24A34 Series
Fan/Heat Sequencers
INSTALLATION INSTRUCTIONS
DESCRIPTION
SPECIFICATIONS
The 24A34 Series Fan/Heat Sequencer gives the service tech-
nician a direct replacement for sequencing both fan and heat.
The terminal markings on the 24A34 sequencers are equivalent
to most other manufacturers’ types.
These sequencers may be wired in series, as shown in wiring
diagrams, to allow sequencing of one through seven element
furnaces.
CAUTION
!
To prevent electrical shock and/or equipment damage,
disconnect electric power to system, at main fuse or
circuit breaker box, until installation is complete.
Do not use on circuits exceeding specified voltage.
Higher voltage will damage control and could cause
shock or fire hazard.
FAILURE TO READ AND FOLLOW ALL INSTRUCTIONS CAREFULLY BEFORE
INSTALLING OR OPERATING THIS CONTROL COULD CAUSE PERSONAL
INJURY AND/OR PROPERTY DAMAGE.
www.white-rodgers.com
www.emersonclimate.com
PART NO. 37-4800C
Replaces 37-4800B
1050
TABLE NOTES:
➀ M1-M2 and M3-M4 are always first switches to turn ON and last to turn OFF. All other switches are random ON and random OFF
➁ 24A34-14 Switch contacts designated F1 - F2 instead of M1 - M2
♦ These contacts switch simultaneously
NOTE: Underwriters Laboratories requires a fan interlock circuit to insure the blower remains operating whenever more than one sequencer is used. The fan in-
terlock should be the M1 / M2 contacts of the second or third sequencer. All M1 / M2 contacts are wired to the blower motor so that any sequencer that is energized
will keep the blower ON.
Electrical Ratings - Single Load Contact Ratings (All Models)
VAC
Resistive (Non-Inductive) Motor Ratings (Inductive)
Pilot DutyWatts Amps Full Load Locked Rotor
120 3000 25.0 14.0A 72.0A 125 VA
240 6000 25.0 7.0A 42.0A 125 VA
480 6000 12.5 – – 480 VA
Electrical Ratings - Single Load Contact Ratings (All Models)
Model
Number Timings Switches
Timings – ON Timings – OFF
M1-M2 M3-M4 M5-M6 M7-M8 M9-M10 M1-M2 M3-M4 M5-M6 M7-M8 M9-M10
24A34-1 1 1 1-20 – – – – 40-110 – – – –
24A34-2 1 1 – – 30-90 – – – – 1-30 – –
24A34-3 ➀1 2 1-20 1-20 – – – 40-110 40-110 – – –
24A34-4 1 2 – – 30-90 30-90 – – – 1-30 1-30 –
24A34-5 ➀2 3 1-110 1-110 1-110 – – 1-110 1-110 1-110 – –
24A34-6 ➀2 4 1-110 1-110 1-110 1-110 – 1-110 1-110 1-110 1-110 –
24A34-14 ➀➁ 4 5 1-160 1-160 1-160 1-160 1-160 1-160 1-160 1-160 1-160 1-160
24A34-15 1 1 1-60 – – – – 75-95 – – – –
♦
♦ ♦
♦
♦♦
♦ ♦ ♦ ♦
♦
♦
2
WIRING DIAGRAMS
FOR ONE ELEMENT FURNACES
FAN DELAY OFF
COMBINATION Fan and Heater Loads
SEPARATE Fan and Heater Loads
ONE POLE
WIRING
M2M1 To 1st element & fan
HH To 24 VAC wall thermostat
(One Timing)
24A34-1 / -2
TWO POLE
WIRING
M2M1 To fan
HHTo 24vAC wall thermostat
(One Timing)
24A34-3 / -4
M4M3 To 1st element
DOTTED LINE BETWEEN "H" TERMINAL
IS A FACTORY-INSTALLED JUMPER
FOR TWO ELEMENT FURNACES
COMBINATION Fan and Heater Loads
SEPARATE Fan and Heater Loads
