You may not know that the finger looking part over the fire-pot is a thermocouple. The ceramic cover keeps the direct heat off of the sensor while underneath is a braided wire. It's purpose is to determine the amount of heat within the stove and its stages of startup and shutdown. Note this does not control the convection blower (Fan that comes on to blow heat across the room). Symptoms of a bad thermocouple include not starting, shutting down after start up and over feeding. The first step to troubleshooting the problem is to check the end of the braided wire by removing the cover. The thermocouple could have cracked where the braid is soldered at the end. Next we must locate the control box on you model stove.
Above is a newer style control box. Older versions are not a clear plastic. They are always located near the reset button. Some Classic Bay 1200 FS stoves have their control box inside the hopper. Other stoves they are behind a side panel. When plugging in your stove, the clear plastic boxes will flash blue. Count the blue flashes to see which setting the box is on. The box will then quickly flash orange to test the thermocouple. If it remains orange, there is no continuity and the thermocouple is bad. Old and new style boxes have both a Red and Green LED light. In the new style boxes, the LED illuminate the whole box while the old style have small LEDs on the top of the box. During startup the stove will drop pellets and ignite. Not until the thermocouple senses heat will the Green LED turn on and the stove will begin to feed more pellets. If the sensor does not read temperatures higher than those producing the Green light, over feeding will occur. Once a normal operating temperature is reached, the Red LED will light. On shut down, the LEDs will turn off along with the exhaust blower.
Remember to inspect the thermocouple cover while cleaning. If light shines though the cover it need to be replaced.
There are many reasons for a stove to not drop pellets. Use these steps to help diagnose the issue.
The hopper should have enough pellets in it to create vacuum. It does not need to be full but should be at least a large bowls worth of pellets.
The hopper and door sensors should read in a closed position. Newer model stoves will not drop pellets if the hopper lid or the glass door is open.
All stoves except for Mt Vernon AE, E2 and Trekker have a call light. A red light should come on when the thermostat calls for heat. This light is usually near the power cord coming off the stove. Be sure look behind the panels on the side. AE models should show "Startup" on the thermostat. If this is not the case, the issue could be the thermostat or thermostat wire.
Use the supplied clean out tool or a bent coat hanger to check the drop tube for an auger jam.
Ensure the stove is clean. You can tell if it is clean by reading the Dirty Door Glass. A dirty stove can prevent the stove from dropping pellets.
Remove the pellets from the hopper looking for foreign objects. Vacuum out remaining pellets that cannot be scooped out. When starting the stove again you will need to hit the reset button or hit "Retry" (for a Mt Vernon AE). Do this until pellets drop. If pellets fall but do not light. You will need to try one more time.
If the problem is not yet solved, a new feed motor could be needed or possibly a new control board/box.
Over time we add bag after bag and ton of ton of pellets. If you are one of the many people who poor the bag directly into the hopper, you may start to experience problems from too much dust. This is the fine saw dust we find at the bottom of each bag. Symptoms of too much dust include a "Min Firepot Temp" error, a low flame or stove not starting (not igniting pellets). Owner's who have a reset button may find that they need to push the reset button on each start up.
After a few years, dust may build at the bottom of the hopper. The auger which is meant to feed pellets to the drop tube will being to turn dust rather than pellets. Your stove does not know how much fuel is dropped, only that the motor has turned. Dust might stay at the bottom of the hopper, work its way up to feed motor and could drop down to the firepot. If dust remains at the hopper then the symptoms you experience are from a lack of fuel. If the dust reaches the feed motor, it can build up. Dust built up around the feed motor often leads to Auger Jams.
Upon noticing dust dropping into the firepot you may want to take action. Start with the hopper low on pellets. Either let the stove run empty or scoop them out. This way we do not waste perfectly good pellets. Vacuum out any remaining dust or pellets from the hopper and around the auger. When starting the stove again you will need to hit the reset button or hit "Retry" (for a Mt Vernon AE). Do this until pellets drop. If pellets fall but do not light. You will need to try one more time.
The glass window of your pellet stove can provide more than just a beautiful fire. Knowing the type of build up and the rate at which the glass gets dirty are indicators of how the stove is running. The color of the build up indicates the use of the stove. More importantly the color of the build up can be used as an efficiency indicator.
Above we have two images from the same stove, a one month old Mt. Vernon AE insert. After one mildly warm week from previously cleaning the glass, we find a white powdery ash. It is possible to find this much build up after only a few days during the colder parts of winter. As the stove runs more, the glass will get dirtier. Notice the white color. Although a picture will not depict the texture well, it is also a factor in the stoves efficiency. A proper Air-to-Fuel ratio produces the white ashy build up.
Two separate stoves are pictured above. Although we do not know how long it has been since the glass was last cleaned we can tell that the stove is not running efficiently. The dark and sooty build up is the result of a lack of air flow.
Poor air flow is most commonly caused by a dirty stove. The first step to troubleshooting this issue to conduct a full cleaning. If you do not have a professional do the cleaning, refer to the owner's manual. Although you may think you have cleaned everything, there might be an area you overlooked or did not know about.
In rarer cases, a vacuum gauge may be required to find where an issue is within the stove. If an airway is completely blocked, your stove will do everything except drop pellets. On a MT Vernon AE you will receive either an "Auger Jam" or "Vacuum Switch" Error