Honeywell 7800 SERIES User manual

1 65-0126—2
7800 SERIES RM7890A,B,C
Relay Module
The Honeywell RM7890 is a microprocessor
based integrated burner control for automatically
firedgas,oilorcombinationfuelsingle-burnerappli-
cations. The RM7890 consists of the Relay Module.
Subbase and Amplifier are required to complete the
system. Options include Keyboard Display
Module, Personal Computer Interface, DATA
CONTROLBUSMODULE™,RemoteDisplayMod-
ule, First-Out Expanded Annunciator and COM-
BUSTION SYSTEM MANAGER™ Software.
The RM7890 is programmed to provide a level of
safety, functional capability and features beyond the
capacity of conventional controls.
Functions provided by the RM7890 include auto-
matic burner sequencing, flame supervision, system
status indication, system or self-diagnostics and
troubleshooting.
— Sequence status.
— Sequence time.
— Total cycles of operation.
— Total hours of operation.
— Fault history providing the six most recent faults:
• Cycles of operation at the time of the fault.
• Expanded annunciator data at the time of the fault.
• Fault message and code.
• Hours of operation at the time of the fault.
• Sequence status at the time of the fault.
• Sequence time at the time of the fault.
— Diagnostic information:
• Device type.
• Flame amplifier type.
• Flame failure response time.
• Manufacturing code.
• On/Off status of all digital inputs and outputs.
• Software revision and version of RM7890 and op-
tional Keyboard Display Module.
• Status of configuration jumpers.
CONTENTS
Specifications .................................................2
Ordering Information ..................................... 2
Principle Technical Features .......................... 8
Safety Provisions ............................................ 8
Installation ..................................................... 9
Wiring .......................................................... 11
Assembly ...................................................... 13
Operation ..................................................... 15
Static Checkout............................................. 17
Checkout ...................................................... 19
Troubleshooting ........................................... 25
G. R. • Rev. 2-94 • © Honeywell Inc. 1994 • Form Number 65-0126—2
65-0126-2
■Safety features:
— Closed loop logic test.
— Dynamic AMPLI-CHECK™.
— Dynamic input check.
— Dynamic safety relay test.
— Dynamic self-check logic.
— Expanded safe-start check.
— Internal hardware status monitoring.
— Tamper resistant timing and logic.
■Access for external electrical voltage checks.
■Application flexibility.
■Communication interface capability.
■Dependable, long-term operation provided by microcom-
puter technology.
■First-out annunciation and system diagnostics are provided
by a 2 row by 20 column Vacuum Fluorescent Display
(VFD) located on the optional Keyboard Display Module.
■First-out expanded annunciation with 26 Light Emitting
Diodes (LEDs) for limits and interlocks (optional).
■Five (LEDs) for sequence information.
■Interchangeable plug-in flame amplifiers.
■LocalorremoteannunciationofRM7890operationandfault
information (optional).
■Nonvolatile memory; RM7890 retains history files and
sequencing status after loss of power.
■Remote reset (optional).
■Report generation (optional).
■Selectable relight or lockout on loss of flame.
■Shutter drive output (RM7890B).
■Burner controller data (optional):
— Expanded annunciator status.
— Flame signal strength.
— Hold status.
— Lockout/alarm status.

65-0126—2 2
RM7890A,B,C
SPECIFICATIONS • ORDERING INFORMATION
Specifications
ELECTRICAL RATINGS, SEE TABLE 1:
VoltageandFrequency:120Vac(+10/-15%),50or60Hz
(+/- 10%). 2
Power Dissipation: RM7890: 10W maximum.
Maximum Total Connected Load: 2000 VA.
Fusing: Total Connected Load: 20A maximum, type
FRN or equivalent.
TABLE 1—TERMINAL RATINGS.
ENVIRONMENTAL RATINGS:
Ambient Temperature:
Operating: -40°F to 140°F.
Storage: -60°F to 150°F.
Terminal No. Description Ratings
G Flame Sensor Ground
Earth G Earth Ground1
L2(N) Line Voltage Common
3 Line Voltage Supply (L1) 120 Vac (+10/-15%), 50 or 60 Hz (+/- 10%).2,3
4 Alarm 120 Vac, 1A pilot duty.
5 Unused
6 Burner Controller and Limits 120 Vac, 3A pilot duty or 1A pilot duty, 4.5A ignition.
7 Unused
8 Pilot Valve/Ignition 120 Vac, 4.5A Ignition and 50 VA pilot duty. 4
9 Main Fuel Valve 120 Vac, 2A pilot duty.5
10 Ignition 120 Vac, 4.5A ignition.4
F(11) Flame Sensor 60 to 220 Vac, current limited.
12 Unused
13 Unused
14 Unused
15 Unused
16 Unused
17 Unused
18 Unused
19 Unused
20 Unused
21 Unused
22 Shutter 120 Vac, 0.5A (RM7890B).
1TheRM7890musthaveanearthgroundprovidingaconnectionbetweenthesubbaseandthecontrolpanelortheequipment.Theearth
ground wire must be capable of conducting the current to blow the 20A fuse (or breaker) in event of an internal short circuit. The RM7890
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 with minimum length conductors having maximum
surface areas. Wide straps or brackets rather than leadwires are preferred. Be careful to verify 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.
2Operating frequency chosen by RM7890 selection.
32000 VA maximum connected load to RM7890 Assembly.
4Can also be 120 Vac, 1A pilot duty.
5Can also be 65 VA pilot duty with motorized valve, 1150 VA inrush, 460 VA open, 250 VA hold.
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 Satisfaction
Honeywell Inc., 1885 Douglas Drive North
Minneapolis, Minnesota 55422-4386 [phone]
In Canada—Honeywell Limited/Honeywell Limitee, 740 Ellesmere Road, Scarborough, Ontario M1P 2V9 International Sales and Service Offices
inallprincipalcitiesoftheworld.ManufacturinginAustralia,Canada,Finland,France,Germany,Japan,Mexico,Netherlands,Spain,Taiwan,United
Kingdom, U.S.A.
Ordering Information

