Honeywell 7800 SERIES User manual

1 65-0120—1
The Honeywell RM7838B is a microprocessor based
integrated burner control for industrial process semi-
automatically fired gas, oil, coal or combination of fuels
for single burner applications. The RM7838B consists
of a Relay Module, Subbase, Amplifier, Keyboard Dis-
play Module and Purge Card. Options include Personal
Computer Interface, DATA CONTROLBUS MOD-
ULE™,RemoteDisplayMounting,First-OutExpanded
Annunciator and software COMBUSTION SYSTEM
MANAGER®.
The RM7838B is programmed to provide a level of
safety, functional capability and features beyond the
capacity of conventional process control combustion
systems.
Functions provided by the RM7838B include auto-
matic modulated high fire and low fire proven purge,
burner pilot start up with pilot valve hold, a special
pilot valve hold from the Run condition, flame supervi-
sion, system status indication, system or self-diagnos-
tics and troubleshooting.
7800 SERIES
RM7838B Relay Module
L.Z. • Rev. 1-95 • ©Honeywell Inc. 1995
65-0120-1
■Safety features:
— Combustion Interlock check.
— Closed loop logic test.
— Dynamic input check.
— Dynamic safety relay test.
— Dynamic self-check logic.
— Expanded safe-start check.
— High Fire Purge Switch test.
— Internal hardware status monitoring.
— Low Fire Purge Switch test.
— Tamper resistant timing and logic.
■Access for external electrical voltage checks.
■Application flexibility.
■Communication interface capability via personal com-
puter utilizing MicroSoft®Windows™ software.
■First out annunciation and system diagnostics provided by
2 row by 20 column Vacuum Fluorescent Display (VFD)
located within the local or remotely mounted Keyboard
Display Module.
■First out expanded annunciation with 24 limit and inter-
lock Light Emitting Diodes (LEDs) (optional).
■Five sequence information LEDs.
■Five function Run/Test Switch.
■Interchangeable plug-in flame amplifiers.
■Local or remote annunciation of operation and fault
information.
■Dependable,long-termoperationprovidedbymicrocom-
puter technology.
■Nonvolatile memory for retaining history files and se-
quencing status after loss of power.
■Remote reset (optional).
■Report generation (optional).
■Burner controller data (optional):
— Sequence status.
— Sequence time.
— Hold status.
— Lockout/alarm status.
— Flame signal strength.
— Expanded annunciator status.
— Total cycles of operation.
— Total hours of operation.
— Fault history of six most recent faults:
• Cycles of operation at time of fault.
• Expanded annunciator data at time of fault.
• Fault message and code.
• Hours of operation at time of fault.
• Sequence status at time of fault.
• Sequence time at time of fault.
— Diagnostic information:
• Device type.
• Flame amplifier type.
• Flame failure response time.
• Manufacturing code.
• On/Off status of all line voltage digital inputs.
• Selected purge time.
• Software revision and version of RM7838B and
Keyboard Display Module.
• Status of configuration jumpers.
• Status of Run/Test switch.
• On/Off status of all line voltage digital outputs.

65-0120—1 2
RM7838B
TABLE OF CONTENTS • ORDERING INFORMATION
Table of Contents
Ordering Information ................................................. 2
Specifications.............................................................. 3
Principal Technical Features.................................... 10
Safety Provisions ...................................................... 10
Installation ............................................................... 12
Operation ................................................................. 24
Static Checkout ......................................................... 33
Checkout .................................................................. 35
Troubleshooting........................................................ 42
Tables:
Table 1—Terminal Ratings....................................... 3
Table 2—Flame Detection Systems........................... 4
Table 3—Sequence Status Display Information ...... 28
Table 4—Selectable Messages ................................ 30
Table 5—Expanded Annunciator ............................ 32
Table 6—Site Configurable Jumper Options........... 33
Table 7—Static Checkout ....................................... 34
Table 8—Flame Signal ........................................... 36
Table 9—Sequence and Status Hold Messages ....... 42
Table 10—Accessing Historical
and Diagnostic Selectable Messages .................. 45
Table 11—Selectable Messages .............................. 46
Table 12—Hold and Fault Message Summary ........ 49
Table 13—Expanded Annunciator Hold Codes....... 52
Table 14—Expanded Annunciator Fault Codes ...... 52
Table 15—Expanded Annunciator Diagnostic
Current Status Messages.................................... 53
Figures:
Fig. 1—Mounting dimensions of the RM7838B
Relay Module and Q7800A Subbase, in in. (mm) ..... 6
Fig. 2—Mounting dimensions of the RM7838B
Relay Module and Q7800B Subbase, in in. (mm) ..... 6
Fig. 3—Mounting dimensions of the Keyboard
Display Module in in. (mm) ..................................... 7
Fig. 4—Rectification Detectors .................................... 7
Fig. 5—Ultraviolet detectors ........................................ 8
Fig. 6—Infrared detectors ............................................ 9
Fig. 7—Internal block diagram of the RM7838B
(See Figs. 8 or 9 for detailed wiring
instructions) .......................................................... 13
Fig. 8—RM7838B wiring with S445 start-stop
station ................................................................... 16
Fig. 9—RM7838B wiring with separate start-stop
station ................................................................... 17
Fig. 10—RM7838B wiring with separate start
and stop stations with 4 to 20 mA firing rate
control circuit........................................................ 18
Fig. 11—Wiring the Keyboard Display Module with
Communication Interface ControlBus Module....... 19
Fig. 12—Wiring for multiple Keyboard Display
Modules ................................................................ 19
Fig. 13—Electrical panel installation......................... 20
Fig. 14—Wall or burner installation .......................... 20
Fig. 15—ST7800 Purge Card installation .................. 20
Fig. 16—Keyboard Display Module mounting ........... 21
Fig. 17—DATA CONTROLBUS MODULE™
mounting ............................................................... 21
Fig. 18—Remote mounting of Jkeyboard
Display Module ..................................................... 22
Fig. 19—Flame signal amplifier mounting ................. 22
Fig. 20—Flame detector wiring ................................. 23
Fig. 21—Operation of the RM7838B Relay
Module .................................................................. 25
Fig. 22—Operation of the RM7838B Relay
Module .................................................................. 26
Fig. 23—Keyboard Display Module and sequence ..... 27
Fig. 24—( ◊ ) SCROLL pushbutton function ................. 29
Fig. 25 ( ↔ )—Change-Level pushbutton function ....... 29
Fig. 26—MODE pushbutton function ......................... 30
Fig. 27—SAVE function ............................................. 30
Fig. 28—Selectable site-configurable jumpers............ 33
Fig. 29—Flame signal measurement .......................... 36
Fig. 30—Flame-out timer lockout............................... 39
Fig. 31—Lockout message state 1 .............................. 48
Fig. 32—Lockout message state 2 .............................. 49
Fig. 33—Lockout message state 3 .............................. 49
Fig. 34—Flush mounting of Keyboard Display
Module template.................................................... 54
OrderingInformation
When purchasing replacement and modernization products from your 7800 SERIES distributor, refer to the TRADELINE®Catalog for
complete ordering number.
If you have additional questions, need further information, or would like to comment on our products or services, please write or
phone:
1. Your local Home and Building Control Sales Office (check white pages of your phone directory).
2. Home and Building Control Customer Logistics
Honeywell Inc., 1885 Douglas Drive North
Minneapolis, Minnesota 55422-4386 [phone]
In Canada—Honeywell Limited/Honeywell Limitée, 740 Ellesmere Road, Scarborough, Ontario M1P2V9. International Sales
and Service Offices in all principal cities of the world. Manufacturing in Australia, Canada, Finland, France, Germany, Japan,
Mexico, Netherlands, Spain, Taiwan, United Kingdom, U.S.A.

