Keston
Keston Heat 45kW
Heat Only Boiler
45kW
2006-2018
ErP A
40 fault codes
<p>The Keston Heat 45kW is a heat-only (regular) boiler from Keston, available at 45kW output. Produced 2006-2018.</p>
Keston Heat 45kW Fault Codes 40
Code
Description
Severity
Type
E01
Ignition Failure — 5 Attempts
The boiler has attempted to light 5 times and failed. The most common Keston fault code.
Medium
DIY
View Guide
E02
False Flame Detected (C36/CSI)
The boiler's ionisation circuit is detecting a flame when none should be present. Possibly a power…
High
Engineer
View Guide
E03
Boiler Overheat
The boiler has overheated — check for closed valves, air in system, or incorrect water pressure.
High
Engineer
View Guide
E05
Fan Failure
The boiler cannot detect fan rotation — the fan may be seized or have a wiring…
High
Engineer
View Guide
E07
Flue Overheat
The flue temperature has exceeded safe limits. The flue temperature should be no more than 10°C…
High
Engineer
View Guide
E08
Flame Circuit Error
There is a fault in the flame monitoring circuit — possibly the control box.
High
Engineer
View Guide
E09
Gas Valve Drive Error
The gas valve or control box has a fault — the valve is not responding to…
High
Engineer
View Guide
E18
Flow Overheat (C40/C55)
On Keston C40 and C55 boilers, E18 indicates the flow temperature has exceeded safe limits. Check…
High
Engineer
View Guide
E23
Water Filling Error
The water pressure sensor has detected an issue during the automatic filling sequence.
Medium
Engineer
View Guide
E24
Water Pressure Lost 4 Times in 24 Hours
The system has lost pressure 4 times within 24 hours — indicating a possible leak.
High
Engineer
View Guide
E26
Flame Drop Out
The boiler flame has dropped out during operation. Check for flue obstruction, blocked condensate drain, or…
Medium
DIY
View Guide
E30
Flow Sensor Short Circuit
The flow temperature sensor has short-circuited.
Medium
Engineer
View Guide
E31
Flow Sensor Open Circuit
The flow temperature sensor circuit is open — the sensor is not connected or has failed.
Medium
Engineer
View Guide
E37
Water Pressure Error
The water pressure is too low — increase system pressure using the filling loop.
Low
DIY
View Guide
E40
Water Pressure Too High
The system water pressure is too high — above 3 bar.
Medium
Engineer
View Guide
E43
Return Sensor Short Circuit
The return temperature sensor has short-circuited.
Medium
Engineer
View Guide
E44
Return Sensor Open Circuit (C55)
The return temperature sensor circuit is open on the C55 boiler.
Medium
Engineer
View Guide
E44 (C36)
Low Water Pressure (C36)
On the Keston C36, E44 specifically indicates low water pressure (this is different from E44 on…
Low
DIY
View Guide