Not really a DIY question however this is the most appropriate group i can
find.

I just had a new combi boiler fitted to replace an old system with boiler
and immersion. Problem is the water temperature varies quite a lot -
sometimes its blazing hot and give it a minute and it goes cold before
getting too hot again.

The guy who fitted it is really good (reputation) and am trusting him to
figure it out however i've got curious as to what it could be.

What could be the cause?

fwiw my house is a 3 bed semi 30 years old and no water supply problems that
i've noticed. New boiler is a Worcester.

Thanks

Paul

"pauly" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Not really a DIY question however this is the most appropriate group i can
> find.
>
> I just had a new combi boiler fitted to replace an old system with boiler
> and immersion. Problem is the water temperature varies quite a lot -
> sometimes its blazing hot and give it a minute and it goes cold before
> getting too hot again.
>
> The guy who fitted it is really good (reputation) and am trusting him to
> figure it out however i've got curious as to what it could be.
>
> What could be the cause?
>
various things but as a starter can you quote the commissioning figures he
has filled in for model number, water temperatures, flow rates, gas rate etc
on your little blue benchmark book that came with the boiler

> Not really a DIY question however this is the most appropriate group i can
> find.
>
> I just had a new combi boiler fitted to replace an old system with boiler
> and immersion. Problem is the water temperature varies quite a lot -
> sometimes its blazing hot and give it a minute and it goes cold before
> getting too hot again.
>
> The guy who fitted it is really good (reputation) and am trusting him to
> figure it out however i've got curious as to what it could be.
>
> What could be the cause?
>
> fwiw my house is a 3 bed semi 30 years old and no water supply problems
that
> i've noticed. New boiler is a Worcester.

I must say I have found our worcester combi a bit more awkard than having a
hot water cylinder. I find you cant really have the hot taps on just a
little as you need a certain flow before the boiler kicks in (so the water
stays cold), opening it a bit more and the boiler kicks in and the water
becomes mad hot, only when the tap is open about half way (a ceramic tap) do
I get a nice hot temperature that doesnt scold my hands! I cant say I have
had the constant hot-cold-hot... with a constant flow.

In news:d1n2ao$l5i$(E-Mail Removed),
John <(E-Mail Removed)> typed:
> "pauly" <(E-Mail Removed)> wrote in message
> news:(E-Mail Removed)...
>> Not really a DIY question however this is the most appropriate group
>> i can find.
>>
>> I just had a new combi boiler fitted to replace an old system with
>> boiler and immersion. Problem is the water temperature varies quite
>> a lot - sometimes its blazing hot and give it a minute and it goes
>> cold before getting too hot again.
>>
>> The guy who fitted it is really good (reputation) and am trusting
>> him to figure it out however i've got curious as to what it could be.
>>
>> What could be the cause?
>>
> various things but as a starter can you quote the commissioning
> figures he has filled in for model number, water temperatures, flow
> rates, gas rate etc on your little blue benchmark book that came with
> the boiler

I haven't seen the book you mention yet. Do you mean figures obtained after
testing or manufacturer figures for that particular boiler?
The Model is a Worcester 28i Junior.... is this table any use?
http://tinyurl.com/3sq4a (its an image on worcester-bosch.co.uk)

Paul

a wrote:
> > Not really a DIY question however this is the most appropriate
group i can
> > find.
> >
> > I just had a new combi boiler fitted to replace an old system with
boiler
> > and immersion. Problem is the water temperature varies quite a lot
-
> > sometimes its blazing hot and give it a minute and it goes cold
before
> > getting too hot again.
> >
> > The guy who fitted it is really good (reputation) and am trusting
him to
> > figure it out however i've got curious as to what it could be.
> >
> > What could be the cause?
> >
> > fwiw my house is a 3 bed semi 30 years old and no water supply
problems
> that
> > i've noticed. New boiler is a Worcester.
>
> I must say I have found our worcester combi a bit more awkard than
having a
> hot water cylinder. I find you cant really have the hot taps on just
a
> little as you need a certain flow before the boiler kicks in (so the
water
> stays cold), opening it a bit more and the boiler kicks in and the
water
> becomes mad hot, only when the tap is open about half way (a ceramic
tap) do
> I get a nice hot temperature that doesnt scold my hands! I cant say I
have
> had the constant hot-cold-hot... with a constant flow.

Which model have you got? You could always turn the DHW temperature
down on your boiler (assuming it's got one)!

> > I must say I have found our worcester combi a bit more awkard than
> having a
> > hot water cylinder. I find you cant really have the hot taps on just
> a
> > little as you need a certain flow before the boiler kicks in (so the
> water
> > stays cold), opening it a bit more and the boiler kicks in and the
> water
> > becomes mad hot, only when the tap is open about half way (a ceramic
> tap) do
> > I get a nice hot temperature that doesnt scold my hands! I cant say I
> have
> > had the constant hot-cold-hot... with a constant flow.
>
> Which model have you got? You could always turn the DHW temperature
> down on your boiler (assuming it's got one)!

we have the Junior 24i I think. Is there any adjustment possible on the flow
rate needed to fire up the boiler?