3 65-0120—1
RM7838B
SPECIFICATIONS
Specifications
ELECTRICAL RATINGS (See Table 1):
VoltageandFrequency:120Vac(+10/-15%),50or60Hz
(+/- 10%)*
Keyboard Display Module: 13.0 Vdc peak full wave
rectified (+20/-15%)
Power Dissipation:
RM7838B: 10W maximum.
Display Module: 3W maximum.
Maximum Total Connected Load: 2000 VA.
Fusing: Total Connected Load: 20A maximum, type
FRN or equivalent.
ENVIRONMENTAL RATINGS:
Ambient Temperature:
Operating: -40°F to 140°F.
Storage: -40°F to 150°F.
Humidity: 85 percent RH continuous, noncondensing.
Vibration: 0.5G environment.
DIMENSIONS: Refer to Figs. 1, 2 and 3.
WEIGHT:
RM7838B: 1 pound 10 ounces, unpacked.
Keyboard Display Module: 4 ounces, unpacked.
IMPORTANT: A Flame Detection System that must be
orderedseparatelyisrequired foroperation.Toselect
your Plug-in Flame Signal Amplifier and matching
Flame Detector, see Table 2.
APPROVAL BODIES:
Underwriters Laboratories Inc. listed, File No. MP268,
Guide No. MCCZ.
Canadian Standards Association certified, LR9S329-3.
Factory Mutual approved, Report No. J.I.2X0A1.AF.
IRI acceptable.
FederalCommunications Commission,Part15,ClassB—
Emissions.
MOUNTING:Q7800A1005forpanelmountorQ7800B1003
for wall or burner mount.
REQUIRED COMPONENTS:
Plug-in Flame Signal Amplifier (see Table 2)
Mounting Subbase:
Q7800A1005 for panel mounting.
Q7800B1003 for wall mount applications.
Plug-in Purge Timer Cards:
TABLE 1—TERMINAL RATINGS.
Terminal No. Description Ratings
G Flame Sensor Ground 60 to 220 Vac, current limited.
Earth G Earth Ground1
L2(N) Line Voltage Common
3 Alarm 120 Vac, 1A pilot duty.
4 Line Voltage Supply (L1) 120 Vac (+10/-15%), 50 or 60 Hz (+/- 10%).2,5
5 Combustion Blower 120 Vac, 9.8AFL, 58.8ALR (inrush).
6 Stop Input 120 Vac, 1 mA.
7 Lockout Interlock 120 Vac, 9A.
8 Interrupted Pilot 120 Vac, 4.5A ignition and 50VA pilot duty.3
9 Main Fuel Valve 120 Vac, 2A pilot duty.4
10 Ignition 120 Vac, 4.5A Ignition.3
(Continued)
Timing Part Number
2 seconds ST7800A1005
7 seconds ST7800A1013
10 seconds ST7800A1021
30 seconds ST7800A1039
40 seconds ST7800A1047
60 seconds ST7800A1054
90 seconds ST7800A1062
2.5 minutes ST7800A1070
4 minutes ST7800A1088
6 minutes ST7800A1096
9 minutes ST7800A1104
12 minutes ST7800A1112
15 minutes ST7800A1120
22 minutes ST7800A1138
30 minutes ST7800A1146
*Operating frequency chosen by selecting RM7838B.

65-0120—1 4
RM7838B
SPECIFICATIONS
TABLE 1—TERMINAL RATINGS (Continued).
Terminal No. Description Ratings
F(11) Flame Sensor 60 to 220 Vac, current limited.
12 Firing Rate High Fire 120 Vac, 75 VA pilot duty.
13 Firing Rate Common 120 Vac, 75 VA pilot duty.
14 Firing Rate Low Fire 120 Vac, 75 VA pilot duty.
15 Firing Rate Modulate 120 Vac, 75 VA pilot duty.
16 Pilot Valve Hold Input 120 Vac, 1 mA.
17 Manual Open Switch 120 Vac, 1 mA.
18 Low Fire Switch 120 Vac, 1 mA.
19 High Fire Switch 120 Vac, 1 mA.
20 Preignition Interlock 120 Vac, 1 mA.
21 Start Switch Input 120 Vac, 1A pilot duty.
22 Shutter 120 Vac, 0.5 A.
1TheRM7838Bmusthavean earth ground providing a connection between thesubbaseandthecontrolpanelorthe boiler. The
earth ground wire must be capable of conducting the current to blow the 20A fuse (or breaker) in event of an internal short
circuit. The RM7838B needs a low impedance ground connection to the equipment frame which, in turn needs a low
impedance connection to earth ground. For a ground path to be low impedance at RF frequencies, the connection must be
made by minimum length conductors having maximum surface areas. Wide straps or brackets are preferred rather than
leadwires. Be careful to ensure that mechanically tightened joints along the ground path, such as pipe or conduit threads or
surfaces held together with fasteners, are free of nonconductive coatings and are protected against mating surface corrosion.
22000 VA maximum connected load to RM7838B Assembly.
3Can also be 120 Vac, 1A pilot duty.
4Can also be 65 VA pilot duty with motorized valve, 1150 VA inrush, 460 VA open, 250 VA hold.
5Operating frequency chosen by RM7838B selection.
TABLE 2—FLAME DETECTION SYSTEMS (FIGS. 4, 5, 6).
(Continued)
Plug-in Flame Signal Amplifiers Applicable Flame Detectors
Type Color Self- Checking Model
Flame
Failure
Response
Time Fuel Type Models
Rectification Green No R7847A .8 or 3 sec Gas Rectifying
Flame Rod
Holders
a
C7004, C7007, C7011.
CompleteAssemblies:
C7008, C7009, Q179.
No R7847A .8 or 3 sec Oil Rectifying
Photocell C7003, C7010, C7013, C7014.
b
No R7847A 3 sec Gas, oil,
coal Ultraviolet (PurplePeeper) C7012A,C.
c
Dynamic
AMPLI-
CHECK™
R7847B
d
.8 or 3 sec Gas Rectifying
Flame Rod
Holders
d
C7004, C7007, C7011.
Complete Assemblies:
C7008, C7009, Q179.
Dynamic
AMPLI-
CHECK™
R7847B
d
.8 or 3 sec Oil Rectifying
Photocell C7003, C7010, C7013, C7014.
b
Dynamic
AMPLI-
CHECK™
R7847B
d
3 sec Gas, oil,
coal Ultraviolet (Purple Peeper) C7012A,C.
c

