7800 SERIES EC7890A,B/RM7890A,B RELAY MODULE
65-0204–1
27
Table 6. Sequence and Status Hold Information.
NOTE:
Normal sequences are in bold type, while abnormal sequences are not in bold type.
Sequence
Information
INITIATE
The LED indicates the burner status, POWER, which is a stabilization period for the 7890
to check for any fluctuations in AC line voltage inputs or control input on powerup or
during normal operation. The timing of the INITIATE period is ten seconds before entering
STANDBY.
If the 7890 is in a HOLD status, the following conditions could exist:
INITIATE HOLD:
(AC Frequency/Noise)
The LED indicates the burner status, POWER, and that the 7890 is waiting for excess line
noise to clear up. The burner sequence will not advance into STANDBY until the excess
line noise, which prevents sufficient reading of the line voltage inputs, ceases or a line
frequency error is corrected (perhaps caused by using a 60 Hz device on a 50 Hz line, or
vice versa).
INITIATE HOLD:
(AC Line Dropout)
The LED indicates the burner status, POWER, and that AC line power has momentarily
dropped out. The burner sequence will not advance into STANDBY until the AC Line
voltage has stabilized throughout the INITIATE sequence.
INITIATE HOLD:
(AC Frequency)
The LED indicates the burner status, POWER, and that line frequency is faster than the
expected value. The burner sequence will not advance into STANDBY until the line
frequency returns to the proper value (perhaps caused by using a 50 Hz device on a
60 Hz line).
INITIATE HOLD:
(Low Line Voltage)
The LED indicates the burner status, POWER, and that low line voltage has occurred.
The burner sequence will not advance into STANDBY until the line voltage is at a
sufficient level for proper operating parameters.
STANDBY
The LED indicates the burner status, POWER. The burner can be placed in STANDBY by
opening the burner switch or if the operating controller indicates its setpoint has been
satisfied. If a demand is present for burner operation, the burner sequence will not
advance from STANDBY to SAFE START CHECK until the recycle limits close.
If the 7890 is in a HOLD status, the following conditions could exist:
STANDBY HOLD: F/G
(Flame Detected)
The LEDs indicate the burner status, POWER and FLAME, and that a flame is detected.
A demand is present for burner operation. The burner sequence will not advance to SAFE
START CHECK because a flame is detected as being present. The sequence will not
advance to SAFE START CHECK until the flame signal clears. If the flame signal does
not clear within 40 seconds, the 7890 locks out.
SAFE START CHECK
The LED indicates the burner status, POWER, which is the period of time after
STANDBY. The 7890 is verifying that a flame is not present before the start of Ignition
Trials. If a flame is present, the 7890 recycles to STANDBY.
PILOT IGN
The LEDs indicate the burner status, POWER, PILOT and FLAME, which is the period of
time the 7890 permits the pilot valve and ignition to be energized and the pilot flame to be
established.
RUN
The LEDs indicate the burner status, POWER, PILOT, FLAME and MAIN, which is the
period of time after the Ignition Trials and before the operating controller set point is
reached. During this time, the burner is firing under the control of the operating controller.
RESET/ALARM TEST
The LED indicates the burner status, POWER and ALARM. This condition indicates that
the reset pushbutton is pressed. If it is held for more than four seconds, the alarm output
is energized. The alarm output will be de-energized after the reset pushbutton is released.