turns on the stove or oven.

Lots of people declare that their stove is more "efficient", or "uses less pellets" in stove-temp mode. I think its only a perception. If they're using less pellets, they're getting less heat. If running in auto burns more pellets, its because the "system" is calling for more heat...and it its calling for more heat, when the room "feels" fine...then there is something wrong with the system...and its probably that they have the temperature sensor in a sub-optimal location.

 

[goatman-68]

I also use room temp on my XXV and it is accurate, although you have to find the right spot for the sensor. I find that with the sensor about two feet off the floor works for mine, but every house is different. Also I think it is important to have an OAK when using room temp........

 

[BJN644]

I use room temp and mine is also very accurate. I also agree if it's burning more in room temp mode it's because it's getting colder outside. Set it and forget it !

 

[jzinckgra]

Overall though, do you think the Empres with a fixed feed would use a lot more pellets compared to the harmons? I am wafflinf so much on which one to go for. Wife likes the look of the empress better (I do too somewhat). It seems to get good reviews, but now I am rethinking the Harmon with teh auto feed. Seems like it would save quite a few pellets.

 

[cac4]

I also use room temp on my XXV and it is accurate, although you have to find the right spot for the sensor. I find that with the sensor about two feet off the floor works for mine, but every house is different. Also I think it is important to have an OAK when using room temp........

I am using oak...why do you think it makes a difference?

the floor is definitely a bad place for the probe. Mine is tucked up behind a couch, about 10' away from the stove, along an adjacent wall. (stove is in the corner). Occasionally, it gets knocked down and falls on the floor, and when that happens, the stove starts cranking away like crazy...because the floor is cold.

 

[BJN644]

I would think on days that you have a lot of temperature fluctuation you would certainly burn fewer with the Harman. It is very, very good at maintaining a set temperature. I supposed if you sat home in front of the stove all day tweaking the settings you might be able to burn a few less pellets. Look at the other important things too, like dealer support, ease of cleaning the stove, have them show you how the stove cleans. If you are looking at the P series Harman's you won't find an easier stove to clean.

 

[goatman-68]

I also use room temp on my XXV and it is accurate, although you have to find the right spot for the sensor. I find that with the sensor about two feet off the floor works for mine, but every house is different. Also I think it is important to have an OAK when using room temp........

I am using oak...why do you think it makes a difference?

the floor is definitely a bad place for the probe. Mine is tucked up behind a couch, about 10' away from the stove, along an adjacent wall. (stove is in the corner). Occasionally, it gets knocked down and falls on the floor, and when that happens, the stove starts cranking away like crazy...because the floor is cold.

I think it helps due to the fact that there is no cold draft being drawn toward the stove, at least where I have my sensor located, which is only about two feet from the stove by the side of stove. Now if you have a steel model Harman vs cast iron, that would also make a difference on where to locate the probe. The steel stoves definitely radiate more heat around the stove so I would think you have to mount the probe much farther away from the stove so it regulates room temp more accurately. My XXV barely gets warm to the touch.........

 

[Souzafone]

I can't compare to an Empress stove but I can say I just crank the feedrate to 4 (out of 5), turn the blower on high, and set the thermostat at the desired temp, the stove adjusts the feed and blower accordingly. If I leave this house in the morning and the outside temp goes to 70 it shuts off, if it's 40 out the stove adjusts to maintain the thermostat setting, and if it's zero out that baby's cooking when I get home. It's really set it and forget it, like cruise control on the highway. Cruise control will almost always be more fuel efficient than driving without it, same principle.

 

[jzinckgra]

I just pulled this statement from the Empress manual about using a T-stat:

"When the thermostat calls for heat (contacts are closed) the stove settings are adjustable as per Manual Mode. When the thermostat contacts open, the HEAT LEVEL and Fans will drop down to the LOW setting until the thermostat contacts close again. *The LOW heat setting can be adjusted for different fuel qualities (see “OPERATING INSTRUCTIONS - CONTROL BOARD FUNCTIONS”). The stove will come back to the previous HEAT LEVEL setting when the thermostat contacts close again."

Doesn't the part about the heat level dropping imply the auger speed will also be reduced automatically until the room temp drops below the set temp? On the control panel there is a push button for HEAT LEVEL controlling what I assume to be the feed rate. If this is true, then in effect the stove operates similarly to the Harman. no?

 

[HEMI]

My XXV barely gets warm to the touch.........[/quote]my P43 get so hot that you can't touch it, this normal?

 

[BJN644]

My XXV barely gets warm to the touch.........

my P43 get so hot that you can't touch it, this normal?[/quote]

Yes it's normal. That was the deciding factor for me when I was thinking XXV or 43, when the salesman said you could boil water on the 43 and sit on top of the XXV.

 

[poconoman]

My XXV barely gets warm to the touch.........

my P43 get so hot that you can't touch it, this normal?[/quote]

Actually, there a vid of a PC45 'cooking'.

http://www.youtube.com/watch?v=u0m98tyOXoc
YouTube - Cooking with a cornburning stove

 

[amick780]

For the past 2 Years I have used the room temp setting on my XXV it always worked great and kept the house very warm. This year I started using the stove temp setting and found that I like it much better. My pellet usage dropped by half a bag a day, and I am able to control the temp in the house much better. I will not go back to using the room temp setting at anytime soon. It takes a little more changing of settings with the weather but again the house is just as warm with less pellet usage. Stove temp setting are feed of 4, and between 3 and 4 depending on the outside temp. Distrubtion fan I change depending on the weather as well.

 

[jzinckgra]

Sorry, but can anyone answer my question:

I just pulled this statement from the Empress manual about using a T-stat:

“When the thermostat calls for heat (contacts are closed) the stove settings are adjustable as per Manual Mode. When the thermostat contacts open, the HEAT LEVEL and Fans will drop down to the LOW setting until the thermostat contacts close again. *The LOW heat setting can be adjusted for different fuel qualities (see “OPERATING INSTRUCTIONS - CONTROL BOARD FUNCTIONS”). The stove will come back to the previous HEAT LEVEL setting when the thermostat contacts close again.”

Doesn’t the part about the heat level dropping imply the auger speed will also be reduced automatically until the room temp drops below the set temp? On the control panel there is a push button for HEAT LEVEL controlling what I assume to be the feed rate. If this is true, then in effect the stove operates similarly to the Harman. no?