Hot water slow to come through

[FlyinBrian]

Hi all, I have a combi boiler fired CH and HW system. The heating is OK although some rads are slow to get hot. As I understand it the house originally had a normal CH and HW system which was changed to combi a few years ago

The hot water seems to take forever to get hot either in the kitchen (where boiler is located) or in the en suite shower, strangely the en suite basin tap produces hot water much quicker than the shower. I can not trace the pipe work as it is behind the wall but the kitchen HW is fed from a pipe that comes downwards from the ceiling then along through the kitchen units.

So I guess I am asking how to make the water flow hot quicker

 

[Space cat]

The problem seems simple enough; your deadlegs are too long. That is to say, there is too much pipework between the source of the hot water (the boiler) and the taps.

The solution is simple in theory but not so easy in practice; reroute the pipes.

If I put myself in the place of a lazy plumber I think I can see how it might have happened. Before the combi went in there would have been a hot cylinder somewhere, most likely upstairs. All the hot taps were supplied from this. There would also have been two pipes connecting the old boiler to the tank - and maybe more in the same general area.

Now all the existing hot taps go back to a point above the spot where the old cylinder stood. How do I connect them all to the new boiler? That's a hard one; maybe worthy of a TV premium rate phone-in! Idea! The combi is in much the same place as the old boiler so let's just use one of those old pipes for the job.

Your hot water must now come out of the boiler, up through the floor to the place where the old cylinder stood, down through the floor again and, finally, along through the kitchen units to the hot tap. To further compound the problem, that first run of old pipe from the boiler will be big stuff - with lots of cold water in it! If the shower is upstairs and its pipework comes down from the ceiling, it was always going to take longer to run hot when the combi went in. The basin alongside it is likely to be closer, pipe-wise, to the new boiler and so it runs hot quicker.

And so, to answer your original question, the only way to get hot water to come out quicker is to replumb your hot taps with less pipe.

 

[FlyinBrian]

Space Cat, sounds very logical but as you say a pain to correct.

Maybe a job for when I retire

Cheers
Brian