Questions about an Evolution

[bob~c]

Wow, I'm happy to have found this forum with active users and folks that own Evolutions!

I've been doing a bunch of work lately just trying to find some basic answers regarding our stove but without much luck. I'm hoping you can share your insights.

We put a Evolution in 4 years ago and we just can't seem to get any heat out of it. This has been the case since Day One. I've been wondering if it's the stove or the pellets. I haven't been able to find anyone else who has owned this stove to find out if the problem is our stove, this model stove or the pellets. Here's what I do know:

Our house is very small by US standards: 700 sq. ft. The room that the stove sits in is 270 sq. ft.(12x23) but is open to the kitchen which is 170 sq. ft. So, the area we're talking is pretty small. I've insulated the house myself and have maxed out the insulation in the floor and walls and have more than doubled the recommended amount in the ceiling. The windows are all double glazed. I still need to do some work on air diffusion (We bought a fixer-upper and stripped it down to the studs, redoing the interior and exterior). But, things are pretty well insulated. The thing is, we have to run the Evolution at max and even after a couple hours, it only takes the chill out of the far side of the living room. It comes as a surprise because the stove is rated at 45,000 BTU's and the installers said that it was going to blow us out of the place with heat. We're located in Christchurch, New Zealand which has winters with temps in the mid 30's and 40's (F) at night and high 40's-low 50's during the day. So, it's not really cold outside but the stove will only heat the house up to low 60's. My flame output looks the same as videos I've found online of properly operating Evolutions. The photo is taken from the far side of the room I'm expecting it to heat. This is a photo from when it was installed. Everything has been insulated and sheet rocked since then and the windows have all been replaced with more efficient ones. The gray in the walls is wool insulation, a really cool alternative to fiberglass (a story for another post...)

It's been this way all along so, it's not a maintenance or cleaning issue. I've read from some of you that your Evolutions are putting out some serious heat. Well, I can sit on mine when it's on high and can have bare skin 1" away from the vents without being forced to take them away. I know that it heats via convection versus radiation but the heat coming out of it still seems tepid. We keep hearing stories of how a lot of people in our area jumped in and bought pellet stoves at the same time when there were big incentives to buy them but have since torn them out of their house and replaced them with electric heat. This is all hearsay, tho.

I just fired it up last week for our first cool day of the fall (seasons are reversed in the S. hemisphere) and the temp outside was low 50's and again,after a couple hours the temp was in the low 60's at the far end of the living room.The air was still with not a breath of air moving outside...

I'm trying to narrow things down and hopefully can, with your help:

For folks that have or sell the Evolution, is it doing the job? This will tell me if it's our stove or the model. I'm assuming the Evolution is a good stove since it's been sold for awhile...


The flip side of the coin are the pellets. In our part of NZ, there is only one supplier of pellets. They are the biggest supplier in NZ and they also supply Europe so, it's not a small operation. They indicated on their site that they create the pellets following European guidelines so it would seem that they are reputable. They do have a monopoly which means that they can do whatever they want but I would think the NZ stove manufacturers and resellers would be on their case if the pellets were poor quality and made pellet stove heating look bad (The benefits of a small country). I've posted on an active NZ forum to see how are people are doing with their pellet stoves and these pellets but not hearing much back.

I just figured all of this was the norm until I came back to southeastern NH this week and a friend of mine just put in a Harman and it just puts out massive heat! I'd like to bring some pellets from here back to NZ with me but NZ has very strict rules on the importation of wood products that it would be too much work for testing purposes only...

So, that's what I know, any thoughts???

Thanks in advance,
-bob

 

[Delta-T]

is this the Enviro EF5-Evolution?? Is your distribution blower working? How would you describe the heat coming out of the exhaust pipe..warmish, or very hot? That unit really should blast you out of the space you are describing. If you run it on high for prolonged periods does it go into shut down for over-temp? Even with very poor pellets you should be getting more from the unit, so I wouldn't initially say its the pellets, but something isn't right.

 

[bob~c]

Thanks for the quick reply.

This is the Enviro Evolution. Sorry, I should have mentioned that in the OP. I'm unsure of the Enviro Evolution model #'s (EF-5 vs. others) . I'll go online and look to see if I can find the differences. We did buy it in 2007. Early on, the circuit board was replaced because the distribution fan wasn't coming on when it was on high...

The distribution blower is working from what I can tell: It cranks up to blow more air out when it is on high vs. lower settings. I've not seen another one in operation so, I don't have anything to compare it to...

The way our vent is set up, it's double insulated pipe. Where it exits the side of the house there is an elbow. At the bottom of the elbow is a cleanout for the inner/vent pipe. It's about 4' out from the backside of the stove. I can put my hand on that and it's only warm (I assumed it was because the stove was super efficient). I can keep my hand on it indefinitely. I can also put my hand on the exhaust pipe right behind the stove and it's only warm to the touch. I can touch any part of the exterior of the stove indefinitely except the chrome louvers in front of the distribution vents and the door, of course.

It's never gone into shut down mode and we typically run it on high for hours at a time...

