LAARS M4-Ext - Installation Manual - Manual (Page 26)

26
OPERATiNg MOdULATiNg BOiLER SETTiNgS
gAiN
Adjustable from -10 to +10 Default: 0
Button: MENU////Gain
• The Gain adjusts the aggressiveness of the modulating PID logic. It controls how much
modulation is changed when the system temperature is different from the Set Point.
• A Gain of 0 is a good starting point for all systems.
• If during normal load conditions, the system temperature tends to oscillate significantly,
decrease the Gain by two numbers (for example, from 0 to -2). Wait for at least 15 minutes
before evaluating how the change has affected the system.
• If, during normal load conditions the system temperature tends to remain consistently below
the Set Point (or consistently above the Set Point), increase the Gain by two numbers (for
example, from 0 to 2). Wait for at least 15 minutes before evaluating how the change has
affected the system.
MODULATION SETTINGS
Gain +0
Lag Delay 0min
Soft-Off Delay 45sec
BACK ▲ ▼ SAVE
------ GAIN ------
+0
[ ]
BACK ▲ ▼ SAVE
LAg dELAY
Adjustable from 0min to 60min Default: 0min
Button: MENU////Lag Delay
• The Lag Delay requires the lead stage to remain at 100% modulation for the full period of
the Lag Delay before the lag stage can be activated. For example, if the Lag Delay was
set to 10 minutes, the Lead Stage must remain at 100% modulation for the full ten minutes
before the lag stage could be activated. The Message Display Line will display Lag Delay
and the remaining time.
• Set the Lag Delay to 0 min when two or more Stages will generally be needed to hold the
load.
• The Lag Delay is useful in installations where one unit should usually have enough output
to hold the load unless it fails or load conditions become extreme.
• The Lag Delay overrides the Modulation Start % selected for each stage. Regardless of
that setting, the previous stage must reach and stay at 100% before the lag stage can be
activated.
• The full Lag Delay must always elapse regardless of what happens to system temperature.
Therefore, set the Lag Delay to 0 min if the object is to achieve a smooth operation and set
point control using multiple units.
• Note that if Parallel was selected as the Modulation Mode (See "Modulating Mode" on
page 18), this value must be set to 0 minutes to avoid having the lead boiler going to 100%
modulation prior to firing the lag boiler.
---- LAG DELAY ----
0 min
[ ]
BACK ▲ ▼ SAVE
SOFT-OFF dELAY
Adjustable from 0sec to 60sec Default: 45sec
Button: MENU////Soft-Off Delay
• When a stage is no longer needed, the Soft-Off keeps that stage burner in Low Fire prior to
turning it off.
• The display will show a percent that is equal to the Ignition % for the stage in Soft-Off
delay. That number will blink for the Soft-Off delay period.
• If during the Soft-Off delay period the M4-CNC needed that stage to turn back on, the stage
will be released from the Soft-Off delay and resume normal operation.
• On a Shutdown initiation or Tstat termination any stage that was on will go into Soft-Off
delay before fully turning off.
-- SOFT-OFF DELAY --
45 sec
[ ]
BACK ▲ ▼ SAVE
ALERT
When using Soft-Off and Last Stage Hold, the last boiler stage will not turn off until both
parameters have elapsed. In this case, Soft-Off will start after the Last Stage Hold.
LAARS Heating Systems
HT# 059104-00 B