The Honeywell S860H Intermittent Pilot Module pro-vides 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 0,000
VAC on the SPARK terminal, and starts the LOCK-OUT timer. If the pilot ignites before the LOCKLOCK-OUT timer expires (5 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
24V (6) 24V (GND)(5) (1) MV (2) MV/PV (3) PV (9) SPARK (4) GND (BURNER) MV MV/PV PV THERMOSTAT FLOW SWITCH OR PRESSURE SWITCH IGNITOR ROD CHASSIS GND IGNITION MODULE S8610H GAS VALVE VR8304M4002
PILOT BURNER/IGNITOR - SENSOR Q345A
BURNER SWITCH
T
o 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 – 6 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.
Problem Possible Cause Recommended Action
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 LOCKOUT
• Reset by cycling burner switch OFF / ON.
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 </8” – Replace ignition module.
Bad Pilot Burner / Ignitor-Sensor
• 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.
Problem Possible Cause Recommended Action
Pilot will not light – have spark (cont.)
Plugged pilot orifice • Remove pilot tube from Pilot Assembly, remove the pilot orifice and observe for obstructions.
Repair or replace as required.
Pilot Valve is not open • Verify 24 +/- .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.
Spark not hot enough to light pilot gas
• 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 re-route it with insulated standoffs away from the cabinet chassis as required.
If pilot does not light with external flame replace gas valve. Pilot lights - but then
goes out
Possible ground problem
• 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. Ignition Module is not
sensing lit pilot
• 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 S860H 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.
Gas problems • Verify incoming gas pressure is between 0 -4 WCI and does not vary when the pilot first lights. It should remain constant.
Problem Possible Cause Recommended Action
Main burner does not light – pilot is lit
Ignition Module • Verify 24 +/- .5 VAC between ignition module terminals MV and MV / PV.
If out of tolerance replace ignition module. Operator Error • Verify thermostat is dialed to max temperature
(if equipped)
• Verify trigger gun is open and water is flowing Temperature and Flow
sensing devices
• Verify 24 +/- .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 tempera-ture sensing device (thermostat or snap switch).
Gas Problem • Verify incoming gas pressure. It should be 0-4 WCI.
• Verify manifold (gas valve outlet) gas pressure. It should be -5 WCI for NG and 0- WCI for LP. Repair and replace as required. Gas valve may be bad. Main burner is lit – then
goes out
Gas Problem • 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 -5 WCI for NG and 0- WCI for LP. Troubleshoot gas valve or gas problem.
Pilot blows out • 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.
Ignition Module • Module removes 24 VAC at MV terminal due to malfunction, loss of pilot, or loss of pilot sense. Troubleshoot, repair, and replace as required. Temperature and Flow
sensing devices
• Verify 24+/- .5 VAC between gas valve terminals MV and MV / PV.
Hotsy Part Numbers
Description Part Number
Ignition Module 7-7050
Gas Valve Natural Gas 7-70002
Conversion of Gas Valve to Liquid Propane 7-70220 Pilot Burner / Ignitor – Sensor 7-7027
