Honeywell RM7840G User Manual

66-1085—3

8

POWER

INITIATE
(INITIAL
POWERUP 
ONLY)

POWER

STANDBY

PREPURGE
HOLD 
DRIVE TO
LOW FIRE 

POWER

PILOT

FLAME

MAIN

POWER

PFEP
10 SEC.
(4 SEC. IF
JR1 CLIPPED

PILOT

FLAME

MAIN

POWER

MFEP

PILOT

FLAME

MAIN

RUN

POWER

POSTPURGE

POWER

STANDBY

00

00

10

25

00

15

20

MOTOR ACTION

BURNER/BLOWER MOTOR

IGN.

15/30 SEC. INTERRUPTED/INTERMITTENT PILOT VALVE 

LIMITS AND BURNER CONTROLLER CLOSED

RUNNING INTERLOCKS CLOSED

PREIGNITION INTERLOCK CLOSED 

LOW FIRE SW.

SAFE START CHECK

FLAME PROVING

10 SEC. IGN./PILOT 8

10

5

5 SEC.

21

6

TO

7

TO

20

TO

5

18

TO

13

15

TO

13

12

TO

M12264A

INTERLOCK. CHECK

13

14

TO

13

14

TO

4

6

L1

MAIN VALVE

9

TIMED
PREPURGE 

POWER

FLAME

MAIN

PILOT

ALARM

POWER

FLAME

MAIN

PILOT

ALARM

ALARM

ALARM

ALARM

00

IC

PII

SSC

RM7800/7840G SWITCHING

M12260B

G 

L2 

3 

4 

5 

6 

7 

8 

9 

10 

F 

(L1)

13  

14  

15  

16  

17  

18  

19  

20  

21

22

12  

RUNNING INTERLOCKS 
(INC. AIR FLOW SWITCH)

MASTER
SWITCH

LOW FIRE 
START SWITCH

5 SECOND IGNITION
(EARLY SPARK
TERMINATION)

MAIN FUEL VALVE(S)

BURNER 
CONTROLLER/LIMITS

BURNER MOTOR 
(BLOWER)

HIGH FIRE

COMMON

LOW FIRE

MODULATE

120V ALARM

10 SEC. INTERRUPTED
PILOT/IGNITION

PREIGNITION
INTERLOCK

SERIES 90
FIRING RATE
MOTOR

SERIES 90
CONTROLLER

FLAME DETECTOR

120V, 50/60 Hz POWER SUPPLY.  PROVIDE DISCONNECT 
MEANS AND OVERLOAD PROTECTION AS REQUIRED.

ADD JUMPER FOR 30 SECOND MAIN FLAME 
ESTABLISHING PERIOD (MFEP).

DO NOT WIRE TO ANY UNUSED TERMINALS.

SEE FLAME DETECTOR INSTALLATION INSTRUCTIONS
FOR CORRECT WIRING.

FOR DIRECT SPARK IGNITION 
(OIL OR GAS)

IGNITION
TRANSFORMER

2ND STAGE 
FUEL VALVE 
(OPTIONAL)

R

W

B

R

W

B

L1 
(HOT)

L2

1

21

9

10 

1ST STAGE 
FUEL VALVE

L2  

Q7800

3

15 OR 30 SEC. 
INTERRUPTED/
INTERMITTENT
PILOT VALVE

2

2

1

3

4

4

4

JUMPER WIRE FOR 30s MFEP