How to Avoid Outdoor Wood Boiler Damage?

Has Your Outdoor Boiler Overheated?

Has Your Outdoor Boiler Overheated?
How To Avoid Permanent Damage

The ideal temperature for an outdoor wood stove is between 160° and 180° F, which is controlled by both the fire and the exhaust system. When the furnace hits 180° F, the blower fan that feeds the fire shuts off and the damper closes, reducing the flames and momentarily stopping the wood from burning any further.

If your outdoor wood-burning boiler has overheated, you may have a problem that will permanently damage your outdoor boiler. This must be addressed immediately!  

We recommend that you evaluate the possible causes (listed below) and the corresponding solutions (also listed below) so that you can take the necessary steps to PROTECT your outdoor furnace from permanent damage.

Is Your Wood Boiler Overheating? Here's Why and What You Can Do About It



  • Water temp is over 190, in some cases over 210.
  • Water/steam boiled out vent tube
  • High limit switch tripped
  • No power to light and blower fan
  • Water level dropped (boiled out)

Possible Causes and Solutions:

  • Door left open
    • An unlimited supply of air to the firebox is bad - it will lead to uncontrolled burning of wood fuel in the firebox that will damage the firebox steel. Please never leave the furnace firebox door open for extended periods of time. The door should only be open for brief moments to add wood fuel to the firebox and remove ash.
  • Circulating Pump failure
    • Remove the silver button on the face of the boiler pump while the pump is in operation to verify the impeller shaft is spinning. If not, replace the pump. See the article on how to diagnose pump failure by clicking on this link HERE. For replacement pump special, click HERE or call (231) 861-8200.
  • High limit switch cannot be reset
    • Must wait until the water temp drops below approx. 150 degrees to reset. Also, High Limit Switches have only a limited number of trips in their lifespan. This depends upon how hot and how many times the furnace has high temps. A very high temp situation may kill the switch in one trip. Or it may last 12+ trips. Always have a spare on hand. Always have a spare on hand. Click HERE for more info on High Limit Switches.
  • Loose Door
    • Adjust Door Hinge for Tightness