When a single bathroom tap provides only a trickle of hot water, the issue is unlikely to be with the boiler, pump, or hot water tank, especially if other hot water outlets, such as the kitchen sink, are functioning normally. This is according to advice from plumbers endorsed as Which? Trusted Traders.
Experts suggest that the most common causes for an isolated problem with a mixer tap include a build-up of limescale or debris within the tap's cartridge or internal components, which can restrict hot water flow. Other potential causes include a worn or blocked cartridge, a kinked flexible hose, or a faulty non-return valve.
Initial checks can include cleaning the tap aerator and ensuring the isolation valve on the hot feed is fully open. If these steps do not resolve the issue, plumbers generally recommend replacing the tap or its cartridge as the most cost-effective solution. A plumber can diagnose the specific problem and advise on repair or replacement options.