18-HD68D1-3
3
Unit Location Considerations
The unit’s rugged design allows installation in closet, attic or other non-condensing locations free from obstruc-
tions or other hazards.
Remove cover by grasping at edges and gently
pulling the cover straight towards you. It should
release without much effort.
Aux2
Relay Panel
Bit Master
Comm
HV
AC System
Sensor
s
Thermostat
and Indoor Unit
Outdoor
Remot
e
Data
Hot
Com
D R B
Indoor
RS
RS
ODT
ODT
24
Va
c
Only
24
Va
c
Only
24
Va
c
Only
Aux2
Aux1
Aux1
Hum
Hum
BK PWM
Fan
G
W3 Stg3
W2 Stg2
W1 Stg1
Y1 Stg1
Y2 Stg2
0 SOV
NORM
Dual Fuel
Switch
DUAL
Aux2
Relay Pane
l
Bitmaster
Comm
HV
AC Syst
em
Sensor
s
Thermosta
t
and Indoor
Unit
Outdoo
r
Remote
Data
Hot
Com
D
R
B
Ind
oor RS
RS
ODT
ODT
24
Va
c
Only
24
Va
c
Only
24
Va
c
Only
Aux2
Aux1
Aux1
Hum
Hum
BK
PW
M
Fan
G
W3
Stg3
W2
Stg2
W1
Stg1
Y1
Stg1
Y2
Stg2
0 SO
V
NORM
Dual Fu
el
Swit
ch
DUAL
Relay Pane
l
Section 3. Installation
Remove Cover
Mark Mounting Location
1
2
Mark four holes on the wall using the base as a
template. A level may be used to ensure accuracy.
Indoor Unit Type
Comm
Furnace
Comm
Air Handler
24V
Furnace
24V
Air Handler
OD Unit Type
Minimum Indoor 24V Control Power
Transformer Size, VA*
Communicating Heat Pump
35
35
See Below
Communicating Air Conditioner
35
35
24Volt-Controlled Single Stage Heat Pump
35
40
35
40
24Volt-Controlled Single Stage Air Conditioner
35
40
35
40
24Volt-Controlled 2-Stage Single Compressor Heat Pump
65
75
65
75
24Volt-Controlled 2-Stage Single Compressor Air Conditioner
50
40
50
40
24Volt-Controlled 2-Stage Dual Compressor Heat Pump
50
75
50
75
24Volt-Controlled 2-Stage Dual Compressor Air Conditioner
35
40
35
40
*Note: The VA rating of all 24V field-installed accessories must be added to the above for sizing indoor unit control transformers or the accessories
must be powered separately.
2.5 System Transformer Sizing Guidelines
