DIY Lambda

[chuck172]

I like simple things. I don't even like cars with computers and sensors.

 

[TCaldwell]

Lambda/o2 control in concept is easily understood, take a batch of wood and manipulate the premetered p/s airflows to maintain a preset o2/lambda value based on optimum combustion for a given boiler design. Basically you are retarding the initial combustion rate by reducing primary air and increasing the secondary. If you looked in the firebox of a lambda controlled boiler 15 minutes after starting the fire, you will see virtually no fire. There is just enough to offgas and reburn in the secondary. Without lambda control you will see more flame in the primary chamber and probably a lower o2% after the same 15 minutes. The premise is a controlled fire is more efficient than one that isn't, less puffing and lower overall flue temps and more consistent burns with varied wood to name a few. A non lambda boiler with the correct air settings for a given moisture content wood with a knowledgeable operator can do just as well, just not as consistent. For alot of folks a burn is good if your only criteria is hot water and no smoke, possibly you might think differently if you felt the need to monitor the combustion process. The predominant sensor used is a bosch 4 wire lsm11 wideband. The sensor gives the controller current feedback to create a output to the dampers. Largely the controller is based upon a propriertary pid algorithim with discrete inputs like temp to trigger alarms that might reduce fan speed when approaching high water temp, or set specific damper positions at start and end of burn. I would be glad to help anybody with diy lambda, it takes alot of time patience and money, the real cost savings would be to buy a proven lambda equipted boiler from the start!!