Maxi Comet Executive Exec-56-G, Instruction Manual, Page: 212 / 244

S8600, S8610, S8660, S8670 INTERMITTENT PILOT MODULE
69-0463—01 12
solution. Bubbles indicate gas leaks. Tighten joints and
screws or replace component to stop gas leak. Recheck
with soap and water.
• Turn thermostat or controller below room temperature.
Make sure main burner and pilot flames go out.
OPERATION
Module operation can be conveniently divided into two
phases for S8600, S8610 and three for S8660, S8670.
The phases are:
• Prepurge (S8660, S8670 only)
• Trial for ignition (all models)
• Main burner operation (all models)
Figures 11 and 12 summarize the normal operating
sequences of the modules.
Prepurge (S8660, S8670 ONLY)
When the S8660 is used in a fan-assisted combustion
system, the combustion air blower starts on a call for heat.
On proof of airflow, the air proving switch closes and
energizes the S8660, S8670. When the module is used in
an atmospheric system, the call for heat energizes the
module.
In either case, the module first initiates a 45 sec. delay to
allow system prepurge. After prepurge, the module starts
the pilot ignition sequence.
Fig. 11. S8600, S8610 Normal Operating Sequence.
Trial for Ignition
Pilot Ignition
Following prepurge timing (S8660, S8670), or on the call
for heat (S8600, S8610), the module energizes the first
main valve operator. The first main valve opens, which
allows gas to flow to the pilot burner. At the same time,
the electronic spark generator in the module produces
over 10,000 volt spark pulse output. The voltage
generates a spark at the igniter (S8600A,B; S8610A,B) or
igniter-sensor (S8600F,H,M; S8610F,H; S8660; S8670)
that lights the pilot.
If the pilot does not light, or the pilot flame current is not at
least 1.0 μ A and steady, the module will not energize the
second (main) valve and the main burner will not light.
S8600A,F; S8610A,F will continue to spark as long as the
thermostat calls for heat, or until the pilot lights.
Safety Lockout (S8600B,H; S8610B,H; S8660D;
S8670D)
These modules provide 100 percent shutoff and safety
lockout. A timer in these models starts timing the moment
the trial for ignition starts. Ignition spark continues only
until the timed trial for ignition period ends. Then the
module goes into safety lockout. Lockout de-energizes
the first main valve operator and closes the first main
(pilot) valve in the gas control, stopping pilot gas flow. The
START
THERMOSTAT (CONTROLLER)
CALLS FOR HEAT
SPARK GENERATOR POWERED
First valve (pilot) operator opens
PILOT BURNER OPERATION
Pilot burner lights.
Module senses
flame current.
Pilot burner does not light.
Module Response
Shutoff/lockout timing is stamped on module
a
Ignition spark continues, pilot
valve remains open until system
is reset
S8600A,F
S8610A,F
S8600B,H
S8610B,H
a
STAGE 1
TRIAL FOR
IGNIITION
STAGE 2
MAIN BURNER
OPERATION
END
MAIN BURNER OPERATION
Module monitors pilot flame
current.
THERMOSTAT (CONTROLLER)
SATISFIED
Valves close, pilot and main
burners are off.
POWER INTERRUPTION
System shuts off, restarts when power is
restored.
PILOT FLAME FAILURE
Main valve closes.
Module starts trial for ignition.
1
FLAME CURRENT SENSED
Spark generator off.
Second valve operator (main)
opens.
•
•
2
3
4
5
6
1
OR
After 15 or 90 sec system
locks out; must be
manually reset.
After 90 sec. system shuts off;
after 5 minutes min. (6 minutes
nom.), module restarts trial for
ignition; ignition trial, shutoff, wait
sequence repeats until pilot lights
or call for heat ends.
a S8600M
M1172C
69-0463-1.fm Page 12 Wednesday, December 19, 2007 1:22 PM
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