Please don't confuse this with a scientific experiment. I cleaned my stove up yesterday and while I had the surround off I installed my e-bay type K thermocouple probes. I installed one in the flue at the back of the stove just above the cleanout tee, one in the OAK pipe near the damper, one above the convection blower inlet under the hopper and one in the convection outlet grill of the stove.
My stove set-up:
St. Croix York insert installed in a Preway ZC fireplace with air cooled firebox and 8" ID/11" OD insulated flue. My 4" Excel ICC pellet vent runs 20' straight up inside the Preway flue, no elbows. It exits through the old rain cap and extends about 2 feet above it. I insulated 10' of the 4" pellet vent with 1" thick ceramic wool refractory insulation. My OAK pipe is 2" automotive flex running up to a 2" automotive exhaust pipe passing through the firebox block-off plate and welded in. It extends past the block-off plate about a foot. I pull my combustion air down the 8" flue through the annular area between the 4" pellet vent and the old fireplace flue.
I had purchased a ton of Vermonts that were bought early in the season from a craigslist ad but, for some reason, they didn't seem to be that hot. I bought ten bags the previous day from a dealer and they seemed super hot. Both were low ash. A few days ago I ran some Northerns(Cubex) and they just about ran me out of the house. Believe it or not, they produces less ash than the Vermonts, too.
Since I was home today I decided to run a few different pellets through the stove to compare the readings on the thermocouples. The way I ran the test was to run tests about an hour and a half long per pellet. The stove was just about out when I got up this morning so I added a few scoops of the Vermonts that I bought by the ton. Once everything was stable and the readings weren't changing much I took readings on each of the TC's, let it run some more, take some more readings, repeat, repeat. When I was ready to change pellets, I would scoop out the remaining pellets until the hopper was almost empty, add the next batch, wait a half hour and start taking readings. Let it burn some more, repeat, repeat. Scoop out remaining pellets, Add next batch, etc, etc. All of these pellets were burned on setting #4 of 5. Also, please note.....I did not adjust the damper to optimize combustion. I left it where it was to reduce one more variable. I can't see the damper plate but it's not open very much. The flames is lively, but too much so.
It's been about 8-1/2 hrs and I'm done for the day. Pretty warm outside so I had the windows open for the last four or five hours and it was still 77 degrees in here. The temperature under the name of the pellet is what the outside temperature was on the thermometer when I ran that batch.
The order of burn was:
Vermonts (the ton I bought)
Vermonts (from the ten bag trial I bought from stove shop)
Cubex (not Northerns, I'm out of those)
Black Hills (Okanagan, bought yesterday to give them another shot)
NEWP (came with stove, last years pellet, probably Jaffrey)
McFeeters (bought same day I bought the Vermonts at the stove shop)
Results (deg F):
Conv Fan In Stove Grill Out OAK Air Temp Flue Temp
Vermont (by the ton)
35 deg F
109 192 111 335
Vermonts (by the bag)
45 deg F
127 246 129 387
Cubex
47 deg F
129 220 121 365
Black Hills
47 deg F
119 221 124 362
NEWP (last years)
48 deg F
119 221 127 366
McFeeters
48 deg F
119 221 128 377
Take it for what it's worth. I did not optimize the damper setting for each pellet. There were obvious differences in the flame size and appearance between the two batches of Vermonts. I plan on taking some samples to work and doing a moisture analysis to see if the ton batch might have higher moisture. The part that sucks is that I have a over half a ton left. Too bad they aren't crankin like the individual bags I bought. They're still gonna be a great shoulder pellet because they're so clean and I only paid $230 for the ton. I wouldn't be very happy if I paid $280-300. If there's a take-away from this for me it's that you should always test burn from the same lot of pellets, if possible, before buying a ton. I was surprised how much heat the NEWP's put out. They are definitly dirtier and that would affect the ability of the stove to transfer the heat. The other surprise was that the Black Hill were about the same as Cubex and McFeeters. I wish I had some more Northerns. They were cranking and lower ash than the Vermonts. They were also better than the Cubex bagged Cubex pellets. I burned a few bags of the Cubex the other day and found clinkers in the pot.....similar to the complaints other people have experiences this year for the Cubex. The Norhterns I got must have been and exceptional batch.
