LAARS M4-Ext - Installation Manual - Manual (Page 25)

Page 25 LAARS Modulating Controls M4 & M4-EXT
IGNITION %
Adjustable 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 0% to 100% Default: 80%
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, Boiler B (if Boiler B is in Auto Mode and is not already on)
will be brought on in low fire.
BACK SAVE
------------ STAGE A ------------
MODULATION START
80
%
[ ]
• When modulation is decreasing, the lag unit will remain on in low modulation, until the previous boiler reaches 40% of its
Modulation Start point, or 2% above the Ignition Point, whichever is higher.
• Using the same example, as the load decreases, Boiler B would modulate down to low. 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.
• The Modulation Start point will generally be set differently based on the Modulating Mode selected.
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. The Mode will not be copied.
IMPORTANT
The Mode MUST be set for each boiler. The Copy Settings
command will not set the Mode for Boilers B, C, and D. Only
Ignition % and Modulation Start % are copied.
-------- COPY SETTINGS -------
From Stage A
to all other stages
BACK COPY