Honeywell RM7838A Installation Instructions Manual

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Page 1

RM7838A

66-1087-2

7800 SERIES Relay Modules

INSTALLATION INSTRUCTIONS

APPLICATION

The Honeywell RM7838A is a microprocessor-based integrated burner control for semi-automatically fired gas, oil, or combination fuel single burner applications. The RM7838A Relay Module is intended to replace the Industrial R4138A,B,C and D Flame Safeguard Primary Control, but does not include an override on momentary power interruptions. The RM7838A System consists of a relay module, keyboard display module, subbase, amplifier and purge card. Options include Personal Computer Interface, Data ControlBus Module™, remote display mounting, first-out expanded annunciator and Combustion System Manager Software.

Functions provided by the RM7838A include semi-automatic burner sequencing, flame supervision, system status indication, system or self-diagnosis and troubleshooting.

This document provides installation and static checkout instructions. Other applicable publications are:

63-2278 Q7700 Network Interface Unit Product Data. 65-0084 Q7800A,B 22-Terminal Wiring Subbase Product

Data.

65-0089 ST7800A Plug-in Purge Timer Installation

Instructions. 65-0090 S7800A Keyboard Display Module Product Data. 65-0091 S7810A Data ControlBus Module™ Product

Data. 65-0101 S7830 Expanded Annunciator Product Data. 65-0109 R7824, R7847, R7848, R7849, R7861, R7886

Flame Amplifiers for the 7800 SERIES Product Data. 65-0131 221818A Extension Cable Assembly 65-0229 7800 SERIES Relay Modules Checkout and

Troubleshooting.

SPECIFICATIONS

Electrical Ratings, see Table 3:

Voltage and Frequency: 120 Vac (+10/-15%), 50/60 Hz

(±10%). Power Dissipation: 10W maximum. Maximum Total Connected Load: 2000 VA. Fusing Total Connected Load: 20A maximum, type FRN

or equivalent.

Environmental Ratings:

Ambient Temperatures:

Operating: -40°F to 140°F (-40°C to 60°C). Storage: -40°F to 150°F (-40°C to 66°C).

Humidity: 85% relative humidity continuous,

noncondensing.

Vibration: 0.5G environment.

Approvals:

Underwriters Laboratories Inc. Listed: File No. MP268,

Guide MCCZ. Canadian Standards Association Certified: LR9S329-3. Factory Mutual Approved: Report No. J.I.1V9AO.AF. Industrial Risk Insurers: Acceptable. Federal Communications Commission: Part 15, Class B,

Emissions.

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

3. Installer must be a trained, experienced, flame safeguard technician.

4. After installation is complete, check out the product operation as provided in these instructions.

WARNING

Fire or Explosion Hazard. Can cause property damage, severe injury, or death.

Verify safety requirements each time a control is installed on a burner.

CAUTION

Electrical Shock Hazard. Can cause electrical shock or equipment/ control damage.

Disconnect the power supply before beginning installation.

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RM7838A 7800 SERIES RELAY MODULES

IMPORTANT

1. Wiring connections for the relay module are unique; refer to Fig. 2 or the correct Specifications for proper subbase wiring and sequence charts.

2. Wiring must comply with all applicable codes, ordinances and regulations.

3. Wiring must comply with NEC Class 1 (Line Voltage) wiring.

4. Loads connected to the RM7838A must not exceed those listed on the RM7838A label or the Specifications; see Table 3.

5. Limits and interlocks must be rated to simultaneously carry and break current to the ignition transformer, pilot valve, and main fuel valves.

6. All external timers must be listed or componentrecognized by authorities having proper jurisdiction.

7. 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 safeguard control and the main fuel valve(s).

8. Two flame detectors can be connected in parallel with the exception of Infrared Flame Detectors (C7015).

9. This equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, can cause interference with radio communications. It has been tested and found to comply with the limits for a Class B computing device of Part 15 of FCC rules, which are designed to provide reasonable protection against such interference when operated in a commercial environment. Operation of this equipment in a residential area can cause interference, in which case, users, at their own expense, may be required to take whatever measures are required to correct this interference.

10. This digital apparatus does not exceed the Class B limits for radio noise for digital apparatus set out in the Radio Interference Regulations of the Canadian Department of Communications.

