Honeywell Electronic Ignition Troubleshooting Tech Tip April 2007 The Honeywell S8610H Intermittent Pilot Module provides the ignition sequencing, pilot spark, pilot flame monitoring, Pilot Valve (PV) control, Main Valve (MV) control, and safety LOCKOUT for gas fueled hot water pressure washers. It is used with a Honeywell 24V gas valve and a pilot burner/ignitor-sensor. The PN s for these common components are listed at the end of this tech tip. When 24 VAC is applied to the module 24V terminal it outputs 24 VAC on the PV terminal, outputs 10,000 VAC on the SPARK terminal, and starts the LOCK- OUT timer. If the pilot ignites before the LOCKOUT timer expires (15 or 90 seconds based on model) the module stops the spark and outputs 24 VAC on the MV terminal. If the pilot does not ignite during this time period then the module will LOCKOUT. This removes the voltage from the PV and SPARK terminals. To clear the LOCKOUT, cycle the input voltage OFF/ON to the 24V terminal. This will start the sequence over again. See Simple Electronic Ignition Wire Diagram below. SIMPLE ELECTRONIC IGNITION WIRE DIAGRAM BURNER SWITCH IGNITION MODULE S8610H 24V (6) 24 VAC LIGHT 24V (GND) (5) (1) MV THERMOSTAT FLOW SWITCH OR PRESSURE SWITCH MV GAS VALVE VR8304M4002 (2) MV/PV MV/PV (3) PV PILOT BURNER/IGNITOR - SENSOR Q345A PV (9) SPARK IGNITOR ROD (4) GND (BURNER) CHASSIS GND Page of 5 Honeywell Ignition Troubleshooting
To use this troubleshooting table start from the top and continue down the table until your problem is found. Required test equipment: Digital Multimeter Used to measure VOLTS AC and OHMS. Manometer (Range 0 16 Water Column Inches) Used to measure gas pressure. High Voltage Test Lead You will need a short jumper wire made from ignition cable or other heavily insulated wire Used to test spark gap. Burner Light on Control Panel does not light No 24 VAC Verify stepdown transformer(s) voltages input and output. Verify associated fuses. Verify associated wires, connections, and switches Replace as required. No spark at ignitor rod Ignition Module in Reset by cycling burner switch OFF / ON. LOCKOUT Bad ignition cable Measure resistance of ignition cable. It should be < 2 ohms. Replace as required. Bad Ignition Module Check spark ignition circuit. Disconnect ignition cable from SPARK terminal on ignition module. Connect one end of High Voltage Test Lead (see Required Test Equipment) to chassis ground. Turn Burner Switch to ON. Immediately move the free end of the High Voltage Test Lead toward the SPARK terminal until a spark is established. Slowly pull High Voltage Test Lead away from the terminal and note the length of the gap when sparking stops. No arc or <1/8 Replace ignition module. Pilot will not light have spark Bad Pilot Burner / Ignitor-Sensor No gas Verify Pilot Burner / Ignitor-Sensor is well grounded. Good ground wire, and connections. Clean ignitor rod tip and hood above the tip with emery cloth. Verify Pilot Burner / Ignitor-Sensor high voltage insulator is not cracked. Verify hood above ignitor is ~ 1/8" from tip of ignitor. Adjust or replace as required. Verify gas valve knob is in ON position (if equipped) Verify gas supply ball valve is open Verify pilot tube ball valve is open Try to light the pilot with an external flame when the ignitor is sparking. Verify no gas leaks. Verify gas and pilot lines are bled of air. Measure incoming gas pressure. It should be 10-14 WCI. Correct as required. Page 2 of 5 Honeywell Ignition Troubleshooting
Pilot will not light have spark (cont.) Pilot lights - but then goes out Plugged pilot orifice Pilot Valve is not open Spark not hot enough to light pilot gas Possible ground problem Ignition Module is not sensing lit pilot Gas problems Remove pilot tube from Pilot Assembly, remove the pilot orifice and observe for obstructions. Repair or replace as required. Verify 24 +/- 3.5 VAC between PV and MV / PV terminal at the gas valve. If out of tolerance, verify voltage again at ignition module. If VAC out of tolerance - Replace ignition module, wires, and connections as required. Clean ignitor rod tip and hood above the tip with emery cloth. Measure resistance of ignition cable. It should be < 2 ohms. Verify gas is at pilot by lighting the gas with an external flame (i.e. butane barbeque lighter). If pilot lights with external flame replace ignition cable or reroute it with insulated standoffs away from the cabinet chassis as required. If pilot does not light with external flame replace gas valve. Verify no corrosion on mounting hardware and wire connections. Verify ground wire integrity between pilot assembly, gas valve, and ignition module GND (Burner). If ground problem repair or replace as required. Clean pilot assembly ignitor rod tip and hood above the tip with emery cloth. Monitor 24 VAC between PV and MV / PV. If it goes to 0 VAC in the time period marked on the S8610H label then the ignition module is in LOCKOUT. It did not sense the pilot light being lit. Replace ignition cable, pilot assembly, and ignition module as required. Verify incoming gas pressure is between 10-14 WCI and does not vary when the pilot first lights. It should remain constant. If out of tolerance, troubleshoot and repair as required. Page of 5 Honeywell Ignition Troubleshooting
Main burner does not light pilot is lit Main burner is lit then goes out Ignition Module Operator Error Temperature and Flow sensing devices Gas Problem Gas Problem Pilot blows out Ignition Module Temperature and Flow sensing devices Verify 24 +/- 3.5 VAC between ignition module terminals MV and MV / PV. If out of tolerance replace ignition module. Verify thermostat is dialed to max temperature (if equipped) Verify trigger gun is open and water is flowing Verify 24 +/- 3.5 VAC between gas valve terminals MV and MV / PV. If out of tolerance troubleshoot to open circuit in wiring, flow device (flow switch or pressure switch), or temperature sensing device (thermostat or snap switch). Verify incoming gas pressure. It should be 10-14 WCI. Verify manifold (gas valve outlet) gas pressure. It should be 3-5 WCI for NG and 10-13 WCI for LP. Repair and replace as required. Gas valve may be bad. Monitor incoming gas pressure. It should remain within 4 WCI of the reading with the gas valve closed. Monitor manifold (gas valve outlet) gas pressure. It should be 3-5 WCI for NG and 10-13 WCI for LP. Troubleshoot gas valve or gas problem. Observe pilot flame when main burner is first lit. If it blows out then the ignition module will shut off voltage to MV and re-start sparking and pilot ignition. Shield pilot with non-flammable material to protect the flame from severe in-rush air currents. Module removes 24 VAC at MV terminal due to malfunction, loss of pilot, or loss of pilot sense. Troubleshoot, repair, and replace as required. Verify 24+/- 3.5 VAC between gas valve terminals MV and MV / PV. If out of tolerance or intermittent troubleshoot to open circuit in wiring, flow device (flow switch or pressure switch), or temperature sensing device (thermostat or snap switch). Page 4 of 5 Honeywell Ignition Troubleshooting
Hotsy Part Numbers Description Part Number Ignition Module 7-701510 Gas Valve Natural Gas 7-700021 Conversion of Gas Valve to Liquid Propane 7-702320 Pilot Burner / Ignitor Sensor 7-702371 Ignition Wire 60 6-01353 Page 5 of 5 Honeywell Ignition Troubleshooting