Boiler Advice

The Viessmann fault codes people see most often are F4 for no flame signal, F2 for overheating, F5 for a fan or air pressure switch fault and 0b for low water pressure. Most of them lock the boiler out until the cause is found, so heating and hot water stop until it’s sorted. Viessmann’s Vitodens […]

Quick answer: The Baxi E20 code means there’s a fault with the central heating temperature sensor, known as the NTC thermistor. The sensor has either failed or its wiring has a break or short, so the boiler can’t read the heating water temperature. Baxi advises noting the code and contacting your installer, so this is

Quick answer: The Baxi E168 code means the boiler has detected a problem but can’t work out exactly what it is. It often appears after a reset, a power cut or another fault. Make a note of any code you saw before it, switch the boiler off at the isolator for a minute, then try

Quick answer: The Vaillant F73 fault means the boiler’s water pressure sensor isn’t giving a proper reading, usually because the sensor itself is faulty or its plug or wiring has a problem. First check the pressure gauge. If the system really is low, top it up and reset once. If the gauge looks normal and

Quick answer: The Vaillant F24 fault means the water inside the boiler is heating up faster than it should, so the boiler has switched itself off to stay safe. The usual cause is poor circulation, from a sticking or weak pump, air in the system or low pressure. Check the pressure, bleed any radiators that

The Potterton fault codes people see most often are E119 for low water pressure, E133 for ignition failure, E110 for overheating, E125 for a circulation fault and E168 for a general internal fault. Most of these lock the boiler out until the cause is dealt with, so you’ll be without heating and hot water until

Quick answer: The Viessmann F4 fault means the boiler tried to light but couldn’t detect a flame, so it locked out. Common causes are a worn flame sensor (ionisation electrode), a gas supply problem, a blocked flue or a faulty control board. Check your other gas appliances, reset once, and if F4 returns call a

Quick answer: The Vaillant F76 fault means the overheating protection on the primary heat exchanger has tripped. The usual causes are a failed thermal fuse, a wiring fault to that fuse, or a heat exchanger that has overheated. You can try one reset, but this isn’t a code to work around at home. Switch the

Quick answer: The Vaillant F32 fault is a fan fault. The boiler can’t confirm the fan is running at the right speed, so it shuts down. Common causes are a blocked flue or air intake, loose wiring, a worn fan motor or a faulty speed sensor. One reset is fine. If F32 comes straight back,

The Alpha boiler fault codes people most often see are E28 for ignition failure, E10 for low water pressure (simple top up DIY), E9 for a fan fault and E37 for a low voltage or circuit board problem. These lock the boiler out, so you lose heating and hot water until the cause is found.