wood pellets not generating enough heat

[gutterboy2ca]

Hey Brokk, hope ya get her tuned, gotta be a setting for sure,curious, did you grab a meat thermometer? like to see what kinda reading your getting at the output tubes.Heres a pic of my 8 year old Enviro EF3, this is on high after 15 min burn time,on a decent grade pellet(EnergeX)not my Highest temp recorded but its right up there, Crappy ranging at 165 F, Best rating at 400 F (EnergeX), curious what temp your running, that should tell if its working right, or just too much Heat Loss, Good Luck.
P.S These Thermometers are less then $15 Walmart, nice to have for Verification of Temp.

 

[Brokk]

It's hard to tell, but is your thermometer actually touching the stove where the vents are blowing air out?

When I put my meat thermometer in front of the vents (about 2" out), I was getting a reading of 120 F on the high feed setting (4.5 PPH) and medium fan.

There is no setting I can find. The two thoughts now, is either the exhaust fan is pulling too fast (or too much draw), or I can't turn the inbound draft down far enough. Either way I'm assuming too much airflow.

Brokk...

 

[gutterboy2ca]

Brokk, the 10 inch Probe is sitting all the way in one of the Heat tubes,and it appears to make a difference in the reading if the 24 inch steel cable is coiled or uncouled,i suppose it cools down the further its stretched out.This is how i've set it for all tests to keep it consistant.

 

[Lance1]

Good to see you adjusted your flame, below the tubes is fine. Be more concerned with flame tuning than height as in achieving a more yellow flame, with minimal torching.

Using a meat thermometer isn't a good way to get a good reading, I'm picturing you holding the tip in front of the tube for a couple of minutes. The probe shank is cooling down the reading as well, picture how a meat thermometer is used. If you could mount the shank parallel to the tube, one can get a better reading. The thermometer that gutterboy has would be better, even though the probe in the tube is not the way to measure air temp. For $15 I would run out and buy one, if I didn't already have a good digital (Fluke brand). With a digital one can see temp changes with different damper settings (the way I tune the flame). Also one can verify the calibration of a digital with an ice cube. BTW; one side of the stove will be hotter than the other.

 

[Brokk]

I taped mine to a long thin peice of wood, then leaned it against the stove. The shank of it is parallel to the air vents blowing out, although it's angled vertically. So the whole shank is in the middle of the air stream. I left it there for 1/2 hour or more, checking it regularly. It hovered around 120. I tried shifting the stick back and forth to check for differences in the air flow (never touching the thermometer itself).

I'm still waiting to hear back from the manufacturer. The only "authorized" installer is half the state away from me. I haven't tried contacting him yet.

Brokk...

 

[Lance1]

Are you taking your temp reading from the hot side of the stove?

What temp do you get with the fan speed on low with the feed rate at #3?

 

[gutterboy2ca]

sure sounds stinkin low to me Brokk,i'd be over 200 F at any given time as soon as the probe gets within 6 inches of the heat tubes,no wonder your freezin man, hope ya get it straightened out before winter officialy gets here,a can of sterno would prob yeild the same temp of 120 Degree's
(Yikes)
I'm at about 145 F on the lowest setting possible without going out.Hope that gives you an idea how to Guage it better,.

 

[Harvick29]

My stove on the highest setting will come very close to bringing water to a full boil. If you can touch the top of your stove directly above the flame then your stove is not performing. My flame is downright violent on the highest setting. The first time I saw it on that setting it actually scared me. The heat that comes out of the front of my stove is very hot as well on the highest setting. You cant keep your hand directly in front of the tubes for long.

 

[Brokk]

I'll run it on #3 with fan on low and get back to you with the temp.

Yeah, I can put my hand directly on the vents where the air comes out, even when it's on high. It's hot to the touch, but not so much that you burn yourself. It's the "feels good" hot. Something you want when your hands are half frozen from being outside. I actually put my hands right on the stove to defrost them, that's how little heat there is.

Brokk...

