17 Fully Metered Combustion Control
Mk8 MM Manual Page | 297
# Default Range Description
FM: Fuel Temperature Sensor Enable
The fuel temperature sensor is wired to terminal T3. This cannot be used
with the mass flow meters for fully metered, or at the same time as
steam/hot water flow metering, see expansion options 141 and 120.
FM: Air Temperature Sensor Enable
The air temperature sensor is wired to terminal T2. This cannot be used
with the mass flow meters for fully metered, or at the
same time as
steam/hot water flow metering, see expansion options 141 and 120.
FM: Fuel Pressure Sensor Enable
The fuel pressure sensor is wired to terminals 31, 32, 33 and 34. This
cannot be used with the mass flow meters for fully metered. The pressure
sensor can still be used for flame safeguard checking such as high/low
FM: Air Pressure Sensor Enable
The air pressure sensor is wired to terminals 31, 32, 33 and 34. This
cannot be used with the mass flow meters for fully metered. The pressure
sensor can still be used for flame safeguard checking such as high/low
FM: Maximum Fuel Channel Compensation (Firing Rate)
This is the maximum percentage of the fuel servomotor angle which the
MM will move towards the closed and open position to maintain the
commissioned firing rate (heat input). The fuel servomotor angle will never
exceed commissioned high fire position or go below the commissioned
low fire position.
FM: Maximum Air Channel Compensation (Fuel/Air Ratio)
This is the maximum percentage of the air servomotor angle which the
MM will move towards the closed and open position to maintain the
commissioned fuel-air ratio. The air servomotor’s movement ranges from
the commissioned closed position to the commissioned open to close
positions.
FM: Action on Air Adjustment Failure
If after the air servomotor has made adjustments to compensate for the
changes in the flow rate, and the fuel-air ratio cannot still be met, an alarm
or warning will occur. For setting 0, the MM generates an alarm and will
lockout the burner upon on an air adjustment failure. For setting 1, the MM
generates a warning. For setting 2, the MM generates a warning and
disables the air adjustment and the air servomotor returns to the original
Generate warning, disable air adjustment