Electrical - Low Voltage; Low Voltage Maximum Wire Length; Low Voltage Hook-Up Diagrams; Thermostat Wiring Diagrams - Bosch BOVB 18 Series Installation Instructions Manual

Installation Instructions

11 Electrical - Low Voltage

11.1 Low Voltage Maximum Wire Length

Table 4 defi nes the maximum total length of low voltage wiring from the outdoor
unit, to the indoor unit, and to the thermostat.
24 Volts - Wire size
18 AWG
16 AWG
14 AWG
Table 4

11.2 Low Voltage Hook-Up Diagrams

Figure 24
Low Voltage Unit Connections

11.3 Thermostat Wiring Diagrams

Be sure power supply agrees with equipment nameplate.

Power wiring and grounding of equipment must comply with local codes.

 Low voltage wiring to be minimum No. 18 AWG conductor.
"- - - - - - - -" represents Field installed electric auxiliary heat connection

Single-stage auxiliary heating supported by 2H thermostat

 Twin-stage auxiliary heating supported by 3H thermostat
W1: The first stage of field installed electric auxiliary heat.

W2: The second stage of field installed electric auxiliary heat.

 The outdoor unit W signal is connected to first or second stage electric
auxiliary heat.
Bosch Thermotechnology Corp. | 10.2020
Max. Wire Length
150 Ft.
225 Ft.
300 Ft.
Control
Board
Access
Panel
NOTES:
- Low voltage connection must be made inside the
outdoor unit control board access panel.
- There is no terminal block for low voltage connections,
wires must be spliced using field supplied wire nuts
- Field supplied wire nuts should be 22-16 gauge.
- Refer to unit wiring diagram for more information.
Dashed lines in the following thermostat wiring diagrams refer to optional
wiring (wiring for Electric Heat). For thermostat wiring please refer to the
Owner's Manual of the thermostat.
B terminal to be connected with thermostat (O/B) wiring. Reversing valve
energizes in heating.

Bosch IDS BOVB 18 | 15

Data subject to change