7800 SERIES EC7885A/RM7885A RELAY MODULE
65-0203
8
Fig. 4. Ultraviolet detectors mounting dimensions in in. (mm) (continued from previous page).
Fig. 5. Infrared Detector dimensions in in. (mm).
PRINCIPAL TECHNICAL FEATURES
The 7885A 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
section.
b.
Four minute INITIATE period was exceeded.
2. STANDBY Period:
a.
Flame signal is present after 40 seconds.
b.
Intermittent pilot valve terminal is energized.
c.
Main valve terminal is energized.
d.
Internal system fault occurred.
3. SAFE START CHECK:
a.
Flame signal is present.
b.
Intermittent pilot valve terminal is energized.
c.
Main valve terminal is energized.
d.
Internal system fault occurred.
4. IGNITION Period:
a.
Intermittent pilot valve terminal is not energized.
b.
Start Switch is energized longer than 15 minutes.
c.
Main valve terminal is energized.
d.
Internal system fault occurred.
5. RUN Period:
a.
No flame is present.
b.
Pilot valve terminal is not energized.
c.
Main valve terminal is not energized.
d.
Internal system fault occurred.
SAFETY PROVISIONS
Internal Hardware Status Monitoring
The 7885A analyzes the integrity of the internal hardware.
The POWER LED blinks every four seconds to signify an
internal hardware check.
Closed Loop Logic Test
The test verifies the integrity of all safety critical loads,
terminals 8 and 9. If the loads are not energized properly; i.e.,
the main valve terminal is powered during STANDBY, the
7885A locks out on safety shutdown. The 7885A 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
spikes or short periods of line dropout. Signal conditioning is
tolerant of synchronous noise (line noise events that 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 7885A 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 7885A if the detection system fails.
Dynamic Input Check
All system input circuits are examined to assure that the
7885A 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 is 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
and 9, can be de-energized, as required, by the Dynamic
Self-Check Logic.
APERTURE
BUSHING WITH
MAGNIFYING LENS
COLLAR, 3/4-14 NPSM
INTERNAL THREADS
3/4-14
NPSM
3/4-14 NPSM
INTERNAL
THREADS
HEAT BLOCK
CELL MOUNT
M1982A
2 LEADS IN A
48 INCH (1.2 METER)
FLEXIBLE CONDUIT
2-3/4
(70)
1-1/4
(32)
1-5/8 (41)
1-1/16 (27)
1-1/4
(32)
C7015
15/16 (24) DIA.
2 (51)
1 (25)
1 INCH NPT
15/16–18 UNC
(2 EACH)
M5084B
2-1/2
(64)
6-7/32
(158)
6-19/32
(168)
2-5/32
(55)
11-13/16 (300)
7-13/16 (198)
1-27/32
(47)
5-13/16 (147)
5-13/16
(147)
C7076D