Location

Humidity

Install the relay module where the relative humidity never reaches the saturation point. The relay module is designed to operate in a maximum 85% relative humidity continuous, noncondensing, moisture environment. Condensing moisture can cause a safety shutdown.

Vibration

Do not install the relay module where it could be subjected to vibration in excess of 0.5G continuous maximum vibration.

Weather

The relay module is not designed to be weather tight. When installed outdoors, protect the relay module in an approved weather-tight enclosure.

Mounting Wiring Subbase

1. Mount the subbase in any position except horizontally

with the bifurcated contacts pointing down. The standard vertical position is recommended. Any other position decreases the maximum ambient temperature rating.

2. Select a location on a wall, burner or electrical panel.

The Q7800 can be mounted directly in the control cabinet. Be sure to allow adequate clearance for service, installation, access or removal of the RM7838A, expanded annunciator, keyboard display module, flame amplifier, flame amplifier signal voltage probes, run/test switch, electrical signal voltage probes and electrical field connections.

3. For surface mounting, use the back of the subbase as a

template to mark the four screw locations, then drill the pilot holes.

4. Securely mount the subbase using four no. 6 screws

(not provided).

Wiring Subbase

CAUTION

Electrical Hazard. Can cause electrical shock or equipment/ control damage.

Disconnect the power supply before beginning wiring. More than one disconnect can be required.

1. For proper subbase wiring and sequence chart, see

Fig. 2.

2. For proper remote wiring of the keyboard display

module, refer to the Specifications for the keyboard display module. (65-0090), network interface unit (63-2278), Data ControlBus Module™ (65-0091) or extension cable assembly (65-0131).

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 routing of leadwires:

a. Do not run high voltage ignition transformer wires

in the same conduit with the flame detector, Data ControlBus Module™, or remote reset module wiring.

b. Do not route flame detector, Data ControlBus

Module™ or remote reset module leadwires in conduit with line voltage circuits.

c. Enclose flame detector leadwires without armor

cable in metal cable or conduit.

d. Follow directions in flame detector, Data

ControlBus Module™ or remote reset module instructions.

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RM7838A 7800 SERIES RELAY MODULES

RESET PUSHBUTTON

STATUS LEDs

BURNER CONTROL

L1 (HOT)

CONFIGURATION JUMPERS

SAFETY RELAY CIRCUIT

120 Vac

50/60 Hz

FAN

MICROCOMPUTER

RELAY DRIVE CIRCUIT

2K 3K 4K

5K 6K 7K 8K

POWER SUPPLY

PLUG-IN PURGE TIMER CARD

FLAME SIGNAL

PLUG-IN FLAME AMPLIFIER

TEST

RELAY STATUS FEEDBACK AND LINE VOLTAGE INPUTS

CONTROL POWER

TEST JACK

RUNNING/ LOCKOUT

LIMITS

3K1

DDL

DDL COMMUNICATIONS

PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED

S7800 INCLUDED WITH RM7838A.

COMBUSTION BLOWER OR EXHAUST RECIRCULATING FANS.

KEYBOARD DISPLAY MODULE

INTERLOCK

HIGH FIRE SWITCH

RS485

REMOTE

RESET

1K1

2K1

7K1

2K2

5K1

LOW FIRE SWITCH

ALARM SILENCING RELAY (DPST)

S445A START

STOP

INDICATES FEEDBACK SENSING OF RELAY CONTACT STATUS AND LINE VOLT INPUTS

FIELD WIRING INTERNAL WIRING

PILOT

IGNITION

MAIN VALVE(S)

ALARM

M5120C

Fig. 1. Internal block diagram of the RM7838A (see Fig. 2 for detailed wiring instructions).

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RM7838A 7800 SERIES RELAY MODULES

5. For recommended wire size and type, see Table 1.

6. For recommended grounding practices, see Table 2.

7. For keyboard display module (KDM). The KDM is

powered from a low voltage, energy-limited source. It can be mounted outside of a control panel if it is protected from mechanical damage.

NOTE: A 13 Vdc power supply must be used any

time more than one keyboard display module is used. A maximum of two keyboard display modules, Data ControlBus Modules™ or S7810B Multi-Drop Switch Modules are allowed in any combination.

