Loss of Boiler Burner Flame in Cold Weather

[KujoChE]

We have a small boiler for our process facility with a load that varies throughout the day. The demand on the burner will cycle from high to low to match this load change.

The problem we have is when the weather changes outside, our boiler performance changes as well. When the boiler drops to a low output, sometimes the flame will snuff itself out. We have had the boiler tuned so that it operates well. Then when the weather changes (as it did this weekend when it dropped from 30F to -7F) the boiler returns to its old ways.

We assume that the denser air caused by the weather change is causing the problem, as a proportionately higher mass of air is getting pushed into the boiler vs. a constant amount of natural gas. We currently have 100% outside air for our intake, with no manual damper.

What is the best way to deal with this problem? Pull in building air? Install a manual damper on the suction of the combusion fan?

Any advice would be appreciated.

 

[hacksaw]

your minimum fire setting on the fuel valve is below what the burner requires. in other words you may have exceeded the turndown capability of the burner. adding a damper may help improve efficiency, but not likely solve your flame out problem entirely.

you need to check the setup of you loss of flame detection, burner turn-down, fuel train turn-down.