CleaverBrooks CFC-500 Operation, Service And Parts Manual page 163

DHW MODULATION SENSOR
DHW
TRUE WHILE
DROPPING FASTER THAN
TAP DETECT DEGREES PER SECOND
DHW
TOD SELECT
TRUE IF DHW <= SETPOINT-
TAP DETECT ON HYSTERESIS
AND THIS PERSISTS FOR LONGER THAN:
TAP DETECT RECOGNITION TIME
DHW
INLET (S1) INLETTEMP
TRUE IF INLETTEMP-DHW =>-
TAP STOP INLET -DHW DEGREES
INLETTEMP
OUTLETTEMP
OUTLET(S3S4)
TRUE IF OUTLETTEMP-INLETTEMP<=
TAP STOP OUTLET -INLET DEGREES
DHW PLATE DEMAND
Parameter
DHW storage enable
DHW storage time
DHW storage setpoint
DHW storage on hysteresis
DHW storage off hysteresis
DHW IS
SETPOINT
TOD SETPOINT
TIMER
PLATE PREHEAT ON HYSTERESIS
PLATE PREHEAT SETPOINT
PLATE PREHEAT OFF HYSTERESIS
PLATE PREHEAT ON RECOGNITION TIME
PLATE PREHEAT DELAY AFTER TAP
PLATE PREHEAT MINIMUM ON TIME
Fig. 16. DHW storage.
Table 15. DHW Storage Demand Parameters.
Enable, Disable
This parameter enables or disables the DHW storage feature. If it is disabled then the other
parameters below are ignored.
mm:ss
The time DHW storage temperature is maintained.
degrees or None
The temperature setpoint that the boiler maintains during the DHW storage time.
degrees or None
This provides the on hysteresis as an offset that is applied to the DHW storage setpoint, used
during DHW storage demand.
degrees or None
This provides the off hysteresis as an offset that is applied to the DHW storage setpoint, used
during DHW storage demand.
WHENEVER SET CHANGES FROM OFF TO ON,
TAP OUTPUT IS TRUE FOR AT LEAST THE
TAP DETECT MINIMUM ON TIME
TAP DEMAND ENDS WHEN:
TIMER
•TIME IS EXPIRED, AND
SET LOAD
•SET IS FALSE, AND
•CLR IS TRUE
IF FORCE IS ON, TREAT AS IF BOTH SET AND
IF SET HAD JUST CHANGED CLR ARE TRUE,
FROM OFF TO ON. IGNORE CLR
FORCE TAP
CLR
DHW FORCE TAP PREHEAT
WHENEVER PREHEAT IS FALSE:
IF TAP IS TRUE, INHIBIT THIS PREHEAT BLOCK, RESET THE
ITEMS, AND RESET THE PREHEAT DELAY-AFTER-TAP TIMER.
IF TAP IS FALSE, ALLOW THE TIMER TO RUN.
IF PREHEAT IS FALSE, IT BECOMES TRUE WHEN:
•TAP IS FALSE
•THE PREHEAT DELAY-AFTER-TAP TIME HAS ELAPSED
• DHW <= PREHEAT (SETPOINT-ON HYSTERESIS)
•THE ABOVE HAVE PERSISTED FOR THE ON RECOGNITION TIME
WHEN PREHEAT TURNS ON, ITS MINIMUM ON TIME IS STARTED
IF PREHEAT IS TRUE, IT BECOMES FALSE WHEN:
•TAP DURING PREHEAT IS RECOGNIZED (SEE BELOW)
•BOTH: • DHW <= PREHEAT (SETPOINT+OFF HYSTERESIS)
INLET
• PREHEAT MINIMUM ON TIME HAS EXPIRED
•TAP DURING PREHEAT IS RECOGNIZED AS:
• TAP HAS BEEN TRUE WHILE PREHEAT WAS TRUE
• EITHER • INLET TEMPERATURE DECREASES BELOW THE LEVEL
IT HAD WHEN PREHEAT STARTED
• DHW >= INLET
WHEN THESE HAVE OCCURRED, THEN A 1 MINUTE TIMER STARTS.
WHEN THIS TIME ELAPSES, THEN PREHEAT ENDS. THE FORCE OUTPUT IS PULSE
TO FORCE TAP DETECTION TO START (AND PREHEAT IS INHIBITED). THIS ALSO
OCCURS IMMEDIATELY IF THE 1 MINUTE TIMEOUT IS PENDING BUT PREHEAT
ENDS DUE TO ABOVE.
Comment
39
PRIORITY
IS
TAP
DHW
IF DHW PLATE
DEMAND LOSES
CONTROL DUE TO
PRIORITY, RESET AND
RESTART THE
OTHERS CONTINUE TO
OPERATE.
TAP
DHW
PLATE
PREHEAT
DEMAND
PREHEAT IS ACTIVE
PREHEAT
TIMER
FLAG
AND
OR
TIMER
CB FALCON
ITEMS.
TIMER
AND
AND
AND
TIMER
OR
AND
750-265