Functional Requirements For Cascade Systems - Worcester GREENSPRING CWi47 Installation And Operating Instructions Manual

8.7 FUNCTIONAL REQUIREMENTS FOR
CASCADE SYSTEMS
8.7.1 HOT WATER REQUESTS
When a water heater reaches 80% of its capacity, it
passes on hot water requests to the next secondary
water heater in the system. Secondary acts like a
primary to the next secondary. When primary reach 30%
of his capacity it will remove the request sent to the
secondary.
8.7.2 WATER DEMAND FROM SOLAR
When the primary reads flow higher than 30 L/min and
inlet temperature is higher than set point, water will flow
through the appliance working with the solar function
and the primary will send a hot water request to the next
Secondary in the system. This way, when the appliances
are in solar mode, the water flow of the cascading
system will not be restricted.
This function is reset when inlet temperature reaches
set point - 4ºC. Appliances will get out of solar mode and
restart normal operation.
8.7.3 ERROR HANDLING
When one appliance in the cascading system is locked,
due to an error code, all actions are passed to the next
appliance. If the appliance is a primary, it will request to
the next appliance to be the primary.
Lead/lag changeover is not possible if the
water heater electronics are damaged or
connection is lost between the appliances.
The system will stop working if the
electronics in the primary are damaged.
Disconnect the damaged appliance and
select a new primary unit.
In this case the damaged appliance must be turn OFF
and the cascading cables must be disconnect from the
appliance. The two connector ends must be connected,
in order to close the cascading circuit.
If the damaged appliance is the primary, another
appliance must be programmed to be the primary.
8.7.4 OPERATING HOURS
The operating hours of each appliance are visible in P4
mode in menus H0, H1 and H2.
The formula to calculate the total amount of working
hours is:
H0 + (H1x100) + (H2x10000)= Total working hours.
6 720 646 322 (2012/05)
Operating hours
Number in H0
Number in H1 ______ (X100)
Number in H2 ______ (X10000)
Total of hours (H0+H1+H2)=
Tab. 12
8.7.5 NUMBER OF HOURS TO ROTATE PRIMARY
The primary appliance will rotate after 100 operating
hours. The rotation will take place when there is no flow
through the water heater.
NOTE: In systems where a re-circulation pump is
installed: ensure the pump is connected to a timer and
turned off for at least 1 hour every day. This will stop
flow through the water heater and allow rotation of the
primary water heater.
8.7.6 TEMPERATURE SET POINT CHANGE
The set point temperature limits are the same in a
cascade as in a stand alone appliance. The temperature
set point is transferred from the primary appliance onto
the secondary units.
8.7.7 REMOTE CONTROL USAGE
In this cascading configuration (Intelligent cascading)
only one remote control is needed to change the
temperature set point in the system. If the set point is
changed in appliance the set point will be updated in all
appliances within 2 seconds.
The error code for the remote control is only displayed
in the appliance where the base unit is installed.
The base unit can be installed in any appliance,
regardless whether it is primary or secondary.
ELECTRICAL CONNECTION
________+
________+
________+
_________
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