34
®
ment and repeats the process. The BurnerLogix steps the firing rate motor until the steam pressure
(or water temperature) reaches the Thermal Shock Exit Point (
THML EXIT
). At that point, the fir-
ing rate motor is at the high fire position, and will remain at the high fire position until the steam
pressure (or water temperature) reaches the modulating range
(MOD RNG)
. See SEQUENCE OF
OPERATING - MODULATING CONTROL section.
Note: If AUX1 is programmed for STNDBY WTR, Thermal Shock Protection - Segment Method will
control according to boiler water temperature and not steam pressure. See SEQUENCE OF OPERA-
TION - STANDBY WATER section.
THML OVRD:
The Timed Override Per Segment Setpoint (
THML OVRD
) allows the user to pro-
gram a maximum time period in which the control will try to increase the steam pressure (or water
temperature) at a specific firing rate position. If the steam pressure (or water temperature) DOES
NOT increase to the appropriate value, the BurnerLogix will automatically advance the firing rate
position to the next position.
FIGURE 11.
Cold Start Thermal Shock Protection - Segment Method
SEQUENCE OF OPERATION - LEAD/LAG CONTROL
In installations having multiple boilers, the BurnerLogix of each boiler can be set up to operate in a
Lead/Lag mode of operation. The BurnerLogix control provides two lead/lag setpoints, LAG1 and
LAG2, each made active by separate 120 VAC digital inputs located on terminals 16 and 21. Please
note these inputs have multiple uses and must be programmed as LAG to utilize this function. The
function of Lead or Lag operation is determined by the status of a maintained 120 VAC wired to Ter-
minals 16 and 21. The logic table for Lead and Lag operation is as follows:
With both inputs open, the BurnerLogix will operate in the LEAD mode. The current operating
mode, (LEAD, LAG1 or LAG2), is displayed on the ALL-INFO screen. LAG1 and LAG2 setpoints
are found in the
BOILER PARMS>
menu under
LAG1 CONFIG>
and
LAG2 CONFIG>
respec-
tively. Assuming LAG1 operation is selected, the BurnerLogix will control according to the follow-
ing setpoints:
LAG1 STPT
(Lag Setpoint for Water Temperature or Steam Pressure): This is the system setpoint
the BurnerLogix will maintain when it is selected for Lag Operation.
LAG 1 (16)
LAG 2 (21)
OPERATING MODE
0
0
LEAD
120 Vac
0
LAG 1
Don’t care
120Vac
LAG 2
LOW
FIRE
STM SP = 100 PSI
CUT IN = 0
CUT OUT = 20
MOD RNGE = 30
10
20
30
40
HIGH
FIRE
100%
20mA
0%
4mA
50
60
70
80
90
100
110
120
130
THML OVRD = 30 MIN
STEAM PRESSURE (PSIG)
BOILER
FIRING
RATE MOTOR
THML STRT = 20 PSI
THML EXIT = 60 PSI
Summary of Contents for BurnerLogiX BLL510
Page 79: ...79 NOTES...
