5.3.2 LOCKOUT
If the fault is persistent or more severe the boiler will lockout with a error code. When the boiler
has entered this error mode it will not attempt to restart until the “Reset” button is pressed.
ERROR CODES
Low water pressure
E 44
Return thermistor open circuit - check/replace connections/thermistor
E 37
Flow thermistor open circuit - check/replace connections/thermistor
E 36
Return thermistor short circuit - check/replace connections/thermistor
E 32
Flow thermistor short circuit - check/replace connections/thermistor
E 31
Difference between flow and return temperatures too high. Check circulation.
E 30
Fan not rotating - check fan connection and fan for fault.
E 28
Flow temperature increased too quickly. Check water circulation.
E 25
Maximum return temperature exceeded. Check circulation.
E 19
Flow overheat - check water circulation
E 18
Thermal fuse blown or flue overheat thermostat activated.
E 12
Internal electronics error - rest or replace control box
E 11
Power has been reset whilst boiler was in lockout
E 04
Gas valve faulty or not connected
E 03
No ignition after restart. Check gas supply, gas valve operation and ignitor
electrode spark generation
E 02
Flame detected when not expected. Check boiler earth and probe condition.
E 00
Description of fault
Display
WD536
Chapter 5 : Fault Finding
The Keston C45, C40P, C55 & C55P
Installation & Servicing Instructions
Page : 30