Potterton E20 Fault

Potterton E20 Fault

The Potterton E20 error code is usually a central heating thermistor sensor fault. This senses the temperature of the water in the central heating system; if faulty, then the boiler’s control unit will not be able to measure this temperature correctly. If the thermistor reads wrongly, it may affect how effectively your boiler can control heating and thus lead to difficulty in maintaining the desired heat levels in your home.
Probable Causes of Potterton E20 Error Code

Faulty Thermistor: Damaged or broken thermistors can give wrong temperatures readings to the boiler’s control unit.

Wiring Problems: Poorly connected wiring between the thermistor and the steam boiler’s main board can disrupt transmission of temperature data.

Improper Placement: Incorrect positioning of a thermal resistor within a heater may result in incorrect temperature measurements.

System Sludge: The presence of sludge or debris could insulate it preventing accurate determination of water temperature by affecting its surface area.

How to Troubleshoot and Fix Potterton E20 Error Code

Examine Thermistor: Check for any visible sign that might indicate faults in your main central heating thermistor. It might need cleaning or replacing if it looks damaged.

Make Sure Wiring & Connections are Okay: Ensure there is good wire connection between themometer and Boiler Control Unit. Alternatively, fix any wire damage noticed.

Validate Thermistor Placement: To ensure that you have properly located a thermal resistor as per manufacturer’s instructions, ascertain its right position. Inaccurate readings can result from wrong placement.

Clean Around Themistor: Carefully clean out any sludge or other foreign matter around where thermometer sits so as to get an accurate measurement for water temperatures.

Reset Your Boiler : Test whether there is an error code clear message after rectifying possible issues and see if it still functions normally again following resetting procedure on it.

Seek Expert Help: If you still get an e20 error on your display monitor; or confused as to the right step to take, you should refer to a Gas Safe registered engineer for help. It could be that the thermistor needs replacing after a professional carries out exhaustive diagnostics.

Regular Maintenance: Your heating system should be serviced on a regular basis in order that the E20 error code does not recur and other problems do not arise. This will go a long way in helping to identify underlying issues early enough before they develop into major breakdowns.


The Potterton E20 error code is an indication of a central heating thermistor sensor fault. Immediate action is necessary to ensure efficient and reliable boiler operations. Although homeowners can do some preliminary checks and cleanings, more complicated matters related to functionalism of thermistors or wiring usually call for expert advice. Therefore, it is important for such systems to be regularly serviced by qualified professionals so as to avoid similar failures in future.