FOR THREE ELEMENT FURNACES WITH
COMBINATION FAN & HEATER LOADS
SINGLE-STAGE Room Thermostat
TWO-STAGE Room Thermostat Option
TWO POLE
WIRING
M2M1 To 1st element & fan
HHTo 24vAC wall thermostat
(One Timing)
24A34-3 / -4
M4M3 To 2nd element
TWO POLE
WIRING
M6M5 To 2nd element or aux. contacts
H
HTo 24vAC wall thermostat
(Two Timings)
24A34-5
M2M1 To fan
M4M3 To 1st element
H
H
ONE POLE
TWO POLE
WIRING
M6M5 To 3rd element
H
H
To 24vAC wall thermostat
(Two Timings)
24A34-5
M2M1 To fan & 1st element
M4M3 To 2nd element
H
H
ONE POLE
TWO POLE
WIRING
M8M7 To 3rd element
H
H
To 24vAC wall thermostat
(Two Timings)
24A34-6
M2M1 To fan & 1st element
M4M3 To 2nd element
H
H
TWO POLE
M6M5
FOR THREE ELEMENT FURNACES WITH
SEPARATE FAN & HEATER LOADS
SINGLE-STAGE Room Thermostat
TWO-STAGE Room Thermostat Option
TWO POLE
WIRING
M8M7 To 3rd element
H
H
To 24vAC wall thermostat
(Two Timings)
24A34-5
M2M1 To fan
M4M3 To 1st element
H
H
TWO POLE
M6M5 To 2nd element
TWO POLE
M8M7 To 2nd element
H
H
To W1 of 24vAC wall thermostat
(Two Timings)
24A34-6
M2M1 To fan
M4M3 To 1st element
H
H
TWO POLE
M6M5 To common of 24v transformer
TWO POLE
WIRING
M2M1 To fan interlock
HHTo W2 of 24vAC wall thermostat
(One Timing)
24A34-3 / -4
M4M3 To 3rd element
WIRING
2
3
INormally close
H
H
Normally open
(One Timing)
24A34-15
3
WIRING DIAGRAMS
FOR FOUR ELEMENT FURNACES
COMBINATION Fan and Heater Loads
SEPARATE Fan and Heater Loads
TWO POLE
WIRING
M8M7 To 4th element
H
H
To 24vAC wall thermostat
(Two Timings)
24A34-6
M2M1 To fan & 1st element
M4M3 To 2nd element
H
H
TWO POLE
M6M5 To 3rd element
SINGLE-STAGE Room Thermostat
TWO POLE
M8M7 To 2nd element
H
H
To W1 of 24vAC wall thermostat
(Two Timings)
24A34-6
M2M1 To fan
M4M3 To 1st element
H
H
TWO POLE
M6M5 To common of 24v transformer
TWO POLE
WIRING
M6M5 To 4th element
H
H
(Two Timings)
24A34-5
M2M1 To fan interlock
M4M3 To 3rd element
H
H
ONE POLE To W2 of 24vAC wall thermostat
TWO-STAGE Room Thermostat Option after 2nd Element
To W1 of 24vAC wall thermostat
To 2nd element
To common of 24v transformer
TWO POLE
WIRING
M6M5 To 4th element
H
H
(Two Timings)
24A34-5
M2M1 To fan interlock
M4M3 To 3rd element
H
H
ONE POLE To W2 of 24vAC wall thermostat
TWO POLE
M6M5
H
H
(Two Timings)
24A34-5
M2M1
M4M3
H
H
ONE POLE
To fan & 1st element
TWO-STAGE Room Thermostat Option after 2nd Element
DOTTED LINE BETWEEN "H" TERMINAL
IS A FACTORY-INSTALLED JUMPER
FOR FIVE ELEMENT FURNACES
COMBINATION Fan and Heater Loads
SEPARATE Fan and Heater Loads
TWO POLE
M8M7 To 3rd element
H
H
To W1 of 24vAC wall thermostat
(Two Timings)
24A34-6
M2M1 To fan & 1st element
M4M3 To 2nd element
H
H
TWO POLE
M6M5 To common of 24v transformer
TWO POLE
WIRING
M6M5 To 5th element
H
H
(Two Timings)
24A34-5
M2M1 To fan interlock
M4M3 To 4th element
H
H
ONE POLE To W2 of 24vAC wall thermostat
TWO-STAGE Room Thermostat Option After 3rd Element