3 65-0126—2
RM7890A,B,C
SPECIFICATIONS
Humidity: 85% RH continuous, noncondensing.
Vibration: 0.5G environment.
DIMENSIONS: Refer to Figs. 1 and 2.
WEIGHT: RM7890 with Dust Cover: 1 pound 13 ounces,
unpacked.
IMPORTANT: Flame Detection System available for use
with RM7890. To select your Plug-in Flame Signal
AmplifierandapplicableFlameDetector,seeTable2
and Figs. 3-5.
!WARNING
Do not use non-shelf check ultraviolet flame
detectors (C7027, C7035, C7044, or C7012A,C)
with the RM7890C.
The RM7890C is designed for standing pilot
applications and does not conduct a Safe Start
Check. It cannot detect a failed non-self check
flame detector.
Inability to detect a failed flame detector could
resultinafireorexplosion hazard which can cause
property damage, severe injury or death.
TABLE 2—FLAME DETECTION SYSTEMS .
3
2
2
1
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 HoldersdC7004, C7007, C7011.
Complete Assemblies:
C7008, C7009, Q179.
No R7847A .8 or 3 sec Oil Rectifying
Photocell C7003, C7010, C7013, C7014.
No R7847A 3 sec Gas, oil,
coal Ultraviolet (PurplePeeper) C7012A,C.a
Dynamic
AMPLI-CHECK™ R7847Bc.8 or 3 sec Gas Rectifying Flame
Rod HoldersdC7004, C7007, C7011.
Complete Assemblies:
C7008, C7009, Q179.
Dynamic
AMPLI-CHECK™ R7847Bc.8 or 3 sec Oil Rectifying
PhotocelleC7003, C7010, C7013,
C7014.
Dynamic
AMPLI-CHECK™ R7847Bc3 sec Gas, oil, coal Ultraviolet (Purple Peeper) C7012A,C.a
Dynamic
Self-Check R7847Cb3 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™ R7848Bc3 sec Gas, oil coal Infrared (Lead Sulfide) C7015.
Ultraviolet Purple No R7849A .8 or 3 sec Gas, oil Ultraviolet
(Minipeeper) C7027, C7035,
C7044.a
Dynamic
AMPLI-CHECK™ R7849Bc.8 or 3 sec Gas, oil Ultraviolet (Minipeeper) C7027, C7035,
C7044.a
Blue Dynamic
Self-Check R7886Ab3 sec Gas, oil, coal Ultraviolet (Adjustable
Sensitivity)
C7076.
3
3
1A 0.8 sec Flame Failure Response Time Amplifier is required when the Relight option has been selected (JR2 is intact, see Table 3). The RM7890 will
lockout and indicate a Fault 46 if a 3.0 second FFRT is used and jumper JR2 (Lockout) is not clipped and removed.
aThe C7012A,C, C7027, C7035 and C7044 Flame Detectors should be used only on burners that cycle on-off at least once every twenty-four hours.
Appliances with burners that remain on continuously for twenty-four hours or longer should use the C7012E,F Flame Detector with the R7847C
Amplifier or the C7076A,D Flame Detector with the R7886A Amplifier as the ultraviolet flame detection system.
bCircuitry 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.
cCircuitry tests the flame signal amplifier at least 12 times a minute during burner operation and shuts down the burner if the amplifier fails.
dOrder flame rod separately; see holder Instructions.
eUse only Honeywell Photocell, part no. 38316.
Use with RM7890B only.
Do not used with RM7890C. See warning at top of page.
2
3

65-0126—2 4
RM7890A,B,C
SPECIFICATIONS
SEQUENCE TIMING FOR NORMAL OPERATION:
Fig. 1—Mounting dimensions of RM7890 Relay Module and Q7800A. Subbase in in. [mm].
POWER
PILOT
FLAME
MAIN
ALARM
RESET
5
[127]
5 [127]
M5148
5 [133]
1
4
BURNER CONTROL
REMOVE ONLY FOR TERMINAL TEST ACCESS.
1
1
*STANDBY and RUN can be an infinite time period.
RM7890A1031 has a fixed PFEP timing of 30 seconds.
Device Initiate Standby PilotFlame Establishing Period Run
RM7890A 10 sec * 4 or 10 sec *
RM7890B 10 sec * 4 or 10 sec *
RM7890C 10 sec * Not applicable *
1
APPROVAL BODIES:
Underwriters Laboratories Inc. listed, File No. MP268,
Guide No. MCCZ.
Canadian Standards Association certified, LR9S329-3.
Factory Mutual approved: 0X4AS.AF.
IRI acceptable.
FederalCommunications Commission: Part15, Class B-
Emissions.
RM7890Conly:UnderwritersLaboratoriesInc.Compo-
nent Recognized.
MOUNTING:Q7800AforpanelmountorQ7800Bforwall
or burner mount.
REQUIRED COMPONENTS:
Plug-in Flame Signal Amplifier, see Table 2.
Q7800A or Q7800B.
ACCESSORIES:
Optional:
COMBUSTION SYSTEM MANAGER™—part no.
ZM7850A1001.
Communication Interface Base Unit—part no.
Q7700A1014.
Communication Interface ControlBus Module—part no.
QS7800A1001.
ControlBus 5-Wire Electrical Connector—part no.
203541.
DATA CONTROLBUS MODULE™—part no.
S7810A1009.
Dust Cover—part no. 221729A.
Expanded Annunciator—part no. S7830A1005.
Flame Simulators:
— part no. 203659 UV Flame Simulator.
— part no. 123514A Rectification Simulator.
Keyboard Display Module—part no. S7800A1001.
Remote Display Mounting Bracket—part no. 203765.
Remote Display Power Supply—part no. 203968A
Plug-in.
Remote Reset Module—part no. S7820A1007.
Sixty-inch Extension Cable Assembly—part no.
221818A.
Tester—part no. A7800A1002.
1

5 65-0126—2
RM7890A,B,C
SPECIFICATIONS
MOUNTING FLANGE
7 [183]
7
32
3
[87]
7
16
3
[95]
3
4
5
[130]
1
8
5 [133]
1
4
1/2–14 NPSM
LEADWIRES FACEPLATE
3/4–14 NPT OR
1–11-1/2 NPT
M1962
THREADED
MOUNTING
HOLES (2)–
10-32 UNF
[13]
1
2
1 [25]
FLAME ROD
[18]
11
16
3
8[10]
[2]
3
32
[20]
25
32 [20]
25
32 [14]
17
32
TARGET
2 [62]
25
32
1
[27]
1
16
1
[36]
13
32
1
[42]
21
32
3
[79]
1
8
CERAMIC
INSULATORS
IGNITION
ELECTRODE
(Q179C ONLY)
BRACKET M1983
1 [32]
1
4
1
[45]
3
4
[21]
13
16 1 [35]
3
8
1 [33]
5
16 5
16 [8]1 [32]
1
4
2
[51]
C7013A C7014A M1847
Q179 C7012A,C,E,F
Fig. 3—Rectification detectors.
POWER
PILOT
FLAME
MAIN
ALARM
RESET
5
[127]
5 [127]
M5149
6 [155]
3
32
BURNER CONTROL
REMOVE ONLY FOR TERMINAL TEST ACCESS.
1
1
Fig. 2—Mounting dimensions of RM7890 Relay Module and Q7800B Subbase in in. [mm].