5 65-0120—1
TABLE 2—FLAME DETECTION SYSTEMS (Continued)
Plug-in Flame Signal Amplifiers Applicable Flame Detectors
Type Color Self- Checking Model
Flame
Failure
Response
Time Fuel Type Models
Rectification
(Continued) Green Dynamic Self-Check R7847C
e
3 sec Gas, oil,
coal Ultraviolet (Purple Peeper) C7012E,F.
Infrared Red No R7848A 3 sec Gas, oil,
coal Infrared (Lead Sulfide) C7015.
Dynamic
AMPLI-
CHECK™
R7848B
d
3 sec Gas, oil,
coal Infrared (Lead Sulfide) C7015.
Ultraviolet Purple No R7849A .8 or 3 sec Gas, oil Ultraviolet
(Minipeeper) C7027, C7035, C7044.
c
Dynamic
AMPLI-
CHECK™
R7849B
d
.8 or 3 sec Gas, oil Ultrviolet
(Minipeeper) C7027, C7035, C7044.
c
Blue Dynamic
Self-Check R7886A
e
3 sec Gas, oil,
coal Ultraviolet (Adjustable
Sensitivity)
C7076.
RM7838B
SPECIFICATIONS
aOrder flame rod separately; see holder Instructions.
bUse only Honeywell Photocell, part no. 38316.
cTheC7012A,C,C7027,C7035andC7044 flamedetectorsshould beusedonlyon burnersthatcycle on-offatleastonceevery
twenty-four hours. Appliances with burners that remain on for twenty-four hours continuously or longer should use the
C7012E,F Flame Detector with the R7847C Amplifier or the C7076A Flame Detector with the R7886A Amplifier as the
ultraviolet flame detection system.
dCircuitry tests the flame signal amplifier at least 12 times a minute during burner operation and shuts down the burner if the
amplifier fails.
eCircuitry tests all electronic components in the flame detection system (amplifier and detector) 12 times a minute during
burner operation and shuts down the burner if the detection system fails.
SEQUENCE TIMING FOR NORMAL OPERATION:
General Purpose Interface ControlBus™ Module—
part no. QS7850A1006.
Electrical Access Slot Covers—part no. 221779
Remote Display Mounting Bracket—part no. 203765.
Tester—part no. A7800A1002.
Remote Display Power Supply—part no. 203968A
Plug-in.
Sixty-inch Extension Cable Assembly—
part no. 221818A.
NEMA 4 Display Enclosure —part no. 204718A.
NEMA 4 Display Enclosure with Remote Reset
Button—part no. 204718C
Flame Simulator
—Ultraviolet—part no. 203659.
—Rectification—part no. 123514A.
Device Initiate Standby Purge Pilot Flame Establishing
Period (PFEP) Main Flame Establishing Period (MFEP) Run
RM7838B 10 sec. * ** 4/10 10 *** *
* STANDBY and RUN can be an infinite time period.
** PURGE will be determined by which ST7800A Purge Card is selected.
*** Immediate or deferred main flame.
ACCESSORIES:
Optional:
ControlBus 5-Wire Connector—part no. 203541.
COMBUSTION SYSTEM MANAGER™—
part no. ZM7850A1001.
Communication Interface Base Unit—
part no. Q7700A1014.
Communication Interface ControlBus™ Module—
part no. QS7800A1001.
Keyboard Display Module—part no. S7800A1001.
DATA CONTROLBUS MODULE™—
part no. S7810A1009.
Remote Reset Module—part no. S7820A1007.
Expanded Annunciator—part no. S7830A1005.

65-0120—1 6
RM7838B
SPECIFICATIONS
Fig. 1—Mounting dimensions of the RM7838B Relay Module and Q7800A Subbase, in in. (mm).
Fig. 2—Mounting dimensions of the RM7838B Relay Module and Q7800B Subbase, in in. (mm).
M1984A
BURNER CONTROL
POWER
PILOT
FLAME
MAIN
ALARM
RESET
SCROLL MODE
SAVE
5
(127)
5 (127)
REMOVE ONLY FOR TERMINAL TEST ACCESS.
1
1
5-1/4 (133)
M1985A
POWER
PILOT
FLAME
MAIN
ALARM
RESET
SCROLL MODE
SAVE
5
(127)
5 (127)
BURNER CONTROL
REMOVE ONLY FOR TERMINAL TEST ACCESS.
1
1
6-3/32 (155)

7 65-0120—1
Fig. 3—Mounting dimensions of the Keyboard
Display Module in in. (mm)
.
RM7838B
SPECIFICATIONS
MOUNTING FLANGE
1/2–14 NPSM
LEADWIRES FACEPLATE
3/4–14 NPT
M1962A
3-3/4
(95)
7-7/32
(183)
5-1/8 (130)
3-7/16
(87)
5-1/4 (133)
C7012A,C,E,F
2
(51)
C7013A
1-1/4 (32) 1-5/16 (33) 5/16
(8)
C7014A
M1847
13/16 (21) 1-1/4 (32) 1-3/8 (35)
1-3/4
(45)
Fig. 4—Rectification Detectors.
M5002B
SCROLL MODE
SAVE
BURNER CONTROL
,

,



4-27/32 (123)
2-3/4
(69)
5/32
(4) 29/32
(23)
5/16
(8)
4-3/32 (104)
19/32
(15) 1-1/4
(32) 1-1/32
(26)
1-15/16
(49) 2-7/16 (62)
29/32
(23)
5/32 (4)
1/2
(13)
2-1/32
(52)
15/
32
(12)
13/
32
(11)
3-7/8 (99)
7/16 (11)
5/15
(8)
THREADED
MOUNTING
HOLES (2)–
10-32 UNF
1 (25)
FLAME ROD
TARGET
CERAMIC
INSULATORS
IGNITION
ELECTRODE
(Q179C ONLY)
BRACKET
M1983
3-1/8
(79)
1-21/32
(42) 1-13/32
(36)
3/8 (10)
1/2 (13)
1-1/16
(27)
25/32
(20) 25/32 (20)
2-25/32
(62)
3/32 (2) 11/16
(18)
17/32
(14)
Q179
Fig. 4—Rectification Detectors (Continued).

65-0120—1 8
Fig. 5—Ultraviolet detectors
RM7838B
SPECIFICATIONS
1/2-14 NPSM
INTERNAL THREADS
2
2 (51)
COLLAR WITH
1–11-1/2 NPSM
INTERNAL
THREADS 1
1DIN APPROVED C7035A1064 HAS 1-11 BSP.P1 INTERNAL THREADS.
DIN APPROVED C7035A1064 HAS 1/2-14 BSP-F INTERNAL THREADS.
MODEL AVAILABLE WITH 12 FOOT [3.66 METER] LEADWIRES.
2
3
INSERTION DEPTH
6 FOOT
[1.83 METER]
LEADWIRES (2) 3
M1945A
2-5/8 (67)
1-1/2
(38)
31/32
(25)
4-1/8 (105)
1-3/16
(30)
C7035
COLLAR WITH 1/2-14 NPSM
INTERNAL THREADS
4 (102) 6 FOOT (1.83 METER)
LEADWIRES (2)
M1943A
MODEL AVAILABLE WITH 24 FOOT (7.32 METER) LEADWIRES.
MODELS AVAILABLE WITH SPUD CONNECTOR (1/2-14 NPSM INTERNAL
THREADS) INSTEAD OF CLAMP TYPE CONNECTOR.
1
2
1
2
3-1/2 (89)
1-1/16
(27)
C7027
MOUNTING BRACKET
6 FOOT [1.83 METER]
LEADWIRES (2)
M1944A
3-5/8 (92)
1/2
(13)
9/16
(14)
7/8
(22)
3/8
(10)
1-27/64
(36)
C7044
15/16 [24] DIA.
2 (51)
1 (25)
1 INCH NPT
15/16–18 UNC
(2 EACH)
M5084
2-1/2
(64)
6-7/32)
(158)
6-19/32
(168)
2-5/32
(55)
11-13/16 (300)
7-13/16 (198) 1-27/32
(47) 5-13/16 (147)
5-13/16
(147)
C7076D

