AUTOFLAME Mk8 MM, Техническое руководство, Страница: 88 / 98

5 Intelligent Boiler Sequencing
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MM Application Possibilities
As well the options/parameters given in section 5.3.1, the following also need to be set for steam
sequencing:
•
Option 41 – Sets whether all the lag boiler states, either the first lag is kept in standby state
with the second lag in warming and the remaining lag MMs off, or all the lag boilers after the
first lag boiler are kept in warming state and there are no boilers offline.
•
Option 42 – Sets the standby setpoint for sequencing where non-return valves are installed;
the first lag boiler will aim to maintain this standby setpoint when in the warming/standby
phase. This is set as absolute value.
• Options 53 – Sets the steam sequencing burner off time. This is the time in minutes for how
long the boiler will be off for during Warming mode.
•
Option 54 – Sets the steam sequencing burner on time. This is the time in minutes for how
long the boiler will be in low flame hold for the boiler to heat up to its standby setpoint, when
in Warming mode. Options 42, sets the standby setpoint.
5.4.3 Low Pressure Steam Sequencing
For steam boiler plants where check (non-return) valves are not installed, or the required setpoint is
less than 2 Bar (20 PSI), it is not possible to use a standby setpoint. Each pressure sensor would
read the same pressure value, regardless of individual boiler temperature/ pressure. A thermostat
(Aquastat) can be installed into the boiler shell, and option 40 must be set to low pressure steam
sequencing.
For the Mk8 MM, a 230V/ 120V input on terminal 93 (see option 79) will initiate the warming for that
lag boiler, and this will fire according to the warming interval timings in options 53 and 54.
For the Mini Mk8 MM, a 230V/ 120V input on terminal 82 (see option/ parameter 156) will initiate
warming for that lag boiler, and this will fire according to the interval timings in options 53 and 54.