65-0126—2 6
RM7890A,B,C
SPECIFICATIONS
Fig. 4—Ultraviolet detectors.
1
[27]
1
16
COLLAR WITH 1/2-14 NPSM
INTERNAL THREADS
4 [102]
3 [89]
1
2
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
1
[38]
1
231
32
[25]
1/2-14 NPSM
INTERNAL THREADS
4 [105]
1
8
2
1
[30]
3
16
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 [67]
5
8
2
3
INSERTION DEPTH
6 FOOT
[1.83 METER]
LEADWIRES (2) 3
M1945A
C7035
[22]
7
8
3 [92]
5
8
1
2[13]
9
16 [14]
1 [36]
27
64
[10]
3
8
MOUNTING BRACKET
6 FOOT [1.83 METER]
LEADWIRES (2)
M1944A
C7044
C7027
4 [123]
4
[102]
27
32
1 [27]
1
16
2 [57]
1
4
4 [102]
2
[57]
1
4
10 [261]
9
32
2
[58]
5
16 7 [188]
13
32
7 [194]
2 [68]
11
16 5
8
1
[41]
19
32
[19]
3
4
[23]
29
32
3/8 INCH NPT
1 INCH NPT
7/8 [22] OPENING
FOR 1/2-INCH CONDUIT
ALLOW 9 INCHES [228 MM] CLEARANCE TO
SWING OUT THE DETECTOR FOR LENS
CLEANING OR SERVICING.
1
M5083
C7076A

7 65-0126—2
C7076D
RM7890A,B,C
SPECIFICATIONS
C7015
1
[32]
1
4
2 [70]
3
4
APERTURE
BUSHING WITH
MAGNIFYING LENS COLLAR, 3/4-14 NPSM
INTERNAL THREADS
3/4-14
NPSM 3/4-14 NPSM
INTERNAL
THREADS
1
[32]
1
4
1 [27]
1
16
1 [41]
5
8
HEAT BLOCKCELL MOUNT
M1982A
2 LEADS IN A
48 INCH [1.2 METER]
FLEXIBLE CONDUIT
7 [198]
13
16
2
[64]
1
2
15/16 [24] DIA.
6
[158]
7
32
6
[168]
19
32
2 [51]
1 [25]
1 INCH NPT
15/16–18 UNC
(2 EACH)
2
[55]
5
32 1
[47]
27
32
11 [300]
13
16
5 [147]
13
16
5
[147]
13
16
M5084
Fig. 5—Infrared detector.
Fig. 4—Ultraviolet detectors (continued).

65-0126—2 8
Principal Technical Features
RM7890A,B,C
PRINCIPAL TECHNICAL FEATURES • SAFETY PROVISIONS
INTERNAL HARDWARE STATUS MONITORING
The RM7890 analyzes the integrity of the configuration
jumpersandinternalhardware.ThePOWERLEDwillblink
every four seconds, signifying an internal hardware check.
CLOSED LOOP LOGIC TEST
The test verifies the integrity of all safety critical loads,
terminals8, 9 and 10.Iftheloadsare not energizedproperly;
i.e., the main valve terminal is powered during STANDBY,
the RM7890 will lockout on safety shutdown. The RM7890
must react to input changes but avoid the occurrence of
nuisance shutdown events. Signal conditioning is applied to
line voltage inputs to verify proper operation in the presence
of normal electrical line noise such as transient high voltage
spikesorshortperiodsoflinedropout.Signalconditioningis
tolerantofsynchronous noise (line noiseeventsthat occur at
the same time during each line cycle).
DYNAMIC AMPLI-CHECK™
Dynamic AMPLI-CHECK™ circuitry tests the flame
signal amplifier during burner operation and shuts down the
RM7890 if the flame amplifier fails.
DYNAMIC FLAME AMPLIFIER AND SHUTTER
CHECK
Self-checking circuitry tests all electronic components in
theflamedetectionsystemandamplifier12timesperminute
and shuts down the RM7890 if the detection system fails.
DYNAMIC INPUT CHECK
All system input circuits are examined to assure that the
RM7890is capable of recognizingthe true status ofexternal
controls, limits and interlocks. If any input fails this test, a
safety shutdown occurs and the fault will be annunciated.
DYNAMIC SAFETY RELAY TEST
Checks the ability of the dynamic safety relay contact to
open and close. Verifies that the safety critical loads, termi-
nals 8, 9 and 10, can be de-energized, as required, by the
Dynamic Self-Check logic.
DYNAMIC SELF-CHECK SAFETY CIRCUIT
The microcomputer tests itself and related hardware, and
atthesametime, the safety relay system tests themicrocom-
puter operation. If a microcomputer or safety relay failure
occursand does notallowproperexecution of theself-check
routine, safety shutdown occurs and all safety critical loads
will be de-energized.
EXPANDED SAFE-START CHECK
(EXCEPT RM7890C)
Theconventionalsafe-startcheck,whichpreventsburner
start-upifflameisindicatedatstart-up,isexpandedtoinclude
a flame signal check during STANDBY and a safety critical
load check.
OFF CYCLE (STANDBY) FLAME SIGNAL CHECK
(EXCEPT RM7890C)
Theflamedetectionsubsystem(flamedetectorandampli-
fier) is monitored during STANDBY. If a flame simulating
condition or an actual flame exists for 40 seconds in
STANDBY, a system hold occurs and start-up is prevented.
If the flame signal exists at any time after the 40 seconds
during STANDBY, a safety shutdown occurs and is annun-
ciated. A shutter-check amplifier and self-checking detector
areenergizedforthe first40seconds duringSTANDBYand
the last two seconds before exiting STANDBY. If a flame
exists after the first 40 seconds of STANDBY, the shutter-
check amplifier and self-checking detector are energized
The RM7890 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. AC line power errors occurred, see Operation.
b. Configuration jumpers have been changed (after
200 hours).
c. Four minute INITIATE period has been exceeded.
2. STANDBY PERIOD
a. Flame signal is present after 40 seconds.
b. Ignition/intermittent pilot valve terminal is ener
gized.
c. Internal system fault occurred.
d. Main valve terminal is energized.
e. Three second Flame Failure Response Time
(FFRT) Amplifier is installed and configuration
jumper is selected for relight (see Table 3).
3. SAFE START CHECK (EXCEPT RM7890C)
a. Ignition/intermittent pilot valve terminal is ener-
gized.
b. Internal system fault occurred.
c. Main valve terminal is energized.
4. PILOT FLAME ESTABLISHING PERIOD (PFEP)
a. Ignition/intermittent pilot valve terminal is not en-
ergized.
b. Internal system fault occurred.
c. Main valve terminal is energized.
d. No flame present at end of PFEP.
5. RUN PERIOD
a. Ignition terminal is energized.
b. Internal system fault occurred.
c. Main valve terminal is not energized.
d. No flame present and configuration jumper is se-
lected for lockout.
e. Pilot valve terminal is not energized.
Safety Provisions

