Smart Boiler Service

Boiler Problems and Fault Finding

Below is a comprehensive guide to assist you in identifying and resolving boiler faults:

1. Blowing Fuses +

Items to Check:

  • Full Sequence/Ignition PCB
  • Regulation PCB
  • Pump
  • Fan
2. Boiler Makes Groaning Sound When Tap Turned Off +

Items to Check:

  • Secondary Heat Exchanger
  • Primary Heat Exchanger
  • System Pressure
  • System Water Quality
3. Boiler Runs Continuously +

Items to Check:

  • DHW Flow Switch
  • Thermistors
  • Diverter Valve
4. Burner Cycles ON/OFF +

Items to Check:

  • Regulation PCB
  • Fan
  • Flue Route/Termination
  • Air Pressure Switch
  • Air Pressure Sensing Tubes
  • Primary Heat Exchanger
  • Detection Electrodes
5. CH Overheats +

Items to Check:

  • Thermistors
  • Internal Wiring
  • System Water Quality
  • Gas Valve
  • Modureg
6. DHW Only Available When Central Heating Is On +

Items to Check:

  • Power Supply/Fuse
  • DHW Flow Switch
  • External Controls
  • Diverter Valve
7. DHW Overheats +

Items to Check:

  • Thermistors
  • Internal Wiring
  • Gas Valve
  • Modureg
8. Fan Not Detected +

Items to Check:

  • Fan
  • Flue Route/Termination
  • Air Pressure Switch
  • Air Pressure Sensing Tubes
9. Flame Lifts from Burner +

Items to Check:

  • Flue Route/Termination
  • Primary Heat Exchanger
10. Ignition Lockout +

Items to Check:

  • Regulation PCB
  • Gas Valve
  • Ignition Electrodes
  • Gas Supply/Meter Governor
11. Ignition Lockout First Thing in the Morning +

Items to Check:

  • Gas Valve
  • Ignition Electrodes
  • Detection Electrodes
  • Modureg
  • Gas Supply/Meter Governor
12. Low Water Pressure Light On +

Items to Check:

  • Expansion Vessel
  • Pressure Relief Valve
  • System Pressure
  • System Water Quality
13. No Ignition +

Items to Check:

  • Regulation PCB
  • Fan Venture
  • Air Pressure Switch
  • Ignition Electrodes
14. No Modulation +

Items to Check:

  • Full Sequence/Ignition PCB
  • Thermistors
  • Internal Wiring
  • Gas Valve
  • Detection Electrodes
  • Modureg
15. No Spark +

Items to Check:

  • Regulation PCB
  • Internal Wiring
  • Ignition Electrodes
  • Polarity
16. Noisy Ignition +

Items to Check:

  • Regulation PCB
  • Flue Route Terminations
  • Gas Valve
  • Modureg
17. Pilot Out Overnight +

Items to Check:

  • Fan
  • Gas Valve
18. Poor Central Heating +

Items to Check:

  • Full Sequence/Ignition PCB
  • Pump
  • Thermistors
  • External Controls
  • System Water Quality
  • Diverter Valve
  • Gas Valve
  • Modureg
  • Gas Supply/Meter Governor
19. Pressure Drops to Zero When Hot Tap Turned On +

Items to Check:

  • Secondary Heat Exchanger
  • Filling Loop
20. Pressure Loss Overnight +

Items to Check:

  • Diverter Valve
  • Pressure Relief Valve
21. Pump Not Detected +

Items to Check:

  • Pump
  • Heating Flow Switch
  • Primary Heat Exchanger
  • System Pressure
  • System Water Quality
22. Radiators Warm Up When Running Hot Water +

Items to Check:

  • Diverter Valve
23. Safety Discharge Runs Continually +

Items to Check:

  • Secondary Heat Exchanger
  • Pressure Relief Valve
  • Filling Loop
24. Water Leaks from Boiler +

Items to Check:

  • System Pressure
  • System Water Quality