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MAINTENANCE PROCEDURES
The following trouble shooting guide and maintenance procedures are meant to be used by Qualified Service Technician
SEQUENCE OF OPERATIONS
When using these instructions refer to the SGL-TI wiring
schematic.
1.
115 VAC is sent through the 3 amp fuse to
■ The primary of the 24 VAC transformer
24 VAC is sent from the secondary of the 24VAC
transformer to the Hi/Off/Low Switch.
■ Contacts of the RI Blower Relay
■ The optional Power Tilt Circuit
2.
With the Hi/Off/Low switch in the Low position.
■ 24 VAC is sent through the normally closed high limit
switch to the mercury switch.
■ If the unit is in the down position then 24 VAC is sent
through mercury switch to pin 9 on the thermostat.
3.
With the Hi/Off/Low Switch in the Hi position 24 VAC is
also sent to the Hi terminal on the gas valve.
■ Gas will not leave the valve until the main gas valve
opens (see step 7).
4.
If the steamer is calling for heat the 24 VAC is sent from
pin number 10 to R1 Blower Relay.
■ The normally open contacts of the blower relay close
sending 115 VAC to the blower.
■ The blower turns closing the air switch.
■ 24 VAC is sent through the now closed air switch to
the ignition module.
5.
Ignition module sends spark from terminal SP to the
igniter.
6.
Ignition module also sends 24 VAC from pins PV and
MV/PV to the pilot coil of the gas valve pins P and C.
■ Pilot valve opens sending gas to the Pilot assembly.
■ Spark and gas meet and pilot is ignited.
■ AC current is passed through the flame and rectified
then sent back to the ignition module.
TROUBLESHOOTING AND
For periodic maintenance recommendations see "Operators Manual".
7.
If the ignition module reads a minimum of 1.0 micro-
amps through the burner ground then 24 VAC is sent
from pins MV and MV/PV of the ignition module to pins
M and C on the Gas valve.
■ The main (low) gas valve opens and gas (3.0" W.C.
natural gas or 8.0" W.C. LP) is sent to the burner.
■ If the unit is in the Hi position (see step 3) 24VAC will
be at the HI terminal and the gas pressure will be 3.5"
W.C. natural or 10.0" W.C. LP.
■ Burner ignites until thermostat is satisfied.
8.
When thermostat is satisfied, 24 VAC is removed from
pin 10 on the thermostat and the heat circuit is de-
energized
9.
If the unit has the optional Power Tilt option and is in the
down position, 115 VAC is sent from the customer
connect through the circuit breaker and the up limit
switch to the tilt switch.
10. With the tilt switch in switch in the Up position
■ 115 VAC is sent to the Bridge Rectifier
115 VDC is sent from the rectifier through the 30-
ohm resistor to the normally open RY10 and RY11
relay contacts.
■ 115 VAC is sent to the RY 10 relay coil.
■ The normally open RY10 contact close and 90 VDC is
sent to the DC motor
■ The DC motor is energized and the unit tilts until the
switch is released or the up limit switch opens.
11. With the Tilt switch in the Down position
■ 115 VAC is sent to the Bridge Rectifier
115 DC is sent from the rectifier through the 30-
ohm resistor to the normally open RY10 and RY11
relay contacts.
■ 115 VAC is sent to the RY 11 relay coil.
■ The normally open RY 11 contact close and the
polarity of the 90 VDC is reversed.
■ The DC motor is energized and the unit lowers until
the switch is released or the Down limit switch opens.
9.
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