9 65-0120—1
RM7838B
SPECIFICATIONS
4
(102)
4 (102)
3/8 INCH NPT
1 INCH NPT
7/8 (22) OPENING
FOR 1/2-INCH CONDUIT
ALLOW 9 INCHES (228 MILLIMETERS)
CLEARANCE TO SWING OUT THE DETECTOR
FOR LENS CLEANING OR SERVICING.
1
M5083A
1-1/16 (27)
2-1/4
(57)
2-1/4
(57)
4-27/32 (123)
1-13/32 (188)
10-9/32 (261)
2-5/16
(58)
29/32 (23)
3/4 (19)
1-19/32
(41)
2-11/16
(68) 7-5/8 (194)
Fig. 5—Ultraviolet detectors (Continued)
C7076A
Fig. 6—Infrared detectors.
APERTURE
BUSHING WITH
MAGNIFYING LENS COLLAR, 3/4-14 NPSM
INTERNAL THREADS
3/4-14
NPSM 3/4-14 NPSM INTERNAL
THREADS
HEAT BLOCKCELL MOUNT
M1982A
2 LEADS IN A
48 INCH [1.2 METER]
FLEXIBLE CONDUIT
2-3/4
(70)
1-1/4
(32)
1-5/8 (41)
1-1/16 (27)
1-1/4
(32)
C7015

65-0120—1 10
PrincipalTechnicalFeatures
The RM7838B provides all customary flame safeguard
functions while providing significant advancements in the
areas of safety, annunciation and system diagnostics.
SAFETY SHUTDOWN (LOCKOUT) OCCURS IF:
1. INITIATE Period
a. Purge card is not installed or removed.
b. Purge card is bad.
c. Configurationjumperswerechangedafter200hours
of operation.
d. AC line power errors, see Operation.
e. Four minute INITIATE period is exceeded.
2. STANDBY Period
a. Flame signal is present after 40 seconds.
b. Preignition Interlock is open after 30 seconds.
c. Ignition/pilot valve/intermittent pilot valve termi-
nal is energized.
d. Main valve terminal is energized.
e. Internal system fault.
f. Purge card is not installed or removed.
g. Purge card is bad.
h. Flame detected during the last two seconds.
3. PURGE Period
a. PreignitionInterlockopensanytimeduringPURGE.
b. Flame signal detected during PURGE .
c. High Purge Rate Switch fails to close within four
minutes,fifteensecondsafterthefiringratemotor
is commanded to drive to high fire position.
d. Low Fire Start Switch fails to close within four min-
utes, fifteen seconds after the firing rate motor is
commanded to drive to low fire position.
e. LockoutInterlockdoesnotclosewithinfiveseconds.
f. Lockout Interlock opens during PURGE .
g. Ignition/pilot valve/intermittent pilot valve termi-
nal is energized.
h. Main valve terminal is energized.
i. Internal system fault.
j. Purge card is not installed or removed.
k. Purge card is bad.
4. Purge Hold: T21
a. Preignition Interlock opens.
b. Flame is detected.
c. Lockout Interlock opens during Hold.
d. Ignition/pilot valve/main valve is energized.
e. Internal system fault.
f. Purge card is removed.
g. Purge card is bad.
5. PILOT FLAME ESTABLISHING Period (PFEP)
a. Low Fire Switch opens.
b. Lockout Interlock opens .
c. Ignition/pilot valve/intermittent pilot valve termi-
nal is not energized.
d. No flame is present at end of PFEP.
e. Internal system fault.
f. Purge card is not installed or removed.
g. Purge card is bad.
6. MAIN FLAME ESTABLISHING Period (MFEP)
a. Low Fire Switch opens.
b. Lockout Interlock opens .
c. Ignition/pilot valve/intermittent pilot valve termi-
nal is not energized.
d. Main valve terminal is not energized.
e. No flame is present at end of MFEP.
f. Internal system fault.
g. Purge card is not installed or removed.
h. Purge card is bad.
7. RUN Period
a. No flame is present.
b. Lockout Interlock opens.
c. Main valve terminal is de-energized.
d. Internal system fault.
e. Purge card is not installed or removed.
f. Purge card is bad.
8. Pilot Valve Hold
a. Low Fire Switch opens.
b. Lockout Interlock opens.
c. Ignition/pilot valve terminal is not energized.
d. No flame is present at end of PFEP.
e. Internal system fault.
f. Purge card is not installed or removed.
g. Purge card is bad.
h. Non Shutter Check Amplifier/Detector used.
RM7838B
PRINCIPAL TECHNICAL FEATURES • SAFETY PROVISIONS
Safety Provisions
theRM7838Bwilllockoutonsafetyshutdown.TheRM7838B
must react to input changes but avoid the occurrence of
nuisance shutdown events. Signal conditioning is applied to
the line voltage detection circuit inputs to ensure proper
operationinthepresenceofnormalelectrical line noise such
as transient high voltage spikes or short periods of line
dropout. Signal conditioning is tolerant of synchronous
noise (line noise events that occur at the same time during
each line cycle).
INTERNAL HARDWARE STATUS MONITORING
The RM7838B checks the purge card for correct parity
to prevent purge timing shifts and circuitry failures. It also
analyzes the integrity of the configuration jumpers and
internal hardware. The POWER LED blinks every four sec-
onds, signifying an internal hardware check.
CLOSED LOOP LOGIC TEST
The test verifies the integrity of all safety critical loads,
terminals 8, 9 and 10. If the loads are not energized prop-
erly;i.e.,themainvalveterminalispoweredduringPURGE,

