7800 SERIES EC7890A,B/RM7890A,B RELAY MODULE
65-0204–1
9
Dynamic Ampli-Check®
Dynamic Ampli-Check® circuitry tests the flame signal
amplifier during burner operation and shuts down the 7890 if
the flame amplifier fails.
Dynamic Flame Amplifier and Shutter Check
Self-checking circuitry tests all electronic components in the
flame detection system and amplifier 12 times per minute and
shuts down the 7890 if the detection system fails.
Dynamic Input Check
All system input circuits are examined to assure that the 7890
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
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 annunciated. A
shutter-check amplifier and self-checking detector are
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 of STANDBY, the shutter-check
amplifier and self-checking detector are energized 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. A standard amplifier is
energized continually through 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 7890 hardware is
running correctly.
Optional multi-function Keyboard Display Module shows
elapsed time during PILOT IGN. 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 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 7890 to distinguish between field (external device) and
internal (system related) problems. Faults associated within
the flame detection subsystem or 7890 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.