we've just moved into new house last week, and there's a long list of
jobs to be done...
but top of the list is get the hot water/central heating working.

I've read the instruction manual but maybe I've misunderstood as still
can't set the combi boiler (it's a Vokera excell 80SP)
to provide decent flow of hot water for baths or shower.
The temp varies from cold - tepid to hot (just briefly), and flow rate
is poor.

any suggestions much appreciated - thanks
-
Katya

"Katya Robin" wrote in message
...
we've just moved into new house last week, and there's a long list of jobs
to be done...
but top of the list is get the hot water/central heating working.

I've read the instruction manual but maybe I've misunderstood as still
can't set the combi boiler (it's a Vokera excell 80SP)
to provide decent flow of hot water for baths or shower.
The temp varies from cold - tepid to hot (just briefly), and flow rate is
poor.

any suggestions much appreciated - thanks

Combi boilers heat the cold water as it passes through the device. For that
reason the water-flow is restricted because if it passed through at normal
'speed' it would not be heated up enough. Personally I wouldn't touch a
combi boiler with a barge-pole. Several relatives and friends of mine have
them, and they do nothing but complain about the unreliability, frequent
need to call out plumbers, and the excessively long time it takes to fill a
bath.
Certainly the water temperature should not fluctuate while the tap is
running so you seem to have a problem somewhere - but what may be causing
that is anyone's guess without examining the thing.

Kev

"Uno Hoo!" wrote in message
...

"Katya Robin" wrote in message
...
we've just moved into new house last week, and there's a long list of
jobs
to be done...
but top of the list is get the hot water/central heating working.

I've read the instruction manual but maybe I've misunderstood as still
can't set the combi boiler (it's a Vokera excell 80SP)

The 80SP is a now an old model, but repairable.

to provide decent flow of hot water for baths or shower.
The temp varies from cold - tepid to hot (just briefly), and flow rate
is
poor.

any suggestions much appreciated - thanks

Combi boilers heat the cold water as it passes through the device. For
that
reason the water-flow is restricted because if it passed through at normal
'speed' it would not be heated up enough. Personally I wouldn't touch a
combi boiler with a barge-pole. Several relatives and friends of mine have
them, and they do nothing but complain about the unreliability, frequent
need to call out plumbers, and the excessively long time it takes to fill
a
bath.

More old wives tales. They bought cheap crap combi's that break down.
Don't complain if you buy a Lada and it breaks down a lot. Combis are
available with high flowrates that fill baths pronto.

In short:

1. Get the combi with the flowrate you need
2. Get a good quality model.

If you don't fulfil Nos 1 & 2 above then don't complain.

Certainly the water temperature should not fluctuate while the tap is
running so you seem to have a problem somewhere - but what may be causing
that is anyone's guess without examining the thing.

"Doctor Drivel" wrote in message
eenews.net...

"Uno Hoo!" wrote in message
...

"Katya Robin" wrote in message
...
we've just moved into new house last week, and there's a long list of
jobs
to be done...
but top of the list is get the hot water/central heating working.

I've read the instruction manual but maybe I've misunderstood as still
can't set the combi boiler (it's a Vokera excell 80SP)

The 80SP is a now an old model, but repairable.

to provide decent flow of hot water for baths or shower.
The temp varies from cold - tepid to hot (just briefly), and flow rate
is
poor.

any suggestions much appreciated - thanks

Combi boilers heat the cold water as it passes through the device. For
that
reason the water-flow is restricted because if it passed through at
normal
'speed' it would not be heated up enough. Personally I wouldn't touch a
combi boiler with a barge-pole. Several relatives and friends of mine
have
them, and they do nothing but complain about the unreliability, frequent
need to call out plumbers, and the excessively long time it takes to fill
a
bath.

More old wives tales.

Not at all. They are not imagining the problems that they have!

They bought cheap crap combi's that break down.

Worcestor Bosch? Baxi?

Don't complain if you buy a Lada and it breaks down a lot. Combis are
available with high flowrates that fill baths pronto.

Well I've yet to find anyone who owns one! Every single person I know who
has a combi says the same thing: "Takes bloody ages to fill a bath."


In short:

1. Get the combi with the flowrate you need
2. Get a good quality model.

Worcestor Bosch? Baxi?

If you don't fulfil Nos 1 & 2 above then don't complain.

I'm not complaining - because I don't have one of the wretched things. But
everyone I know who has one has exactly the same complaints. They can't all
have cheap 'crap' with poor flow rates!

Kev

"Uno Hoo!" wrote in message
...

"Doctor Drivel" wrote in message
eenews.net...

"Uno Hoo!" wrote in message
...

"Katya Robin" wrote in message
...
we've just moved into new house last week, and there's a long list of
jobs
to be done...
but top of the list is get the hot water/central heating working.