9 65-0126—2
CAUTION
1. Disconnect the power supply before beginning
installationtopreventelectricalshockandequip-
ment damage. More than one power supply
disconnect may be involved.
2. WiringconnectionsfortheRM7890areunique;
therefore,refertoFig.7orthecorrectSpecifica-
tions for proper subbase wiring.
3. Wiring must comply with all applicable codes,
ordinances and regulations.
4. Wiring,whererequired,mustcomplywithNEC
Class 1 (Line Voltage) wiring.
5. Loads connected to the RM7890 must not ex-
ceed those listed on the RM7890 label or the
Specifications, see Table 1.
6. Limitsand interlocks must be ratedto carry and
break current simultaneously to the ignition
transformer,pilot valve, andmainfuelvalve(s).
7. Allexternal timers must be listed or component
recognizedby authorities who have jurisdiction
forthespecificpurposeforwhichtheyareused.
RM7890A,B,C
SAFETY PROVISIONS • INSTALLATION
during the last 10 seconds of the 40 second flame detection
period. If a flame exists, a safety shutdown occurs. An
AMPLI-CHECK™ Amplifier is energized continually
through STANDBY to detect any possibility of a runaway
detector or a flame. If a flame exists, a safety shutdown
occurs.Astandardamplifierisenergizedcontinuallythrough
STANDBY, if a flame exists a safety shutdown occurs.
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 assure early spark
termination (ten seconds ignition and pilot and ten seconds
pilot and main only).
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
blinks every four seconds, signifying that the RM7890
hardware is running correctly.
Optionalmulti-functionKeyboardDisplayModuleshows
elapsed time during PILOT IGN. As an additional trouble-
shooting aid, it provides sequence timing, diagnostic infor-
mation, historical information and expanded annunciator
information during normal operation or when a safety shut-
down or hold occurs.
First-out Annunciation reports the cause of a safety shut-
downoridentifiesthecauseofafailuretostartorcontinuethe
burner control sequence with an English text and numbered
codevia the optional KeyboardDisplayModule.Itmonitors
all field input circuits, including the flame signal amplifier.
Thesystemdistinguishes39modesoffailureanddetectsand
annunciates difficult-to-find intermittent
failures.
Self-Diagnostics add to the First-out Annunciation by
allowingtheRM7890todistinguishbetweenfield(external
device) and internal (system related) problems. Faults asso-
ciated within the flame detection subsystem or RM7890 are
isolated and reported by the optional Keyboard Display
Module. See the 7800 SERIES System Annunciation Diag-
nostics and Troubleshooting, form 65-0118.
WARNING
FIRE OR EXPLOSION HAZARD
CAN CAUSE PROPERTY DAMAGE,
SEVERE INJURY, OR DEATH
To prevent possible hazardous burner operation,
perform verification of safety requirements
each time a control is installed on a burner.
WHEN INSTALLING THIS PRODUCT…
1. Read these instructions carefully. Failure to follow
them could damage the product or cause a hazardous condi-
tion.
2. Checktheratingsgivenintheinstructionsandmarked
on the product to make sure the product is suitable for your
application.
3. Installer must be a trained, experienced, flame safe-
guard service technician.
4. After installation is complete, check out the product
operation as provided in these instructions.
Installation
! !

65-0126—2 10
RM7890A,B,C
INSTALLATION
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. Two detectors can be connected in parallel with the
exception of Infrared Detectors (C7015).
3. Thisequipmentgenerates,usesandcanradiateradio
frequency energy and, if not installed and used in
accordancewiththeinstructions,maycauseinterfer-
enceto radio communications.It has beentested and
found to comply with the limits for a Class B comput-
ingdeviceofpart15ofFCCrules,whicharedesigned
to provide reasonable protection against such inter-
ferencewhenoperatedinacommercialenvironment.
Operationofthisequipmentinaresidentialareamay
cause interference; in which case, the users at their
own expense may be required to take whatever mea-
sures are required to correct this interference.
4. This digital apparatus does not exceed the Class B
limitsforradionoiseofdigitalapparatussetoutinthe
Radio Interference Regulations of the Canadian De-
partment of Communications.
HUMIDITY
Install the RM7890 where the relative humidity never
reaches the saturation point. The RM7890 is designed to
operate in a maximum 85% RH continuous, noncondensing
moisture environment. Condensing moisture may cause a
safety shutdown.
VIBRATION
Do not install the RM7890 where it could be subjected to
vibration in excess of 0.5G continuous maximum vibration.
WEATHER
The RM7890 is not designed to be weather tight. If
installed outdoors, the RM7890 must be protected by an
approved weather-tight enclosure.
Fig. 6—Internal block diagram of the RM7890 (see Fig. 7 for detailed wiring instructions).
CONFIGURATION
JUMPERS
MICROCOMPUTER
RESET
PUSH-
BUTTON
STATUS LEDs SAFETY RELAY
CIRCUIT
POWER SUPPLY
OPTIONAL KEYBOARD
DISPLAY MODULE
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 CONTROLLER 1K1 2K1
120 Vac FLAME SIGNAL
TEST
PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
RS485
123
L1
(HOT) L2
3
64K1
2K2
10
8
9
4K
3K
2K
F
G
22
1
ALARM
3K1 4
L2
1M9093
F
RM7890C
N. O.

