3 Hand, Low Flame Hold and Auto
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MM Application Possibilities
3
HAND, LOW FLAME HOLD AND AUTO
3.1
Hand Operation
Hand operation enables the firing rate positions to be set to a specific position, in the range of low to
high fire, when the burner is firing. Fuel flow metering must be entered. Sequencing will not operate
correctly if the MM is in hand mode. Hand mode can only be activated when the burner is firing.
Mk8 MM
The Mk8 MM will go into hand mode when a voltage is detected on Terminal 94 or when the hand
mode button is pressed in the Status screen. Arrows will then appear on the screen which can be
used to increase and decrease the firing rate. Once the hand mode is deactivated, the MM will go to
auto mode and fire according to normal modulation. On the Mini Mk8 MM the transfer between hand
and auto mode is always bumpless.
If Hand and Low Flame Hold are selected at the same time via Terminals 94 and 95, then Low Flame
Hold takes priority.
Mini Mk8 MM
The Mini Mk8 MM will go into hand mode when the hand mode button is pressed in the Status screen.
Arrows will then appear on the screen which can be used to increase and decrease the firing rate.
Once the hand mode is deactivated, the MM will go to auto mode and fire according to normal
modulation. On the Mini Mk8 MM the transfer between hand and auto mode is always bumpless.
If the low flame hold input is activated on terminal 81 (see option/parameter 155), then this will take
priority over the hand button pressed in the Status screen.
3.2
Low Flame Hold
Low flame hold is the state when the MM’s firing rate goes to its low fire position, while the burner is
firing. Fuel flow metering must be entered. Sequencing will not operate correctly if the MM is in low
flame hold.
Mk8 MM
To put the Mk8 MM into low flame hold, put an input on terminal 95 go to the Status screen and press
the low flame hold button. The low fire position will be maintained until the input on terminal 95 is
removed or the button is pressed again. When switching from low flame hold to auto the MM will
return to normal modulation.
Mini Mk8 MM
To put the Mini Mk8 MM into low flame hold, go to the Status screen and press the low flame hold
button, or put an input on terminal 81 (option/parameter 155 must be set to 2). Once out of low flame
hold, the MM will return to normal modulation.
3.3
Auto Operation
The MM ‘Auto’ operation enables the burner modulation to maintain the setpoint; the firing rate will
modulate according to how far away the actual temperature or pressure is away from the required
setpoint. The firing rate is determined from the fuel flow metering entered via option 57; the more
accurate the fuel flow metering, the more accurate the firing rate.
Summary of Contents for Mk8 MM
Page 1: ...Combustion Management Systems MM APPLICATION POSSIBILITIES Technical Manual 18 12 2019...
Page 8: ...1 Sensors Page 2 MM Application Possibilities Gas Pressure Sensor...
Page 27: ...1 Sensors Page 21 MM Application Possibilities Air Pressure Sensor...
Page 32: ...1 Sensors Page 26 MM Application Possibilities Steam Pressure Sensor...
Page 36: ...1 Sensors Page 30 MM Application Possibilities Outside Temperature Sensor...
Page 37: ...1 Sensors Page 31 MM Application Possibilities Outside Temperature Module...
Page 38: ...1 Sensors Page 32 MM Application Possibilities Outside Temperature Module Wiring...
Page 42: ...2 Flame Safeguard Page 36 MM Application Possibilities 2 1 1 Interrupted Pilot Gas...
Page 43: ...2 Flame Safeguard Page 37 MM Application Possibilities 2 1 2 Interrupted Pilot Oil...
Page 46: ...2 Flame Safeguard Page 40 MM Application Possibilities IR End View Scanner...
Page 72: ...2 Flame Safeguard Page 66 MM Application Possibilities 2 9 3 Wiring...
Page 81: ...5 Intelligent Boiler Sequencing Page 75 MM Application Possibilities 5 1 3 Hot Water Example...
Page 83: ...5 Intelligent Boiler Sequencing Page 77 MM Application Possibilities 5 1 5 IBS Communications...