9. Be sure loads do not exceed the terminal ratings. Refer

to the label on the RM7838A or to the terminal ratings in Table 3.

10. The keyboard display module, Data ControlBus

Module™ (for remote mounting or communications) or

8. Maximum wire lengths:

a. RM7838A leadwires: The maximum leadwire

length is 300 feet (91 meters) to terminal inputs (Control, Running Interlock, High Fire Switch and Low Fire Switch).

b. Flame detector leadwires: The maximum flame

sensor leadwire length is limited by the flame signal strength.

Communication Interface ControlBus Module must be wired in a daisy chain configuration, (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 modules on the closest and farthest end of the daisy chain configuration string require a 120 ohm (1/4 watt minimum) resistor termination across terminals 1 and 2 of the electrical connectors for connections over 100 feet (30.5m).

Table 1. Recommended Wire Size and Part Numbers.

Application Recommended Wire Size Recommended Part Numbers

Line voltage terminals 14, 16, or 18 AWG copper conductor,

600 volt insulation wire.

Keyboard Display Module 22 AWG two-wire twisted pair with ground,

or five-wire.

Data ControlBus Module™ 22 AWG two-wire twisted pair with ground,

or five-wire.

Remote Reset Module 22 AWG two-wire twisted pair, insulated for

low voltage.

Comunications Interface

22 AWG two-wire twisted pair with ground. Belden 8723 shielded cable or equivalent.

ControlBus™ Module 13 Vdc full wave rectified

transformer power input.

18 AWG wire insulated for votlages and temperatures for given application.

c. Remote reset leadwires: The maximum length of

wire is 1000 feet (305 meters) to a remote reset pushbutton.

d. Data ControlBus Module™: The maximum 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 Data ControlBus Module™ interconnecting wire is 4000 feet (1219 meters).

TTW60C, THW75C, THHN90C

Belden 8723 shielded cable or equivalent.

—

TTW60C, THW75C, THHN90C

Table 2. Recommended Grounding Practices.

Ground type Recommended Practice

Earth ground (subbase and relay module). 1. Use to provide a connection between the subbase and the control

panel of the equipment. Earth ground must be capable of conducting enough current to blow the 20A fuse (or breaker) in the event of an internal short circuit.

2. Use wide straps or brackets to provide minimum length, maximum surface area ground conductors. If a leadwire must be used, use 14 AWG copper wire.

3. Make sure that mechanically tightened joints along the ground path are free of nonconductive coatings and protected against corrosion on mating surfaces.

Signal ground (Keyboard Display Module, Data Controlbus Module™, Communications Interface ControlBus™ Module).

66-1087—2

Use the shield of the signal wire to ground the device to the signal gorund terminals [3(c)] of each device. Connect the shield at both ends of the daisy chain to earth ground.

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RM7838A 7800 SERIES RELAY MODULES

Table 3. Terminal Ratings.

Terminal No. Description Ratings

GFlame Sensor Ground Earth G Earth Ground L2(N) Line Voltage Common — 3 Alarm 120 Vac, 1A pilot duty. 4 Line Voltage Supply (L1) 120 Vac, (+10/-15%), 50/60- Hz (±10%) 5 Unused — 6 Start/Stop Switch Input 120 Vac, 1 mA. 7 Running Interlock 120 Vac, 8A run, 43A inrush. 8 Intermittent Pilot 120 Vac. 9 Main Fuel Valve 120 Vac. 10 Ignition 120 Vac. F(11) Flame Sensor 60 to 220 Vac, current limited. 12-18 Unused. — 19 High Fire Switch Input 120 Vac, 1 mA. 20 Unused — 21 Run Enable/Flame Proven 120 Vac, 2A pilot duty. 22 Shutter 120 Vac, 0.5A.

See Table 2.

2000VA maximum connected load.

See Tables 4 and 5.

— —

Table 4. Combinations for Terminals 8, 9 and 10.

Combination No. Pilot Fuel 8 Main 9 Ignition 10

1CFNo Load 2BFNo Load 4FFA 5FNo Load A 6DFA 7DDA 8DNo Load A

Table 5. Composition of each Combination.

