Thomas & Betts LDAP 1200 Burner Orifices, Ignition System, Heat Section Venter Motor and Wheel

31.Burner Orifice(s)

2.Attach the Gas Train - Slide the gas train so that the orifice adapter is through the bracket. Fasten the gas train to the bracket with the locking nut. Install the gas orifice. Re-connect the wires to the gas valve. Re-connect the union(s) inside of the control compartment.

3.Reconnect the gas supply at the union outside of the cabinet. Turn on the gas supply and leak test the connections with leak detecting solution.

4.Close the access panel.

5.Turn on the electric. Check for proper operation.

A burner orifice usually only needs to be replaced when installing a gas conversion kit. If ordering replacement orifice(s) only, give BTUH content and specific gravity of gas, as well as the model and serial number of the heater. When removing or replacing a burner orifice, use two wrenches being careful not to damage the venturi tube and/or the bracket.

32.Ignition System

DSI Integrated Control Module (circuit board) - See FIGURE 24. The module monitors the operation of the heater including ignition. The only replaceable compo- nent is the 3 amp Type ATC or ATO fuse. If the fuse is blown, the problem is most likely an external overload. Correct the problem and replace the fuse.

FIGURE 24 - DSI

Integrated Control

Module (Circuit

Board)

Only replaceable part is a Type ATC or ATO 3 amp fuse (Color Code Violet), P/N 201685

Do not attempt to disassemble the control mod- ule. However, each heating season check the lead wires for insulation deterioration and good connections. Size 400 has one control mod- ule; Size 800 has two control modules; and Size 1200 has three control modules.

Proper operation of the direct spark ignition system requires a minimum flame signal of 1.0 microamps as measured by a microampmeter. For further information and check out proce- dure on the direct spark ignition system, refer to Paragraph 19 and the Troubleshooting Flow Chart in Paragraph 43.

CAUTION: Due to high voltage on the spark wire and electrode, do not touch when energized. See Hazard Levels, page 2.

Ignitor

Flame Sensor

33.Heat Section Venter Motor and Wheel

Ignitor - Refer to FIGURE 22 and locate the ignitor. Disconnect the wire; remove the screw and the ignitor. Clean the ignitor assembly with an emery cloth.

Spark gap must be maintained to 1/8". See FIGURE 25.

FIGURE 25 - Ignitor
showing required
Spark Gap	1/8 inch
measurement	(3.2mm)

IMPORTANT: When re-assembling, the brown ground wire must remain attached to the ignitor.

CAUTION: Due to high voltage on the spark wire and electrode, do not touch when energized. See Hazard Levels, page 2.

Flame Sensor - Refer to FIGURE 22 and locate the flame sensor. Disconnect the wire; remove the screw and the flame sensor. Clean with an emery cloth.

Remove dirt and grease from the motor casing, the venter housing, and the venter wheel. Venter motor bearings are permanently lubricated. Follow these instructions for replacement of the venter motor and wheel assembly. Keep all hardware re- moved to be used in re-assembling and installing the replacement parts.

Form RZ-NA-I-LDAP, P/N 207733 (Rev 2), Page 35