Schwank STSp-WP - Manual (Page 26)

SP-MSWP-BX-09A
STSp-WP Manual
RD: MAY 2004
RL: 9
KH
Page 22
CA Series: The STS-p Burner with direct spark ignition, sequence is as follows :
1. Upon a call for heat by the line voltage
Thermostat or "ON/OFF" switch, the Blower
and the 120/24 volt Transformer are powered
simultaneously with 115 volts.
1a. Field installed 24 volt option:
The 120 volt supply to heater will power the
120v/24v Transformer and the 120V side of the
Blower switching relay simultaneously.
A call for heat by the 24 volt Thermostat
energizes the 24 volt control circuit and the
24v/120 volt relay powering the Blower.
2. The 24 volt control circuit powers the DSI con
trol in series through the normally open Air
Pressure Switch (APS) and the normally closed
Blocked Flue Switch (BFS).
3. The Blower creates a positive pressure and
closes a normally open contact inside the (APS).
4. 24 volts supplied to the DSI control initiates
the 30 second pre-purge cycle.
5. After completing the 30 second pre-purge
cycle the DSI control generates high voltage
to the Spark Igniter, and 24 volts to energize
the Gas Valve.
6. The Burner will light and establish a steady
flame.
19. CA SERIES SEQUENCE OF OPERATION - GASLITER MICRO 50N
7. Once the flame sensor determines there is a
steady flame established, the spark igniter is
then de-energized.
8. If a flame is not established during the first 20
second Trial for Ignition (T.F.I.), the unit will
perform an inter-purge and T.F.I. If a flame is
not established during this attempt, another in-
ter-purge and T.F.I. will be performed. If a
flame is not established during the final at-
tempt, the unit will enter the soft lockout
mode. (The soft lockout mode is a 30 minute
delay time after which the unit will reset to try
to ignite the gas again as in NORMAL OP-
ERATION)
9. If there is a loss of flame during the run mode,
the unit will energize the spark within 0.8 sec-
onds and perform a T.F.I., without the gas
valve being closed first, this is called Spark
Restoration. If a flame is not established during
Spark Restoration the unit will repeat the proc-
ess in step number 8 (above).
10. If a flame is present with the Gas Valve de-
energized the unit will enter a hard lockout
mode. If there is an internal fault detected
within the control, this will also cause hard
lockout.