Honeywell ST9120U Installation Manual

ST9120B,U

WARNING

Universal Electronic Fan Timers

INSTALLATION INSTRUCTIONS

APPLICATION

The ST9120B,U Universal Electronic Fan Timers integrate control of all combustion blower and circulating fan operations in a gas warm air appliance. This control is the central wiring point for most of the electrical components in the furnace. The basic purposes of the ST9120B,U are to monitor the thermostat for heat, cool and fan demands, run the induced draft blower motor and run a circulating fan (up to two speeds) as required. The ST9120B,U also monitors limit switch strings and energizes separate ignition control systems through pressure switches. The ST9120B,U can replace any ST9101, ST9120, ST9141 or ST9160 listed in Table 3 below. The ST9120B,U features a field-adjustable heat fan-on delay, a field-adjustable heat fan-off delay, a fieldadjustable cool fan-on delay and a field-adjustable cool fan-off delay.

Electronic air cleaner (EAC) and humidifier (HUM) convenience terminal connections and continuous low speed indoor air circulation are provided.

SPECIFICATIONS

On/Off Delay Settings:

NOTE: Timing is derived from 24 VAC supply frequency

and is valid for 60Hz. At 50 Hz, the timings are lengthened 20%.

Heat Speed:

Delay On: Field-adjustable, 30 or 60 seconds. Delay

timing starts when gas valve is energized.

Delay Off: Field-adjustable, 60, 120, 150 or 180 sec-

onds. Delay timing starts when gas valve is deenergized.

Cool Speed:

Delay On: Field Adjustable, 4 or 30 seconds. Delay Off: Field Adjustable, 30 or 60 seconds.

Timing Tolerance: Larger of ±2% or ±2 seconds.

Post Purge Timing:

5 seconds.

Environmental Ratings:

Temperature: -40°F (-40°C) to +175°F (+79°C). Humidity: 5 to 95 percent, noncondensing.

Approvals:

Underwriters Laboratories Inc.

Electrical Ratings:

Power Voltage Requirements: 18 to 30 VAC, 50/60 Hz.

Contact Ratings: Combustion Blower:

1.5A full load, 10A locked rotor at 115 VAC.

0.75A full load, 5A locked rotor at 230 VAC.

(Reduce full load rating by humidifier [HUM] load.) Circulating Fan: Heat-Cool speed:

15A full load, 30A locked rotor at 115 VAC.

7.5A full load, 15A locked rotor at 230 VAC.

(Reduce full load rating by electronic air cleaner [EAC]

load.)

Continuous speed (optional):

8A full load, 16A locked rotor at 115 VAC.

4A full load, 8A locked rotor at 230 VAC. EAC and HUM:

0.8A maximum combined load at 115 VAC

0.4A maximum combined load at 230 VAC

Thermostat W Load: 100mA at 24 VAC, plus ignition sys-

tem load. Thermostat G, Y, Primary Limit, Burner Limit, Pressure

Switch Load: 22mA at 24 VAC load/cleaning current.

INSTALLATION

When Installing this Product...

1. Read these instructions carefully. Failure to follow

them could damage the product or cause a hazardous condition.

2. Check the ratings and specifications given in the

instructions and on the product to make sure the product is suitable for your application.

3. Installer must be a trained, experienced service

technician.

4. After installation is complete, check out the product

operation as provided in these instructions.

Electrical Shock Hazard. Can cause severe injury, death or property damage.

Disconnect power supply before wiring to prevent electrical shock or equipment damage. More than one disconnection can be required.

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ST9120B,U UNIVERSAL ELECTRONIC FAN TIMERS

CAUTION

Location and Mounting

Mount the ST9120B,U Electronic Fan Timer in the appliance wiring compartment using the two # 8 1/2-in. self-tapping screws.

Wiring

Explosion or fire hazard.

When installing the ST9120B,U, carefully check all appliance wires to make sure they are all connected to desired terminals at ST9120B,U. Incorrect wiring can lead to explosion hazard, fire, or equipment damage.

Make sure that all wiring complies with local codes and ordinances. Disconnect power before making wiring connections. Refer to Fig. 1–6 for standard wiring connections. Refer to Fig. 7–9 for schematic of provided wiring adapters.

