27
Figure 30. FT_BUS Wire Connection
A
B
A
B
A
B
A
B
PIM FOLLOWER 2, 3 OR 4
TO PIM MASTER
VERSA
MASTER
F10159
1 2 3 4 5 6 7 8
ON
Figure 31.
XTherm Cascade System Wiring
3.13.6.
Cascade System Pump and Sensor
Wiring
1. On the heater designated as the Master, connect
the system pump enable wiring to the field-
wiring terminal block inside the junction box. The
connections are dry contacts rated for pilot duty
only (5A maximum). See
Figure 32
.
2. Connect the system supply sensor to terminals 6
and 7 on the field wiring strip located on the Master
heater. See
Figure 29.
FACTORY
WIRING
FIELD
WIRING
Figure 32.
Cascade Master-Pumps
3.
Connect the Outdoor sensor (if used) to terminals 8
and 9 on the field wiring strip located on the Master
heater. See
Figure 29.
4. Connect the Enable/Disable wiring to terminals 11
and 12 on the field wiring strip located on the Master
heater. This connection must be provided through
dry contacts closure. See
Figure 29.
Applying
24VAC to these terminals will result in blowing the
fuse on PIM.
NOTE:
The 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.
3.13.7.
Cascade Follower Pump and
Sensor Wiring
1. Once the primary heater has been identified,
additional heaters will be designated as follower
heaters. Ensure DIP switch 2 on each follower
VERSA is set to the OFF/Down position. See
Figure
33
.
2. The System and DHW pump outputs are not used
in the Cascade Follower configuration. For Cascade
configuration System pump (All models) and DHW
pump (H models only) follower outputs must be
connected in parallel respectively in order to support
operation during “limp along” mode. For detailed
wiring instructions see VERSA IC manual (5000.72).
