Adjusting blower fan flap on any multi fuel boiler is the single most important task that has to be performed before firing up.
In most modern solid fuel burners introduction of fan gives an electronic control over fire and thus heat generation by burning coal, wood, slack, pellets or other similar fuels.
To make a successful burn, we need fuel, oxygen and a source of ignition, to make a successful burn whilst maintaining high efficiency we need to control either fuel, oxygen or both.
The air blowing fan has a very important role, it delivers air to induce burn and once the operating conditions are met the fan FLAP has the opposite effect, it has a purpose of choking the fire.
The semi automatic boilers can only be controlled by adjusting air flow quantity whilst the fully automated multi fuel and pellet boilers have control of both fuel and oxygen.
The diagram showing correct angle of counter weights mounted on a shaft controlling choking flap. This is a very simple and reliable system and variants shown are depending on the type of boiler you have purchased.
The counter weights are in a form of two nuts, depending on strength flue drought force of closure can be adjusted. Always start with the two nuts screwed out and locked tight, use of thread lock or additional products to stop these coming loose, is advised.
What we are looking for is a positive and solid “clunk” noise when the lever is lifted by hand and allowed to drop naturally.
Please check your boiler blower fan flap position before firing up as incorrect position can lead to boiler overheating or not getting up to correct temperature.
Adjusting fan to give correct air fuel ratio.
Red Flame black smoke not enough air.
White Fire means too much air blowing.
Good Strong yellow flame means good fuel air ratio.
Checking should be performed once the boiler reached its operating temperature as performance is affected greatly when boiler is cold. Check the position and correct operation regularly from there on.