11 65-0126—2
RM7890A,B,C
INSTALLATION • WIRING
MOUNTING WIRING SUBBASE
NOTE: For installation dimensions, see Figs. 1 or 2.
1. Mountthesubbasein anypositionexcept horizontally
with the bifurcated contacts pointing down. The standard
vertical position is recommended. Any other position de-
creases the maximum ambient temperature rating.
2. Select a location on a wall, burner or electrical panel.
TheQ7800canbemounteddirectlyinthecontrolcabinet.Be
sure to allow adequate clearance for servicing, installation,
access and removal of the RM7890, Dust Cover, flame
amplifier, flame amplifier signal voltage probes, electrical
signal voltage probes and electrical field connections.
3. Forsurfacemounting,use the back of the subbase asa
template to mark the four screw locations. Drill the pilot
holes.
4. Securley mount the subbase using four no. 6 screws.
b. The earth ground terminal for each RM7890 must
begrounded tothemetalcontrol panelwithwire as
short as practical. Each ground wire must be ca-
pable of carrying a fault current equal to 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 for flame detector
leadwires:
• Do not run high voltage ignition transformer wires
inthesameconduitwiththeflamedetectionwiring.
• Do not route scanner wires in a conduit with line
voltage circuits.
• Enclosescannerwireswithoutarmorcableinmetal
cable or conduit.
• Follow directions given in the flame detector In-
structions.
7. Maximum wire lengths:
a. For the RM7890, the maximum length of leadwire
to the control terminal input is 300 feet.
b. For the flame detector leadwires, the maximum
flamesensorleadwirelengthislimitedbytheflame
signal strength.
8. Make sure loads do not exceed the terminal ratings.
Refer to the label on the RM7890 or to the ratings in the
Specifications, see Table 1.
9. Check the power supply circuit. The voltage and
frequency tolerance must match those of the RM7890. A
separatepowersupplycircuitmayberequiredfortheRM7890
with the required disconnect means and overload protection
added.
10. Check all wiring circuits and complete the Static
Checkout, see Table 4, before installing the RM7890 on the
subbase.
11. Install all electrical connectors.
12. Restore power to the panel.
1. a. For proper subbase wiring, refer to Fig. 7.
b. For proper remote wiring of the Keyboard Display
Module; refer to the Specifications for the Key-
board Display Module (65-0090), Communi-
cation 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 topreventelectricalshock
and equipment damage. More than one disconnect may be
involved.
3. Allwiring must complywith all appropriateelectrical
codes, ordinances and regulations. Wiring, where required,
must comply with NEC Class 1 (Line Voltage) wiring.
4. Recommended wire size and type: Use no. 14, 16, or
18copper conductor(TTW60Cor THW75CorTHHN90C)
600 volt insulation wire for all line voltage terminals. For
high temperature installations, use wire selected for a tem-
perature rating above the maximum operating temperature.
All leadwires must be moisture resistant.
5. Recommended grounding practices:
a. Use the earth ground to provide a connection be-
tween the subbase and the control panel or the
equipment.Theearthground wire must be capable
of conducting the current to blow the 20A fuse (or
breaker) in event of an internal short circuit. The
RM7890 needs a low impedance ground connec-
tion to the equipment frame which, in turn, needs a
low impedance connection to earth ground. For a
groundpathtobelowimpedanceatRFfrequencies,
theconnectionmustbemadewithminimumlength
conductors that have a maximum surface area.
Wide straps or brackets are preferred rather than
leadwires. Be careful to verify that mechanically
tightenedjointsalongtheground path,suchaspipe
or conduit threads or surfaces held together with
fasteners, are free of nonconductive coatings and
are protected against mating surface corrosion.
Wiring

65-0126—2 12
RM7890A,B,C
WIRING
Fig. 7—Wiring the RM7890A,B,C.
M9094
G
L2
3
5
6
7
8
9
10
F
(L1)
13
14
15
16
17
18
19
20
21
22
12
MASTER
SWITCH
IGNITION
MAIN FUEL
VALVE(S)
BURNER
CONTROLLER/LIMITS
120V ALARM
INTERMITTENT
PILOT/IGNITION
RECTIFYING FLAME
ROD, RECTIFYING
PHOTOCELL, OR INFRA-
RED (LEAD SULFIDE)
FLAME DETECTOR
C7027A, C7035A, OR
C7044A ULTRAVIOLET
FLAME DETECTOR
C7012A,C,E,F OR
C7076A ULTRAVIOLET
FLAME DETECTOR
120V, 60 Hz POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
DO NOT CONNECT ANY WIRES TO UNUSED TERMINALS.
TERMINAL 22 IS ONLY ON THE RM7890B.
FOR A CONTINUOUS OR STANDING PILOT, INSTALL AN EXTERMAL RELAY TO SWITCH THE F LEAD. THE
RELAY MUST HAVE GOLD-CLAD OR GOLD-FLASH CONTACTS AND A 120 VAC COIL. POWER THE RELAY
COIL FROM THE Q7800SUBBASE TERMINAL 8. CONNECT THE RELAY CONTACTS BETWEEN THE F LEAD OF
THE DETECTOR AND THE F TERMINAL OF THE Q7800 SUBBASE. THE R4222N1002 OR R4222V1002 RELAY IS
ACCEPTABLE TO USE IN THIS TYPE OF APPLICATION. USE THE N.O. PILOT DUTY CONTACTS.
INSTALL A LINE VOLTAGE CONTROLLER IN SERIES WITH THE LIMITS. IF USING A LOW VOLTAGE
CONTROLLER IS DESIRABLE, INSTALL AN EXTERMAL RELAY WITH THE N. O. CONTACTS IN SERIES WITH
THE LIMITS. THE LOW VOLTAGE RELAY COIL WILL BE IN THE LOW VOLTAGE CONTROLLER CIRCUIT. NOTE
THAT IT MAY BE NECESSARY TO PROVIDE AN EXTERNAL LOW VOLTAGE TRANSFORMER.
DO NOT USE NON-SELF CHECK ULTRAVIOLET FLAME DETECTORS WITH RM7890C.
FOR DIRECT SPARK IGNITION (OIL
OR GAS)
L1
(HOT)
L2 1
OR
OR
BLUE
BLUE
WHITE
YELLOW
L2
WHITE
WHITE
BLACK
BLACK L1
L2
8
9
10 IGNITION
TRANSFORMER
MAIN VALVE
1
Q7800
2
2
3
3
5
4
L2
4
5
6
6
4

13 65-0126—2
MOUNTING RM7890
NOTE: For installation dimensions, see Figs. 1 or 2.
RELAY MODULE MOUNTING
1. Mount the RM7890 vertically, see Figs. 8 or 9, or
mount horizontally with the knife blade terminals pointing
downward. When mounted on the Q7800A, the RM7890
must be in an electrical enclosure.
2. Select the location in the electrical enclosure. Be sure
to allow adequate clearance for servicing, installation and
removalof the RM7890,DustCover,flame amplifier, flame
amplifier signal voltage probes, electrical signal voltage
probes and electrical connections.
a. AllowanadditionaltwoinchesbelowtheRM7890for
the flame amplifier mounting.
b. Allowanoptionalthree-inchminimumtobothsidesof
the RM7890 for electrical signal voltage probes.
3. Makesure no subbase wiring is projecting beyondthe
terminal blocks. Tuck in wiring against the back of the
subbasesoitdoesnotinterferewiththeknifebladeterminals
or bifurcated contacts.
IMPORTANT: The 7890 must be installed with a plug-in
motion rather than a hinge action.
4. Mount the RM7890 by aligning the four L shaped
corner guides and knife blade terminals with the bifurcated
contacts on the wiring subbase and securely tightening the
two screws without deforming the plastic.
RM7890A,B,C
ASSEMBLY
Assembly
Fig. 8—Electrical panel installation.
Fig. 9—Wall or burner installation.
Fig. 10—Dust Cover mounting.
MOUNTING DUST COVER
1. Alignthetwointerlocking earsofthe DustCoverwith
the two mating slots on the RM7890, see Fig. 10.
2. Insert the two interlocking ears into the two mating
slots,andwithahingeaction,pushontheuppercornersofthe
Dust Cover to secure it to the RM7890.
3. Be sure the Dust Cover is firmly in place.
INSTALLING PLUG-IN FLAME SIGNAL
AMPLIFIER
1. Disconnect the power supply before beginning instal-
lation to prevent electrical shock and equipment damage.
More than one disconnect may be involved.
2. Align the amplifier circuit board edge connector with
the keyed receptacle on the RM7890. Verify that the ampli-
fier nameplate faces away from the Relay Module, see
Fig. 11.
3. Push in the amplifier until the circuit board is fully
inserted into the receptacle and then push the amplifier
toward the RM7890 retaining clasp.
4. Verify the amplifier is firmly in place.
5. Perform all required checkout tests.