AB CDF

4.5A ignition 50 VA Pilot Duty plus 4.5A ignition. 180 VA Ignition plus Motor valves with:

2A Pilot Duty 65 VA Pilot Duty plus

Motor valves with: 660 VA inrush, 360 VA open, 250 VA hold.

Final Wiring Check

1. Check the power supply circuit. The voltage and

frequency tolerance must match those of the RM7838A. A separate power supply circuit can be required for the RM7838A. Add the required disconnect means and

2. Check all wiring circuits and complete Static Checkout

in Table 7 before installing the RM7838A on the subbase.

3. Install all electrical connectors.

4. Restore panel power.

overload protection.

3850 VA inrush, 700 VA open, 250 VA hold.

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RM7838A 7800 SERIES RELAY MODULES

STATIC CHECKOUT

After checking all wiring, perform this checkout before installing the RM7838A on the subbase. These tests verify that the Q7800 Wiring Subbase is wired correctly and that the external controllers, limits, interlocks, actuators, valves, transformers, motors and other devices are operating properly.

WARNING

Explosion Hazard. Can cause explosion, electrical shock or equipment damage.

1. Close all manual fuel shutoff valves before starting these tests.

2. Use extreme care while testing the system. Line voltage is present on most terminal connections when power is on.

3. Open the master switch before installing or removing a jumper on the subbase.

4. Before continuing to the next test, be sure to remove test jumpers used in the previous test.

5. Replace all limits and interlocks that are not operating properly. Do not bypass limits and interlocks.

CAUTION

Equipment Damage Hazard. Can cause equipment damage.

Do not perform a dielectric test with the RM7838A installed. Internal surge protectors will break down and conduct a current. This can cause the RM7838A to fail the dielectric test or possibly destroy the internal lightning and high current protection.

Equipment Recommended

1. Voltmeter (1M ohm/volt minimum sensitivity) set on the 0 to 300 Vac scale.

2. Two jumper wires, No. 14 wire, insulated, 12 in. (304.8 mm) long with insulated alligator clips at both ends.

General Instructions

1. Perform all applicable tests listed in Static Checkout,

Table 7, in the order listed.

2. Make sure all manual fuel shutoff valves are closed.

3. Raise the setpoint of the operating controller to simulate

a call for heat.

4. For each test, open the master switch and install the jumper wires between the subbase wiring terminals listed in the Test Jumpers column.

5. Close the master switch before observing operation.

6. Read the voltage between the subbase wiring terminals

listed in the Voltmeter column.

7. If there is no voltage or the operation is abnormal, check the circuits and external devices as described in the last column.

8. Check all wiring for correct connections, tight terminal screws, correct wire and proper wiring techniques.

9. Replace all damaged or incorrectly sized wires.

10. Replace faulty controllers, limits, interlocks, actuators,

valves, transformers, motors and other devices as required.

11. Make sure normal operation is obtained for each

required test before continuing the checkout.

12. After completing each test, be sure to remove the test

jumpers.

WARNING

Explosion Hazard. Can cause serious injury or death.

Be sure all manual fuel shutoff valves are closed.

Table 7. Static Checkout.

Test

No. Test Jumpers Voltmeter Normal Operation

1 None 4-L2 Line voltage at terminal 4. 1. Master switch.

2 4-21 6-L2 Line voltage at terminal 6. 1. Stop station.

3 4-10 — Push Start pushbutton and

ignition sparks.

4 4-8 — Automatic pilot valve opens. 1. Listen for click or feel head of valve for

5 4-9 — Automatic main fuel valve(s)

opens.

6 4-3 — Alarm (if used) turns on. 1. Alarm.

2. Power connected to the master switch.

3. Overload protection (fuse, circuit breaker, etc.) has not opened the power line.

2. Alarm silencing relay.

1. Watch for spark or listen for buzz. a. Ignition electrodes are clean. b. Ignition transformer is okay. c. Damper not at low fire position. d. Low Fire Switch.

activation. a. Actuator if used. b. Pilot valve.

1. Listen for and observe operation of the main fuel valve(s) and actuator(s).

2. Valve(s) and actuator(s).

If Operation is Abnormal,

Check the Items Listed Below

(continued)

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RM7838A 7800 SERIES RELAY MODULES

Table 7. Static Checkout (continued).

