Ideal Boilers Mexico Super FF440 Installation And Servicing Manual

37Mexico Super FF440 - FF480 - Installation & ServicingFAULT FINDINGFAULT FINDING FAULT FINDING FAULT FINDING FAULT FINDING FAULT FINDING FAULT FINDINGCheck all connections to PCB.If no fault found, replace PCBReset the overheat 'stat. Set control'stat to maximum. Allow the boilerto reach temperature - if theoverheat 'stat trips again, measureflow temperature.If above 90∞C replace control 'stat.If below 90∞C replace overheat 'stat.STARTCheck that the mains on neon'I3' is illuminated.YESNOYESYESNOIs there a live supply to bothterminals of overheat 'stat?(if fitted)Is the ignition electrode sparking?YESYESYESChange fanYESNO Rectify bad connectionCheck mains supply and fuses.Check programmer and systemthermostats are all ON. Check thatboiler connections are OK .Check that the boiler thermostatis set at maximum and the mainson/off switch is ON.Is the fan turning ?Check connections to pressureswitch. If no faults found, changepressure switch.Replace the boiler thermostatCheck connections and leads topressure switch/boiler thermostatand check that fan is operating.Check all connections to PCB.If no fault found change PCB.YESCheck pressure switch sensingpipes for blockages, badconnections and reversedconnection.Is pressure difference at switchgreater than 0.9 mbar?Change fanYES NOChangepressure switchDoes the pilot light ?NOYESNOYESDoes thespark stopafter pilot islit?NOIs there a gas supplyto the boiler?Is the pilot injectorblocked?YESReplacegas valveNOIs there a supply onterminals of main gasvalve?YESNOYESNO NOIs there a supply on the fanconnector at PCB ('Molex 'marked 'FAN'?).YESYESNONOCheck the polarity ofthe mains supply.Check the continuity ofthe ignition lead fromconnector to electrode.Does the spark nowcease when gas is lit ?Ensure pilot andmain gas valveleads are notcrossed over.Is there a supplyvoltage at pilotgas valve?Is there a livesupply on the redlead to pressureswitch?NOIs there a regularspark from tube 'SG1'on the PCB?Can the overheat 'statbe reset when thesystem is cold ?NO YESNOReplace fuse BUT, beforeattempting to start boiler, checkfor short between live andneutral, also between live andearth, on all items plugged intoPCBCheck all connections to PCB.If no error found, replace PCB.Is there continuityacross the controlthermostat ?YES NONOYESHas the fuse blown on PCB ?NONOIs there a live supply on theviolet lead to pressure switch?Is there asupply atthe fan ?Replace the overheat thermostatDoes main burnercross-light from pilot?Is the main burnerinjector clear?Replace main gassolenoid valveCheck gap at ignition electrode.Check electrode and lead areundamaged, and not close toearthed metalwork.