Our boiler is one end of our bungalow, which means a good 10m run to the
bathroom bath/sink taps.

Of late, when these have been running, the boiler seems to cycle between
pumping out water at max temp, then shutting down, then refiring. This
being noticeable by hot/cold/hot/cold at the taps.

The cloakroom sink next to the boiler (so a 2m run) doesn't seem affected.

This has only started, so I presume something needs cleaning or
replacing ?

We live in a very soft water area, and it's 21 year old Vaillant.

I did have it covered under one of these schemes. But dropped that over
10 years ago when I saw the "service" consisted of pointing a vacuum
inside, and imperceptibly loosening a pipe (presumably for a call back
"repair").

In the event of a replacement needed, I imagine I would get odds of
1,000,000:1 if the pipes lined up :)

On Fri, 14 Apr 2023 15:53:16 +0000, Jethro_uk wrote:

> Our boiler is one end of our bungalow, which means a good 10m run to the
> bathroom bath/sink taps.
>
> Of late, when these have been running, the boiler seems to cycle between
> pumping out water at max temp, then shutting down, then refiring. This
> being noticeable by hot/cold/hot/cold at the taps.
>
> The cloakroom sink next to the boiler (so a 2m run) doesn't seem
> affected.
>
> This has only started, so I presume something needs cleaning or
> replacing ?
>
> We live in a very soft water area, and it's 21 year old Vaillant.
>
> I did have it covered under one of these schemes. But dropped that over
> 10 years ago when I saw the "service" consisted of pointing a vacuum
> inside, and imperceptibly loosening a pipe (presumably for a call back
> "repair").
>
> In the event of a replacement needed, I imagine I would get odds of
> 1,000,000:1 if the pipes lined up :)

Just a follow up that this boiler has also just started not firing with
an F.28 fault. I don't think that's directly the cause of the fluctuating
HW, but an interesting development.

Maybe get it replaced before gas is illegal ?