Test

No. Test Jumpers Voltmeter Normal Operation

7 May need to

jumper limits

and/or Running

Interlocks

FINAL ALL

19-L2 Manually drive damper motor

open and look for High Fire Switch closure.

CAUTION

Equipment Damage Hazard. Can cause equipment damage.

After completing these tests, open the master switch and remove all test jumpers from the subbase terminals. Also remove bypass jumpers from limits if used.

Mounting RM7838A Relay Module

1. Mount the RM7838A on the 7800 Subbase vertically,

or mount horizontally with the knife blade terminals pointing down. When mounted on the Q7800A, the RM7838A must be in an electrical enclosure.

2. When mounted in an electrical enclosure, provide

adequate clearance for servicing, installation and removal of the RM7838A, keyboard display module, flame amplifier, signal probes, electrical signal voltage probes and electrical connections.

a. Allow an additional two inches (51 mm) below

the RM7838A for the flame amplifier mounting.

b. Allow an optional three-inch (76 mm) minimum

to both sides of the RM7838A for electrical signal voltage probes.

3. Make sure no subbase wiring is projecting beyond the

terminal blocks. Tuck in wiring against the back of the subbase so it does not interfere with the knife blade terminals or bifurcated contacts.

If Operation is Abnormal,

Check the Items Listed Below

1. High Fire Switch.

2. Firing rate motor and transformer.

3. Burner control.

4. Limits.

5. Running Interlocks.

IMPORTANT

The RM7838A must be installed with a plug-in motion rather than a hinge action.

4. Mount the RM7838A 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.

Mounting Other System Components (Fig. 3)

Refer to the applicable specifications for mounting other system components.

66-1087—2

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RM7838A 7800 SERIES RELAY MODULES

L1 (HOT)

ALTERNATE CONNECTION WHEN USING THE R4155A ALARM SILENCING RELAY. THE REMAINING CONNECTIONS ARE THE SAME FOR THE RM7838A.

R4155A

120V ALARM

FOR DIRECT SPARK IGNITION (OIL OR GAS)

STOP

MAIN FUEL VALVES

MASTER SWITCH

S445A

Q7800 SUBBASE

BURNER CONTROL

FAN

120V ALARM

DPST ALARM SILENCING SWITCH

LIMITS

S445A

START

STOP

IGNITION

RUNNING INTERLOCKS

PILOT

MAIN FUEL VALVE(S)

LOW FIRE PURGE SWITCH

FLAME DETECTOR

Q7800 SUBBASE

(L1)

HIGH FIRE PURGE SWITCH

VFD DISPLAY

LED DISPLAY

BURNER

START

OPERATING CONTROLS AND INTERLOCKS

FLAME SIGNAL

120V, 50/60 Hz POWER SUPPLY. PROVIDE DISCONNECT

MEANS AND OVERLOAD PROTECTION AS REQUIRED.

EXTERNAL ISOLATION REQUIRED OF INPUT AND OUTPUT TERMINALS TO CONNECT THE RM7838A IN A PARALLEL APPLICATION.

INITIATE

STANDBY

00 00 00 10

PURGE

POWERPOWER

SAFE START CHECK

POWER

COMBUSTION BLOWER, RECIRCULATING, EXHAUST FANS

RUNNING INTERLOCKS AND BURNER CONTROLLER CLOSED

HIGH FIRE SW.

Fig. 2. Wiring subbase and sequence chart for RM7838A Relay Module.

RM7838A

HOLD

4 OR 10 SEC

POWER PILOT FLAME MAIN

ALARMALARM ALARM ALARM ALARM

ISOLATION CONTACT REQUIRED FOR STANDING PILOT APPLICATION. DRIVE 120 VAC RELAY FROM TERMINAL 8.

COMBUSTION BLOWER OR EXHAUST RECIRCULATING FANS.

SEE FLAME DETECTOR SPECIFICATION FOR CORRECT WIRING.

PFEP

START/IGN.

