On Wed, 04 Feb 2009 02:01:15 +0000, Arfa Daily wrote:

I then asked her how the kitchen water was, and she said that it was too
hot to hold your hand in. Initially, I thought that she might be looking
at an issue with the temperature of the incoming water, but the fact
that the downstairs water was very hot seemed to knock that one on the
head.

Not necessarily. I'd check the flow rate at the various taps. Is the
kitchen tap drawing at a significantly lower rate than the bath tap? If
so, does reducing the flow rate at the bath tap (and waiting up to a
minute while the water in the pipes is changed) increase the temperature?



--
John Stumbles -- http://yaph.co.uk

Question Authority

"YAPH" wrote in message
...
On Wed, 04 Feb 2009 02:01:15 +0000, Arfa Daily wrote:

I then asked her how the kitchen water was, and she said that it was too
hot to hold your hand in. Initially, I thought that she might be looking
at an issue with the temperature of the incoming water, but the fact
that the downstairs water was very hot seemed to knock that one on the
head.

Not necessarily. I'd check the flow rate at the various taps. Is the
kitchen tap drawing at a significantly lower rate than the bath tap? If
so, does reducing the flow rate at the bath tap (and waiting up to a
minute while the water in the pipes is changed) increase the temperature?



--
John Stumbles -- http://yaph.co.uk

Question Authority

That was my first thought too John, but I turned both the basin and bath
taps down to perhaps a quarter of fully on, and left them running, in turn,
for perhaps 2 minutes each. There did seem to be a slight improvement in
temp, but not as much as I might have expected. Just to make sure that I've
got the operating principle right. These combi boilers heat the water
'on-the-fly', right ? A heat exchanger with cold water in and a bloody great
fan-blown flame up its chuff to give hot water out the other end, yes ? Some
already-hot water 'stolen' from the CH via a diverter valve and a secondary
heat exchanger comes into it somewhere ? So basically the gas equivalent of
an electric 'on-demand' shower ?

I see from the manual that there is a season correction valve built into
this boiler. As I understand it, this alters the flow rate through the heat
exchanger, to compensate for differences in the temperature of the incoming
water. Given that we have had a couple of weeks now of pretty cold weather,
when I first thought about this problem, it occured to me that something
might have gone wrong with this system (or the setting of it), and that the
(very cold) incoming water was passing through the exchanger at full chat,
so not having time to get heated properly, but again, if that were the case,
it seems to me that both down and upstairs water would be equally affected,
and that the 'reduce the flow' test from turning the taps down, would have
resulted in a significant increase in the water temp.

Not that any of that seems relevant to the problem, as the hot water in the
kitchen is fine. Just that I like to at least have a working understanding
of the system that I am dealing with.

Thanks for suggestions so far. Appreciated.

Arfa