 

[Brokk]

I was curious about the pellet feed rate, so I measured out three pounds of pellets and burned just them. From startup to shut down was 90 minutes. According to the manual it should have burned 4 PPH at setting #3. In reality it only burned about 2 PPH. It could be my scale is off. It's broken but I thought it was reliable enough to measure out a pound at a time. It also could be the feeding is slower at the beginning until the fire gets going, which could account for some variance. I'll have to try calibrating against another scale, but we could be looking at a lower feed rate than advertised. Of course in the long term (full bag) it could average out to what they claim.

As for temperature, it was still hovering around 120 F, but I shifted it around in the vents. Maybe I found a hot spot, or maybe the flames were larger at that moment (which they looked to be), but it up just above 140 F, at least for a little while. Again, the fan was at the lowest setting and the feed rate was #3 (which they don't recommend).

Brokk...

 

[Lance1]

You should have gotten some increase of heat with a lower fan setting, sounds like your fan speed control is not working and your always on high.

Are you noticing a flow change adjusting the fan speeds?

 

[Brokk]

Very much so. I don't think the fan is always on high. I have 5 settings and I can tell the difference between them (even hear the difference). You can even turn the fan off, which should result in a safety switch kicking the fan on within about 12 minutes. However, when testing this out with the support people, my switch didn't kick on until around 28 minutes and I tested it twice with the same results. Again, this is showing me that the unit is not generating as much heat as it should. Since it's not generating as much heat, it took more than twice the normal time to reach the heat level needed to kick on the safety switch. When I asked support about it, they just made noises about some variance can be expected and not to worry about it since it did eventually come on.

Brokk...

 

[Lance1]

Very much so. I don't think the fan is always on high. I have 5 settings and I can tell the difference between them (even hear the difference). You can even turn the fan off, which should result in a safety switch kicking the fan on within about 12 minutes. However, when testing this out with the support people, my switch didn't kick on until around 28 minutes and I tested it twice with the same results. Again, this is showing me that the unit is not generating as much heat as it should. Since it's not generating as much heat, it took more than twice the normal time to reach the heat level needed to kick on the safety switch. When I asked support about it, they just made noises about some variance can be expected and not to worry about it since it did eventually come on.

Brokk...

Your stove has 3 fan settings not 5 and 4 feed settings. See 'specs'. http://www.homeclick.com/web/catalog/product_detail.aspx?pid=176643

An air output of 120° no matter what you do and what the inside/outside temperatures are, is impossible.
Are your clean out covers are missing?

I would have to say at this point your trolling.

 

[Brokk]

There are three "lights" for the setting. Hi, medium and low. You can set it between them as well. So you can set it as:
Low
Low-medium
Medium
Medium-high
High

You can also turn it off (all the lights are off).

Yes, 4 feed rates. No setting in-between them.

The link you posted shows what I just described, but does not claim to have only three fan settings. It just says you can change the fan settings faster or slower. I'm guessing you are basing your statement on the picture of the control panel (unless I missed some text elsewhere).

I'm not sure what I would be trolling for. I'm not saying anything negative about anyone or anything or trying to get a rise out of folks. I'm just a frustrated new-stove owner desperately trying to figure out what to do. Right now my stove is sitting in pieces as I have taken off the back panel to see if I can turn the exhaust fan down. There are only some sensors and nothing that can be changed. It's all pretty much hardwired to specific settings.

I'm not sure what covers you are talking about. Could you provide some details?

So far I've only tested the temperature twice with a thermometer based on the suggestions here. I'm not sure what the outside temperature was each time, but the inside temperatures where probably similar to each other. I do know that I couldn't get past 120 on fan setting "medium", but it got up over 140 on fan setting "low". So it is showing some variance, but not anywhere near the numbers suggested here. I do appreciate all the help people are trying to provide here. I'm sorry you sound so frustrated with my situation, but I'm grateful to all of you for giving me *something* to try.

Brokk...

 

[webbie]

The idea of comparing one stove to another.....as far as output temperature of the hot air tubes...is complete folly. I have explained why a bunch of times. Any time you spend doing that is wasted.

Weighing the pellets in another thing....although such calculations could be made by the bag...or by a larger quantity....try 10 pounds, etc.