INTERMITTENT PILOT

STOP SWITCH

RUN

POWER POWER

PILOT FLAME MAIN

POWER

PILOT FLAME MAIN ALARM

MAIN VALVE

FLAME PROVING

STANDBY

621

ALARM

SSC

M11498B

66-1087—2

Page 9

SEQUENCE STATUS LED PANEL

PURGE TIMER

RELAY MODULE

CONFIGURATION JUMPERS

RUN/TEST SWITCH

WIRING SUBBASE

RM7838A 7800 SERIES RELAY MODULES

HONEYWELL

POWER PILOT FLAME MAIN ALARM

RESET

KEYBOARD DISPLAY MODULE

RESET BUTTON

SCROLL

BURNER CONTROL

MODE

- SAVE -

Fig. 3. RM7838A Relay Module exploded view.

PRINCIPAL TECHNICAL FEATURES

The RM7838A provides all customary flame safeguard functions as well as significant advancements in 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. Configuration jumper was changed (after 200

hours). 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. Intermittent pilot valve/ 1st stage oil terminal is

energized. c. Start Switch terminal energized. d. Main valve terminal is energized. e. Internal system fault.

CAPTIVE MOUNTING SCREW

FLAME AMPLIFIER

M12300

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. Flame signal detected during PURGE . b. High fire switch fails to close within four minutes,

15 seconds after the burner switch, limit and interlock string is closed.

c. Intermittent pilot valve/1st stage oil terminal is

energized. d. Main valve terminal is energized. e. Internal system fault. f. Purge card is removed. g. Purge card is bad. h. Start Switch terminal is energized.

4. PILOT FLAME ESTABLISHING Period (PFEP)

a. Intermittent pilot valve/1st stage oil terminal is not

energized. b. No flame is present at end of PFEP. c. Internal system fault. d. Purge card is not installed or removed. e. Purge card is bad. f. Main valve terminal is energized.

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RM7838A 7800 SERIES RELAY MODULES

5. RUN Period

a. Intermittent pilot valve/1st stage oil terminal is not

energized. b. Main valve terminal is not energized. c. No flame is present. d. Main valve terminal is de-energized. e. Internal system fault. f. Purge card is removed. g. Purge card is bad.

OPERATION

Sequence of Operation

The RM7838A has the operating sequence listed below; see Fig. 2. The RM7838A LEDs provide visual indication of the program sequence: POWER, PILOT, FLAME, MAIN and ALARM and are displayed on the Keyboard Display Module.

Initiate

The RM7838A enters the INITIATE sequence when the relay module is initially powered. The RM7838A can also enter the INITIATE sequence if the relay module verifies voltage fluctuations of +10/-15% or frequency 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 is initiated and displayed on the KDM for at least five seconds. When the tolerances are met, the INITIATE sequence restarts. If the condition is not correct and the hold condition exists for four minutes, the RM7838A locks out. Causes for hold conditions in the INITIATE sequence include:

a. AC line dropout is detected. b. AC line noise that can prevent a sufficient reading of the

line voltage inputs.

c. Brownouts caused by low line voltage.

The alarm, terminal 3, is energized during INITIATE.

Standby

The RM7838A is ready to start an operating sequence. When the Burner Switch is closed, the Blower/Combustion Fan is powered. The Airflow Switch closes and provides power to terminal 7 through any additional limits or interlocks.

After terminal 7 is energized, "Safe Start Check" is displayed on the KDM as the RM7838A transitions from Standby to Purge. During safe start check, the RM 7838A verifies that the flame detection system and all components are not in a flame simulating condition. On applications using a shutter, the shutter is energized to make sure no flame is present.

The alarm, terminal 3, is energized all the time the system is in standby.

Normal Start-Up Purge

Closing the burner control switch energizes the combustion fan and provides power to terminal 7 through all limits and interlocks. Powering terminal 7 with all the microcomputer monitored circuits in the correct state, the relay module begins the PURGE sequence.

Purge Hold T19 (High Fire Switch) is displayed until the High Fire Switch is proven.

PURGE timing begins when the damper motor is manually driven to the High Fire Purge position and the High Fire Switch is energized. Four minutes and 15 seconds are provided to drive the damper to the fully open position. A jumpered or welded High Fire Switch adds a 30 second hold to the beginning of purge timing. When PURGE timing is complete, “PILOT:HOLD:T6 (Start Switch)” is displayed on the KDM.