65-0126—2 14
RM7890A,B,C
ASSEMBLY
INSTALLING THE FLAME DETECTOR
NOTE: Table 2 and Fig. 12 list the flame detection systems
availableforuse with the RM7890. Make sure the correct
combination of amplifier and flame detector(s) is used.
Properflamedetectorinstallationisthebasisofasafeand
reliableflamesafeguardinstallation.RefertotheInstructions
packed with the flame detector and the equipment manufac-
turer instructions.
Keep the flame signal leadwires as short as possible from
the flame detector to the wiring subbase. Capacitance in-
creases with leadwire length, reducing the signal strength.
The maximum permissible leadwire length depends on the
type of flame detector, leadwire and conduit. The ultimate
limiting factor in the flame detector leadwire is the flame
signal, see Table 5.
Fig. 11—Flame signal amplifier mounting.
Fig. 12—Flame detector wiring.
M9095
1FLAME DETECTOR LEADS ARE COLOR CODED. THE BLUE LEAD MUST BE CONNECTED TO THE F TERMINAL AND THE WHITE
MUST BE CONNECTED TO THE G TERMINAL. THE UV SENSING TUBE IS POLARITY SENSITIVE. REVERSING THE LEADS EVEN
MOMENTARILY CAN DAMAGE OR DESTROY THE UV TUBE.
FLAME DETECTOR LEADS ARE COLOR CODED. THE BLUE LEAD MUST BE CONNECTED TO THE F TERMINAL AND THE YELLOW
MUST BE CONNECTED TO THE G TERMINAL. THE UV SENSING TUBE IS POLARITY SENSITIVE. REVERSING THE LEADS EVEN
MOMENTARILY CAN DAMAGE OR DESTROY THE UV TUBE.
DO NOT USE WITH RM7890C.
2
3
BLUE
YELLOW
WHITE
WHITE
BLACK
BLACK
F
G
22
L2
L1
L2
BLUE
WHITE
F
G
WHITE
BROWN
F
G
INFRARED (C7015)
ULTRAVIOLET (C7027/C7035/C7044)
SOLID STATE SELF-CHECKING
ULTRAVIOLET (C7012E,F)
BLUE
YELLOW
BLACK
BLACK
F
G
L1
L2
SOLID STATE
ULTRAVIOLET (C7012A,C)
1
22
F G
4
5
3
L2
C7076A,D ULTRAVIOLET DETECTOR
522
6
SHUTTER
G
SHUTTER
F
1
8
2
7
7800 SERIES
L1
L2
3a 3b
REMOTE
SENSOR
2b
2a
EARTH
GROUND
C7076A
OR
C7076D
TERMINAL
BLOCK
L2 (COMMON)
L1 (HOT)
G
F
X
X
FLAME ROD
G
F
X
X
PHOTOCELL
3
3

15 65-0126—2
RM7890A,B,C
OPERATION
Operation
Sequence of Operation
The RM7890 has the following operating sequences, see
Figs. 13 and 15.
INITIATE
TheRM7890 enters the INITIATE sequenceif the Relay
Module verifies voltage fluctuations of +10/-15% or fre-
quency fluctuations of +/- 10% during any part of the
operating sequence. The INITIATE sequence lasts for ten
seconds unless the voltage or frequency tolerances are not
met. When the tolerances are not met, a hold condition will
be initiated and will be displayed on the optional VFD for at
least five seconds. When the tolerances are met, the INI-
TIATEsequencewillrestart.Iftheconditionisnotcorrected
and the hold condition exists for four minutes, the RM7890
will lockout. Causes for hold conditions in the INITIATE
sequence are:
• AC line dropout is detected.
• AClinefrequencyerrorcausedbyusinga60Hzdevice
on a 50 Hz line or vice versa.
• AC line noise that can prevent a sufficient reading of
the line voltage inputs.
• Brownouts caused by a low line voltage.
STANDBY
TheRM7890isreadytostartanoperatingsequencewhen
the operating control input determines a call for heat is
present.Theburnerswitch,limits,operatinglimitcontroland
all microcomputer monitored circuits must be in the correct
state for the RM7890 to continue into the SAFE-START
CHECK.
NORMAL START-UP SAFE-START CHECK
(EXCEPT RM7890C)
The RM7890 verifies that a flame does not exist and
proceeds into the Ignition Trial. If a flame is present, the
RM7890willrecycletotheSTANDBYperiod.Ifthecritical
loads are not in the correct state, a safety shutdown occurs.
IGNITION TRIALS
a. Pilot Flame Establishing Period (PFEP):
1. The pilot valve and ignition transformer, terminals
8 and 10, are energized. The RM7890A,B has an
intermittent pilot valve, terminal 8.
2. Flame must be proven by the end of the 4 or 10
second PFEP (30 second for RM7890A1031) to
allow the sequence to continue. If flame is not
proven by the end of PFEP, a safety shutdown
occurs.
3. With flame proven, the ignition, terminal 10, is
de-energized and the main valve, terminal 9, is
energized.
RUN
TheRM7890isnowinRUNandwillremaininRUNuntil
the controller input, terminal 6, opens, indicating that the
demand is satisfied or a limit has opened.
SELECTABLE SITE-CONFIGURABLE JUMPERS
The RM7890 has two site-configurable jumper options,
seeFig.16andTable3.Thesite-configurablejumpersshould
be clipped with side cutters and the resistors removed from
the Relay Module.
Fig. 13—RM7890A,B sequence.
POWER
00
LED
DISPLAY
OPERATING
CONTROLLER
AND LIMITS
BURNER
START
FLAME
SIGNAL
INITIATE
ALARM
POWER
STANDBY
POWER POWER
PILOT
FLAME
MAIN
PFEP
4 OR 10 SEC
PILOT
FLAME
MAIN
POWER
RUN STANDBY
10
IGNITION
INTERMITTENT PILOT
MAIN VALVE
LIMITS AND BURNER CONTROL CLOSED
9
8
10
+ 6
TO
M5135B
00
POWER
SAFE-
START
MAIN FUEL VALVE WILL BE ENERGIZED DURING PFEP IF FLAME IS PROVEN.
RM7890A1031 PFEP IS FIXED 30 SECOND.
1
2
2
1
ALARM
S S C
SAFE START CHECK FLAME PROVING