Adjustable DIP Switch

The ST9120B,U control provides a wide variety of configurable heat on, heat off, cool on and cool off delays. Set the delay DIP switches as shown in Fig. 10 The heaton delay time starts when the main gas valve is energized at the start of a thermostat call for heat; the heat-off delay time starts when the main gas valve is deenergized at the end of a thermostat call for heat. The cool fan-on delay time starts when the compressor is energized at the start of a thermostat call for cool. The cool fan-off delay time starts when the compressor is deenergized at the end of thermostat call for cool.

Twinning

Twinning mode is used when two ST9120B,U controls operate in parallel. In this mode blower outputs (heat, cool and continuous speed) are activated or deactivated at both controls at the same time. Both ST9120B,U are synchronized through a communication bridge utilizing TWIN quick connect terminals, communication hardware and special software package.

To get into twinning mode both ST9120B,U must share common 24 VAC ground, both must be supplied off the same 24 VAC transformer or two identically-phased transformers and the TWIN terminals must be interconnected together. One or both ST9120B,U must be connected to the thermostat.

If two 24 VAC transformers are used (one for each ST9120B,U) then the transformers must be phased in (24 VAC HOT legs connected to X terminals at each ST9120B,U unit must be in the same phase relative to the 24 VAC common ground). If the transformers are phased out the twinning mode will not be achieved.

It is permissible to interconnect just two ST9120B,U to operate in the twinning mode. The ST9120B,U Twinning mode is not backwards compatible with legacy Electronic Fan Timers.

To operate in twinning mode:

1. Interconnect C quick connect terminals at both

twinned ST9120B,U.

2. Interconnect TWIN quick connect terminals at both

twinned ST9120B,U.

3. Use insulate wires of wire gauge at least AWG 24

for the interconnections. Wire lengths shall not exceed 5 m (15 ft.). Both C and TWIN wires shall lead in parallel to each other. Keep the wires out of wires under line voltage, ignition cable and other sources of electrical noise.

ST9120B,U Wiring Conversion Instructions

1. Turn off power to appliance. Carefully remove each

wire and connect directly to the corresponding location on the new ST9120B,U control board. Be careful to directly connect to the new terminal with the same labeled identity or label each wire prior to removing from the original board.

2. Identify the model number of the board being

replaced and set the dip switches based on Table 3.

Explosion Hazard/Fire Hazard

ST9101 wiring harness adapter and ST9141 wiring harness adapter are very similar because both use identical connectors. Ensure proper harness is selected for the target system. Using the wrong wiring harness adapter leads to target system and/or ST9120B,U control damage.

ST9101 to ST9120B,U Wiring Conversion Instructions

1. Turn off power to appliance and carefully remove

each wire and connect directly to the new ST9120B,U control board before removing the existing control. Use Table 1 to determine the proper ST9120B,U terminal for each corresponding ST9101 connection. Connect the wiring in accordance with schematic at Fig. 3. Be careful to directly connect to the new terminal or label each wire prior to removal from original board.

Electronic air cleaner use.

If electronic air cleaner is used in systems with continuous blower speed, connect the electronic air cleaner to line voltage input L1.

2. Unplug the 9-pin connector and plug existing wiring

harness directly into the 9-pin connector found on the ST9101 wiring adapter 50011959. See Fig. 7 and Table 4 for further wire harness adapter description.

3. Plug the 6-pin connector found on the ST9101 wir-

ing adapter directly to the open 6-pin connector on the new ST9120B,U control board.

4. Take the two remaining white wires on the ST9101

wiring adapter and connect to Neutral quick connect terminals on the ST9120B,U.

5. Take the black wire on the ST9101 wiring adapter

and connect to the L1 quick connect terminal on the ST9120B,U.

6. Take the blue wire on the ST9101 wiring adapter

and connect to the IND quick connect terminal on the ST9120B,U.

7. Identify the model number of the board being

replaced and set the dip switches based on Table 3.

