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© Baxi Heating UK Ltd 2012
The Commissioning Function (CF) - Description
The CF is a one off forced function that is activated on the first power up of the boiler after it has left the factory. The boiler
cannot be operated unless the CF has been completed and the CF can be activated only once.
There are two stages to the CF - De-aeration of the system followed by a Gas Type Check.
De-aeration
This function operates the pump and the diverter valve moves from DHW to CH periodically to purge the system of air.
It ensures maximum evacuation of air and prevents damage to the heat exchanger coils at initial fire up. This takes
approximately 7 minutes to complete.
Gas Type Check
This automatically follows the de-aeration function and checks the flame signal to determine if the gas supply is NG or LPG.
It is done by first running at IGN rate, then at full power for the final stage. From these two speeds two values are measured
which are used to recognize the gas type being supplied.
IMPORTANT: When checking at full power, the combustion can go higher than normal for a few seconds, therfore it is not
advisable to insert the analyser probe into the flue sampling point to measure combustion, as saturation may occur and
affect subsequent readings. This stage takes approximately 4 minutes to complete.
The total time for the CF is between 10 and 12 minutes.
Activation of Commissioning Function (CF) from initial Power On
See page 32 for the flow diagram.
Once power is supplied to the boiler the display will show ‘000’ which indicates that the CF needs to be activated.
• Press and hold the ‘CH +ve’ and the ‘ip’ button, together for 6 seconds
• ‘312’ should be displayed and the boiler is now performing the de-aeration cycle
• After approx 7 minutes, the boiler will fire and the Gas Type check cycle will start
• The boiler will remain at a reduced rate for approx 3 minutes, in the final minute it will ramp to ‘100’, during this
time the boiler temp will be displayed. It is advised to open a DHW tap to dump the heat.
• Once the Gas Type check has finished, the display will show what type of gas the boiler is connected to:
• If it is natural gas, it will flash ‘NG’ for a few seconds and then be ready to operate
• If it is LPG, it will flash ‘LPG’ and this will need to be confirmed by pressing the ip button for 6 seconds. All
software values are automatically modified and the boiler is ready to use
If the boiler display shows ‘LPG’ when NG is being supplied, it can be cancelled by pressing the ‘ip’ and reset ‘R’ button
together for 4 seconds.
When there is an error present (e.g. Low Water Pressure – E118) it must be rectified before the CF can be started or
completed.
If there is an interruption to CF it will start again. If de-aeration has been completed, it will start from gas type check.
5.0 Commissioning Function