65-0126—2 16
RM7890A,B,C
OPERATION
TABLE 3—SITE-CONFIGURABLE JUMPER OPTIONS
Fig. 15—Led sequence status display information (see Fig. 14).
INITIATE STANDBY
STANDBY
HOLD: F/G
(FLAME
DETECTED)
POWER
PILOT
FLAME
MAIN
POWER
PILOT
FLAME
MAIN
PILOT
IGNITION
SAFE-
START
CHECK
ALARM
POWER
FLAME
MAIN
PILOT
ALARMALARM
POWER
FLAME
MAIN
PILOT
ALARM
POWER
FLAME
MAIN
PILOT
ALARM
POWER
FLAME
MAIN
PILOT
ALARM
POWER
FLAME
MAIN
PILOT
ALARM
RESET/
ALARM
TEST
RUN
M3362
2
Fig. 14—Sequence status LEDs.
Jumper Number Description Intact Clipped RM7890 Type
JR1 Pilot Flame Establishing Period 10 seconds 4 seconds (ALL)
JR2 Flame Failure Action Relight Lockout (ALL) 3
1
1The Relight feature (JR2 intact) requires a 0.8 sec FFRT Flame Amplifier. The RM7890 will lockout and indicate a Fault
46 if a 3.0 second FFRT is used and jumper JR2 (Lockout) is not clipped and removed.
Not applicable for RM7890A1031 (30 second PFEP). JR1 removed.
Not applicable for RM7890C (Standing Pilot).
30 seconds for RM7890A1031.
2
3
4
4 4
SEQUENCE
STATUS
LEDs
RESET
PUSHBUTTON
FLAME
SIMULATOR INPUT FLAME CURRENT
TEST JACKS
CAPTIVE
MOUNTING
SCREW
DUST
COVER
RELAY
MODULE
FLAME
AMPLIFIER
M8995

17 65-0126—2
RM7890A,B,C
OPERATION • STATIC CHECKOUT
Fig. 16—Selectable site-configurable jumpers. SERVICE NOTE: Clipping and removing a site-
configurablejumperenhancesthelevelofsafety. Ifusing
a 3-second amplifier, site-configurable jumper JR2 must
be clipped and removed. If not removed, an F46 Lockout
will occur.
Static Checkout
!CAUTION
1. Useextreme care while testingthesystem.Line
voltageispresenton most terminal connections
when power is on.
2. Open the master switch before installing or
removing a jumper on the subbase.
3. Before continuing to the next test, be sure to
remove the test jumper(s) used in the previous
tests.
4. Replace all limits and interlocks not operating
properly. Do not bypass limits and interlocks.
5. Close all manual fuel shutoff valve(s) before
starting these tests.
EQUIPMENT RECOMMENDED
1. Voltmeter (20 kohm/volt minimum sensitivity) set on
the 0-300 Vac scale.
2. Two jumper wires; no. 14 wire, insulated, 12 inches
(304.8 mm) long, with insulated alligator clips at both ends.
GENERAL INSTRUCTIONS
1. Perform all applicable tests listed in Static Checkout,
Table 4, in the order listed.
2. MAKE SURE THAT ALL MANUAL FUEL
SHUTOFF VALVE(S) ARE CLOSED.
3. Perform only those tests designated for the specific
RM7890 model being tested.
4. Raise the set point of the operating controller to simu-
late a call for heat.
5. For each test, open the master switch and install the
jumperwire(s)betweenthesubbasewiringterminalslistedin
the Test Jumpers column of Table 4.
6. Close the master switch before observing operation.
7. Readthevoltagebetweenthesubbasewiringterminals
listed in the Voltmeter column of Table 4.
8. If there is no voltage or the operation is abnormal,
checkthecircuitsandexternaldevicesasdescribedinthelast
column.
9. Checkallwiringforcorrectconnections,tightterminal
screws, correct wire, and proper wiring techniques. Replace
all damaged or incorrectly sized wires.
10. Replace faulty controllers, limits, interlocks, actua-
tors, valves, transformers, motors and other devices as re-
quired.
11. Obtain normal operation for each required test before
continuing the checkout.
12. After completing each test, be sure to remove the test
jumper(s).
SELECTABLE CONFIGURATION JUMPERS 1 2
1
2
3
JR1 REMOVED FROM 30 SECOND FIXED PFEP MODEL.
JR2 REMOVED FROM RM7890C.
RM7890A1031 PFEP IS 30 SECONDS. M11589

65-0126—2 18
RM7890A,B,C
STATIC CHECKOUT
TABLE 5—STATIC CHECKOUT.
Test
No. RM7890 Models Test Jumpers Voltmeter Normal Operation If Operation Is Abnormal, Check The Items Listed Below
WARNING
Make sure all manual fuel shutoff valves are closed.
IMPORTANT: Low fuel pressure limits, if used, could be open. Bypass them with jumpers for the remaining Static
tests (if required).
1 All None 3-L2 Line voltage at terminal 3. 1. Master switch.
2. Power connected to the
master switch.
3. Overload protection (fuse,
circuit breaker) has not
opened the power line.
2 All None 6-L2 Line voltage at terminal 6. 1. Limits.
2. Burner controller.
3 All 3-10 — Ignition spark (if ignition
transformer is connected to
terminal 10).
1. Watch for spark or listen for
buzz.
a. Ignition electrodes are
clean.
b. Ignition transformer is
okay.
4 All 3-8 — 1. Ignition spark (if ignition
transformer is connected to
terminal 8).
2. Automatic pilot valve opens
(if connected to terminal 8).
NOTE: Refer to wiring diagram
of system being tested.
1. Watch for spark or listen for
buzz.
a. Ignition electrodes are
clean.
b. Ignition transformer is
okay.
2. Listen for click or feel head
of valve for activation.
a. Actuator if used.
b. Pilot valve.
5 All 3-9 — Automatic fuel valve(s) opens. If
using direct spark ignition, check
the first stage fuel valve(s)
instead of the pilot valve.
Same as test no. 5. If using direct
spark ignition, check the first
stage fuel valve(s) instead of the
pilot valve.
6 All 3-4 — Alarm (if used) turns on. 1. Alarm
Final All CAUTION
After completing these tests, open the master switch and remove all test jumpers from the
subbase terminals. Also remove bypass jumpers from the low fuel pressure limits (if used).
!
!

