Weil-McLain BMC-6X Boiler User Manual


 
26
BMC and BMC-6X Installation and Operation Manual
Auto - The BMC will control the boiler’s operation to maintain the desired Set Point. Only boilers set to Auto can be Lead
boilers.
Standby Standby boilers can only be activated when all boilers in Auto have been at 100% modulation for a selectable period of
time. Standby is generally used when you want a specific boiler to be available in extreme load conditions. Note that a
Standby boiler Cannot be a Lead boiler.
Manual The Manual Mode should only be used when testing a boiler. Manual overrides the Prove input. The exact percent of
modulation for a boiler can be set with the Manual mode. Once selected, the unit will immediately turn on and modulate to
the selected percentage.
Off Any output Boiler A through D not connected to a physical unit should be set to Off. The Off Mode can also be used to
disable units that are being serviced.
On The On Mode should only be used when testing a boiler. The On Mode overrides the PROVE input. Once set to On the
boiler will immediately start firing and modulate to 100%.
IGNITION %
Adjustable from 1% to 50% Default: 1%
Button: STAGE/Ignition %
The Ignition Point is the percent of modulation that must be attained before the unit can
be activated.
For most modern power draft units, the Ignition Point should be set at 1%.
Older units or atmospheric units may require the modulating fuel valve to be open from
20-50% before proper ignition can be attained. Check with the boiler manufacturer if
you are in doubt about the minimum position of the fuel valve for ignition.
BACK SAVE
------------ STAGE A ------------
IGNITION POINT
1%
[ ]
MODULATION START %
Adjustable from 0% to 100% Default: 75%
Button: STAGE/Mod Start %
The Modulation Start determines at what modulation percent the previous boiler should
be for the current boiler to be activated.
For example, if the Modulation Start for Boiler B is set to 75%, then when Boiler A
reaches 75% modulation plus Ignition%, Boiler B (if Boiler B is in Auto Mode and is not
already on) will be brought on at the Ignition % level.
BACK SAVE
------------ STAGE A ------------
MODULATION START
75%
[ ]
When modulation is decreasing, the lag unit will remain on at the Ignition % modulation until the previous boiler reaches 40%
of lag boiler's Modulation Start, or 2% above the Ignition Point, whichever is higher.
Using the same example, as the load decreases, Boiler B would modulate down to its Ignition %. Boiler A would then modulate
down to 30%. Only then would Boiler B turn off.
If the Lag Delay is set to anything other than 0, a boiler must always go up to 100% modulation before the next boiler is
activated. However, the Modulation Start % should still be set correctly, because it will be valid when modulation is decreasing.
COPY SETTINGS - BOILER A ONLY
Button: STAGE/Copy Settings
If all the active boilers will have the same Ignition Start Point and Modulation Point,
they can be set for Boiler A and then copied to the other boilers.
It is still required to select the Mode for all other boilers as the Mode is NOT copied.
ALERT
The Mode MUST be set for each boiler. The Copy Settings command will not set the
Mode for the remaining boilers. Only Ignition % and Modulation Start % are copied.
-------- COPY SETTINGS -------
From Stage A
to all other stages
BACK COPY