What happens when Pellets have high moisture in a top feed pellet stove? - Auger Jam - see pics

[Don2222]

Hello

Moisture is the biggest enemy of the pellet stove.
These pellets were stored outside on the porch and absorded alot of moisture.
The stove jammed and it was baled and freed, but it just jammed again. The drop chute was completely clogged with pellets and the auger kept cranking and squeezing the pellets at the top of the auger chute until the motor jammed and wore the bearings in the motor until grease started leaking out of the new motor output shaft! The auger motor was a good quality motor that had a new bronze oil lite auger bearing installed earlier in the season. The motor was damaged and the bearing was scored. If the jam and cause is corrected right away then these parts may not have been damaged so heavily. Continued use did cause the damage!
The stove is an older St Croix York and it does have a small opening into the drop chute from the auger flight shaft. I heard this was corrected on newer stoves. However moisture in the fire box from a damp cleaning or damp inlet air or high moisture pellets can still cause this issue in many stoves.
Therefore a new auger motor, auger end plate gasket and bearing was installed.
Has anyone else seen this? See pics below
Click on pic to Enlarge

Pic 1 - Shows pellets fused together and clogging up drop chute completely
Pic 2 - Shows drop chute after clearing pellets by sticking a brush up drop chute in fir box
Pic 3 - shows damaged auger motor, auger bearing and end plate gasket
Pic 4 - shows close up for grease leaking from auger motor output shaft
Pic 5 - shows auger bearing with small gouge rings from auger motor jamming.

On Jan 2, 2017 I had seen a moisture jam. See similar details
I had a new ocurance of a moisture jam today and I was reluctant to call it that until I was 100% sure. In this case it was the top auger in a 25-pdvc that was stuck solid. The first time I went there I pulled the augers and cleaned them thoroughly. The stove was clean and then it happened a couple of days later. The same top auger jammed. This time all the pellets were scooped out of the hopper and by slowly turning the top auger by hand I freed it up so it would wiggle up and down again. The bag of pellets were stored in the garage for about a year and may have picked up some moisture in the hot humid summer. The previous owner brought up bags and stored them in a dry warm closet so there were no jams. I am beginning to believe that any stove can choke on damp pellets and some stoves have a higher tolerance. However if the pellets are damp enough even a Harman P61 may choke and I have seen them not light in a Harman even if they do feed ok.
The augers were clean, the motors almost new and the bearings greased and moving easily.
This is New England near the coast and we do get alot of Damp and Humid air compared to other regions!

Here was the first time I saw this about 6 years ago
The first time we cleaned our pellet stove when it got dirty my wife used a warm wet sponge on the iron fire and put it back in damp!
When my friend first cleaned his pellet stove, he used a warm damp cloth to clean the fire box!
My other friend put in a bag of pellets that she stored in a very damp basement!
Bingo Three ways to cause a pellet stove auger
"Moisture Jam"
They were mostly top feeding pellet stoves and the jam happened at the top of the auger chute just before sliding down.

 

[vinny11950]

Good thread, Don. I just had a jam a few weeks ago. First one. This season I stored my pellets outside under multiple tarps. Rain water didn't get in but condensation does build up, so I made sure to bring in 15 bags at a time to give them time to dry out whatever moisture they have. Usually the house is 30% humidity, so they dry up fast. Still, I think my issue was the long pellets in the Green Supremes I have been burning, combined with a new bag I had thrown in the hopper from outside.

But I don't see how a damp firebox would cause an auger jam. Whatever moisture is in there will burn up quick.

 

[Don2222]

Good thread, Don. I just had a jam a few weeks ago. First one. This season I stored my pellets outside under multiple tarps. Rain water didn't get in but condensation does build up, so I made sure to bring in 15 bags at a time to give them time to dry out whatever moisture they have. Usually the house is 30% humidity, so they dry up fast. Still, I think my issue was the long pellets in the Green Supremes I have been burning, combined with a new bag I had thrown in the hopper from outside.

But I don't see how a damp firebox would cause an auger jam. Whatever moisture is in there will burn up quick.

Thanks
The pellets expand and stick together if they absorb enough moisture. Most of the time, that does not happen fortunately. I have only seen it happen on 2 St Croix, 1 Englander and 1 Avalon Astoria in 6 years.
Let’s try putting a handful of pellets in a small cup and sprinkle water on them. However it may need some heat like a stove. It maybe the heat and water makes them expand and stick? Maybe a warm mug and sprinkle water on the pellets.
You are also correct in that Long pellets would certainly cause bridging and exacerbate the situation!!
Also the Lignin in the wood helps to keep the shape when they are made using pressure, heat and moisture. So moisture with heat can change the shape and the lingin will keep the new shape.

Did u ever see a clump of pellets like this?