Other FWIW info, it goes thru a bag (33lbs.) in around 4-5 hours when on high.

 

[Delta-T]

by my math thats like 6+ lbs./ hour and that should = ridiculous heat. Maybe there is something "up" with the pellets. WHen on high, does the flame consume the entire combustion chamber or do you find that there is little difference between low and high settings?

As for the pellets...if you rub them in your palms do they fall apart? Is the surface of the pellets shiny and smooth or sorta hazy and fractured?

 

[bob~c]

Yeah, that's what I expected also.

When the fire is on high, it's not much higher than on low. In the photo I attached above, those flames are atypical and only occur when there's a buildup of pellets that finally catch fire. On high, the flames extend 5-6" (guessing) up, just a little bit higher than the top of the auger port. But, what makes me think that it is running correctly is that the flames look just like the flames in this video when the stove is shown as running correctly:

http://www.youtube.com/watch?v=SYNoWkW8cuE

The pellets have always been shiny and smooth (except the ends) and hard. Can't break averaged sized ones except with my teeth (PS. They aren't great tasting....)

 

[Delta-T]

I've not gotten to play with the Evolution, but several other enviro units and on high the flames are all over the place. DOes your glass get dirty in a rather short timeframe...say 24 hrs?

This is a stumper Bob, because given the flow of pellets and the relatively low exhaust temp there is an awful lot of un-accounted for heat going somewhere. DO you get large collections of "clinker" in the burnpot (too little combustion air), or do you notice the pellets jumping out of the burnpot when running, possibly from excessive combustion air being driven through the burnpot?

 

[bob~c]

Hmm, good questions and thanks for your time

Yes, the glass does get dirty. I clean it each day. Given the climate in Christchurch and our schedules, the stove is off all day long and just runs in the evening for 5-6 hours. So, the glass gets rather dirty for 5-6 hours of run time. Now, one may think that the house gets too cold and I'm asking too much of the stove to warm the whole house back up in only a few hours. But, it is a temperate environment and the house will be mid-high 50's when we arrive and the far end of the living room only gets up to low 60's after running the 5-6 hours.

As for your thoughts about flow of pellets and low exhaust temp, that's why I'm thinking it's the pellet quality.. As for clinker amounts, only a half dozen after the 5-6 hours. Whole pellets won't jump out. Do, get a lot of embers with a lot of buildup of ash on the firebox liner. The flames don't look like those in the video when there's too much air....

I may call around here in Southeast NH to see if any shops still have one hooked up that I could take a look at...

 

[Delta-T]

cleaning the glass after 6 hours should not be necessary...sounds like too little combustion air on that front...give the damper a little pull to increase the airflow. If you have access to one, a magnahelic pressure gauge would be very helpful in setting that up correctly, but just "eyeballing" it works most of the time...ideally you want enough air to cause a few of the pellets (whole, not the little pieces) to vibrate a little, without jumping out of the burnpot....not to be confused with pellets moving around when new pellets fall in and bang into everyone.

 

[TLHinCanada]

If you can put your hand on the vent 4' away from stove and burn 6 lb. an hour you are having a problem. Without a lot of combustion air you wouldn't be burning 6 lb. an hour. This heat must be going somewhere, if not into the room via the heat exchanger then out the vent. Since you are getting neither I going to guess you may have something open (do you have oak). If you have a lot of draft with a short run of vent it may allow for your condition. This shouldn't happen with the combustion fan pressurizing the vent (what is the size of the vent).

 

[bob~c]

Thanks folks, for the ideas.

From the NZ forum I posted on, I'm still not getting any responses from people about their experiences with pellet quality in my area so, that variable still exists.

It sounds from what you're saying and a local (NH) dealer I talked to this AM who I feel was shooting straight, the model (the Evolution) isn't the problem.

So, from what Pyro (and the NH dealer) says, I should adjust the combustion air to get the pellets vibrating and a more efficient flame. And, if I get it right, I should less ash build-up on the glass and inside the combustion chamber, more heat coming out into the room via the distribution vents and the exhaust vent should be hotter, right? The dealer described the adjustment by watching the flame height gradually decrease until there is a sudden and noticeable increase in flame height. That's the sweet spot.

Burning, I'll open the stove up and take a look and see if there's something amiss. What's worth noting is that the stove has always acted this way right from when they installed it. They have opened it up later that year when they replaced the circuit board and I have in subsequent years when cleaning it so, you'd think I would have spotted something. The stove is stock in that I've not altered the air intake, the exhaust or the location of the exhaust blower.

I mentioned in the OP that the exhaust is double-walled. I'm pretty sure it is but if it is, the actual vent pipe diameter is pretty small. The cleanout cover is only a couple of inches in diameter but then, the vent coming out of the stove is 4" roughly from what I recall when I pulled the stove away from the wall when doing renovations (I know that a standard size for Dura-Vent piping is 5" ID). This photo shows the exhaust (and the house prior to renovations). The exposed portion of each clapboard is about 4".... I'll email Sweetie and see if she can take measurements of the pipe and deduce if it's double-walled and to try adjusting the combustion air....