When your auto light pellet stove does not fire up, there can be many reasons and from my years of experience here is what I have found.
1. The igniter is Bad
The first thing that may come to mind is the igniter, after all it lights the pellets. This is easy to test but some tests may not reveal it is the problem. It's helpful to know if the igniter tests bad, but occasionally the the igniter could have a good reading and still be bad.The igniter should read approx 50 ohms on an ohm meter. It should also read approximately 2 to 3 amps on a current meter.I came across one instance where an igniter I tested read 47 ohms, a proper reading, but in the stove, it was causing the 6 amp control panel fuse to blow. When I plugged it into an AC outlet, the igniter smoked and one of the wires burned off, so I knew that igniter was bad. I have also seen cases in some stoves, especially ones with 400 watt igniters, where the igniter is weak and cannot light the pellets.
I came across one instance where an igniter I tested read 47 ohms, a proper reading, but in the stove, it was causing the 6 amp control panel fuse to blow. When I plugged it into an AC outlet, the igniter smoked and one of the wires burned off, so I knew that igniter was bad. I have also seen cases in some stoves, especially ones with 400 watt igniters, where the igniter is weak and cannot light the pellets.
2. Poor/ Limited Airflow Throughout the Stove
However, the igniter is often not the reason why the stove doesn't light. Another common cause is not enough air flowing through the stove to light the pellets.
Check for Blockage
You may start by checking the air inlet pipe and the outside air kit for blockages, but these are not the most easily clogged areas. Focus in on any blockages inside the stove down wind from the burn pot. This includes behind the baffles, inside the air chambers leading to the exhaust blower,
and the exhaust venting. Start by brushing all areas to loosen up the blockage. Then use an air compressor to clear the fire box and a leaf blower to suck out the exhaust pipe. Reaching those areas is crucial.
Check for Birds Nest
A birds nest trapped in the venting may also obstruct the airflow needed for ignition. This is common on installations where the exhaust venting termination cap is approximately 20 feet off the ground at bird height.
A preventative bird cap termination can be installed to completely alleviate this issue.https://www.eastcoasthearth.com/products/duravent-pellet-vent-pro-round-horizontal-termination-cap-pellet-vent-with-bird-screen?_pos=1&_sid=1149333ae&_ss=r
Check Exhaust/Combustion Blower and Control Board
If the exhaust or combustion blower is not spinning that would also limit airflow and may need replacement. Check this blower by plugging it into the AC wall outlet directly.
If the combustion blower works but does not come on right as the stove is turned on, then the control panel is suspect and may need replacement.
3. Pellets are Damp or Moist
After checking the other possibilities and finding the stove still won't light, then the issue may be damp pellets. If the pellets are damp or moist, they will not ignite. Always keep pellets in a dry place in your home. For pellets to ignite, there must be 35 parts air to 1 part fuel and the fuel must be low in moisture. When the wood or corn pellets are stored for an extended period, they may absorb moisture during a humid summer if stored in a damp basement or outside. Pellets that have damage with extreme moisture crumble and turn to mush, but sometimes they are not noticeably damp, but it is enough to prevent pellets from lighting.To help determine whether moist pellets are the issue, light the pellets manually with starting gel or hand sanitizer and see if the stove runs properly
Note: Corn has a much higher flash temperature than pellets so a 500 or 600 watt igniter and air pump is used in well designed multi-fuel stoves for this purpose. Other multi-fuel stoves state to use wood pellets for ignition.
Summary
A bad igniter is commonly the reason why the stove doesn't light, but. not always. Running the proper tests will help determine the issue. The key issues that prevent a stove from lighting are moist pellets, a bad igniter, or poor airflow. Always store pellets in a dry place away from moisture or humidity. Check for blockages and birds nests that may prevent airflow. A combustion blower that won't spin or a faulty control board can also affect airflow. Having your stove professionally cleaned once or twice a year can help maintain proper airflow.
