Hot water issue - possibly pipework - Plumbing job in Highbury, North London

Job Description

For the last 6 months we have had issues obtaining hot water in our flat. Water temperature from all 4 internal taps (kitchen, bathroom sink, shower and bath) is only ever lukewarm and never piping hot. The water thermostat on our Vaillant TurboMAX Plus boiler is turned up to the maximum.

We have had the boiler serviced twice recently and each time it has been given a clean bill of health (it is only two years old). The last engineer suggested it could be an issue with the pipework in the flat, more specifically where the hot and cold water mixes at one of the taps or perhaps the shower unit.

By way of a demonstration he isolated the hot water at the boiler and turned on the hot tap in the kitchen. Cold water continued to flow from the hot water tap at a rate of around 3 litres per minute. The same thing occurred in the bathroom. His explanation for our temperature issue was that each time we turn on a hot tap it is being diluted by this cold water hence it only ever comes out warm. I am pretty sure we don’t have a leak anywhere as water pressure is absolutely fine so it would make sense that the hot and cold water is mixing somehow.