Garland 200 service manual Service, Preliminary Check, System Trouble Shooting, Check Grounding

SERVICE

Preliminary Check

The following visual checks should be made before trouble shooting and after installation or maintenance.

1.Check power to the appliance and S86.

2.Manual shutoff cocks in the gas line must be open.

3.Make certain all wiring connections are clean and tight.

4.First de-energize the system and wait at least one (1) minute. This resets the module allowing a return to the start condition.

5.Review the S86 system normal sequence of operation.

System Trouble Shooting

Start the system by setting the controller above the required temperature. Observe the system response. Establish the type of malfunction or deviation from the normal operation. Use the S286 Intermittent Pilot system trouble shooting table to check for normal system operation.

Use the table by following the instruction questions in the box. If the conditions is true or okay (answers yes), go down to the next box underneath. If the condition is not true of not okay (answer no), go right to the next box alongside. Continue checking and answering conditions in each box encountered, until a problem and/or the repair is explained. After any maintenance or repair, the trouble shooting sequence should be repeated until the trouble shooting procedure ends with a normal system operation.

Check Grounding

A common ground is required for the pilot burner, the igniter-sensor, the GND terminal of the S86, and the main burner. The main burner generally serves as the common ground. If the ground it poor or erratic, safety shutdowns may occur occasionally even though operation is normal at time of check out. Therefore, if nuisance shutdowns have been reported, be sure to check the grounding.

Note: If the ground circuit path is incomplete, the S86H system control will allow one trial for ignition before going into safety lock out.

Electric grounding connections at the pilot burner, igniter/sensor and S86 must be clean and tight. If a lead wire is damaged or deteriorated, use only No. 14 or 18 gauge moisture resistant thermoplastic insulated wire with 105°C (221°F) minimum ratings as replacement. Excessive temperature at the ceramic flame rod can also permit electrical leak to ground. Examine the flame rod and mounting bracket, and correct if bent out of position. Replace igniter/sensor if insulator is cracked.

Check Spark Ignition Circuit

The electronic module and step-up transformer in the S86 provides a spark ignition at 30,000 volts (open circuit). This circuit can be checked at the S86 module as follows:

1.Turn off the manual gas cock to prevent the flow of gas.

2.Disconnect the ignition cable at the S86 stud terminal to isolate the circuit from the pilot burner/igniter/sensor, and prepare a shot jumper lead using heavily insulated wire, such as ignition cable.

3.Energize the S86 touch one of the jumper firmly to the S86 ground terminal (GND). Do not disconnect the existing ground lead. Move the free end slowly toward the stud terminal to establish a spark and then pull the lead wire slowly away from the stud. Not the length of the gap at which the arching stops.

CAUTION: Do not touch either the stripped end of the jumper or stud terminal. This is a very high voltage circuit and electrical shock can result. Perform the test immediately upon energizing the system – before the S86H goes into safety lock out and interrupts the spark circuit.

4.An arch length of 1/8" (3.2mm) or more indicates a satisfactory voltage output. Replace the S86 if not arc can be established or the maximum gap is less then 1/8" (3.2mm), and the fuse and power to the S86 input terminal was okay.

Page 30 Part # MCOSM06 Rev 1 (11/03/08)