8. Check proper connection using Fig. 3.

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ST9120B,U UNIVERSAL ELECTRONIC FAN TIMERS

ST9101 ST9120 ST9141 ST9160 ST9120B,U

HEAT HEAT HEAT HEAT HEAT COOL COOL COOL COOL COOL

CONT CONT CONT CONT

ACC --- --- --- * for systems with one

DI DI --- IND S S1 to S3 S1 to S3 L1 L1 M1 UNUSED MOTOR LEADS UNUSED MOTOR LEADS M1 UNUSED M2 UNUSED MOTOR LEADS UNUSED MOTOR LEADS M2 UNUSED N N N N N X X XI 24 VAC X C C C COM C

--- SPEED UP SPEED UP --- ---

--- Z1 Z1 TWIN H ** TWIN (see note

--- Z2 Z2 TWIN C ** TWIN (see note

--- --- --- DATA DATA

Thermostat Terminals

R R R R R Y Y Y Y Y C C C C C W W W W W G G G G G

* ACC terminal is used in ST9101 systems, which use the same fan speed for both heating and cooling. In order to use

the ST9120B,U to replace ST9101 devices in this type of system, the fan connection that originally was connected to ACC on the ST9101 needs to be connected to both heat and cool connections on the ST9120B,U.

**TWIN terminal is used to interconnect two ST9120B,U units to operate blower outputs simultaneously. Twinning at

new ST9120B,U control is not backwards compatible with legacy controls.

Table 1. ST9101 to ST9120B,U Wiring Conversions.

ON fan speed (see note below)

below)

ST9141 to ST9120B,U Wiring Conversion Instructions

1. Turn off power to appliance and carefully remove

each wire and connect directly to the new ST9120B,U control board before removing the existing control. Use Table 1 to determine the proper ST9120B,U terminal for each corresponding ST9141 connection. Be careful to directly connect the new terminal or label each wire prior to removal from original board.

2. Unplug the 9-pin connector and plug existing wiring

harness directly into the 9-pin connector found on the ST9141 wiring adapter 50034962. See Fig. 8 and Table 5 for further wire harness adapter description.

3. Plug the 6-pin connector found on the ST9141 wir-

ing adapter directly to the open 6-pin connector on the new ST9120B,U control board.

4. Take the gray wire on the ST9141 wiring adapter

and connect to the LIM quick connect terminal on the ST9120B,U.

5. Take the brown wire on the ST9141 wiring adapter

and connect to the PRSW quick connect terminal on the ST9120B,U.

6. Identify the model number of the board being

replaced and set the dip switches based on Table 3.

7. Check proper connection using Fig. 4.

ST9160 to ST9120B,U Wiring Conversion Instructions

1. Turn off power to appliance and carefully remove

2. Unplug the 6-pin connector and plug it into the J3

connector found on ST9120B,U.

3. Plug the jumper plug into the J1 connector at

ST9120B,U.

4. Identify the model number of the board being

replaced and set the dip switches based on Table 3.

5. Check proper connection using Fig. 5 or 6.

LED Diagnostic

The ST9120 control provides the following status information and diagnostic troubleshooting code sequence as shown in Table 2.

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ST9120B,U UNIVERSAL ELECTRONIC FAN TIMERS

Table 2. LED Diagnostic Troubleshooting Codes.

No. of flashes Condition

dim/on (heartbeat) Device works correctly.

1 Limit switch (ST9120) or burner limit switch (ST9141) is open. 2 Primary limit switch (ST9141) is open.

Pressure switch is improperly closed or pressure switch open when inducer blower has been

running for >30 sec. 4 Control is in lockout due to air not circulating (overheated). 5 Smart Valve II limit switch is open. 6 Twinning communication corrupted (check system transformers' phasing). 7 Wrong 24 VAC supply condition.

Table 3. Recommended Default Dip Switch Settings.

