Raypak 503A Installation & Operating Instructions Manual page 23

Wiring the Indirect Sensor
1. An indirect sensor connection is not required if an
indirect water heater is not used in the installation.
2. When the Indirect DHW call for heat is active, the
PIM™ communicates this to the VERSA. The
VERSA calculates the optimal operation and
sends the firing rate and pump output requests to
the PIM™ so it can activate the Indirect DHW
pump and Boiler pump as needed. If an optional
Indirect DHW sensor is connected, the PIM™ will
pass this signal to the VERSA. This allows the
VERSA to optimize the Indirect DHW demand to
maintain the Indirect DHW setpoint. The Indirect
DHW thermostat switch closure is still required
when using the Indirect DHW sensor. If a VERSA
is not present the PIM™ shall activate the Indirect
DHW pump whenever the Indirect DHW call is
active. The Boiler pump will also be activated
based on the Indirect DHW piping configuration
setting. Consult the VERSA IC manual (Cat.
5000.72) for additional configurations.
3. Connect the indirect tank sensor to the terminals
marked INDIRECT DHW SENSOR (see wiring
diagram). Caution should be used to ensure nei-
ther of these terminals becomes connected to
ground.
NOTE: Alternately, a thermostat contact closure can
be used in lieu of the sensor for indirect operation.
Connect the thermostat to the terminals marked IND
REMOTE THERMOSTAT.
CAUTION: Sensor and control wiring must NOT be
run in conduit or chases with line voltage.
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 cas-
cade of up to 4 boilers, or the firing rate of a single
MVB boiler.
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 (Cat. 5000.72).
4. Connect an Energy Management system or other
auxiliary control signal to the terminals marked 0-
10V (+ /-) on the PIM™ (see Fig. 23). Caution
should be used to ensure that the +0-10V connec-
tion does not create a short to ground.
Wiring the Cascade System
Communication Bus
1. Designate the primary boiler as the master
boiler/boiler1 by leaving dip switch 2 on the
VERSA in the ON position. All other VERSA con-
trols require dip switch 2 to be toggled OFF,
designating them as followers. Follower VERSA
boards are ignored by their corresponding PIM™
modules. Use standard 18 AWG wire to connect
the master VERSA to the PIM™ on the followers.
A total of 3 followers can be connected to the
VERSA on the master. For systems requiring more
than 4 connected boilers, an external sequencer
such as the Raypak Temp Tracker Mod+ Hybrid
can be used.
2. It is recommended that the shortest length cable
possible be used to reach between the boilers. Do
not run unprotected cables across the floor or
where they will become wet or damaged. Do not
run communication cables parallel with, or close to
or against, high voltage (120 volt or greater)
wiring. Raypak recommends that the total maxi-
mum length of each set of communication bus
cables not exceed 200 feet.
3. Connect the FT_BUS wires to the PIM™ by press-
ing down on the slots with a small screwdriver and
then inserting the wires into the holes.
Fig. 24.
Fig. 24: FT_BUS Wire Connection
23
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