 

[Overfireinthehole]

What’s really fun is when so much rain leaks on an insert that there is standing water in the hopper and you have to drill out the auger tube. I spent three hours last week cleaning up a cb 1200i that was like that. The same thing happened last year and I gave them the information on a company that could reseal their chimney crown. Instead, they had a roofing company “fix” it by putting a new flashing around the chimney. This time out I took a picture and showed them a 1/2 crack in the crown and reminded them that I had told them the crown needed resealed the year before. The combination of the torrential rains we’ve been having and the fact that someone had tried to fix the crown several times in the past by coating it in white rubber sealant instead of crown coat left them with a crown that was pretty much beyond repair so now they had to pay for another service call and for a company to come out and put a new crown on. Maybe next time they’ll listen to the opinion of the person they are paying to work on something for them. This

 

[vinny11950]

What’s really fun is when so much rain leaks on an insert that there is standing water in the hopper and you have to drill out the auger tube. I spent three hours last week cleaning up a cb 1200i that was like that. The same thing happened last year and I gave them the information on a company that could reseal their chimney crown. Instead, they had a roofing company “fix” it by putting a new flashing around the chimney. This time out I took a picture and showed them a 1/2 crack in the crown and reminded them that I had told them the crown needed resealed the year before. The combination of the torrential rains we’ve been having and the fact that someone had tried to fix the crown several times in the past by coating it in white rubber sealant instead of crown coat left them with a crown that was pretty much beyond repair so now they had to pay for another service call and for a company to come out and put a new crown on. Maybe next time they’ll listen to the opinion of the person they are paying to work on something for them. This View attachment 225225

That is nasty.

 

[vinny11950]

Thanks
The pellets expand and stick together if they absorb enough moisture. Most of the time, that does not happen fortunately. I have only seen it happen on 2 St Croix, 1 Englander and 1 Avalon Astoria in 6 years.
Let’s try putting a handful of pellets in a small cup and sprinkle water on them. However it may need some heat like a stove. It maybe the heat and water makes them expand and stick? Maybe a warm mug and sprinkle water on the pellets.
You are also correct in that Long pellets would certainly cause bridging and exacerbate the situation!!
Also the Lignin in the wood helps to keep the shape when they are made using pressure, heat and moisture. So moisture with heat can change the shape and the lingin will keep the new shape.

Did u ever see a clump of pellets like this?

That looks like candy.

 

[Don2222]

Here is more info on wood pellet moisture
From this link
(broken link removed)
WOOD PELLET MOISTURE TESTER

TEST for MOISTURE in all WOOD PELLETS You Purchase Look for 4-10% MOISTURE CONTENT or less WHEN YOU PURCHASE YOUR WOOD PELLETS

Use this Wood Pellet Moisture Tester to test all the Wood Pellets you find or use. Your wood pellets should have between 4 to 10% or less mositure. This is a wood tester that is programmed for either wood pellet testing, wood chip testing, or saw dust testing. (We have cheaper Grain Testers that will work with wood pellets). It will test for 4 to 23% Moisture in Wood Pellets, 15 to 65% Moisture in Wood Chips, and 6 to 30% for Saw Dust. You need to search for DRY Wood Pellets at approximately 4-10 % DRYNESS or dryer to burn well in a pellet stove. Most wood pellet bags come in air-tight plastic bags ranging 4-10% Moisture content. Some warehouses have high humidity and moisture, and if the bags are not air-tight sealed, moisture will creep in. Also your supplier may inadvertenly slip you some WET Wood Pellets and you should have a way of monitoring that. Note that your pellet Stove, Furnace or Boiler will run much better with 4-10% (or less) DRY Wood Pellets and the dryer the wood pellets, the higher your BTU/Hr output. High moisture wood pellets can become impacted and jam the auger and/or auger shaft. High moisture wood pellets will crush into a dough-like putty and crate JAMS galore! High moisture wood pellets can also cause clinkers in the fire pot, a characteristic normally indentified only with corn-burning. . Dry wood pellets can help eliminate costly agitator and auger repair, burn higher BTU output, and save you money in the long run. A MOISTURE TESTER is used by people that own and operate Pellet and Multifuel Stoves, Inserts, Furnaces, Boilers, or any device that burns pellets or corn.

FURTHER NOTE: we sell cheaper Grain Testers that will work with wood pellets. You can buy an upgraded Grain Tester model that will test from 5 to 40% Moisture in around 16 grains where grain settings 5, 7, 11 test similar to wood pellets... and it is far less costly than a wood-pellet tester -- see Option (2). NOTE: We also sell a CORN Moisture Tester at a lower price, and it will also test for wood pellet moisture. Check out our other Corn and Pellet Stove items listed in our Ebay Store. Visit My eBay Store: Corn Pellet Stove Furnace Boiler

MOISTURE TESTING RESULTS for Fuel King Premium Hardwood Pellets (Blue Plastic 40 lb Bag) tested out to be less than 5% Moisture. They burn good, are premium hardwood, and are the right length 1/2 to 3/4 inches. Fuel King, the blue-bag company, is a division of Midwest Sawdust, Inc, P.O. Box 883, Spencer, IA 51301 and you can contact them.

OPTIONS:

(1) CORN MOISTURE TESTER $175, (2) WIDER TESTING RANGE: For a wider testing range of 5 to 40% for 16 grains where grain settings 5, 7, and 11 can be used to test similar to wood pellets and it is priced at $299, (some people use this instead to test wood pellets!), or (3) MULTIGRAIN MOISTURE TESTER that will test 39 to 40 grains for $349 in a mosture range of 5-40%. A picture of it is the same as it looks physically identical to the Corn Stove Moisture Tester. It will include testing of grains such as: corn, big red hard wheat, oats, soy beans, barley, sun flower seeds, olives pits, cherry pits, etc...