Ignition Trials

1. Pilot Flame Establishing Period (PFEP):

a. With the damper motor manually driven to the Low

Fire position:

(1) Press the START pushbutton and the ignition

transformer is energized with power from terminal 10. Power is also applied to terminal 6 through the Start/Stop Switch internal jumper. The STOP Switch and the Alarm Silencing Switch. The RM7838A then energizes the Intermittent Pilot valve (terminal 8).

(2) During PFEP, the Low Fire Switch and the

START switch must remain closed. If one opens before the flame is proven, the pilot valve shuts off , but the pilot flame establishing timer continues to time.

b. Flame must be proven by the end of the ten-

second PFEP (four if configuration JRI jumper is removed) to allow the sequence to continue. If flame is not proven by the end of PFEP, a safety shutdown occurs.

c. With flame proven, terminal 21 outputs line voltage

to maintain the input to terminal 6, which allows the Start Switch to be released and the ignition to be shut off.

NOTE: Terminal 10 verifies that the Start Switch is

released. If the Start Switch is not released, a shutdown occurs.

d. Alarm LED and terminal 3 are turned off when

flame is detected.

Run

1. When the flame is proven, the FLAME LED lights and the

ALARM LED turns off. Release the Start push-button and the ignition transformer shuts off. At the end of PFEP, the RM7838A proceeds to the RUN period by energizing the main valve, terminal 9, and the MAIN status LED on the relay module.

2. The firing rate damper motor can now be positioned to

meet the setpoint of the process controller.

3. The RM7838A is in RUN and remains in RUN until the

STOP pushbutton is pushed, or a limit opens terminal 7.

4. The alarm, terminal 3, is de-energized during RUN and

energized when shutdown occurs.

Selectable PURGE timing from two seconds to 30 minutes is available for the RM7838A.

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Keyboard Display Module (KDM)

SELECTABLE CONFIGURATION JUMPER

M11502

The Keyboard Display Module (see Fig. 3) is provided with the RM7838A Relay Module. The first line of the Vacuum Fluorescent Display (VFD) provides:

1. Current status of the burner sequence (STANDBY,

PURGE, PILOT IGN, MAIN IGN and RUN).

2. Timing information (PURGE, PILOT IGN, and MAIN

IGN) in minutes and seconds.

3. Hold information (PURGE HOLD:T19).

4. Lockout information (Lockout, Fault Code, Message and

Sequence).

The extreme right side of the first line is either blank or shows a small arrow pointing to the second line followed by a twoletter code (DI, Diagnostic Information; Hn, Fault History Information; EA, Expanded Annunciator). When the arrow and two-letter codes are displayed, it indicates the second line is showing a selectable message submenu. The second line displays selectable or pre-emptive messages.

A selectable message supplies information for flame strength, system status indication, system or self-diagnostics and troubleshooting.

A pre-emptive message has parentheses around the message and supplies a detailed message to support the sequence status information. A pre-emptive message can also be a lockout message. A pre-emptive message replaces a selectable message to support the sequence status information. It also replaces a selectable message after 60 seconds or if a lockout message is available.

RM7838A 7800 SERIES RELAY MODULES

Fig. 4. Selectable site-configurable jumper.

Table 6. Site-Configurable Jumper Options.

Jumper Number Description Intact Clipped

JR1 Pilot Flame Establishing

Period (PFEP)

SERVICE NOTE: Clipping and removing a site-cofigurable-

jumper enhances the level of safetyand removing a site-configurable-jumper after 200 hours of operation causes a nonresettable fault 110.

seconds4seconds

SETTINGS AND ADJUSTMENTS

Selectable Sit-Configurable Jumpers

The RM7838A has one site-configurable jumper option, see Fig. 4 and Table 6. If necessary, the site configurable jumper should be clipped with side cutters and the resistor removed from the relay module.

66-1087—2

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RM7838A 7800 SERIES RELAY MODULES

Home and Building Control

Honeywell Inc. Honeywell Plaza P.O. Box 524 Minneapolis MN 55408-0524

66-1087—2

66-1087—2 R.R. Rev. 8-98

Home and Building Control

Honeywell Limited-Honeywell Limitée 155 Gordon Baker Road North York, Ontario M2H 3N7

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