No Hot Water? Work Through This Before You Call
Five checks that fix a surprising share of no-hot-water mornings for free.
Check the obvious first
Timer clock wrong after a power cut. Thermostat nudged down. Prepay meter out of credit. A tripped fuse on the boiler spur. These sound insulting and account for a real share of winter callouts, check them before you spend money.
Combi vs cylinder
A combi with heating but no hot water usually has a failed diverter valve, an engineer job, but a modest one. A cylinder system that's lukewarm may just have a failed immersion or a thermostat set low; scalding then cold suggests the cylinder stat.
Airlocks
If one hot tap spits and dies after work on the system, an airlock is likely. Running the mains cold tap through a hose into the affected hot tap for 30 seconds often shifts it. If all hot taps are dead, the problem is upstream, stop there and call.