TWO POLE
M8M7
To 3rd element
H
H
To W1 of 24vAC wall thermostat
(Two Timings)
24A34-6
M2M1 To fan
M4M3
To 2nd element
H
H
TWO POLE
M6M5 To common of 24v transformer
To 5th element
To fan interlock
To 4th element
To W2 of 24vAC wall thermostat
TWO POLE
WIRING
M8M7
H
H
(Two Timings)
24A34-6
M2M1
M4M3
H
H
TWO POLE
M6M5
To 1st element
TWO-STAGE Room Thermostat Option After 2nd Element
TWO POLE
M8M7
To 5th element
H
H
To W1 of 24vAC wall thermostat
(Two Timings)
24A34-6
M2M1 To fan & 1st element
M4M3
To 4th element
H
H
TWO POLE
M6M5
To common of 24v transformer
To 7th element
To fan interlock
To 6th element
To W2 of 24vAC wall thermostat
TWO POLE
M8M7
H
H
(Two Timings)
24A34-6
M2M1
M4M3
H
H
TWO POLE
M6M5
To 3rd element
TWO POLE
WIRING
M6M5
H
H
(Two Timings)
24A34-5
M2M1 To fan interlock
M4M3
H
H
ONE POLE
To W2 of 24vAC wall thermostat
To common of 24v transformer
To 2nd element
TWO-STAGE Room Thermostat Option After 3rd or 5th Element
TWO POLE
M8M7
To 5th element
H
H
To W1 of 24vAC wall thermostat
(Two Timings)
24A34-6
M2M1 To fan
M4M3
To 4th element
H
H
TWO POLE
M6M5
To common of 24v transformer
To 7th element
To fan interlock
To 6th element
To W2 of 24vAC wall thermostat
TWO POLE
M8M7
H
H
(Two Timings)
24A34-6
M2M1
M4M3
H
H
TWO POLE
M6M5
To 3rd element
WIRING
To fan interlock
To W2 of 24vAC wall thermostat
To common of 24v transformer
To 2nd element
TWO-STAGE Room Thermostat Option After 3rd or 5th Element
TWO POLE
M8M7
H
H
(Two Timings)
24A34-6
M2M1
M4M3
H
H
TWO POLE
M6M5
To 1st element
FOR SIX ELEMENT FURNACES
COMBINATION Fan and Heater Loads
SEPARATE Fan and Heater Loads
DOTTED LINE BETWEEN "H" TERMINAL
IS A FACTORY-INSTALLED JUMPER
TWO POLE
M8M7
To 4th element
H
H
To W1 of 24vAC wall thermostat
(Two Timings)
24A34-6
M2M1 To fan & 1st element
M4M3
To 3rd element
H
H
TWO POLE
M6M5 To common of 24v transformer
To 6th element
To fan interlock
To 5th element
To W2 of 24vAC wall thermostat
TWO POLE
WIRING
M8M7
H
H
(Two Timings)
24A34-6
M2M1
M4M3
H
H
TWO POLE
M6M5
To 2nd element
TWO-STAGE Room Thermostat Option After 3rd Element
TWO POLE
M8M7
To 4th element
H
H
To W1 of 24vAC wall thermostat
(Two Timings)
24A34-6
M2M1 To fan
M4M3
To 3rd element
H
H
TWO POLE
M6M5
To common of 24v transformer
To 6th element
To fan interlock
To 5th element
To W2 of 24vAC wall thermostat
TWO POLE
M8M7
H
H
(Two Timings)
24A34-6
M2M1
M4M3
H
H
TWO POLE
M6M5
To 2nd element
TWO POLE
WIRING
M6M5
H
H
(Two Timings)
24A34-6
M2M1 To fan interlock
M4M3
H
H
ONE POLE
To W2 of 24vAC wall thermostat
To common of 24v transformer
To 1st element
TWO-STAGE Room Thermostat Option After 2nd or 4th Element
FOR SEVEN ELEMENT FURNACES
COMBINATION Fan and Heater Loads
SEPARATE Fan and Heater Loads
WIRING DIAGRAMS
White-Rodgers is a division
of Emerson Electric Co.
The Emerson logo is a
trademark and service mark
of Emerson Electric Co.
www.white-rodgers.com
www.emersonclimate.com