11 65-0120—1
RM7838B
SAFETY PROVISIONS
DYNAMIC FLAME AMPLIFIER AND
SHUTTER CHECK
Self-checking circuitry tests all electronic components in
the flame detection system and amplifier 10 to 12 times per
minuteandshutsdowntheRM7838Bifthedetectionsystem
fails.
DYNAMIC INPUT CHECK
All system input circuits are examined to ensure the
RM7838B is capable of recognizing the true status of
external controls, limits and interlocks. If any input fails
this test, a safety shutdown will occur and the fault will be
annunciated.
DYNAMIC SAFETY RELAY TEST
Checks the ability of the dynamic safety relay contacts to
open and close. It also verifies that the safety critical loads,
terminals8,9and10,canbede-energized,asrequired,bythe
Dynamic Self-Check logic.
DYNAMIC SELF-CHECK SAFETY CIRCUIT
Themicrocomputertestsitselfandrelatedhardwarewhile
at the same time the safety relay system tests the microcom-
puter operation. If a microcomputer or safety relay failure
occursanddoesnot allow proper execution of the self-check
routine, safety shutdown will occur and all safety critical
loads will be de-energized.
EXPANDED SAFE-START CHECK
Theconventionalsafe-start check, which preventsburner
start-up if flame is indicated at start-up, is expanded to
include a flame signal check during STANDBY, a preigni-
tion interlock check, an airflow switch check, and a safety
critical load check.
HIGH PURGE RATE AND LOW FIRE START
SWITCH TESTS
HighPurgeRateSwitchTestexaminesthePurgePosition
Interlock Switch at the moment the firing rate motor is
commanded to the High Purge Rate position. If the switch is
bypassed, welded or otherwise closed prematurely, the sys-
tem will automatically add 30 second hold to allow addi-
tional drive time for the firing rate motor to reach or near the
open position before starting the purge timing; otherwise,
purge timing starts when the High Purge Rate Switch is
closed. Four minutes, 15 seconds is allowed for the closure
of the High Purge Rate Switch or a hold of four minutes,
15 seconds is initiated if the switch opens during purge. The
RM7838B will lockout and annunciate an alarm if the
switch fails to close within the hold time period.
Low Fire Start Switch Test examines the Low Fire Start
Switch at the moment PURGE is completed. If the switch is
bypassed, welded or otherwise prematurely closed, the sys-
tem automatically adds a 30 second hold to allow the firing
ratemotoradditionaltimetoreachorbenearthelowfirestart
position before ignition trials; otherwise, ignition trials start
after the Low Fire Switch closes. The test also is used to
provethatthefiringratemotorisatlowfirepositionthrough-
outtheignitiontrialperiod.Thisswitchwillalsocauseahold
(fourminutes15 seconds) condition if the switch opens after
purging is complete. The RM7838B will lockout and an-
nunciatean alarm if the switch failstoclose within the hold
time period.
OFF CYCLE (STANDBY OR PURGE) FLAME
SIGNAL CHECK
The flame detection subsystem (flame detector and amp-
lifier)monitorsthe shutter-check amplifier and self-check-
ingdetectorforthefirst40secondsduringSTANDBYand
the last two seconds of STANDBY before entering the
PURGE period. If a flame exists, a safety shutdown will
occur.
PREIGNITION OUTPUT CIRCUIT CHECK
At the end of PURGE, the Dynamic Safety Relay opera-
tion is checked. Also, all safety critical loads, terminals 8, 9
and 10, are checked to verify the terminals are not powered.
IftheDynamicSafety Relay operation is faulty, or if any of
the safety critical loads are powered, safety shutdown occurs
and is annunciated.
TAMPER RESISTANT TIMING AND LOGIC
Safety and logic timings are inaccessible and cannot be
altered or defeated.
VERIFIED SPARK TERMINATION
The ignition terminal is monitored to verify early spark
termination (five seconds ignition and pilot and five seconds
pilotonly).If foursecondsPFEPisselected, thereisnoEarly
Spark Termination.
PILOT VALVE HOLD (TERMINAL NO. 16)
If closed on startup, the RM7838B will hold in pilot.
When initiated with an input to the RM7838B (terminal
no. 16) from the RUN condition, The RM7838B commands
thefiringrate motor to the low fire position. The pilot valve
(terminal 8) is commanded on for 45 seconds while the
main valve (terminal no. 9) is held on. The main valve
(terminal 9) is then turned off and ignition (terminal 10) is
turned on for 10 seconds. Failure to light the pilot or
proving of the low fire switch will result in a safety shut--
down with the fault annunciated.
Safety shutdown will occur if Non Shutter Check Ampli-
fier/Detector is uded.
MANUAL OPEN VALVE (TERMINAL NO. 17)
The RM7838B will hold in PFEP indefinitely until the
Manual Open Valve Input (terminal 17) is powered. A ten
second MFEP is now initiated to light the main flame.
With Configuration Jumper JR3 clipped, the ten second
MFEP is started. Manual Open Valve Input (terminal 17)
must be closed in ten seconds or safety shutdown occurs.
FIRST-OUT ANNUNCIATION AND
SELF-DIAGNOSTICS
Sequence Status Lights (LEDs) provide positive visual
indication of the program sequence: POWER, PILOT,
FLAME, MAIN and ALARM. The green POWER LED
blinkseveryfoursecondstosignifytheRM7838Bhardware
is running correctly.

65-0120—1 12
Multi-function Keyboard Display Module shows elapsed
time during PURGE, PILOT IGN, and MAIN IGN. As an
additional troubleshooting aid, it provides sequence timing,
diagnosticinformation,historical information and expanded
annunciator information when a safety shutdown or hold or
normal operation occurs.
First-out Annunciation reports the cause of a safety
shutdown or identifies the cause of a failure to start or con-
tinue the burner control sequence with an English text and
numbered code via the Keyboard Display Module. And it
monitors all field input circuits, including the Flame Signal
Amplifier and Firing Rate Position Switches. The system
distinguishes 63 modes of failure and detects and annunci-
ates difficult to find intermittent failures.
Self Diagnostics adds to the First-out Annunciation by
allowing the RM7838B to distinguish between field (exter-
nal device) and internal (system related) problems. Faults
associated within the flame detection subsystem, RM7838B
or plug-in Purge Card, are isolated and reported by the
Keyboard Display Module. See Table 12, Hold and Fault
MessageSummary, orthe7800SERIESService Handbook,
form 65-0111.
INTERLOCK REQUIREMENTS
The following interlock inputs are provided:
LOCKOUT INTERLOCK (ILK) (TERMINAL NO. 7)
The Lockout Interlock (ILK) is typically the Combustion
Air Blower Switch. If the Lockout Interlock is de-energized
five seconds after the combustion air Blower is turned on or
anytime during ignition trials or run, a Lockout occurs.
NOTE: The five second timing does not begin for the
RM7838B until the low fire proving switch is closed at
the end of PURGE and the RM7838B turns on termi-
nal 5, starting the Combustion Air Blower.
Low Fire Interlock (Terminal No. 18)
This interlock verifies the firing rate motor is in the low
fire position before and during ignition trials.
High Purge Rate Interlock (Terminal No. 19)
This interlock verifies the firing rate motor is in the high
purge rate position prior to and during PURGE.
Preignition Interlock (Terminal No. 20)
The Preignition Interlock input is typically connected to
proof-of-closure switches for fuel valve(s). The Preignition
Interlock must be energized throughout STANDBY and
PURGE. If Preignition Interlock opens during STANDBY,
itcausesaholdandwilllockoutiftheinterlockdoesnotclose
within 30 seconds. If the Preignition Interlock opens during
PURGE,the RM7838Bwilllockout.IfthePreignitionInter-
lockisopenafterfivesecondsintoSTANDBY(afterthestop
button is pushed),the RM7838B will lockout. The Preignition
Interlock is ignored during the ignition trials state during
RUN, and Pilot Valve Hold.
RM7838B
SAFETY PROVISIONS • INSTALLATION
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 given in the instructions and on
the product to make sure the product is suitable for the
application.
3. Installer must be a trained, experienced, flame safe-
guard control technician.
4. After installation is complete, check out the product
operation as provided in these instructions.
CAUTION
1. Disconnectthepower supply beforebeginning
installationto preventelectricalshock andequip-
ment damage. More than one power supply
disconnect may be involved.
2. WiringconnectionsfortheRM7838Bareunique;
therefore,refertoFig.7orthecorrectSpecifica-
tions for proper subbase wiring.
3. Wiring must comply with all applicable codes,
ordinances and regulations.
4. Wiring, where required, must comply with NEC
Class 1 (Line Voltage) wiring.
5. Loads connected to the RM7838B must not
exceedthoselistedontheRM7838Blabelorthe
Specifications, see Table 1.
6. Limits and interlocks must be rated to simulta-
neously carry and break current to the ignition
transformer, pilot valve, and main fuel valve(s).
7. All external timers must be listed or component
recognized by authorities who have jurisdiction
forthespecificpurposeforwhichtheyareused.

