DIY Doctor UK DIY Forums

Hi. Does anyone know why my hot water cylinder has started venting? It's pouring hot water down the drain which seems like a lot of waste.

There are mainly two reason behind the water heater cylinder venting as given below:
The pipework configuration is wrong and unless you have changed something.
A sludged up system causing a partial blockage making the open vent the easier route for the water to follow.

Normally caused by faulty thermostat over heating the water. However there are some weird and wonderful system, like the Willis so more than one reason.