CB FALCON
750-265 36
Fig. 15. Plate heat exchanger subsystem.
Table 12. Plate Heat Exchanger Parameters.
Parameter Comment
Tap detect degrees per second Degrees or None
This tap demand “set” criteria depends on rate of change of the DHW sensor. The rate of
change of this temperature is monitored. If it falls at a rate faster than specified degrees per
second then the Tap demand block is “Set” (Tap demand becomes true and the minimum on
timer is started).
Tap detect on hysteresis Degrees or None
The second tap demand “set” criteria depends on the value of the DHW sensor. If the
temperature is less than or equal to the threshold given by subtracting this parameter from
the normal DHW setpoint, and if this condition has persisted for the time specified by the Tap
detect recognition time parameter, the Tap demand block is “Set” (Tap demand becomes true
and the minimum on timer is started).
The timer that measures the Tap detect recognition time resets if the temperature rises above
the threshold and a new Tap detect event will not occur again until the threshold has again
been met or exceeded (on the low side) for the recognition time.
Tap detect on recognition time hr:mm:ss or None
This provides the time for a Tap detect event due to the Tap detect on hysteresis, as
described just above.
Tap detect on threshold -17 °C to 82 °C (-0 °F to 180 °F)
DHW
DHW
TOD
SET
TIMER
LOAD
CLR
FORCE
TAP
TAP
PREHEAT
PREHEAT IS ACTIVE
TAP DETECT MINIMUM ON TIME
TAP DEMAND ENDS WHEN:
PRIORITY
IS
DHW
DHW
PLATE
DEMAND
AND
AND
AND
AND
AND
OR
OR
IF DHW PLATE
DEMAND LOSES
CONTROL DUE TO
PRIORITY, RESET AND
RESTART THE ITEMS.
OTHERS CONTINUE TO
OPERATE.
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 PREHEAT IS FALSE, IT BECOMES TRUE WHEN:
WHEN THESE HAVE OCCURRED, THEN A 1 MINUTE TIMER STARTS.
WHEN THIS TIME ELAPSES, THEN PREHEAT ENDS. THE FORCE OUTPUT IS PULSED
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.
WHEN PREHEAT TURNS ON, ITS MINIMUM ON TIME IS STARTED
IF PREHEAT IS TRUE, IT BECOMES FALSE WHEN:
IF TAP IS FALSE, ALLOW THE TIMER TO RUN.
•TIME IS EXPIRED, AND
•SET IS FALSE, AND
•CLR IS TRUE
•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
•TAP DURING PREHEAT IS RECOGNIZED (SEE BELOW)
•BOTH: • DHW <= PREHEAT (SETPOINT+OFF HYSTERESIS)
• PREHEAT MINIMUM ON TIME HAS EXPIRED
•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
WHENEVER SET CHANGES FROM OFF TO ON,
TAP OUTPUT IS TRUE FOR AT LEAST THE
TAP
PREHEAT
TRUE IF DHW <= SETPOINT-
TRUE IF INLETTEMP-DHW =>-
INLETTEMP
INLET
OUTLETTEMP
OUTLET(S3S4)
INLETTEMPINLET (S1)
TRUE IF OUTLETTEMP-INLETTEMP<=
AND THIS PERSISTS FOR LONGER THAN:
DHW
TAP DETECT DEGREES PER SECOND
TRUE WHILE DHW IS
DROPPING FASTER THAN
SETPOINT
SELECT
TOD SETPOINT
TAP DETECT ON HYSTERESIS
TIMER
PLATE PREHEAT ON HYSTERESIS
PLATE PREHEAT ON RECOGNITION TIME
PLATE PREHEAT DELAY AFTER TAP
PLATE PREHEAT MINIMUM ON TIME
PLATE PREHEAT OFF HYSTERESIS
PLATE PREHEAT SETPOINT
TAP DETECT RECOGNITION TIME
TAP STOP INLET -DHW DEGREES
TAP STOP OUTLET -INLET DEGREES
TIMER
FLAG
TIMER
TIMER
TIMER
IF FORCE IS ON, TREAT AS
IF SET HAD JUST CHANGED
FROM OFF TO ON.
IF BOTH SET AND
CLR ARE TRUE,
IGNORE CLR
DHW PLATE DEMAND
DHW MODULATION SENSOR
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