Ideal Boilers LOGIC MAX HEAT H 18 Installation & Servicing

Also see for LOGIC MAX HEAT H 12: User guide

53Installation and ServicingSECTION 3 - SERVICING3.20 HEAT ENGINE REPLACEMENTNote. To remove the flow and return pipe connections from the heat exchanger, it may be necessary to cut the pipes above the boiler.IMPORTANTBefore starting the removal procedure, protect the gas andelectrical controls with a waterproof sheet or plastic bag.1. Refer to Section 3.8.2. Remove rubber plug from base to drain the boiler using thedrain point.3. Remove the fan / venturi assembly and place on one side.Refer to Section 3.9.4. Remove the burner and place on one side. Refer to Section3.11.5. Remove the ignition and detection electrodes. Refer toSections 3.13 & 3.14.6. Remove flow and return thermistors from locations.7. Remove the spark generator. Refer to Section 3.15.8. Remove the gas valve. Refer to Section 3.16.9. Remove the 2 M5 screws retaining the gas valve mountingbracket and transfer bracket to the new heat exchanger.10. Pull the clips, retaining the water flow switch housing,forward and remove the water flow switch.11. Remove the screw securing the pipe to the heat exchangerand remove the “c” clip. Lift the housing/return pipeassembly upwards to disengage from the heat exchangerreturn pipe elbow.12. Remove the screw retaining the flow pipe bracket andremove the bracket from its rear retention slot.13. Pull the flow pipe to the right to disengage from the heatexchanger.14. Remove the condensate rubber pipe. Refer to Section3.17.15. Remove the LH heat exchanger fixing screw.16. Pull the heat exchanger to the left to disengage the rearretention pegs and remove the heat exchanger.17. If replacement sump required: Rotate heat exchangerassembly 180º. Place new sump onto heat exchanger,ensuring correct orientation and seal is in place. Thengently apply pressure to the base of the sump at each tabfixing point and engage tabs onto the heat exchanger.18. Reassemble in reverse order, ensuring the heat exchangeris correctly positioned. Replace any new ‘o’ rings suppliedwith new heat exchanger and replacing gaskets or seals ifany sign of damage is evident. Note. Ensure that the flowpipe is fitted through the “V” bracket when refitting.19. Ensure the trap/siphon is filled with water. Refer to Section3.17.20. Refill the boiler, ensuring rubber plug from base is re-fitted,and drain point is fully closed.21. Ensure all gas valve connections are gas tight with a gassoundness check up to the gas control valve.22. Check operation of the boiler. Refer to Sections 2.26 & 2.27.91514121361162111817Shown as 180º position- Refer also to Section 2.1 - ‘Boiler Exploded View’10SERVICING