Honeywell S8910U3000 Instrucciones Para La Instalación página 16

S8910U3000
Trial for Ignition
At the end of the warmup period, the gas control opens for the
ignition trial time determined by the DIP switch configuration.
The hot surface igniter stays powered for an ignition activation
period of two seconds if the four second trial time is used or
five seconds if the seven second trial time is used. The igniter
turns off after the ignition activation period. Near the end of the
ignition trial time, the flame rectification sensing circuit
determines if the main burner flame is present. If so, the gas
control remains open and the burner operation phase begins.
Burner Operation
When the main burner is lit, a flame rectification circuit is
completed between the flame sensor (igniter on local sense
systems or flame rod on remote sense systems) and the main
burner (burner ground). The S8910U flame sensing circuit
detects the flame current and holds open the gas control. The
main flame is monitored continuously during the call for heat.
Safety Shutdown
One Trial
If flame is not sensed by the end of the timed trial for ignition,
the gas control closes and the module locks out. It must be
manually reset by removing power or setting the thermostat
below the room temperature for at least 30 seconds.
If the burner lights and flame is proved but goes out during the
run cycle, the gas control closes and the module locks out. It
must be manually reset by removing power or setting the
thermostat below the room temperature for at least 30
seconds.
Three Trial
If flame is not sensed by the end of the first timed trial for
ignition, the gas control closes and the module initiates a
second 96 seconds between trial purge cycle, followed by
igniter warmup and a second trial for ignition. If flame is not
established, the between trial purge, warmup, trial for ignition
cycle is repeated a third time. If flame is still not established
following the third trial, the gas control closes and the module
locks out. It must be manually reset by removing power or
setting the thermostat below the room temperature for at least
30 seconds.
If the burner goes out during the run cycle, the gas control
closes and the module checks for the number of ignition trials
performed during the current call for heat. If the number is less
than three, the module initiates a between trial purge, warmup
and trial for ignition. After the third trial during a single call for
heat, the module locks out. The module must be manually
reset following the lockout.
34-00008EFS—01
MAINTENANCE
WARNING
FIRE OR EXPLOSION HAZARD.
CAN CAUSE PROPERTY DAMAGE, SEVERE
INJURY, OR DEATH.
Do not attempt to take apart the module or to clean it.
Improper assembly and cleaning can cause unreliable
operation.
Regular preventive maintenance is important in applications
that place a heavy load on system controls such as those used
in the commercial cooking and agricultural and industrial
industries because:
• In many such applications, particularly commercial cooking,
the equipment operates 100,000 to 200,000 cycles per
year. This heavy cycling can wear out the gas control in one
to two years.
• Exposure to water, dirt, chemicals and heat can damage the
gas control and shut down the control system. A NEMA 4
enclosure can reduce exposure to environmental contami-
nants.
The maintenance program should include regular checkout of
the system as outlined in the Startup and Checkout section,
and checkout of the control system as described in the
appliance manufacturer literature.
Maintenance frequency must be determined individually for
each application. Some considerations are:
• Cycling frequency. Appliances that may cycle 20,000 times
annually should be checked monthly.
• Intermittent use. Appliances that are used seasonally
should be checked before shutdown and again before the
next use.
• Consequence of unexpected shutdown. Where the cost of
an unexpected shutdown would be high, the system should
be checked more often.
• Dusty, wet, or corrosive environment. Because these
environments can cause the gas control to deteriorate more
rapidly, the system should be checked more often.
Any control should be replaced if it does not perform properly
on checkout or troubleshooting. In addition, replace any
module if it is wet or looks like it has ever been wet. Protective
enclosures, as described in the Planning the Installation
section, are recommended regardless of checkout frequency.
TROUBLESHOOTING
IMPORTANT
1. The following service procedures are provided as a
general guide. Follow the appliance manufacturer
service instructions if available.
2. Meter readings between gas control and ignition
module must be taken within the trial for ignition
period. Once the ignition module shuts off, wait for
retry or reset at the thermostat.
3. If any component does not function properly, make
sure it is correctly installed and wired before replacing
it.
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