87
3.4.2 Setting parameters
Set the parameters as shown in the table to ensure that the con-
troller recognises the system.
System identification
–
Setting mode = INSTALLER
(refer to section on parameter setting levels)
–
Setting mode = MANUFACTURER
(Refer to section on parameter setting levels)
3.4.3 Checking for correct recognition
To check that the controller has correctly recognised the type of
system on the basis of the parameters entered, display the installer
parameter in row 53.
System n. 1 should appear.
3.4.4 Minimum return thermostat
The thermostat on the return is not supplied with the probe kit. It ser-
ves to activate the by-pass pump if the return temperature is low. It
should be set to 35° C.
NOTE: Once parameters have been set, the unit’s led will be
off during regular operation, and will flash when not required by
the room thermostat. This is NOT a fault signal.
3.5
SYSTEMS I3/I4: CASCADE OPERATION
OF 2/3 BOILERS FOR HEATING ONLY
AND ZONE VALVES/PUMPS
The features of this type of system may be summed up as follows:
– Operation of 2/3 boilers in cascade
– Step power modulation of the entire cascade with automatic inclu-
sion and exclusion of individual units
– Automatic adaptation to demand for heat
– Maintaining minimum boiler temperature
– Automatic rotation of boiler sequences
– Automatic summer/winter switching
– Climate control with outdoor temperature probe
– Boiler works only on demand from at least one room thermostat
– System pump works only on demand from at least one room ther-
mostat
– Weekly heating programming
The components included in the boiler kit to be purchased are as fol-
lows (the outdoor temperature probe QAC31 and the 2 cascade deli-
very/return probes QAD21 are sold separately):
In this case the MASTER (par. 140 = 1) is connected to the cascade
delivery probe and SLAVE 1 (par. 140 = 2) is connected to the casca-
de return probe.
NB: Relays for management of demand for heating in various areas,
shown in the wiring diagrams, are not included in the cascade mana-
gement kit supplied.
Par Description Default values Setup
90 Minimum limitation of boiler temperature 8 40
91* Type of burner 1 0
121 Release of d.h.w. heating 1 2
127 D.h.w. priority 1 0
140 LPB device address 1 0
170 Input H1 0 1
173 Operating action of contact H1 1 0
* For single stage boilers only
Par Description Default values Setup
9 Operating mode of boiler 2 1
Par Description Value
53 Display of plant type 1
Code Description Quantity
RVA43.222 Control unit 1
QAZ21 (immersion) Boiler delivery probe/boiler probe 1
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