Bradford-White Corp Residential Gas-Fired Hydronic Boilers, BJVS, BJVT warranty Start

Brute Mini Hydronic Boiler Page 29

9.3 Troubleshooting Honeywell S8600 Intermittent Pilot System

Some boilers may be equipped with an ignition module that shuts off pilot gas if pilot fails to light.

Start

Turn off gas supply.

Turn thermostat

(controller) to call for

heat.

Power to module

(24V nominal).

￿YES

Spark across igniter/

sensor gap.

￿YES

Turn gas supply on. Pilot burner lights?

￿YES

Spark stops when pilot

is lit?

￿YES

Main burner lights?

￿YES

System runs until call

for heat ends?

￿YES

Call for heat ends. System shuts off?

￿YES Troubleshooting ends

To reset, interrupt power to heater

Note: Before troubleshooting, familiarize yourself with the start-up and checkout procedure.

￿			Check line voltage power, low voltage transformer, hi- limit switch,
		NO	thermostat (controller) and wiring.
			Pull ignition lead and check spark at module.
		NO	Spark okay?
			￿
		￿YES
			•	Check ignition cable ground wiring, ceramic insulator and gap, and correct.
			•	Check boot of the ignition cable for signs of melting or buckling. Take
				protective action to shield cable and boot from excessive temperatures.
		￿	•	Check that all manual gas valves are open, supply tubing and pressures
				are good, and pilot burner orifice is not blocked.
			•	Check electrical connections between module and pilot operator on gas
		NO
				control.
			•	Check for 24 Vac across PV-MV/PV terminals on module. If voltage is
				okay, replace gas valve; if not, replace module.
		NO	•	Check continuity of ignition cable and ground wire.
			•	Clean flame rod.
	￿		•	Check electrical connections between flame rod and module.
			•	Check for cracked ceramic flame rod insulator.
			•	Check that pilot flame covers flame rod and is steady and blue.
			•	Adjust pilot flame.
			•	If problem persists, replace module.
￿
			•	Check for 24 Vac across MV-MV/PV terminals. If no voltage, replace
		NO
				module.
			•	Check electrical connections between module and gas valve. If okay,
				replace gas valve.
	￿		•	Check continuity of ignition cable and ground wire.
		NO
				Note: If ground is poor or erratic, shutdowns may occur occasionally even
				though operation is normal at the time of checkout.

•Check that pilot flame covers flame rod and is steady and blue.

•If checks are okay, replace module.

￿
	•	Check for proper thermostat (controller) operation.
NO
	•	Remove MV lead at module; if valve closes, recheck temperature
		controller and wiring; if not, replace gas valve.
	Repeat procedure until trouble-free operation is obtained.