AUTOFLAME Mk8 MM - 4.4 Dual Fuel Output Mode (DFOM)

4 Fuel Output Modes and Changeover Options
Mk8 MM Manual Page | 109
4.4 Dual Fuel Output Mode (DFOM)
Dual Fuel Output Mode (DFOM) can be selected by setting Option / Parameter 131 to 1. The main MM
screen displays the fuel trains for fuel 1 and 2 based on the optioned fuel types (Option 150/151), with fuel 1
displayed on the right side of the screen and fuel 2 on the left, it is also possible to display 2 gas fuels or 2 oil
fuels at the same time. In this mode the boiler configuration setting for fuel trains displayed (Option 15) has
no effect.
4.4.1 Fuel Configuration and Wiring in DFOM
In Dual Fuel Output Mode both fuels are wired directly to the MM using 2 independent sets of outputs without
the use of relays;
• Fuel 1 is controlled by Channel 1
• Fuel 2 is controlled by Channel 3
• Air is controlled by Channel 2 (and a VSD channel if using a VSD)
“Proof of Closure” (CPI) inputs are required for both fuels and must remain active for the non-firing fuel while
firing on the other fuel.
Terminal
Description
Function
T60
Main Fuel Valve 1
Mains voltage output for valve 1 - fuel 1
T61
Main Fuel Valve 2
Mains voltage output for valve 2 - fuel 1
T55
Main Fuel Valves CPI/POC
Proving Circuit – Fuel 1 Proof of Closure
T62
Main Fuel Vent Valve
Mains voltage output – vent valve
T31,32,33 & 34
Main Fuel Gas Pressure Sensor
In case of gaseous fuel
T35, 48 & 49
Main Fuel Oil Pressure Sensor
In case of liquid fuel
T64
2
nd
fuel Valve 1
Mains voltage output for valve 1- fuel 2
T83
2
nd
Fuel Valve 2
Mains voltage output for valve 2 - fuel 2
T82
2
nd
Fuel Valves CPI/POC
Proving Circuit – Fuel 2 Proof of Closure
T84
2
nd
Fuel Vent Valve
Mains voltage output – vent valve
DT+, DT-, DP-
& DP+
2
nd
Fuel Gas Pressure Sensor
In case of gaseous fuel
4.4.2 Pressure Sensors in DFOM
If 2 gas fuels are going to be configured in DFOM, 2 separate gas pressure sensors may be used for both
fuels simultaneously for the purpose of limits testing as well as valve proving, depending on Options 125 &
126 setting.
The main gas pressure sensor which can be wired to terminals 31-34 on the main MM board is used for Fuel
1, an additional gas pressure sensor can be used for fuel 2 if required; this can be wired to terminals (DT+,
DT-, DP-, DP+) on the MM Expansion Board.
Valve proving may be used with or without a vent valve (Option 130 setting 2 or 3).
If 2 liquid fuels are configured in DFOM, it is not possible to use pressure sensors for both fuels at the same
time.