Time for a beer......wait....that's what I've been doing between dumping pellets and taking readings....
My stove set-up:
St. Croix York insert installed in a Preway ZC fireplace with air cooled firebox and 8" ID/11" OD insulated flue. My 4" Excel ICC pellet vent runs 20' straight up inside the Preway flue, no elbows. It exits through the old rain cap and extends about 2 feet above it. I insulated 10' of the 4" pellet vent with 1" thick ceramic wool refractory insulation. My OAK pipe is 2" automotive flex running up to a 2" automotive exhaust pipe passing through the firebox block-off plate and welded in. It extends past the block-off plate about a foot. I pull my combustion air down the 8" flue through the annular area between the 4" pellet vent and the old fireplace flue.
I had purchased a ton of Vermonts that were bought early in the season from a craigslist ad but, for some reason, they didn't seem to be that hot. I bought ten bags the previous day from a dealer and they seemed super hot. Both were low ash. A few days ago I ran some Northerns(Cubex) and they just about ran me out of the house. Believe it or not, they produces less ash than the Vermonts, too.
Since I was home today I decided to run a few different pellets through the stove to compare the readings on the thermocouples. The way I ran the test was to run tests about an hour and a half long per pellet. The stove was just about out when I got up this morning so I added a few scoops of the Vermonts that I bought by the ton. Once everything was stable and the readings weren't changing much I took readings on each of the TC's, let it run some more, take some more readings, repeat, repeat. When I was ready to change pellets, I would scoop out the remaining pellets until the hopper was almost empty, add the next batch, wait a half hour and start taking readings. Let it burn some more, repeat, repeat. Scoop out remaining pellets, Add next batch, etc, etc. All of these pellets were burned on setting #4 of 5. Also, please note.....I did not adjust the damper to optimize combustion. I left it where it was to reduce one more variable. I can't see the damper plate but it's not open very much. The flames is lively, but too much so.
It's been about 8-1/2 hrs and I'm done for the day. Pretty warm outside so I had the windows open for the last four or five hours and it was still 77 degrees in here. The temperature under the name of the pellet is what the outside temperature was on the thermometer when I ran that batch.
The order of burn was:
Vermonts (the ton I bought)
Vermonts (from the ten bag trial I bought from stove shop)
Cubex (not Northerns, I'm out of those)
Black Hills (Okanagan, bought yesterday to give them another shot)
NEWP (came with stove, last years pellet, probably Jaffrey)
McFeeters (bought same day I bought the Vermonts at the stove shop)
Results (deg F):
Conv Fan In Stove Grill Out OAK Air Temp Flue Temp
Vermont (by the ton)
35 deg F
109 192 111 335
Vermonts (by the bag)
45 deg F
127 246 129 387
Cubex
47 deg F
129 220 121 365
Black Hills
47 deg F
119 221 124 362
NEWP (last years)
48 deg F
119 221 127 366
McFeeters
48 deg F
119 221 128 377
Take it for what it's worth. I did not optimize the damper setting for each pellet. There were obvious differences in the flame size and appearance between the two batches of Vermonts. I plan on taking some samples to work and doing a moisture analysis to see if the ton batch might have higher moisture. The part that sucks is that I have a over half a ton left. Too bad they aren't crankin like the individual bags I bought. They're still gonna be a great shoulder pellet because they're so clean and I only paid $230 for the ton. I wouldn't be very happy if I paid $280-300. If there's a take-away from this for me it's that you should always test burn from the same lot of pellets, if possible, before buying a ton. I was surprised how much heat the NEWP's put out. They are definitly dirtier and that would affect the ability of the stove to transfer the heat. The other surprise was that the Black Hill were about the same as Cubex and McFeeters. I wish I had some more Northerns. They were cranking and lower ash than the Vermonts. They were also better than the Cubex bagged Cubex pellets. I burned a few bags of the Cubex the other day and found clinkers in the pot.....similar to the complaints other people have experiences this year for the Cubex. The Norhterns I got must have been and exceptional batch.
Time for a beer......wait....that's what I've been doing between dumping pellets and taking readings....