13 65-0120—1
RM7838B
INSTALLATION
CONFIGURATION
JUMPERS
MICROCOMPUTER
RESET
PUSHBUTTON
RUN/TEST
SWITCH
STATUS LEDs
PLUG-IN PURGE
TIMER CARD
SAFETY RELAY
CIRCUIT
POWER SUPPLY
KEYBOARD
DISPLAY MODULE
HIGH PURGE
COMMON
MODULATE
LOW FIRE
PLUG-IN
FLAME
AMPLIFIER
RELAY
DRIVE
CIRCUIT
CONTROL
POWER
TEST
JACK
REMOTE
RESET
DDL
DDL
COMMUNICATIONS
INDICATES FEEDBACK SENSING
TO RELAY STATUS FEEDBACK
AND LINE VOLT INPUTS
FIELD WIRING
INTERNAL WIRING
IGNITION
PILOT
MAIN VALVE
1K
RELAY
STATUS
FEEDBACK
AND LINE
VOLTAGE
INPUTS
LIMITS
PREIGNITION
INTERLOCK
1K1 2K1 5K1
8K1
8K2
9K1
9K2
120 Vac
FLAME SIGNAL
TEST
PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
RS485
123
L1
(HOT) L2
4
6
7
4K1
2K2
10
8
9
7K
5K
4K
3K
2K
F
G
22
1
6K1 5
ALARM
3K1 3
L2
12
13
15
14
M5195A
1
RECIRCULATING
BLOWER
STOP SWITCH
RECIRCULATING
A F S
COMBUSTION
AIR BLOWER
16
17
18
19
20
21
COMBUSTION
AIR BLOWER
SWITCH
1/2 OF DPST
ALARM SILENCING
SWITCH
1/2 OF DPST
ALARM SILENCING
SWITCH
PILOT VALVE
HOLD SWITCH
MANUAL VALVE
OPEN SWITCH
LOW START
SWITCH
HIGH PURGE
RATE SWITCH
START SWITCH
BURNER CONTROL
Fig. 7—Internal block diagram of the RM7838B (See Figs. 8 or 9 for detailed wiring instructions).

65-0120—1 14
IMPORTANT:
1. For on-off gas-fired systems, some authorities who
have jurisdiction prohibit the wiring of any limit or
operating contacts in series between the flame safe-
guard control and the main fuel valve(s).
2. Do not connect more than two C7012E,F or C7076A,D
Ultraviolet Flame Detectors (with self-checking shutter)
in parallel to the same terminal.
3. This equipment generates, uses and can radiate radio
frequency energy and, if not installed and used in
accordance with the instructions, may cause interfer-
encetoradiocommunications.Ithasbeentestedand
foundto comply with the limitsfor a Class B comput-
ing device of Part 15 of FCC rules, which are designed
to provide reasonable protection against such interfer-
ence when operated in a commercial environment. Op-
eration of this equipment in a residential area may cause
interference; in which case, the users at their own expense
mayberequiredtotake whatevermeasuresarerequired
to correct this interference.
4. This digital apparatus does not exceed the Class B
limits for radio noise for digital apparatus set out on
the Radio Interference Regulations of the Canadian
Department of Communications.
5. The RM7838B cannot be connected in parallel with-
out isolation circuits between the input and output
circuits of each device.
HUMIDITY
Install the RM7838B where the relative humidity never
reaches the saturation point. The RM7838B is designed to
operateinamaximum 85% RH continuous,noncondensing,
moisture environment. Condensing moisture may cause a
safety shutdown.
VIBRATION
Do not install the RM7838B where it could be subjected to
vibration in excess of 0.5G continuous maximum vibration.
WEATHER
The RM7838B is not designed to be weather tight. If
installed outdoors, the RM7838B must be protected by an
approved weather-tight enclosure.
MOUNTING THE WIRING SUBBASE
NOTE: For installation dimensions, see Fig. 1 and 2.
1. Mount the subbase in any position except horizon-
tally with the bifurcated contacts pointing down. The stan-
dard vertical position is recommended. Any other position
decreases the maximum ambient temperature rating.
2. Selectthelocationonawall,burnerorelectricalpanel.
The Q7800 Subbase can be mounted directly in the control
cabinet. Be sure to allow adequate clearance for servicing,
installation, access or removal of the RM7838B, S7830
Expanded Annunciator, S7800 Keyboard Display Module,
flame amplifier, flame amplifier signal voltage probes, Run/
Test Switch, electrical signal voltage probes and electrical
field connections.
3. Forsurfacemounting, usethetemplate(see Fig.32)to
mark the four screw locations. Drill the pilot holes.
4. Securely mount the subbase using four no. 6 screws.
WIRING
1. For proper subbase wiring, refer to Figs. 8, 9 or 10.
For proper wiring of the Keyboard Display Module, refer to
Figs. 9 and 10, or to the Specifications of the Keyboard Dis-
play Module (65-0090), Communication Interface Base Unit
(63-2278), DATA CONTROLBUS MODULE™ (65-0091)
or Extension Cable Assembly (65-0131).
2. Disconnect the power supply from the main discon-
nectbefore beginning installation to preventelectrical shock
and equipment damage. More than one disconnect may be
involved.
3. All wiring must comply with all applicable electrical
codes, ordinances and regulations. Wiring, where required,
must comply with NEC, Class 1 (Line Voltage) wiring.
4. Recommended wire size and type:
a. All Line Voltage terminals use no. 14, 16, or 18
copper conductor (TTW60C or THW75C or
THHN90C) 600 volt insulation wire. For high
temperature installations, use wire selected for a
temperature rating above the maximum operating
temperature. All leadwires should be moisture
resistant.
b. Keyboard Display Module—For communications
purposes, use an unshielded 3-wire twisted cable if
the leadwire run and noise conditions permit; how-
ever, some installations may need up to five wires,
three for communications and two for remote reset
(in either a single cable or separate cables for com-
munications or remote reset) or use Belden 8771
shielded cable or equivalent. The Keyboard Display
Module,DATACONTROLBUSMODULE™(for
remotemountingorcommunications)orCommuni-
cationInterfaceControlBusModule must be wired
inadaisychainconfiguration,(1(a)-1(a),2(b)-2(b),
3(c)-3(c)). The order of interconnection of all the
deviceslisted aboveisnot important.Beaware that
modulesontheclosest and farthest endofthedaisy
chain configuration string may require a 120 ohm
(1/4 watt minimum) resistor termination across
terminals 1 and 2 of the electrical connectors, see
Figs. 11 and 12.
c. DATA CONTROLBUS MODULE™—For com-
munications purposes, use an unshielded 3-wire
twisted cable if the leadwire run and noise condi-
tionspermit;however,someinstallationsmayneed
upto five wires, three for communicationsandtwo
for remote reset (in either a single cable or separate
cables) or use a Belden 8771 shielded cable or
equivalent.TheKeyboardDisplayModule,DATA
CONTROLBUSMODULE™(forremotemount-
ing or communications) or Communication Inter-
face ControlBus Module must be wired in a daisy
chainconfiguration,(1(a)-1(a),2(b)-2(b),3(c)-3(c)).
The order of interconnection of all the devices
listed above is not important. Be aware that mod-
ules on the closest and farthest end of the daisy
RM7838B
INSTALLATION

