Table of Contents
Keston Boiler Error Codes
Who are Keston?
Keston was originally founded in 1928. Their aim has always been to provide domestic and commercial heating. In 2006, the company was purchased by Ideal. Production then moved to Ideal’s factory, which is based in Hull.
Keston boilers are ideal to be used in compact spaces such as flats or any properties which are small in size. It is perfect for properties in London. This is due to the fact that Keston boilers have a twin flue system that can make every job easier and simpler.
You will have the ability to run the flue either vertically or horizontally from an elevation of 1.5 degrees. What is more, the flue can be extended up to 27 meters from the location of the boiler. This is done to achieve maximum flue flexibility. In addition, this process would allow for hassle-free and easy installation. It can also mean that your new boiler can be fitted in the most practical and suitable place in your property.
What do Keston offer?
With a Keston boiler you will get 7 years of warranty as well as a large range of compatible controls like the Keston 22mm/28mm system filter, the RF Electrical Programmable Room Thermostat and lastly the Mechanical Timer which guarantees a maximum performance from your boiler.
However, in some cases, getting a new boiler might be more cost-effective than getting your old boiler fixed. Some issues might be costly to fix. What is more, a new boiler will probably be more efficient and can help you save both money and energy. That is why getting a new boiler is a good investment in the long run.
Get a quote from Let’s Heat. We have a large range of products and our staff of Gas Safe engineers provide an excellent service that is both professional and reliable. In addition, we can help you get the boiler that best fits your house and heat requirements.
What to do if I have a problem with my Keston Boiler?
If you think that there is a problem with your Keston boiler, make sure to check the information below. We have prepared a list of the error and fault codes that you may see displayed by your boiler. These codes can help you identify the exact problem with your boiler. This will make it easier for you tell the Gas Safe Engineer what the exact issue is.
C36 Combi Gas Boiler Error Codes
| Fault Code | The Problem |
| E01 | Ignition failure – the boiler has attempted to light 5 times and not succeeded – check the gas supply is on |
| E02 | False flame – possibly a problem with the power supply |
| E03 | Boiler overheat – check that any valves to the heating circuit have not been shut down, no air in the system and that the water pressure is correct |
| E05 | Fan failure – boiler cannot detect fan rotation – check fan operation and both connectors onto fan |
| E07 | Flue overheat – check combustion and flue temperature vs. return temperature – the flue temperature should be no more than 10C above return temperature. Possible heat exchanger fault. |
| E08 | Flame circuit error – possible control box fault |
| E09 | Valve drive error – possible gas valve or control box fault |
| E10 | Control box errors – possible faulty control box |
| E11 | The automatic test for calibration of flow and return sensors has failed – check both flow and return sensors are located on the correct pipes and are producing the correct readings |
| E12 to E22 | Control box errors – possible faulty control box |
| E23 | Water filling error – check water pressure sensor |
| E24 | Water pressure lost 4 times in 24 hours – possible leak, check system and boiler |
| E25 | Control box errors – possible faulty control box |
| E26 | Flame drop out – check for obstruction of the flue and/or air terminals, blockage/freezing of the drain pipe or a low gas supply (LPG). |
| E30 | Flow sensor short circuit – check connections to flow sensor |
| E31 | Flow sensor open circuit – check connections to flow sensor are in place |
| E32 | DHW sensor short circuit – check connections to domestic hot water (DHW) sensor |
| E33 | Domestic hot water (DHW) sensor short circuit – check connections to DHW sensor are in place |
| E34 | Mains supply voltage < 180V – may be a problem with your power supply |
| E35 | Mains supply frequency incorrect – may be a problem with the power supply |
| E37 | Water pressure error – increase the system water pressure |
| E38 | Reset key fault – replace fascia PCB |
| E40 | Water pressure too high |
| E41 | Communication error between fascia and control box – check cables |
| E43 | Return sensor short circuit – check connections to return sensor |
| E44 | Return sensor open circuit – check connections to return sensor are in place |
| E45 | Flue sensor short circuit – check connections to flue sensor |
| E46 | Communication error between fascia and control box – check cables |
| E99 | Flue sensor short circuit – check connections to flue sensor are in place |
S30 System Gas Boiler Error Codes
| Fault Code | The Problem |
| 0 | The boiler is in standby mode awaiting either a central heating call or hot water demand |
| C | The boiler has a call for central heating / hot water but the appliance has reached the desired temperature set on the boiler |
| C and Burner Light | The boiler is operating for central heating / hot water |
| F and Burner Light | The boiler is operating in frost mode |
| F0 | Boiler Chip Card (BCC) not fitted |
| F6 | Outside sensor failure |
| F7 | Low mains voltage |
| F9 | Printed circuit board (PCB) Fault |
| L5 | 5 boiler resets in 15 minutes |
| L6 | False flame lockout |
| C0 | Boiler Chip Card (BCC) activation fault |
| C2 | Boiler Chip Card (BCC) fault |
| F1 | Low water pressure |
| L1 | Flow temperature overheat |
| F2 | Flame loss |
| L2 | Flame loss |
| F3 | Fan fault |
| F4 | Control / No flow thermistor |
| F5 | Return thermistor |
C40 C55 Combi Gas Boiler
| Fault Code | The Problem |
| Enn | Fault causing a boiler shutdown |
| E00 | Flame detected when not expected – check boiler earth and probe condition |
| E02 | No ignition after restart – check gas supply, gas valve operation and ignitor electrode spark generation |
| E03 | Gas valve faulty or not connected |
| E04 | Power has been reset whilst boiler was in lockout |
| E11 | Internal electronics error – rest or replace control box |
| E18 | Flow overheat – check water circulation |
| E19 | Maximum return temperature exceeded – check circulation |
| E25 | Flow temperature increased too quickly – check water circulation |
| E30 | Difference between flow and return temperatures too high – check circulation. |
| E31 | Flow thermistor short circuit – check/replace connections/thermistor |
| E32 | Return thermistor short circuit – check/replace connections/thermistor |
| E36 | Flow thermistor open circuit – check/replace connections/thermistor |
| E37 | Return thermistor open circuit – check/replace connections/thermistor |
| E44 | Low water pressure |
FAQs
How long do Keston Boilers last?
With the right amount of care and maintenance, a Keston boiler can heat your home for 10-15 years.
Who makes Keston boilers?
Keston’s was originally established in 1928 to provide domestic and commercial heating installations and servicing. In 2006, Keston was purchased by Ideal Heating before moving production to Ideal’s Hull manufacturing site in 2013.
What type of boiler is a Keston C40?
The Keston C40 and C55 use a variable speed combustion blower to deliver a premix of gas and air to a downward firing burner in a high efficiency, single pass heat exchanger. The flue system is room sealed and fan powered.
How do I increase the pressure on my Keston boiler?
The most common Keston boiler fault is low water pressure. The amount of water in your boiler and the water pressure are directly connected. So, if you add water, you be able to also increase the pressure.
Where are Keston Boilers made?
An early pioneer of condensing boilers, Keston was purchased by Ideal Boilers in 2006. Boiler production was moved to Ideal’s Hull manufacturing site in 2013 and all Keston boilers since have been designed, developed and manufactured in the UK.