What you have to do is to try and burn as many pellets as possible per hour, and then calculate what the output should be - and then determine if you think your stove is doing that. Figure conservatively....like:

If you can burn 4 lbs per hour on high - and figure that stove may not have the highest efficiency in the pack, then figure on 5,000 BTU output per pound, or 20,000 BTU per hour. That is the size of a larger kerosene heater.....would that do the job?

Please do not use the information in this thread as reference. I have a pellet stove in an INSULATED 1.5 car garage and I can heat it after MANY hours with the unit on full blast. It is very possible for your room to have the same heat loss as my garage...again, because this has an insulated ceiling, walls, good windows and an insulated door.

If you really want to suss this out further, I suggest the following:
1. Wait for a string of days when the approx high and low temps are similar.
2. Use the stove for a number of hours at full blast - for instance, for 8 hours - and record the amount of pellets used per hour, and the approx. temp in the room at a distance from the stove.
3. Calculate the estimate of output using the lbs of pellets burned per hour times 5,000 (a conservative rough calc)....for instance if you are burning 4 lbs per hour, use the figure of 20,000 BTU.

OK, now you have a baseline. Go to the local rental store and rent a good Kerosene heater for a day. Most of the larger ones are rated somewhere around 20,000 BTU per hour.

Run the rented heater in the same room and see if the results are similar.

If so, you know what the situation is. If the kero heater does a much better job, then it's time to ask more questions.

 

[Wet1]

I think I'd run the stove wide open and see how long it takes to go through one full bag. It doesn't sound like the stove is getting very warm, so I don't think there's any harm in doing this, but it will give you a better idea how many lbs/hr you're burning. Trying to do this with smaller quantities will likely be inaccurate. I'm still not buying into the "it's the room" theory, something is not right with your stove. Your room should be hot with that thing running at its highest setting, and you should not be able to touch it for more than a fraction of a second...

 

[Lance1]

Take some pictures while you have it all apart.

There should be a cover on each side of the burn pot on the back wall.

Yes I'm referencing the picture, there is a fan trim and the three fan settings.

You called the 140 as a hot spot and said 120 as the temp range for low fan and #3 feed before.

Webmaster, the problem here is the stove, not the house. Read post #42. The tube output needs to be hotter than 120° and is important. Every tube output that I have read is higher than 120°. On my lowest feed rate I get about 125-130°. Your explanations on the subject that I have read, I don't agree with.

 

[Brokk]

Sorry, I put it back together and ran more tests before you asked to see pics of it apart. I found a better (older) manual on-line and it gave me some better information as well as a picture of the area around the combustion fan.

The trim levels seem to have been messing me up. I set them following the manual when I first ran the stove (as they recommended), but I think I got them reversed. When reading them again I was able to set the #4 feed rate to a much higher setting. Now it's sending down pellets like crazy and the flames are much higher than previously. Before doing this I played with the combustion fan speed rate. It really seemed to be doing something, then after finishing the startup cycle, it seemed to ignore the trim setting for the fan and just kicked into high. I'm not sure why or what's at play. Lastly, the manual mentioned a "high" cut off switch. If the back of the firebox goes to 250 F. So it seems unlikely I'd be getting 300 or more out of this stove at any time. If so, it would go into a shut down.

So here are some numbers of the temp in my "hot spot" I found before changing the feed rate trim level:
Low fan - 160
Low-med fan - 125
Med fan - 115

After kicking up the feed rate:
Low fan - 215
Low - med fan - 158
Med fan - 142
Med - high fan - 137
High - 138

As the fan speed got higher, it seemed to make less of a difference. Although there was some variance in the fire burning (I was running out of pellets) so I had to re-do a few numbers.

I tried with 3 lbs, but I changed the feed rate in the middle. That took an hour, but is useless. I then put in another three pounds and I feel confident it will burn through that 30-45 minutes. I'll let you know.

Here is a new picture with the air input turned down and the feed rate turned all the way up.

Brokk...

 

[webbie]

Webmaster, the problem here is the stove, not the house. Read post #42. The tube output needs to be hotter than 120° and is important. Every tube output that I have read is higher than 120°. On my lowest feed rate I get about 125-130°. Your explanations on the subject that I have read, I don't agree with.