15 65-0120—1
chain configuration string may require a 120 ohm
(1/4 watt minimum) resistor termination across
terminals 1 and 2 of the electrical connectors, see
Figs. 11 and 12.
d. Remote Reset—Use no. 22 or greater twisted pair
wire,insulatedfor lowvoltage,see Figs.11and12.
e. Communication Interface ControlBus Module—
For communications purposes, use an unshielded
3-wire twisted cable if the leadwire run and noise
conditions permit or use a Belden 8771 shielded
cable or equivalent. The Keyboard Display Mod-
ule, DATA CONTROLBUS MODULE (for remote
mounting or communications) or Communication
Interface ControlBus Module must be wired in a
daisychainconfiguration,(1(a)-1(a),2(b)-2(b),3(c)-
3(c)). The order of interconnection of all the de-
vices listed above is not important. Be aware that
modulesontheclosest and farthest endofthedaisy
chain configuration string may require a 120 ohm
(1/4 watt minimum) resistor termination across
terminals 1 and 2 of the electrical connectors, see
Figs. 11 and 12.
5. Recommended grounding practices:
a. The earth ground provides for a connection be-
tween the subbase and the control panel or the
equipment. The earth ground wire must be capable
of conducting the current to blow the 20A fuse (or
breaker) in event of an internal short circuit. The
RM7838Bneeds a low impedance ground connec-
tion to the equipment frame which, in turn, needs a
low impedance connection to earth ground. For a
groundpathtobe low impedance at RF frequencies,
theconnection mustbemadewithminimumlength
conductorsthathaveamaximumsurfacearea.Wide
strapsorbracketsarepreferredratherthanleadwires.
Be careful to ensure that mechanically tightened
jointsalongthegroundpath,suchaspipeorconduit
threadsorsurfaces heldtogetherwithfasteners, are
free of nonconductive coatings and are protected
against corrosion on mating surfaces.
b. Keyboard Display Module, DATA CONTROL-
BUS MODULE™ or Communication Interface
ControlBus Module—The shield, if used, should
be connected to the signal ground terminal 3(c)
provided as part of the 7800 SERIES device
ControlBus connection. Connect the shield at both
ends to earth ground.
c. Each RM7838B will have an earth ground termi-
nalthatmustbegroundedtothemetalcontrolpanel
with wire as short as practical. Each ground wire
mustbecapableofcarryingafaultcurrentequalto
the rating of the protective fuse (20A). A number
14 copper conductor is adequate, but wide straps
or brackets are preferred rather than leadwires.
6. Recommended wire routing:
a. Flame detector leadwires:
1. Do not run high voltage ignition transformer
wires in the same conduit with the flame detec-
tor wiring.
2. Do not route flame detector wires in conduit
with line voltage circuits.
3. Enclose the flame detector wires without armor
cable in metal cable or conduit.
4. Follow directions in flame detector Instructions.
b. DATA CONTROLBUS MODULE™:
1. Do not run high voltage ignition transformer
wires in the same conduit or close proximity
with the DATA CONTROLBUS MODULE
wiring.
2. Do not route DATA CONTROLBUS MOD-
ULE wires in conduit with line voltage circuits.
c. Keyboard Display Module (VFD):
1. Because the VFD is powered from a low volt-
age, energy limited source, it can be mounted
outside of a control panel, without special wiring
procedures, if it is protected from mechanical
damage.
d. Remote Reset:
1. Do not run high voltage ignition transformer
wiresinthesameconduitwiththeRemoteReset
wiring.
2. Do not route the Remote Reset wires in conduit
with line voltage circuits.
7. Maximum wire lengths:
a. The maximum length of leadwire is 300 feet to the
terminalinputs(Control,PreignitionInterlock,Run-
ning/LockoutInterlock,High FireSwitchand Low
Fire Switch).
b. Flame Detector leadwires—The maximum flame
sensorleadwirelengthislimitedbytheflamesignal
strength.
c. RemoteResetleadwires—Themaximumlengthof
wire is 1000 feet to a Remote Reset pushbutton.
d. DATA CONTROLBUS MODULE—The maxi-
mum DATA CONTROLBUS MODULE cable
length depends on the number of system modules
connected, the noise conditions and the cable used.
The maximum length of all interconnecting wire is
1000 feet.
8. Make sure loads do not exceed the terminal ratings.
Refer to the label on the RM7838B or to the ratings in Speci-
fications, see Table 1.
9. Checkpowersupplycircuit.The voltage and frequency
tolerance must match those of the RM7838B. A separate
power supply circuit may be required for the RM7838B. Add
the required disconnect means and overload protection.
10. Check all wiring circuits and complete the Static
Checkout,seeTable7,beforeinstallingtheRM7838Bonthe
subbase.
11. Install all electrical connectors.
12. Restore power to the panel.
RM7838B
INSTALLATION

65-0120—1 16
RM7838B
INSTALLATION
M3390A
G
L2
3
5
6
7
8
9
10
F
4(L1)
13
14
17
18
19
20
21
22
12
16
15
LIMITS
MAIN FUEL
VALVE(S)
10 SEC.
INTERRUPTED
PILOT/IGNITION
C7012A, C, E, F OR
C7076A, D ULTRAVIOLET
FLAME DETECTOR
120V, 60 HZ POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
120V ALARM
L1
(HOT)
L2
MASTER
SWITCH
1
C7027A, C7035A OR
C7044A ULTRAVIOLET
FLAME DETECTOR
BLUE
BLUE
OR
RECTIFYING FLAME ROD,
RECTIFYING PHOTOCELL,
OR INFRARED
(LEAD SULFIDE)
FLAME DETECTOR
OR
YELLOW
WHITE
WHITE
L2
WHITE
BLACK L1
BLACK L2
1
Q7800 SUBBASE
DPST ALARM
SILENCING SWITCH
STOP
BA
START
D C
HIGH FIRE
COMMON
LOW FIRE
MODULATE
B
R
W
SERIES 90
FIRING RATE
MOTOR
B
R
W
SERIES 90
CONTROLLER
PILOT VALVE
HOLD
MANUAL VALVE
OPEN SWITCH
LOW FIRE
START SWITCH
HIGH PURGE
RATE SWITCH
PREIGNITION
INTERLOCK
5 SECOND IGNITION
(EARLY SPARK
TERMINATION)
COMBUSTION
BLOWER AFS
RECIRCULATING
AFS
BURNER
CONTROL
RECIRCULATING
BLOWER
COMBUSTION
AIR FAN
S445
Fig. 8—RM7838B wiring with S445 start-stop station.

