Hot Water Runs Cold After a Few Minutes
The shower starts hot and turns cold long before it should, or the bath never fills hot..
The shower starts hot and turns cold long before it should, or the bath never fills hot.
What is actually going on
The shower starts hot and turns cold long before it should, or the bath never fills hot.
The realistic causes, in order
A cylinder coil that has scaled or a heat exchanger that can no longer reheat at the rate you draw off A destratified cylinder where the thermostat is satisfied while most of the store is cool On a combi, a flow rate above the appliance's capability — the boiler simply can't heat that much water that fast
What we test on site
Recovery time from a full draw-off, measured against the cylinder's rating Coil performance and primary flow temperature to the cylinder Draw-off rate at the shower against the appliance or cylinder capability
Safe checks to make with hot water that runs out fast
- Time how many minutes of usable hot water you actually get from cold
- Check whether the immersion heater has been left as the only heat source
- An unvented cylinder must be inspected annually by someone holding the relevant unvented qualification — the safety devices are not optional.
Who does the work
- Gas Safe registered engineers — registration 554328
- Worcester Bosch accredited installer
- John The Plumb Ltd, company registration 10026483
Get hot water that runs out fast diagnosed properly
The answer is sometimes a component, sometimes correct cylinder sizing. We'll tell you which before any work is quoted.
Questions we get asked
Does hot water that runs out fast mean the cylinder needs replacing?
A cylinder coil that has scaled or a heat exchanger that can no longer reheat at the rate you draw off
What normally puts hot water that runs out fast right?
The answer is sometimes a component, sometimes correct cylinder sizing. We'll tell you which before any work is quoted.
Is it safe to keep using the system with hot water that runs out fast?
An unvented cylinder must be inspected annually by someone holding the relevant unvented qualification — the safety devices are not optional.