Reality does not care whether you and I agree!

The test which I gave is a reasonable, but rough, way of seeing what the output of the stove is. This idea of using:
1. Different thermometer types
2. Different Stove models
3. Different Input air temps
4. Different locations
5. Different heat exchanger types, blower outputs, etc.

as an indicator of the stove total BTU output is foolish. In fact, IMHO, using any temp output from hot air will not tell you much....or at least nothing close enough to be of value.

The heat from the pellets can only go a few places. It is either coming into the house, going up the flue, or not being burned (high smoke and creosote output would be the result of that). We can guess that if the vent system is not getting plugged or a lot of smoke is not exiting, then the heat is either coming into the room or going up the flue.

It is important to get a baseline...using some kind of other appliance...as to what another heat source does in the same room. That, along with lbs per hour burned over time (and the results of both) will say a lot.

My guess is that a LOT of pellet stoves "in the field" are not running at anywhere near the claimed efficiencies (for many reasons). But, even taking figures with some fudge......

7500 BTU (after moisture) per lb of pellets.
66% efficient= 5000 BTU into the house per lb.

If getting a kerosene or LP heater is too much trouble, another experiment would be to use two plug-in electric heaters. These would have to be on two separate electrical circuits. The total output of those would be about 11,000 BTU or a little over 2 Lbs of pellets per hour.

I'm not saying it isn't fun to "take your temperature"....just that it does not help in this case because we still don't know the "x" factor of what amount of heat that room actually needs.

 

[webbie]

Flame sure looks right. A Flame like that has to be burning the pellets, that's for sure.

 

[Brokk]

Quick update. As anticipated, the new feed rate for #4 used up the three pounds of pellets in about 45 minutes, which means I should now be at 4 PPH or more. I'm leaving the fan on high since it showed little difference in temperature of the air between medium, medium-high and high. It was still showing around 140 when I moved it out of the way to add more pellets. Tomorrow I'll try to track how long it takes to use one bag. I'm also trying to find a cheap digital thermometer, as our local Walmart did not have the one somone posted earlier.

Brokk...

 

[Brokk]

I realize the variety of advice and the wild variations/gyrations back and forth feels like a "shotgun" effect rather than a methodical science. However I've tried to listen to everyone to see if there was something I was missing that I hadn't tried or thought of. Trimming of my feed rate was a key so far. Also, there is a draft/exhaust trim setting that I hadn't realized when reading through the manual before (it said fan, and I was assuming it was talking about the blower for the room). Measuring the heat output temp is good because it allowed me to see when I was being sucessful in tuning the flame and feed rate.

I will try to measure the feed rate, change in room temp, etc tomorrow. I also have a number of space heaters around and can likely put them on multpile circuits in the room. I'll have to check their BTU ratings. The only problem is that I won't be able to get them all close to where the stove is, so that will be some variance in room temp I'll have trouble accounting for.

Again, thanks for all the advice. I'll try to post an update tomorrow.

Brokk...

 

[Xena]

Before you got the pellet stove how were you heating this room?
Just curious.

 

[Lance1]

That is a nice looking flame. OK, now the data looks more reasonable. From the cut away that I saw of your stove, I don't think you have to be concern with a pre-mature cutout.

I was at Wal-Mart today and didn't see that thermometer either.

Measuring the heat output temp is good because it allowed me to see when I was being sucessful in tuning the flame and feed rate.

This is the best way to tune.

The actual wattage output on small heaters is usually lower than claimed. Doesn't make for a good BTU comparison, unless you have an amprobe.

*************

Stove air temp matters and is useful data, to those of us that know how to use it.

 

[Brokk]

Zeta, I bought the house in April and the previous owner has just refinished it and said the existing heating he had in place was not sufficient. It was always cold when we came to see the house during the purchasing process. We use it as a family room, and I was thinking I could let the rest of the house get pretty cold as long as our primary area stayed warm. So I was looking to this stove for a major cut in our heating bills.

Right now there are two steam radiators. Unfortunately the larger of the two has a big leak in the middle so it's shut off. The second is kind of small and this room is a bit far from the boiler so it doesn't get the best heat.

Brokk...