Ideal Boilers LOGIC MAX HEAT H 18 Installation & Servicing

Also see for LOGIC MAX HEAT H 12: User guide

56FAULT FINDING FAULT FINDING FAULT FINDING FAULT FINDING FAULT FINDINGInstallation and ServicingSECTION 4 - FAULT FINDING4.2 ‘L1’ - FLOW TEMPERATURE OVERHEAT LOCKOUT OR NO WATER FLOW LOCKOUTIs the Boiler and CH System filled with water and allisolation, system filter and radiator valves open?YESFill and vent the system and open allisolation valves, then restart boilerIs the Flow/Return Differential across the Boiler inexcess of 30°C?NOCheck that the Pump is rotating freely. Isthe Differential now below 20°C?YESNOCheck the Control/No Water Flow and ReturnThermistors (Refer to Section 3.12)Replace the Pump,then restart boilerNOOK, nowrestart boilerYES4.3 ‘L2’ - IGNITION LOCKOUTIf the boiler is restarted does theboiler ignite for a short time andthen extinguish?YESIs the Gas Pressure available atthe Boiler Inlet (>18 mbar)?Check the detection electrodeand associated harness for:continuity, visual condition andposition (Refer to Section 3.14).Check if the condensate pipe isblocked.Check flue is installed correctly.Replace as necessaryNO Check gas supply andrectify faultNOYESIs 24Vdc supply available at theGas Valve?YESCheck spark generator andassociated harness for: continuityand visual condition. (Referto Section 3.15) Are thesefunctioning correctly?YESCheck ignition electrode andassociated harness for: continuity,visual condition and position.(Refer to Section 3.13) Are thesefunctioning correctly?NOCheck siphon and condensatedrain pipe work for blockage andrectify if necessary. Boiler nowworking OK?Check wiring connectionfrom gas valve to PCB forcontinuity. If the wiring isOK then replace the PCBNOReplace SparkGenerator and harnessas necessaryNOReplace IgnitionElectrode andassociated harness asnecessaryNOReplace Gas ValveYESUnplug gas valve. Is resistancebetween outside pins 4KΩ (±2)?YESReplace Gas ValveNORESTART PROCEDURE - To restart boiler, press the RESTART button.RESTART PROCEDURE - To restart boiler, press the “RESTART” button.