Loss of hot water is a disruptive emergency, particularly for families with young children or elderly residents. In Bristol properties with combi boilers, the most common causes are diverter valve failure, low system pressure, and limescale buildup in the plate heat exchanger — the latter being more prevalent here than in softer water areas. Properties with conventional (regular) boilers and hot water cylinders may lose hot water due to a failed cylinder thermostat, immersion heater element, or motorised valve. Properties still using electric immersion heaters as primary hot water sources may have a blown element or faulty timer. Our engineers diagnose the root cause accurately and carry the most common diverter valves, thermostats, and elements on the van to restore hot water in a single visit wherever possible.
We establish your hot water system type (combi, system with cylinder, or immersion) to focus the diagnosis correctly.
We test diverter valves, thermostat settings, motorised valves, immersion elements, and system pressure as appropriate.
On combi boilers we check for plate heat exchanger limescale restriction — common in Bristol — and advise on descaling or replacement if needed.
Failed components are replaced on the spot where parts are available. We'll confirm a return date for any parts requiring ordering.
We run hot water from multiple outlets to confirm full temperature restoration before leaving.
No hot water diagnosis from £85. Common repairs such as diverter valve or immersion element replacement are typically £120–£220 all-in. Cylinder thermostat replacement from £95. Prices confirmed before work begins.
This is a classic diverter valve symptom. The valve controls whether the boiler heats the central heating circuit or the hot water circuit. When it sticks in the heating position, you get heat but no hot water.
Yes. Limescale can block the plate heat exchanger in combi boilers, reducing or eliminating hot water output. A power flush or heat exchanger descale typically resolves this.
This can indicate a failing cylinder thermostat set too low, or a motorised valve not opening to allow heat to reach the cylinder. Both are straightforward repairs.