Checkout

Check out the gas control system:

  • At initial installation of the appliance.

  • As part of regular maintenance procedures. Maintenance intervals are determined by the application. See Planning the Installation for more information.

  • As the first step in troubleshooting.

  • Any time work is done on the system.

If this is a replacement application, refer to the specific instructions provided by the heating appliance manufacturer (if available). Additionally, since the auxiliary controls used in any DSI system may vary, refer to the manufacturer's instructions for checkout and start-up procedures for other system components.

WARNING: FIRE OR EXPLOSION HAZARD

Failure to heed these warnings may cause fire or explosion with property damage, injury, or loss of life.

  1. If you smell gas or suspect a gas leak, turn off gas at manual service valve and evacuate the building. Do not try to light any appliance, do not touch any electrical switch or telephone in the building until you are sure no spilled gas remains.

  2. Gas leak test must be done as described in the steps below on initial installation and any time work is done involving the gas piping.

Step 1: Perform Visual Inspection.

  1. With power off, make sure all wiring connections are clean and tight.

  2. Turn on power to appliance and ignition module.

  3. Open manual shutoff valves in the gas line to the appliance.

  4. Perform Gas Leak Test ahead of gas control if piping has been disturbed.

    GAS LEAK TEST (Upstream of gas control)
    Paint the gas control gasket edges and all pipe connections upstream of the gas control with a rich soap and water solution. Bubbles indicate gas leaks. Tighten the joints and screws or replace component to stop gas leak. Recheck with soap and water solution.

Step 2: Verify control system ground.

For the system to operate properly, the spark igniter, flame sensor, and S8701 control module must share a common ground with the main burner. Use thermoplastic-insulated wire with a minimum rating of 105°C (221°F) for the ground wire; asbestos insulation is not acceptable. If necessary, use a shield to protect the wire from radiant heat generated by the burner. Connect wire as follows:

  1. Fit one end of the ground wire with a female 1/4 in. quick-connect terminal and connect it to the male quick-connect GND (BURNER) terminal on the S8701 control module.

  2. Strip the other end of the wire and fasten it under the igniter bracket mounting screw. If necessary, use a shield to protect the ground wire from radiant heat. The burner serves as the common grounding area.

Step 3: Review Normal Operating Sequence and Module Specifications.

  1. See Operation and Specifications.

Step 4: Reset the Module.

  1. Turn the thermostat to its lowest setting.

  2. Wait one minute.

As you do the remaining steps, watch for points where operation deviates from normal. Refer to the Troubleshooting Guide to correct problems.

Step 5: Check Safety Shutoff Operation.

  1. Turn gas supply off.

  2. Set the thermostat or controller above room temperature to call for heat.

  3. Watch for spark at the igniter either immediately or following pre-purge dependent on the model.

  4. Time spark duration from start to shutoff and ensure it matches the model specifications

  5. For models with multiple ignition trials, verify that the ignition sequence restarts as expected.

  6. Once system locks out, open manual gas cock and ensure no gas is flowing to the main burner.

  7. Set thermostat below room temperature and wait one minute before proceeding.

Step 6: Check Normal Operation.

  1. Turn on the gas supply.

  2. Set thermostat or controller above room temperature to call for heat.

  3. Make sure spark turns on.

  4. Once the gas valve opens, verify that the main burner lights smoothly without flashback.

  5. Ensure the spark shuts off once the burner flame is established.

  6. Confirm that the burner operates smoothly without floating, lifting, or flame rollout into the furnace vestibule, or heat buildup in the vestibule.

  7. Perform a gas leak test in the appliance.

    GAS LEAK TEST (Downstream of gas control) Apply a rich soap and water solution to the gas control gasket edges and all pipe connections downstream of the gas control. If bubbles appear, this indicates a gas leak. Tighten joints and screws or replace the faulty component to stop the leak. Recheck the area with the soap-and-water solution to ensure the leak is sealed.

  8. Lower the thermostat or controller below room temperature. Ensure that the main burner flames extinguish properly.

Reset After Safety Lockout

If the control goes into safety lockout, it will remain locked out for 1 hour unless the system is reset sooner. To reset the system, adjust the thermostat setting below room temperature, wait one minute, and move the thermostat setting up to call for heat. Normal ignition should occur as described in Normal Operating Sequence for Standard Models flowchart.