Honeywell Y343B1002 - Manual (Page 8)

The following start-up and checkout procedures are
basic to the S87. If possible, refer to the specific
instructions provided by the appliance manufacturer
since the appiication and controls used may differ.
NOTE: If one of the system components fails, the S87
will either not operate or it will go into safety iockout
(depending on the type of failure). If the system does
not perform as outlined in START SYSTEM and
CHECK SAFETY LOCKOUT steps below, refer to the
SERVICE section to determine the cause.
START SYSTEM
1. Turn on power and gas suppiy.
2. Perform the following Test for Gas Leaks.
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DO NOT OMIT THIS TEST.
With main burner in operation, paint pipe joints,
gas tubing connections, and valve gasket lines
with rich soap and water solution. Bubbles in­
dicate gas leaks. To stop leak, tighten joints
and/or screws, or replace gasket. Never use a
flame to check for gas leaks.
3. Set temperature controller to call for heat and
watch for spark at the igniter. Time the length of the
spark operation; it must be within the lockout timing
period (see Table 3).
4. Check that the system starts as follows: Spark
turns on, gas valve opens at once, and burner ignites
after gas reaches the main burner. Once burner flame
is established, spark igniter shuts off.
NOTE: If the gas control has been replaced or serviced,
lightoff may not be satisfactory until air has been
purged from the gas line or the gas input and
combustion air have been adjusted (see manufac­
turer’s instructions).
CHECK SAFETY LOCKOUT
1. With the system power off and the temperature
controller set to call for heat, manually shut off the gas
supply.
2. Turn power on to energize the S87 and begin
spark ignition. Immediately start timing.
3. Determine the number of seconds to safety
lockout (spark cutoff). It should not exceed the time
shown in Table 3.
TABLE 3—S87 LOCKOUT TIMES.
SPECIFIED S87 LOCKOUT
TIME (stamped on
S87 Control Module)
SAFETY LOCKOUT TIME
SHOULD NOT EXCEED—
11.0 sec. 15.0 sec.
4. After spark cutoff, manually reopen gas supply
cock. No gas should flow to the main burner.
5. Reset system as described below.
RESET S87 AFTER SAFETY LOCKOUT
If the control goes into safety lockout, it will remain
locked out until the system is reset.
To reset the system, adjust the thermostat setting
below room temperature, wait 30 seconds, and move
the thermostat setting up to call for heat. Normal
ignition should occur as described in START SYSTEM,
above.
CHECKOUT
Start system and observe operation through at least
one complete cycle to make certain all controls are
operating safely.
OPERATION
OPERATION
The S87D is powered by a 24 Vac transformer and
activated when the temperature controller calls for
heat. Operation is as follows (refer to Fig.
8 ).
When the S87 is activated, an internal transformer
provides power to the electronic generator circuit for
spark ignition and the safety lockout timing begins. At
the same time, the S87 opens the gas control’s main
valves which allows gas to flow to the main burner.
Power is supplied to the generator until:
• the main burner lights and flame sensor current
reaches 1.5 uA, or...
• the safety lockout timing period ends.
If the main burner lights, a circuit is completed
through the flame to the burner head to ground. This
current flow returns the safety lockout timer to the reset
(normal) condition and interrupts the spark ignition
circuit. Should the current flow be interrupted; i.e.,
flame-out condition, the trial-for-ignition begins again.
The S87 will keep the gas control main valve open as
long as there is a call for heat and current through the
flame sensing circuit. If, however, the safety lockout
timing period ends before the main burner lights or the
flame sensor establishes enough current, the system
will go into safety lockout.
When the system goes into safety lockout, power to
the generator is interrupted, the gas control circuit is
interrupted and the alarm relay circuit is completed.
The system will stay locked out until it is reset by
moving the thermostat set point below room tem­
perature, no call for heat, for 30 seconds.Then,
re-energize the system by moving the thermostat set
point 5 F [2.8 C] above room temperature.