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The cascade will be controlled by the System Sensor
connected to the Master boiler (S3a).
Sensor Installation on page 9. The VERSA IC
each boiler will provide Max Delta T control to cycle the
burner to ensure that the Delta T is not exceeded
(between Boiler Outlet Sensors (S1a-b-c-d) and Boiler
Inlet Sensors (S2a-b-c-d)).
In order to enable MIX settings, VERSA
set to ON position. Raypak's Cold Water protection sys-
tem utilizes a proportional 3-way valve to bypass water
from the boiler outlets to the inlets (S2 a-b-c-d) during
operation, when the system return water temperature is
below the minimum acceptable level, among all active
units, as defined in the Installation and Operating manu-
al for the product being installed.
The Boiler Pumps (P1a-b-c-d) run during any call for that
pumps associated boilers burner and is delayed "off" as
user-defined in the BOILER menu. The System Pump
(P2a) runs whenever the system is enabled for heating
and the outdoor air temperature is lower than the WWSD
temperature setting (if utilized). The System Pump is
delayed "off" as user-defined in the SETUP menu. It is
recommended the system pump be connected in parallel
from each cascade follower output, to allow the system
pump to be functional during limp-along operation.
Each Follower boiler connects back to the Master boiler
via a 2-wire connection for communication within the cas-
cade. All sensors (System (S3a) and Outdoor Air (S4a))
connect to the Master boiler at the field wiring strip on
Maximum distance not to exceed 4 pipe
diameters or 12" whichever is less
Fig. 14: MODE 1 Hydronic Multi-Boiler (MIX TYPE = PLNT)
See System
®
DIP #3 must be
®
MVB
/ XTherm
, or the PIM J2 terminal block. Each boil-
®
®
er in the cascade connects to and controls its own
respective Boiler Pump (P1a-b-c-d). The System Pump
of
(P2a) gets its enable signal from the Master boiler. It is
important to remember to enable a boiler to be a follower
in the cascade by turning DIP switch #2 on the VERSA
Control Board to the "OFF" position for each of the follow-
ers. Once the followers have been configured correctly
you must then enable the followers within the SETUP
menu of the Master boiler by turning them from "OFF" to
"ON". DIP switch #2 on the master boiler must remain
ON. MODE 1 is used for this configuration. See SETUP
menu items in Table B page 15. This configuration sup-
ports BMS 0-10 VDC input for temperature control (rate
not supported) and can be configured for connectivity to
BMS via the onboard Modbus port covered later in this
manual.
Ensure DIP switches #1 and 2 on the VERSA
Control Board are in the ON position to make program-
ming changes. Prior to setting any DIP switches, the
heater must be turned off. Prior to enabling the master
boiler, apply power to all units for initial programming of
cascade settings. This is accomplished from the master
boiler user interface.
The next menu items are not necessarily in the order in
which they will appear.
13
CWP Valve detail
R
GY
BK
(+ 24VAC)
(+ MOD)
(GND)
A
AB
B
®
master
®
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