Infra red flicker detector causing false flame failure

[nospamthankyou]

We recently installed a Weishaupt Natural Gas burner on a Petersen bread oven. The Weishaupt use an infra red flicker detector. If the load is between 90% to 100% load the flame signal is steady between 92% and 96%. Once the load modulates below the 90% range the flame signal bounces momentarily into the high 80% range and we occasionally get a flame failure. We have tried repositioning the scanner, adjusting combustion pressures, however it seems the detector a
Siemens Infrarot-Flammenfühler QRI 2 B2.B180B reacts too quickly to the modulating flame and is the cause of the flame failures.

Has anyone run into this problem before with an infra red flicker detector?

Cheers,
Bob Craig, Carmichael Engineering

 

[Jimway55]

Infrared is usually used for Oil flames - usually gas flames use UV scanners - look at your flame relay make sure you use the right scanner, amplifier for the unit. the scanner needs to see the flame at all times throughout the firing rate. Pull the scanner and have someone put a lighter in front of it - look intothe scanner port and raise and lower the firing rate - then you wll see what the scanner sees.


Good luck

Jimmy