Bosch DX Series Installation And Maintenance Manual page 21

Connecting Controller
thermostat to the "O" & "C" connections on the
Auto Changeover Controller. If a DDC controller
with a dry contact is to be used then route wires
from the "DRY" contacts of the DDC controller to
the "DRY" contacts on the Auto Changeover
Controller. Refer to Figure 10 below.
Either use the "O" & "C" connection from the
thermostat or the "DRY" contacts from a DDC
controller on this accessory. Do not attempt to
connect both.
If the water-to-water unit is an existing piece of
equipment already in service, and the hydronic air
handler is being added to the system, then locate
the two wires connected to the "S2" connections
on the back of the unit mounted controller and
follow them to where they are attached to the side
of the water pipe (the point of contact will be
underneath some insulation tape). Carefully
remove the insulation tape to free the loose ends of
the wire. Crimp on 1/4" insulated terminal
connections to the wires and proceed following the
instructions already mentioned. Replace any
damaged insulation tape to ensure that no exposed
piping remains.
Use 18 AWG wire when making all connections to
the Auto Changeover Controller to the unit
mounted controller and to the thermostat or DDC
controller.
Revised 11-11
Unitary Air Handler DX and Hydronic Series
figure 10
Subject to change without prior notice
When installing the
controller, locate the four
holes provided in the
electrical box on the right
hand side and snap in the
location as shown.
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