Settings And Adjustments; Selectable Site-Configurable Jumpers - Honeywell 7800 SERIES Instruction Manual

1. The Preignition Interlocks, Limits and Burner Control,
Run/Test Switch, Airflow Switch Input, Lockout Input,
and all microcomputer-monitored circuits must also be
in the correct operating state.
2. The blower motor output, terminal 5, is powered to start
the PURGE sequence. The firing rate motor is driven to
the high fire position (EC/RM7850A). The PURGE
timing does not begin until the Airflow Switch Input and
High Fire Switch (EC/RM7850A) are both closed.
3. The Preignition Interlock Input must remain closed
throughout PURGE or a safety shutdown occurs.
4. The Airflow Switch Input must close by ten seconds into
PURGE or a safety shutdown occurs.
5. After the firing rate motor reaches the PURGE rate
position and PURGE timing is completed, the motor
drives to the low fire position (EC/RM7850A).
Ignition Trials
1. Preignition: With the firing rate motor at the low fire
position (EC/RM7850A), the ignition transformer,
terminal 10, is energized for three seconds.
2. First Safety Time (SAFETY1):
a. With the firing rate motor at the low fire position
(EC/RM7850A):
(1) The pilot valves and ignition transformer,
terminals 8, 10 and 21, are energized. Terminal
8 is an interrupted pilot valve and terminal 21 is
an intermittent pilot valve.
(2) During SAFETY1, the Low Fire Switch Input
must be closed. If it opens, a safety shutdown
occurs (EC/RM7850A).
(3) The Preignition Interlock Input is ignored during
SAFETY1, PILOT STAB., MAIN TRIAL, RUN
and POSTPURGE.
b. Flame must be proven by the end of the First Safety
Time to allow the sequence to continue. A safety
shutdown occurs if there is no flame.
3. Pilot stabilization (PILOT STAB.): With flame proven,
the ignition, terminal 10, is de-energized. The duration
of this state is five seconds.
4. Main Trial (MAIN TRIAL):
a. The MAIN TRIAL time is selectable as three or five
seconds. After PILOT STAB., and with the presence
of a flame, the main fuel valve, terminal 9, is pow-
ered. If a flameout occurs, the relay module locks
out within one or two seconds, depending on the
amplifier Flame Failure Response Time (FFRT).
Thus, the second safety time is defined as MAIN
TRIAL time plus the amplifier FFRT.
b. During MAIN TRIAL, the Low Fire Switch Input must
be closed (EC/RM7850A). If it opens, a safety
shutdown occurs.
c. After three or five seconds of MAIN TRIAL, terminal
8 is de-energized for main stabilization. Flame must
remain proven during this five-second period.
Run
1. The firing rate motor releases to modulation.
2. The relay module is now in RUN and remains in RUN
until the controller input, terminal 6, opens, indicating
that the demand is satisfied or a limit has opened.
EC7830A, RM7830A, EC7850A, RM7850A 7800 SERIES RELAY MODULES
Postpurge
The relay module (model specific) provides a two-, 15- or
30-second POSTPURGE following the completion of the RUN
period. The blower motor output is powered to drive all
combustion products and any unburned fuel from the
combustion chamber. It also supplies combustion air to burn
fuel being purged from the fuel line downstream from the fuel
shutoff valve.
1. The main fuel valve and the intermittent pilot valve,
terminals 9 and 21, are de-energized and the firing rate
motor is commanded to the low fire position
(EC/RM7850A) to begin the POSTPURGE period.
2. The Preignition Interlock Input is ignored during
POSTPURGE.
3. After the POSTPURGE period is completed, the relay
module re-enters STANDBY.
Run/Test Switch
The Run/Test Switch is located on the top side of the relay
module, see Fig. 5. The Run/Test Switch allows the burner
sequence to be altered as follows:
1. In Purge Drive to High Fire position, the Run/Test
Switch, when placed in the TEST position, holds in
PURGE with the firing rate motor in the High Fire
position (EC/RM7850A).
2. In the measured PURGE sequence, the Run/Test
Switch, placed in the TEST position, causes the
PURGE timing to stop. The firing rate motor is in the
High Fire position.
3. In Purge Drive to Low Fire position, the Run/Test
Switch, when placed in the TEST position, holds the
burner in PURGE with the firing rate motor in the Low
Fire position (EC/RM7850A).
4. During the PILOT STAB. period, the Run/Test Switch,
when placed in the TEST position, stops the timer,
allowing for pilot turn-down test and other burner
adjustments. This activates a 15-second flameout timer
that permits pilot flame adjustment without nuisance
safety shutdowns.
5. During Run, the Run/Test Switch, when placed in the
TEST position, drives the firing rate motor to the Low
Fire position.
IMPORTANT
When the relay module is switched to the TEST
mode, it stops and holds at the next Run/Test Switch
point in the operating sequence. Make sure that the
Run/Test Switch is in the RUN position before
leaving the installation.

SETTINGS AND ADJUSTMENTS

Selectable Site-Configurable
Jumpers
The relay module has three site-configurable jumper options,
see Fig.5 or 6 and Table 7. If necessary, clip the site-
configurable jumpers with side cutters and remove the
resistors from the relay module. The relay module reads the
settings of these configuration jumpers at startup. After 200
hours of main valve operation, the relay module locks the
jumper settings into internal memory. If these jumpers are
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