Legacy Timing New ST9120B,U

Replaced

Control Model

Number

Original OEM

Appliance

Heat OnHeat

sec sec sec sec 1 sec 2 3 sec 4 sec 5 sec

Off

Cool OnCool

Off Heat On Heat Off Cool On Cool Off

ST9101A1006 Rheem 30 100 4 0 off 30 off off 120 off 4 off 30 ST9101A1014 Rheem 30 100 4 0 off 30 off off 120 off 4 off 30 ST9101A1022 Trade 30 100 4 0 off 30 off off 120 off 4 off 30 ST9120A1006 Armstrong 30 100 4 0 off 30 off off 120 off 4 off 30 ST9120A2004 Armstrong 30 140 4 0 on 30 off on 150 off 4 off 30 ST9120B1005 Ducane 30 60 4 0 off 30 on off 60 off 4 off 30 ST9120C1012 Snyder General 60 100 4 0 on 60 off off 120 off 4 off 30 ST9120C1020 Nordyne 60 100 4 0 on 60 off off 120 off 4 off 30 ST9120C2002 York 30 100 4 30 off 30 off off 120 off 4 off 30 ST9120C2010 Ducane 30 100 4 30 off 30 off off 120 off 4 off 30 ST9120C2028 Armstrong 30 100 4 60 off 30 off off 120 off 4 on 60 ST9120C3000 ICP 30 140 30 30 off 30 off on 150 on 30 off 30 ST9120C3018 Bard 60 100 4 60 on 60 off off 120 off 4 on 60 ST9120C4008 ICP 30 140 30 30 off 30 off on 150 on 30 off 30 ST9120C4016 ICP 30 140 30 30 off 30 off on 150 on 30 off 30 ST9120C4040 ICP 30 140 30 30 off 30 off on 150 on 30 off 30 ST9120C4057 ICP 30 140 30 30 off 30 off on 150 on 30 off 30 *ST9120C5005 ICP 30 140 4 30 off 30 off on 150 off 4 off 30 *ST9120C5013 ICP 30 140 4 30 off 30 off on 150 off 4 off 30 *ST9120D3009 Goodman 30 140 4 60 off 30 off on 150 off 4 on 60 ST9120G2008 ICP 60 100 30 0 on 60 off off 120 on 30 off 30 ST9120G2016 ICP 30 100 30 30 off 30 off off 120 on 30 off 30 ST9120G2024 Skymark 30 60 30 30 off 30 on off 60 on 30 off 30 ST9120G2032 Skymark 30 60 4 100 off 30 on off 60 off 4 on 60 ST9120G4004 ICP 30 140 30 30 off 30 off on 150 on 30 off 30 ST9120G4012 ICP 30 140 30 30 off 30 off on 150 on 30 off 30 ST9120G4038 Trade 30 140 30 30 off 30 off on 150 on 30 off 30 ST9120U1003 Trade 30 140 4 30 off 30 off on 150 off 4 off 30

ST9141A1002

ST9141A1028

ST9141B1001

ST9150A1003

Consolidated Industries

30 140 6 60 off 30 off on 150 off 4 on 60

75 180 6 60 on 60 on on 180 off 4 on 60

36 168 7 72 off 30 on on 180 off 4 on 60

*Heat fan off delay setting may need adjustment based on performance. See Fig. 10 to adjust timings.

69-2252EF—07 4

ST9120B,U UNIVERSAL ELECTRONIC FAN TIMERS

Table 3. Recommended Default Dip Switch Settings. (Continued)

Legacy Timing New ST9120B,U

Replaced

Control Model

Number

Original OEM

Appliance

Heat OnHeat

sec sec sec sec 1 sec 2 3 sec 4 sec 5 sec

Off

Cool OnCool

Off Heat On Heat Off Cool On Cool Off

ST9150B2000 36 144 7 0 off 30 off on 150 off 4 off 30 ST9150B2018 ICP 30 140 30 30 off 30 off on 150 on 30 off 30 ST9150B2026 Ducane 36 144 7 36 off 30 off on 150 off 4 off 30 ST9150B2034 36 144 7 36 off 30 off on 150 off 4 off 30 ST9160A1002 Armstrong 30 90 6 60 off 30 off off 120 off 4 on 60 ST9160B1001 30 120 6 30 off 30 off off 120 off 4 off 30 ST9160B1019 30 120 6 30 off 30 off off 120 off 4 off 30 ST9160B1027 30 120 6 60 off 30 off off 120 off 4 on 60 ST9160B1035 30 120 6 30 off 30 off off 120 off 4 off 30 ST9160B1043 ICP 30 140 6 30 off 30 off on 150 off 4 off 30 ST9160B1050 ICP 30 140 6 60 off 30 off on 150 off 4 on 60 ST9160B1068 Armstrong 30 120 6 60 on 30 off off 120 off 4 on 30 ST9160B1076 Ducane 30 120 6 30 off 30 off off 120 off 4 off 30 ST9160B1084 ICP 30 140 6 90 off 30 off on 150 off 4 on 60 ST9160C1000 30 140 30 30 off 30 off on 150 on 30 off 30 ST9160C1018 30 140 30 30 off 30 off on 150 on 30 off 30 *ST9120B,U Factory Default

Setting

off 30 off off 120 off 4 off 30

*Heat fan off delay setting may need adjustment based on performance. See Fig. 10 to adjust timings.

NOTE: Timings may not be exactly the same as the replaced control and adjustments may need to be made.