17 65-0120—1
RM7838B
INSTALLATION
M5155A
G
L2
3
5
6
7
8
9
10
F
4(L1)
13
14
17
18
19
20
21
22
12
16
15
LIMITS
MAIN FUEL
VALVE(S)
10 SEC.
INTERRUPTED
PILOT/IGNITION
C7012A, C, E, F OR
C7076A, D ULTRAVIOLET
FLAME DETECTOR
120V, 60 HZ POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
120V ALARM
L1
(HOT)
L2
MASTER
SWITCH
1
C7027A, C7035A OR
C7044A ULTRAVIOLET
FLAME DETECTOR
BLUE
BLUE
OR
RECTIFYING FLAME ROD,
RECTIFYING PHOTOCELL,
OR INFRARED
(LEAD SULFIDE)
FLAME DETECTOR
OR
YELLOW
WHITE
WHITE
L2
WHITE
BLACK L1
BLACK L2
1
Q7800 SUBBASE
DPST ALARM
SILENCING SWITCH
STOP
START
HIGH FIRE
COMMON
LOW FIRE
MODULATE
B
R
W
SERIES 90
FIRING RATE
MOTOR
B
R
W
SERIES 90
CONTROLLER
PILOT VALVE
HOLD
MANUAL VALVE
OPEN SWITCH
LOW FIRE
START SWITCH
HIGH PURGE
RATE SWITCH
PREIGNITION
INTERLOCK
5 SECOND IGNITION
(EARLY SPARK
TERMINATION)
COMBUSTION
BLOWER AFS
RECIRCULATING
AFS
BURNER
CONTROL
RECIRCULATING
BLOWER
COMBUSTION
BLOWER
Fig. 9—RM7838B wiring with separate start-stop station.

65-0120—1 18
RM7838B
INSTALLATION
M9737
G
L2
3
5
6
7
8
9
10
F
4(L1)
13
14
17
18
19
20
21
22
12
16
15
LIMITS
MAIN FUEL
VALVE(S)
10 SEC.
INTERRUPTED
PILOT/IGNITION
C7012A, C, E, F OR
C7076A, D ULTRAVIOLET
FLAME DETECTOR
120V, 60 HZ POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
120V ALARM
L1
(HOT)
L2
MASTER
SWITCH
1
C7027A, C7035A OR
C7044A ULTRAVIOLET
FLAME DETECTOR
BLUE
BLUE
OR
RECTIFYING FLAME ROD,
RECTIFYING PHOTOCELL,
OR INFRARED
(LEAD SULFIDE)
FLAME DETECTOR
OR
YELLOW
WHITE
WHITE
L2
WHITE
BLACK L1
BLACK L2
1
Q7800 SUBBASE
DPST ALARM
SILENCING SWITCH
STOP
START
HIGH FIRE
LOW FIRE
COMMON
MODULATE
F
+
-
+
-
M7284
FIRING RATE
MOTOR
4-20 mA
OUTPUT
CONTROLLER
PILOT VALVE
HOLD
MANUAL VALVE
OPEN SWITCH
LOW FIRE
START SWITCH
HIGH PURGE
RATE SWITCH
PREIGNITION
INTERLOCK
5 SECOND IGNITION
(EARLY SPARK
TERMINATION)
COMBUSTION
BLOWER AFS
RECIRCULATING
AFS
BURNER
CONTROL
RECIRCULATING
EXHAUST
BLOWER
COMBUSTION
BLOWER
Fig. 10—RM7838B wiring with separate start and stop stations with 4 to 20 mA firing rate control circuit.

19 65-0120—1
RM7838B
INSTALLATION
1
1
120 OHM
RESISTOR
1
120 OHM
RESISTOR
A B
A B CC (GND)
+13 VDC
RESET
123 45
123
MOMENTARY
PUSH BUTTON
SWITCH
S7800 KEYBOARD DISPLAY MODULE
(MOUNTED ON 7800 SERIES RELAY MODULE)
QS7800
COMMUNICATIONS
INTERFACE
CONTROLBUS
MODULE
THREE WIRE SHIELDED CABLE MAY BE REQUIRED. TWO 120
OHM TERMINATING RESISTORS ARE REQUIRED FOR
CONNECTIONS OVER 100 FEET (30 METERS). CABLE SHIELD
MUST BE TERMINATED TO EARTH GROUND AT BOTH ENDS.
IF SHIELDED CABLE IS NOT USED, TWISTED PAIR
WIRE MUST BE USED.
M1990D
L1
(HOT)
L2
1
2
A
B
C (GND) +13 VDC
RESET
123 54
13 Vdc
POWER SUPPLY
THREE WIRE SHIELDED CABLE MAY BE REQUIRED. TWO
120 OHM TERMINATING RESISTORS ARE REQUIRED FOR
CONNECTING OVER 100 FEET [30 METERS]. CABLE SHIELD
MUST BE TERMINATED TO EARTH GROUND AT BOTH ENDS.
IF SHIELDED CABLE IS NOT USED, TWISTED PAIR WIRE
MUST BE USED.
WHEN CONNECTING THE KEYBOARD DISPLAY MODULE DATA
CONTROLBUS MODULE™, OR REMOTE RESET MODULE
EXTERNAL FROM THE CONTROL CABINET, APPROPRIATE
MEASURES MUST BE TAKEN TO MEET EN60730 SAFETY
LOW VOLTAGE REQUIREMENTS (SEE APPROVALS).
M5006E
123 54
A
B
1
S7800 KEYBOARD DISPLAY MODULE
(MOUNTED ON 7800 SERIES RELAY MODULE)
MOMENTARY
PUSH BUTTON
SWITCH
1
S7800 REMOTE KEYBOARD DISPLAY MODULE
2
C (GND)
+13 VDC
RESET
120 Ω
RESISTOR
120 Ω
RESISTOR
Fig. 11—Wiring the Keyboard Display Module with Communication Interface ControlBus Module.
Fig. 12—Wiring for multiple Keyboard Display Modules.

65-0120—1 20
MOUNTING THE RM7838B
NOTE: For installation dimensions, see Figs. 1 or 2 .
RELAY MODULE MOUNTING (FIGS. 13 or 14)
1. Mount the RM7838B vertically (see Figs. 11 or 12) or
mount horizontally with the knife blade terminals pointing
downward. When mounted on the Q7800A, the RM7838B
must be in an electrical enclosure.
2. Select the location in the electrical enclosure. Be sure
toallow clearances for servicing, installationand removal of
the RM7838B, Keyboard Display Module, flame amplifier,
flame amplifier signal voltage probes, electrical signal volt-
age probes, and electrical connections.
a. AllowanadditionaltwoinchesbelowtheRM7838B
for the Flame Amplifier mounting.
b. Allow an optional three inch minimum to both
sides of the RM7838B for electrical signal voltage
probes.
3. Make sure no subbase wiring is projecting beyond the
terminalblocks. Tuck wiring against the backofthe subbase
so it does not interfere with the knife blade terminals or
bifurcated contacts.
IMPORTANT: The RM7838B must be installed with a
plug-in motion rather than a hinge action.
4. Mount the RM7838B by aligning the four L shaped
corner guides and knife blade terminals with the bifurcated
contacts on the wiring subbase and tightening the two screws
securely without deforming the plastic.
Fig. 13—Electrical panel installation.
RM7838B
INSTALLATION
INSTALLING OR REPLACING ST7800
PURGE CARD (FIG. 15)
1. Remove the Keyboard Display Module or the DATA
CONTROLBUS MODULE.
2. Remove the current ST7800 from the RM7838B by
pulling upward the plastic support cover.
3. Make sure that the ST7800 selected has the desired
timing.
4. Insert the Purge Card into the opening in the top of the
RM7838B compartment (see Fig. 15).
5. Reinstall the Keyboard Display Module or the DATA
CONTROLBUS MODULE onto the RM7838B and restore
power to the device.
6. Run the burner system through at least one complete
cycle to ensure the system is operating as desired.
Fig. 15—ST7800 Purge Card installation.
Fig. 14—Wall or burner installation.