19 65-0126—2
WARNING
Do not allow fuel to accumulate in the combustion
chamber.If fuelisallowed toenterthe chamberfor
longer than a few seconds without igniting, an
explosive mixture could result. It is recommended
that you limit the trial for pilot to ten seconds, and
limit the attempt to light the main burner to two
seconds from the time the fuel has reached the
burner nozzle. In any case, do not exceed the
nominal lightoff time specified by the equipment
manufacturer.Closethemanualfuelshutoffvalve(s)
if the flame is not burning at the end of the
specified time.
CAUTION
1. Useextreme care while testingthesystem.Line
voltageispresenton most terminal connections
when power is on.
2. Open the master switch before removing or
installing the RM7890.
3. Make sure all manual fuel shutoff valve(s) are
closed before starting the initial lightoff check
and the Pilot Turndown tests.
4. Do not put the system in service until you have
satisfactorily completed all applicable tests in
this section and any others required by the
equipment manufacturer.
CAUTION
If an RM7890 is replaced with a lower or higher
functioning7800SERIESRelayModule,theburner
will not sequence unless wiring changes are made.
IMPORTANT:
1. If the system fails to perform properly, refer to 7800
SERIES System Annunciation Diagnostics and
Troubleshooting, form 65-0118.
2. Repeat ALL required Checkout tests after all adjust-
ments are made. ALL tests must be satisfied with the
flame detector(s) in its FINAL position.
Checkout
!
RM7890A,B,C
CHECKOUT
!
!
EQUIPMENT RECOMMENDED
Volt-ohmmeter (20 kohm/volt minimum sensitivity).
• 0-300 Vac capability.
• 0-6000 ohm capability.
• 0-10 Vdc capability.
CHECKOUT SUMMARY
• Preliminary inspection—all installations.
• Flame signal measurement—all installations.
• Initial lightoff check for proved pilot—all installa-
tions using a pilot.
• Initiallightoffcheckfordirectsparkignitionofoil—
all burners using DSI.
• Pilot turndown test—all installations using a pilot.
• Hotrefractorysaturationtest—allinstallationsusing
Infrared (lead sulfide) Flame Detectors.
• Hot refractory hold-in test—all installations.
• Ignition interference test—all installations using
flame rods.
• Ignitionspark pickup—all installations using Ultra-
violet Flame Detectors.
• Response to other ultraviolet sources—all installa-
tions using Ultraviolet Flame Detectors.
• Flame signal with hot combustion chamber—all
installations.
• Safety shutdown tests—all installations.
See Fig. 14 for location of component parts and, see
Fig. 7 or Q7800 Specifications for terminal locations.
PRELIMINARY INSPECTION
Perform the following inspections to avoid common
problems. Make certain that:
1. Wiringconnectionsarecorrectandallterminalscrews
are tight.
2. Flame detector(s) is clean, installed and positioned
properly. Consult the applicable Instructions.
3. Correctcombinationofamplifierandflamedetector(s)
is used. See Table 2 in the Specifications.
4. Plug-in amplifier is securely in place.
5. Burner is completely installed and ready to fire; con-
sult equipment manufacturer instructions. Fuel lines are
purged of air.
6. Combustion chamber and flues are clear of fuel and
fuel vapor.
7. Power is connected to the system disconnect switch
(master switch).
8. Lockout switch is reset (push in reset pushbutton)
only if the RM7890 is powered, see Figs. 1 and 2.
9. Systemis intheSTANDBYcondition. POWER LED
is energized.
10. All limits and interlocks are reset.

65-0126—2 20
TABLE 5—FLAME SIGNAL (see Fig. 17).
RM7890A,B,C
CHECKOUT
FLAME SIGNAL MEASUREMENT
Fig. 17—Flame signal measurement.
Measurethe flamesignalatthe appropriate timesdefined
inthefollowingcheckouttests.Readtheflamesignalvoltsdc
at the flame amplifier test jacks + and - (Com).
1. Usea20kohm/voltmeterwitha0to10Vdccapability.
2. Set the 20 kohm/voltmeter to the 0 to 10 Vdc range.
3. Insert the positive (red) probe into the + jack of the
flame amplifier. Insert the negative (black) probe into the -
(Com) jack of the flame amplifier (see Fig. 17).
4. Allowafewsecondsforthemeterreadingtostabilize.
5. If using AMPLI-CHECK™ or shutter check amplifi-
ers, read the average stable voltage, disregarding the peaks
and valleys caused by the self-checking operation.
6. ThemeterreadingmustbeasspecifiedinTable5after
all tests are completed and all adjustments are made.
Asanoption,theflamesignalcanbecheckedbyusingthe
optional Keyboard Display Module.
If the signal is unstable or less than the minimum accept-
able voltage, check the flame detector installation and cir-
cuitry.
1. Check the supply voltages at terminals 3 (L1) and
L2 (N). Make sure the master switch is closed, connections
are correct, and the power supply is of the correct voltage,
frequency and is sinusoidal.
2. Check the detector wiring for defects including:
• Deteriorated wire.
• Incorrect connections.
• Leakagepathscausedbymoisture,sootoraccumu-
lated dirt.
• Open circuits.
• Short circuits.
• Wrong type of wire.
3. For a flame rod, make sure:
• Flame rod is properly located in the flame.
• Ground area is large enough.
• Temperatureattheflamerodinsulatorisnogreater
than 500°F [260°C].
4. For all optical detectors, clean the detector viewing
window and inside of the sight pipe as applicable.
5. With the burner running, check the temperature at the
detector. If it exceeds the detector maximum rated tempera-
ture: • Addaheatblocktostopconductedheattravelingup
the sight pipe.
• Add a shield or screen to reflect radiated heat.
• Add cooling (refer to sight pipe ventilation in the
detector Instructions).
6. Make sure that the flame adjustment is not too lean.
7. Make sure that the detector is properly sighting the
flame.
8. If necessary, resight or reposition the detector.
INITIAL LIGHTOFF CHECK FOR PROVED PILOT
Perform this check on all installations that use a pilot. It
should immediately follow the preliminary inspection.
NOTE: Low fuel pressure limits, if used, could be open. If
so, bypass them with jumpers during this check.
Flame Detector Flame Signal Amplifier Minimum Acceptable Steady dc VoltageaMaximum Expected dc Voltage
Flame Rod
Photocell
C7012A,C
R7847A,Bc1.25 Vdc 5.0 Vdc at the Keyboard
Display Module.
C7012E,F R7847Cbor
C7015A R7848A,Bc
C7027A
C7035A
C7044A
R7849A,Bc5.0 Vdc at a 20
kohm/voltmeter.
C7076A,D R7886A
aThisminimumorastrongersignalshouldeasilybeobtainedifthedetectoriscorrectlyinstalledandpositionedtoproperlysense
the flame. This voltage must be obtained before completing checkout.
bThe flame signal amplifier circuitry is tested one-half second every five seconds during burner operation and shuts down the
burner if the amplifier fails (all installations).
cThe flame amplifiers are AMPLI-CHECK™ type.
NEGATIVE (-)
METER LEAD
POSITIVE (+)
METER LEAD 1 MOHM/
VOLT METER
M10683