Air conditioner/heat pump interface, Low voltage peak control connections, Line voltage electrical connections – Steffes 3120 Simplified Installation Guide User Manual
Page 3: Low voltage outdoor sensor connections, Warning, Full load current

6
AIR CONDITIONER/HEAT
PUMP INTERFACE
When interfacing a heat pump with the Comfort Plus,
the A-coil MUST be placed in the return air plenum.
Risk of fire. Any one ducting system MUST
NOT contain more than one air handling
(blower) system.
The 3120 Comfort Plus heating system can accom-
modate most heat pump or air conditioner indoor
coils up to a 3 1/2 ton capacity provided the heat
pump or air conditioner is sized in accordance to
supply air delivery rates of the Comfort Plus.
The maximum coil size the factory supplied return air
plenum can accomodate through the front access is
25.5" (W) x 22" (D) x 29.93" (H). The inner dimensions
of the coil area are 26" (W) x 22" (D) x 30.96" (H).
7
1. Route low voltage wire from load control device to terminal
block.
2. Connect field wiring to RP and P positions.
LOW VOLTAGE PEAK CONTROL
CONNECTIONS
If utilizing a Steffes Time Clock Module or Power Line
Carrier control, refer to the instructions shipped with that
device for installation information.
WARNING
WARNING
WARNING
WARNING
WARNING
To ensure proper operation and safety, all line voltage circuits
must be segregated from low voltage wiring.
To reduce electromagnetic fields associated with electrical
circuits and to avoid induced voltage on sensors and electronic
devices, the circuit phases MUST be alternated as shown.
DO NOT install any wiring in the line voltage compartment of
the Comfort Plus heating system unless it is rated for line
voltage.
8
LINE VOLTAGE ELECTRICAL CONNECTIONS
WARNING
WARNING
WARNING
WARNING
WARNING
9
LOW VOLTAGE OUTDOOR SENSOR CONNECTIONS
The outdoor temperature sensor can be installed by wiring it
directly to the system or to the Steffes power line carrier (PLC)
system.
Direct Wired:
1. Mount outdoor sensor in a location where it can accurately
sense outdoor temperature.
2. Route low voltage wire from outdoor sensor to electrical
compartment:
Outdoor sensor wire MUST NOT be combined with other
control wiring in a multi-conductor cable.
Seal external wall openings.
Outdoor sensor lead can be extended to 250 ft.
Unshielded Class II (thermostat) wire can be used
provided it is segregated from any line voltage wiring.
3. Connect outdoor sensor wires to the two "OUTDOOR" posi-
tions of the low voltage terminal block.
If connecting to the Steffes power line carrier sys-
tem, follow the installation instructions in the PLC
systems Owners and Installers Guide.
C i r c u i t B r e a k e r s
LINE 2
LINE 1
LINE 2
LINE 1
C H A R G E C I R C U I T # 2
C H A R G E C I R C U I T # 1
B L O W E R S / C O N T R O L S C I R C U I T
LINE 2
LINE 1
To Servi
c
e (Breaker) Panel
HAZARDOUS VOLTAGE: Risk of electric shock. Can cause injury or
death. Do not energize the Comfort Plus heating system until installa-
tion is complete.
1. Route all line voltage wires through knockout(s) and into electrical panel.
2. Make proper field wiring connections, phasing circuits as shown.
Reference the Unit Identification label for circuit information.
Model
Control Crct Chrg Crct #1 Chrg Crct #2
3120 - 14.0kW
6.00
29.17
29.17
3120 - 17.0kW
6.00
36.46
36.46
3120 - 21.6kW
6.00
45.00
45.00
Full Load Current
Show n for 240VAC only. Circuit deration not included.
P8
P9
Aux.
COM
NC
AP
NO
Relay
Outdoor Sensor
O
W/
Y1
AUX
Y2 G
Ou
td
oo
r
Ou
td
oo
r
Y2
R
H/E
2
Y1
C
O
2
2
RP P
R
C
P1
P11
D3
D7
D5
W
E
Y
1
Y
2
Wa
te
r
Ai
r
P6
D1
P5
Blower
J3
J1
J2
J4
D2
To Control Board
P3
C
Blower
Speed
A
B
J5
J6
C3
D
P4
P2
Inputs
Peak
P7
LV Circuit Board
Comfort Plus
To Control Board
P10
Fid 2
RLY1
D4
D6
R2
R1
P9
Aux.
COM
NC
AP
NO
Relay
P8
O
W/
Y1
AUX
Y2 G
Ou
td
oo
r
Ou
td
oo
r
Y2
R
H/E
2
Y1
C
O
2
2
RP P
R
C
P1
Inputs
Peak
P7
LV Circuit Board
Comfort Plus
To Control Board
P10
Fid 2
RLY1
D4
D6
R2
R1
P11
D3
D7
D5
W
E
Y
1
Y
2
Wat
e
r
Ai
r
P6
D1
P5
Blower
J3
J1
J2
J4
D2
To Control Board
P3
C
Blower
Speed
A
B
J5
J6
C3
D
P4
P2
Dry Contact Peak
Control Switch