RM7890, RM7895 100 Vac
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 microcom-
puter operation. If a microcomputer or safety relay failure oc-
curs and does not allow proper execution of the
self-check routine, safety shutdown occurs and all safety crit-
ical loads will be de-energized.
Expanded Safe-Start Check
The conventional safe-start check, which prevents burner
startup when flame is indicated at startup, 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 con-
dition or an actual flame exists for 240 seconds in STAND-
BY, a system hold occurs and startup is prevented. If the
flame signal exists at any time after the 240 seconds during
STANDBY, a safety shutdown occurs and is annunciated. An
AMPLI-CHECK™ Amplifier is energized continually through
STANDBY (and PREPURGE in the RM7895) to detect any
possibility of a runaway detector or a flame. When a flame
exists, a safety shutdown occurs. A standard amplifier is en-
ergized continually through STANDBY (and PREPURGE in the
RM7895). When a flame exists, a safety shutdown occurs.
Tamper Resistant Timing and Logic
Safety and logic timings are inaccessible and cannot be al-
tered or defeated.
Verified Spark Termination
The ignition terminal is monitored to assure spark termination.
First-Out Annunciation and Self-Diagnostics
Sequence Status Lights (LED) provide positive visual indi-
cation of the program sequence: POWER, PILOT, FLAME,
MAIN and ALARM. The green POWER LED blinks every four
seconds, signifying that the relay module hardware is running
correctly.
The optional multi-functional KDM shows elapsed time during
PILOT IGN. As an additional troubleshooting aid, it provides
sequence timing, diagnostic information, historical informa-
tion and expanded annunciator information during normal
operation or when a safety shutdown or hold occurs.
First-out Annunciation reports the cause of safety shutdown
or identifies the cause of a failure to start or continue the
burner control sequence with text and numbered code using
the optional KDM. It monitors all field input circuits, including
the flame signal amplifier.
Self-Diagnostics add to the First-Out Annunciation by allow-
ing the relay module to distinguish between field (external
device) and internal (system related) problems. Faults asso-
ciated within the flame detection subsystem or relay module
are isolated and reported by the optional KDM. See the 7800
SERIES Relay Modules Checkout and Troubleshooting, form
65-0229.
Interlock Requirements (RM7895 Only)
The Airflow Switch Interlock input provided in the RM7895 is
typically connected to an airflow switch. The Airflow Interlock
(ILK) input must close ten seconds into PREPURGE or within
the specified purge card timing; otherwise, a recycle to the be-
ginning of PREPURGE or lockout occurs, depending on how
the airflow switch selectable jumper is configured (see Table 5
in the Operation section).
INSTALLATION
WARNING
Fire or Explosion Hazard.
Can cause severe injury, death or property damage.
To prevent possible hazardous burner operation, verify
local safety requirements are observed each time a
control is installed on a burner.
WARNING
Electrical Shock Hazard or Equipment Damage
Hazard.
Can cause severe injury, death or equipment and
control damage.
Disconnect the power supply before beginning
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 the
application.
3 .
Installer must be a trained, experienced, flame
safeguard service technician.
4 .
After installation is complete, check out the product opera-
tion as provided in these instructions.
IMPORTANT
1 .
Wiring connections for the relay modules are unique; re-
fer to Fig. 6 and 7 or the correct Specifications for proper
subbase wiring.
2 .
Wiring must comply with all applicable codes, ordinanc-
es and regulations.
3 .
Wiring must comply with NEC Class 1 (Line Voltage) wir-
ing.
4 .
Loads connected to the relay module must not exceed
those listed on the relay module label or the Specifica-
tions; see Table 1.
7
32-00216-01