5 69-2252EF—07

ST9120B,U UNIVERSAL ELECTRONIC FAN TIMERS

TO 115/230 VAC POWER SUPPLY

L1 (HOT)

L2 (N)

MV MV/PV PV

MV MV/PV PV BRN 24V 24V SPARK

S8600 IGNITION CONTROL

GND

DENOTES LINE VOLTAGE WIRING DENOTES LOW VOLTAGE WIRING

GND

FUSE

PRESSURE

PILOT BURNER

LIMIT SWITCH

ROLLOUT SWITCH

SWITCH

SENSE

NEUTRAL

UNUSED

FUSE

CXLIM

HUMIDIFIER

INDUCER

AIR

CLEANER

HUM

IND

CONT

EAC

COOL

HEAT

STATUS

C G Y W R

PRSW

CGYW

CONNECT ONLY IF CONTINUOUS SPEED IS AVAILABLE AND USED.

CONNECT ONLY IF CONTINUOUS SPEED IS NOT USED.

DELAY

TWIN

THERMOSTAT

STARTING

FAN

HI ML MH LO

115/230 VAC TRANSFORMER 24 VAC

CAP

M27704

Fig. 1. Typical ST9120B,U wiring connections in ST9120 system with S8600 Intermittent Pilot Ignition Control.

69-2252EF—07 6

ST9120B,U UNIVERSAL ELECTRONIC FAN TIMERS

CGYW

HUM

IND

NEUTRAL

C G Y W R

THERMOSTAT

115/230 VAC TRANSFORMER 24 VAC

CONNECT ONLY IF CONTINUOUS SPEED IS AVAILABLE AND USED.

CONNECT ONLY IF CONTINUOUS SPEED IS NOT USED.

PRESSURE SWITCH

ROLLOUT

SWITCH

LIMIT

SWITCH

SV9500 HOT SURFACE IGNITION CONTROL

CXLIM

PRSW

FAN

STARTING CAP

AIR CLEANER

HUMIDIFIER

TO 115/230 VAC POWER SUPPLY

L2 (N)

L1 (HOT)

FUSE

INDUCER

DELAY

CONT

EAC

COOL

HEAT

TWIN

FUSE

STATUS

UNUSED

DENOTES LINE VOLTAGE WIRING DENOTES LOW VOLTAGE WIRING

M27705

24 VOLT COMMON

24 VOLT HOT

EFT OUTPUT

24 VOLT THERMOSTAT OR PRESSURE SWITCH

Fig. 2. Typical ST9120B,U wiring connections in ST9120 system with SV9500/SV9501 SmartValve™ Control.

7 69-2252EF—07

ST9120B,U UNIVERSAL ELECTRONIC FAN TIMERS

C G Y W R

DELAY

NEUTRAL

HUM

IND

CONT

EAC

COOL

HEAT

UNUSED

TWIN

CXLIM

PRSW

STATUS

THERMOSTAT

FAN

STARTING

CAP

115/230 VAC TRANSFORMER 24 VAC

LO HL HH

AUX

VENT

ROLLOUT

MAIN LIMIT

PRESSURE

SWITCH

FUSE

L2 WHITE

PS/MV DRIVE ORANGE

LIMIT RED LIMIT RED L1 BLACK 24V GND YELLOW MV SENSE VIOLET INDUCER BLUE

WIRE HARNESS ADAPTER

GAS

VALV E

TO 115/230 VAC

POWER SUPPLY

L2 (N)

L1 (HOT)

FUSE

INDUCER

L2 WHITE

DENOTES LINE VOLTAGE WIRING DENOTES LOW VOLTAGE WIRING

3 6 1 4 2 5

1 2 3

4 5

6 7 8 9

M27777

C G Y W R

CXLIM

PRSW

CGYW

THERMOSTAT

115/230 VAC TRANSFORMER 24 VAC

PRESSURE

SWITCH

TO 115/230 VAC POWER SUPPLY

L2 (N)

L1 (HOT)

1 2 3 4 5 6 7 8 9

24V 24V GND W 24V FT BRN LIM PRSW PRIM LIM

1 2 3 4 5 6

ST9141 WIRE HARNESS ADAPTER

SV9500 HOT SURFACE IGNITION CONTROL

N.C.

N.O.

COM

N.C.

