Question:

Boiler works fine most of the time, but occassionally there is a delay in the hot water. Sometimes when the bathroom basin tap is run there is piping hot water coming out which is great, but turn the tap off and turn on a bath tap or the shower full blast afterwards, and the water runs from hot to luke warm to nearly cold, before eventually coming back to being piping hot again! This can take a minute or longer.

The pipe run from the boiler to the bathroom is less than 5m across the landing, so it can be a case of the water in the pipe getting cold as it does not have time, and it would take less than a couple of seconds to run the water out of that length of pipe anyway. It seems to be the boiler getting confused with switching on, then off, then immediately on again.

I know this model is supposed to keep small back up of hot water, but I sense this may be causing the problem.

This drives me mad when it happens. Like I say, it does not happen all of the time, and was considering tapping up my local agent to check it out.

Should I be concerned (I am because it cost me a small fortune to install and expect it to work right) and should it do this in the first place?

Hopefully, there is someone out there who knows the exact in's and out's of combi's and why they do this!!!