St. Croix Technical, Overfeed – Airflow

This is a common situation we see with St. Croix stoves, especially older models. In most cases it appears the stove is overfeeding or feeding fuel continuously, when in fact the issue is with proper air-flow.

Dennis Writes In:

I have an older Prescott series St Croix stove that is not working properly.  It continually feeds pellets and overfills the burn pot. The auger never quits. Any suggestions?

Mr. Pellethead Replies:

Dennis, We are happy to assist. When you say that the unit feeds continuously, does the auger motor not stop turning? Inspect the feed motor while in operation (After the start-up cycle). If it is truly turning constantly and does not stop then that would indicate a control board issue. If the motor is starting and stopping and you see differences in the start and stop timing as you go to different heat settings than it more than likely is not the control board. In most cases where you are having this issue will be one, or a combination of the following.

  1. Ash blockage. Inspect & clean the vent pipe, combustion housing, firebox ash traps and heat exchange area.
  2. The ash drop/shaker is not closing completely underneath the burn pot area. That shaker rod needs to be pushed all the way in during operation. Over time ash build-up down there can prevent it from closing fully. Remove your burn pot and versa grate plate under the burn pot to thoroughly inspect and clean this area.
  3. Burn Pot & Versa Grate Shaker Plate. Inspect both the burn pot and shaker plate beneath. Make sure there’s no areas burned through and that everything is seating correctly; firepot has no air-gaps, seating securely against the firebox floor.
  4. Shaker plate to burn pot bottom clearance – should be no greater than 1/16 inch (out of adjustment or worn versa grate shaft bushings).  Too great of clearance reduces air velocity through the pot air holes.
  5. Gasket leakage. Check both your door and ash pan gaskets. Use a dollar bill, put half in and half out, close the door and see how much resistance there is. Check every few inches around the firebox door and the ash pan door. Should be significant resistance. –Typically gaskets go 6-8 years on average before needing to be replaced.
  6. Air Intake. Check for ash accumulation in the intake tube below the burn pot – commonly overlooked and not always visible. Make sure the rear damper is set correctly. For 99% of installations, stick a pencil in the intake, close the butterfly damper down on the pencil and pull it out. This is as much as the damper should be open.
  7. Your Combustion/Exhaust fan. The motor itself could be weak/no longer providing correct voltage or it could just be ash blockage in the housing there. You can use a volt meter to test the combustion fan. After start-up cycle it should change voltages between each heat setting.

Happy to assist, let us know what you find. We offer all parts & accessories for St. Croix and guarantee the lowest prices.

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HAVE FURTHER QUESTIONS OR NEED TECHNICAL ASSISTANCE? CONTACT MR. PELLETHEAD TODAY!

 

  • Dianna says:

    My St croci pellet stove is creating a lot of black soot in side walls top and glass I’ve changed ash pan door gasket and still does it what can I do nest

    • Earth Sense Energy System says:

      Dianna,

      Thanks for contacting us, happy to assist. In most cases this would be a combustion air issue.

      1. Thoroughly clean the stove, ash traps and vent pipe
      2. Inspect all gaskets – Door and Glass as well. Make sure there are no air gaps and tight seals all the way around.
      3. Inspect your burn grate. Make sure it is seating properly and make sure the shaker plate (bottom of the burnpot) is working correctly and moving back and forth – Versa Grate. Make sure the air holes are open in the shaker plate and that ash is cleaned out of that cavity. Make sure the ash dump rod in that area is closing fully while in operation.
      4. Inspect the combustion fan/exhaust blower and make sure it appears to be operating at proper voltage. Should be near line voltage during start-up.
      5. Inspect the air inlet on the back of your stove. Use a good light and make sure nothing foreign is blocking it.

      In 95% of the cases like this it is simply ash that is accumulated in areas that is restricting proper air flow from coming to the burn grate area. Remove the interior brick and use a mallet to tap on the rear firewall. Move that heat exchange scraper rod back and forth and even get a small bottle brush up there to release trapped ash. Open the trap doors to the left and right of the burn grate area and clean out all the ash that comes out. Our number one cleaning tool for removing ash that is difficult to get to is the leafblower vac. Take a look at the link here. https://pellethead.com/product/toro-vacuum-leafblower-pellet-corn-stove-exhaust-vent-cleaning-system-3-4-venting/

      Hope that is helpful, any other questions please let us know.

      Thanks,
      ESESstoves

  • Dennis Kruse says:

    We have a St Croix Lancaster. In the last month our pellets have been building up in the burn pot. Have to rake the top every 4-6 hours. Otherwise, it would overflow. We just replaced our combustion fan because it was shutting down shortly after it started up. But this build up was happening before that. I thoroughly clean my stove weekly and recently took everything apart and blew and shop vacuumed it all out, also. We have been using the same brand hard wood pellets for 6 years. We don’t use corn. Cannot see that any doors are leaking or not shutting right. Any suggestions? Thank you!

    • Earth Sense Energy System says:

      Thanks for contacting us Dennis. Definitely sounds like there is a fuel to air ratio issue at hand. You should not have to clean your burnpot anywhere near that often burning premium hardwood pellets. Are you using a retro-fit pellet pot or are you using the cornpot that’s in the unit? There’s been quite a few changes to the burnpots and retro-fit pellet pots over the years for St Croix. St Croix has now gone to one multi-fuel burnpot for the Lancaster and other corn models. Better air-flow and combustion efficiency. Definitely inspect your burnpot and the holes. You should have a nice crisp torchy flame.

      Additionally St Croix corn models were notorious for ash accumulation in that back wall area. Very difficult to access or get to and definitely contributes to the air flow through the burnpot. If you can, first take a mallet and bang against that back firewall (remove brick panels if you have in place). This should allow more ash to fall down into the traps below. Best way is to pull the unit outside and use an air compressor or you can use the sucking part of a leafblower on the exhaust of the stove to pull out any trapped ash you can’t see or reach.

      Happy to help anyway we can.

      Thanks,
      ESESstoves

  • Dennis Kruse says:

    We have an older St Croix Lancaster. In the last month our pellets have been building up in the burn pot. Have to rake the top every 4-6 hours. Otherwise, it would overflow. We just replaced our combustion fan because it was shutting down shortly after it started up. But this build up was happening before that. I thoroughly clean my stove weekly and recently took everything apart and blew and shop vacuumed it all out, also. We have been using the same brand hard wood pellets for 6 years. We don’t use corn. Cannot see that any doors are leaking or not shutting right. Any suggestions? Thank you!

    • Earth Sense Energy System says:

      Dennis,

      Also, check your door gaskets for tightness. ON A COLD STOVE, Take a dollar bill, stick it half in and half out of the door, close the door, pull it out. Should be heavy resistance. Check multiple spots around the door – both front door and ash pan door. If we have even a slight leak in either one of these areas it will cause the issue you are having.

      Thanks,
      ESESstoves

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