7800 Series RM7824A Relay Module Pages 04-06. CSI 3-Part Specifications.

7800 SERIES RM7824A Relay Module

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REMOVE ONLY FOR TERMINAL TEST ACCESS.

Fig. 2. Mounting dimensions of RM7824A Relay Module and Q7800B Subbase in in. (mm).  Dust Cover is part number 221729A.

Accessories:
Optional:
COMBUSTION SYSTEM MANAGER™: Part number ZM7850A1001.

Communication Interface Base Unit: Part number Q7700A1014.

Communication Interface ControlBus Module: Part number QS7800A1001.

ControlBus 5-Wire Electrical Connector: Part number 203541.

DATA CONTROLBUS MODULE™: Part number S7810A1009.

Flush Mounting Kit for S7800 Keyboard Display Module: Part number 205321B.

Keyboard Display Module (S7800A): English, Spanish, French, German, Italian.

NEMA 4 and NEMA 1 Weatherproofing Kit for S7800
Keyboard Display Module: Part number 204718A,B.

Remote Display Mounting Bracket: Part number 203765.

Remote Reset Module: Part number S7820A1007.

Sixty-inch Extension Cable Assembly: Part number 221818A.

Fig. 3. Infrared detector dimensions in in. (mm).

Fig. 4. Rectification detectors in in. (mm).

 

PRINCIPAL TECHNICAL FEATURES

The RM7824A 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. 24 Vdc power errors occurred, see Operation section.
b. Configuration jumper has 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 energized.
c. Internal system fault occurred.
d. Main valve terminal is energized.

3. SAFE START CHECK.

a. Flame signal is present.
b. Ignition/intermittent pilot valve terminal is energized.
c. Internal system fault occurred.
d. Main valve terminal is energized.

4. PILOT FLAME ESTABLISHING PERIOD (PFEP).

a. Ignition/intermittent pilot valve terminal is not energized.
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.
e. Pilot valve terminal is not energized.

SAFETY PROVISIONS

Internal Hardware Status Monitoring
The RM7824A analyzes the integrity of the configuration jumper and internal hardware. The POWER LED will blink every four seconds, 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 properly; i.e., the main valve terminal is powered during STANDBY, the RM7824A will lockout on safety shutdown. The RM7824A must react to input changes but avoid the occurrence of nuisance shutdown events. Signal conditioning is applied to 24 Vdc voltage inputs to verify proper operation in the presence of normal electrical line noise such as transient high voltage spikes or short periods of voltage dropout.

Dynamic Flame Amplifier and Shutter Check
Self-checking circuitry tests all electronic components in the flame detection system and amplifier twelve times per minute and shuts down the RM7824A if the detection system fails.

Dynamic Input Check
All system input circuits are examined to assure that the RM7824A is capable of recognizing the true status of external 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, terminals 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 at the same time, the safety relay system tests the microcomputer operation. If a microcomputer or safety relay failure occurs and does not allow proper execution of the self-check routine, safety shutdown occurs and all safety critical loads will be de-energized.

Expanded Safe-Start Check
The conventional safe-start check, which prevents burner start-up if flame is indicated at start-up, is expanded to include a flame signal check during STANDBY and a safety critical load check.

Off Cycle (Standby) Flame Signal Check
The flame detection subsystem (flame detector and amplifier) is monitored during STANDBY. If a flame simulating condition or an actual flame exists for 40 seconds in STANDBY, a safety shutdown occurs and startup is prevented. If the flame signal exists at any time after the 40 seconds during STANDBY, a safety shutdown occurs and is annunciated. The self-checking detector is energized for the first 40 seconds during STANDBY and the last two seconds before exiting STANDBY. If a flame exists after the first 40 seconds during STANDBY, the self-checking detector is energized during the last ten seconds of the 40 second flame detection period. If a flame exists, a safety shutdown occurs. 

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 RM7824A hardware is running correctly.

Optional multi-function Keyboard Display Module shows elapsed time during PILOT IGNITION. As an additional troubleshooting aid, it provides sequence timing, diagnostic information and historical information during normal operation or when a safety shutdown or hold occurs.

First-out Annunciation reports the cause of a safety shutdown or identifies the cause of a failure to start or continue the burner control sequence with an English text and numbered code via the optional Keyboard Display Module. It monitors all field input circuits, including the flame signal amplifier. The system distinguishes 39 modes of failure and detects and annunciates difficult-to-find intermittent failures.

Self-diagnostics add to the First-out Annunciation by allowing the RM7824A to distinguish between field (external device) and internal (system related) problems. Faults associated within the flame detection subsystem or RM7824A are isolated and reported by the optional Keyboard Display Module. See the 7800 SERIES System Annunciation Diagnostics and Troubleshooting, form 65-0118.

INSTALLATION

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

! CAUTION
To prevent electrical shock and equipment damage, disconnect the power supply before beginning installation. More than one power supply disconnect may be involved.

1. To prevent electrical shock and equipment damage, disconnect the power supply before beginning installation. More than one power supply disconnect may be involved.
2. Wiring connections for the RM7824A are unique; therefore, refer to Fig. 6 or the correct specifications 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 wiring.
5. Loads connected to the RM7824A must not exceed those listed on the RM7824A label or the specifications (see Table 1).
6. Limits and interlocks must be rated to carry and break current simultaneously 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 for the specific purpose for which they are used.

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 safeguard control and the main fuel valve(s).
2. Two C7024E,F Detectors can be connected in parallel.
3. This equipment generates, uses and can radiate radio frequency energy, and if not installed and used in accordance with the instructions, may cause interference to 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 may cause interference, in which case the users, at their own expense, may be required to take whatever measures are required to correct this interference.
4. This digital apparatus does not exceed the Class B limits for radio noise of digital apparatus set out in the Radio Interference Regulations of the Canadian Department of Communications.

Humidity
Install the RM7824A where the relative humidity never reaches the saturation point. The RM7824A is designed to operate in a maximum 85 percent relative humidity, continuous, noncondensing moisture environment.   Condensing moisture can cause a shutdown.

Vibration
Do not install the RM7824A where it could be subjected to vibration in excess of 0.5G continuous maximum vibration.

Weather
The RM7824A is not designed to be weather tight. If installed outdoors, the RM7824A must be protected by an approved weather-tight enclosure.

Mounting Wiring Subbase
NOTE: For installation dimensions, see Fig. 1 or 2.

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 in an electrical panel. The Q7800 can be mounted directly in the control cabinet. Be sure to allow adequate clearance for servicing, installation, access and removal of the RM7824A, dust cover, flame amplifier, flame amplifier signal voltage probes, 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. Drill the pilot holes.
4. Mount the subbase securely using four No. 6 screws.