FUSE

PRIMARY

LIMIT

BURNER

LIMIT

24 VOLT COMMON

24VOLT HOT

EFT OUTPUT

24 VOLT THERMOSTAT OR PRESSURE SWITCH

FAN

STARTING

CAP

AIR

CLEANER

HUMIDIFIER

INDUCER

DELAY

HUM

IND

CONT

EAC

COOL

HEAT

TWIN

FUSE

STATUS

NEUTRAL

UNUSED

RED

YELLOW

RED

VIOLET

ORANGE

GRAY

BROWN

RED

CONNECT ONLY IF CONTINUOUS SPEED IS AVAILABLE AND USED.

CONNECT ONLY IF CONTINUOUS SPEED IS NOT USED.

DENOTES LINE VOLTAGE WIRING DENOTES LOW VOLTAGE WIRING

M27722

Fig. 3. Typical ST9120B,U wiring connections in ST9101 system.

Fig. 4. Typical ST9120B,U wiring connections in ST9141 system with SV9500/SV9501 SmartValve™ Control.

69-2252EF—07 8

ST9120B,U UNIVERSAL ELECTRONIC FAN TIMERS

TO 115 VAC POWER SUPPLY

L1 (HOT)

L2 (N)

115 VAC TRANSFORMER 24 VAC

LOAD

DENOTES LINE VOLTAGE WIRING DENOTES LOW VOLTAGE WIRING

FUSE

COMMON

NEUTRAL

HUMIDIFIER

UNUSED

AIR CLEANER

STARTING

CAP

INDUCER

NEUTRAL

SV9501; SV9520

HUM

IND

EAC

COOL

CONT

C G Y W R

THERMOSTAT

THERE MUST BE 115 VAC CONNECTED TO L1 (HOT) ON ST9120U, ST9120B.

APPLIANCE CHASSIS MUST HAVE RELIABLE CONNECTION TO EARTH GROUND.

JUMPER PLUG MUST BE ATTACHED TO J1 CONNECTOR.

CONNECT ONLY IF CONTINUOUS SPEED IS AVAILABLE AND USED.

CONNECT ONLY IF CONTINUOUS SPEED IS NOT USED

FAN

HI ML MH LO

HEAT

C R

DATA

NEUTRAL L1

PRESSURE

SWITCH

HOT

ROLLOUT

LIMIT

SWITCH

FLAME ROD HOT

SURFACE IGNITER

M16880

Fig. 5. Typical ST9120B,U wiring connections in ST9160 system with SV9510/SV9520 SmartValve™ Control.

9 69-2252EF—07

ST9120B,U UNIVERSAL ELECTRONIC FAN TIMERS

TO 115/230 VAC

POWER SUPPLY

L1 (HOT)

L2 (N)

115/230 VAC

TRANSFORMER

24 VAC

DENOTES LINE VOLTAGE WIRING DENOTES LOW VOLTAGE WIRING

FOR 115 VAC / 50, 60 HZ INSTALLATIONS, THERE MUST BE 115 VAC CONNECTED TO L1 (HOT) ON ST9120U, ST9120B. FOR 230 VAC / 60 HZ INSTALLATIONS, THERE MUST BE 115 VAC BETWEEN L1 (HOT) AND APPLIANCE CHASSIS. FOR 230 VAC / 50 HZ INSTALLATIONS, USE ONLY WITH SMART VALVE RATED FOR THE SAME LINE VOLTAGE PARAMETERS.

APPLIANCE CHASSIS MUST HAVE RELIABLE CONNECTION TO EARTH GROUND.

JUMPER PLUG MUST BE ATTACHED TO J1 CONNECTOR.

CONNECT ONLY IF CONTINUOUS SPEED IS AVAILABLE AND USED.

CONNECT ONLY IF CONTINUOUS SPEED IS NOT USED

FUSE

LOAD

COMMON

HUMIDIFIER

NEUTRAL

UNUSED

AIR

CLEANER

PRESSURE

INDUCER

HOT

SWITCH

LIMIT

ROLLOUT

SWITCH

Q345 IGNITERSENSOR

M27724A

STARTING

FAN

IND

HUM

EAC

CONT

C G Y W R

THERMOSTAT

COOL

HEAT

HI ML MH LO

C R 24VAC

DATA

NEUTRAL L1

CAP

NEUTRAL

SV9540; SV9640

Fig. 6. Typical ST9120B,U wiring connections in ST9160 system with SV9540/SV9640 SmartValve™ Control.

69-2252EF—07 10

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