Rheem Raypak MVB 503A Installation And Operation Manual page 23

Wiring the Optional 0–10 Volt Building
Control Signal
1. A signal from an energy management system may
be connected to the MVB boiler. This signal should
be a 0-10 volt positive DC signal, and an energy
management system can be used to control either the
setpoint temperature of a single MVB or a cascade
of multiple boilers, or the firing rate of a single MVB
boiler. Refer to the VERSA IC
additional information on Cascade Systems.
2. To enable this remote control function, set dip
switch 5 to the UP position on the PIM. Dip
switch 5 Toggles between an EMS (UP) signal
or a demand signal from the VERSA (DOWN).
Dip switch 2 on the PIM toggles between a Direct
Drive (UP) input and a Target Temperature (DOWN)
setpoint.
3. For a 4-20mA application, refer to the VERSA IC
manual (241493).
4. Connect an Energy Management system or other
auxiliary control signal to the terminals marked 0-10V
(+ /-) on the PIM. See Figure 22. Caution should be
used to ensure that the +0-10V connection does not
create a short to ground.
Wiring the Cascade System
Communication Bus
®
Refer to VERSA IC manual (241493) for details on
Cascade wiring and communication setup.
Cascade System Pump and Sensor Wiring
1. On the boiler designated as the Master, connect the
system pump enable wiring to the terminal block at
the rear of the unit. The connections are dry contacts
rated for pilot duty only (5A maximum).
2. Connect the system supply sensor to terminals 6
and 7 on the field wiring strip located on the Master
PIM. See Figure 22.
3. Connect the Outdoor sensor (if used) to terminals 8
and 9 on the field wiring strip located on the Master
boiler. See Figure 22.
4. Connect the Enable/Disable wiring to terminals 11
and 12 on the field wiring strip located on the Master
boiler. See Figure 22. This connection must be
provided through dry contacts closure.
NOTE: This dry contacts closure can come from a
room thermostat or a remote relay. No power of any kind
should be applied to either of these terminals.
®
manual (241493) for
®
FIELD WIRING
G
SYSTEM
SUPPLY
W
PUMP
5A MAX
BK
G
DHW
W
PUMP
5A MAX
BK
12 AWG
G
12 AWG
W
BK 12 AWG
F10222
Figure 23. MVB Cascade Master Pumps
Cascade Follower Pump and Sensor Wiring
1. Once the primary boiler has been identified, additional
boilers will be designated as follower boilers. Ensure
dip switch 2 on each follower VERSA is set to the
OFF/Down position.
2. For each follower boiler, connect the boiler pump
wires to the pump contactor at the rear of each unit.
3. The System and DHW pump outputs are not used in
the Cascade Follower configuration.
Modbus BMS Communication
®
The VERSA IC control is equipped as standard with
a communications port for connectivity to building
automation via Modbus protocol. Refer to the VERSA IC
manual (241493) for further information.
FIELD WIRING
N/A
SYSTEM
SUPPLY
PUMP
5A MAX
N/A
DHW
PUMP
5A MAX
G
12 AWG
W
12 AWG
BK
12 AWG
F10223
Figure 24. VERSA Follower
9
GND
COM
8
HOT
7
(120V)
6
GND
COM
5
HOT
4
(120V)
3
GROUND
2
COMMON
HOT
1
(120V)
P/N 902062 REV 1
FACTORY WIRING
9
GND
COM 8
HOT
7
(120V)
6
GND
COM 5
HOT
4
(120V)
GROUND 3
2
COMMON
HOT
1
(120V)
P/N 902062 REV 1
FACTORY WIRING
®
23