2964 B High
Your boiler has detected that water is not moving through its internal heating unit fast enough, which can cause the system to overheat and shut down.
Technical description: Flow rate in heat exchanger is too low
Typical repair cost: £120-£450 (including labour)
DIY fix possible
Check that your system pressure is between 1 and 1.5 bar on the front displayEnsure all radiator valves are fully open to allow water to circulateInspect the magnetic system filter, if fitted, to see if it needs cleaning
Protect yourself from future repair bills
A boiler cover plan would cover faults like 2964 B — no call-out fees, no surprises.
*Affiliate links — we may earn a commission at no extra cost to you. Prices shown are starting prices.
Parts commonly replaced
- Internal pump
- Plate heat exchanger
- Flow temperature sensor
*Affiliate links — we may earn a commission at no extra cost to you.