I've read the instruction manual but maybe I've misunderstood as
still
can't set the combi boiler (it's a Vokera excell 80SP)

The 80SP is a now an old model, but repairable.

to provide decent flow of hot water for baths or shower.
The temp varies from cold - tepid to hot (just briefly), and flow
rate
is
poor.

any suggestions much appreciated - thanks

Combi boilers heat the cold water as it passes through the device. For
that
reason the water-flow is restricted because if it passed through at
normal
'speed' it would not be heated up enough. Personally I wouldn't touch a
combi boiler with a barge-pole. Several relatives and friends of mine
have
them, and they do nothing but complain about the unreliability,
frequent
need to call out plumbers, and the excessively long time it takes to
fill
a
bath.

More old wives tales.

Not at all. They are not imagining the problems that they have!

Did you read what I wrote. More combi's are sold in the UK, and the EU,
than any other type of domestic boiler. They don't all fail every other
week.

They bought cheap crap combi's that break down.

Worcestor Bosch? Baxi?

W-B did make the odd dog, and Baxi? Forget it.

Don't complain if you buy a Lada
and it breaks down a lot. Combis are
available with high flowrates that fill baths pronto.

Well I've yet to find anyone who owns one!

Because you not seen one doe not mean they are not there. Look at the Alpha
CD50

Every single person I know who
has a combi says the same thing:
"Takes bloody ages to fill a bath."

You have been told, can't you focus and understand? High flowrate models
are available, and have been for a long time. Read it all again if you
can't understand it.

In short:

1. Get the combi with the flowrate you need
2. Get a good quality model.

Worcestor Bosch? Baxi?

W-B did make the odd dog, and Baxi? Forget it.

If you don't fulfil Nos 1 & 2 above then don't complain.

I'm not complaining

Then don't whinge then.

But everyone I know who has one has exactly the same complaints. They
can't all
have cheap 'crap' with poor flow rates!

Kev

"Doctor Drivel" wrote in message
eenews.net...

"Uno Hoo!" wrote in message
...
#

W-B did make the odd dog, and Baxi? Forget it.

Don't complain if you buy a Lada
and it breaks down a lot.

Actually, during my poorer years I owned two Ladas in succession over eight
years and neither of them broke down ever!

Combis are
available with high flowrates that fill baths pronto.

Well I've yet to find anyone who owns one!

Because you not seen one doe not mean they are not there. Look at the
Alpha
CD50

Yes - it sounds impressive - but at over £1000.00 plus fitting charges it's
more than most householders would be prepared to pay!

So I'll modify my criticism of combi's to: The majority of moderately
priced combis will take ages to fill a bath!

Kev

In article ws.net,
Doctor Drivel wrote:
Every single person I know who
has a combi says the same thing:
"Takes bloody ages to fill a bath."

You have been told, can't you focus and understand? High flowrate models
are available, and have been for a long time. Read it all again if you
can't understand it.

What you've got to realise, Kev, is that Drivel has his own standards for
everything, so his idea of high flow is not the same as everyone else's.

My storage system fills a bath with water as hot as anyone would want at a
rate of near 50 litres a minute between the two taps. Regardless of the
time of year.

I'd like to know of any combi that gives approx 25 litres a minute at 60C
all year round, but I'd not like to pay for it and the upgrading of the
gas and water mains to feed it. Because my mains doesn't deliver 50 litres
a minute.

--
*It ain't the size, it's... er... no, it IS ..the size.

Dave Plowman London SW
To e-mail, change noise into sound.

"Uno Hoo!" wrote in message
...

Combi boilers heat the cold water as it passes through the device. For
that
reason the water-flow is restricted because if it passed through at
normal
'speed' it would not be heated up enough. Personally I wouldn't touch a
combi boiler with a barge-pole. Several relatives and friends of mine
have
them, and they do nothing but complain about the unreliability,
frequent
need to call out plumbers, and the excessively long time it takes to
fill
a
bath.

More old wives tales.

Not at all. They are not imagining the problems that they have!

Did you read what I wrote. More combi's are sold in the UK, and the EU,
than any other type of domestic boiler. They don't all fail every other
week.

They bought cheap crap combi's that break down.

Worcestor Bosch? Baxi?

W-B did make the odd dog, and Baxi? Forget it.

Don't complain if you buy a Lada
and it breaks down a lot. Combis are
available with high flowrates that fill baths pronto.

Well I've yet to find anyone who owns one!

Because you not seen one doe not mean they are not there. Look at the Alpha
CD50

Every single person I know who
has a combi says the same thing:
"Takes bloody ages to fill a bath."

You have been told, can't you focus and understand? High flowrate models
are available, and have been for a long time. Read it all again if you
can't understand it.

In short:

1. Get the combi with the flowrate you need
2. Get a good quality model.

Worcestor Bosch? Baxi?

W-B did make the odd dog, and Baxi? Forget it.

If you don't fulfil Nos 1 & 2 above then don't complain.

I'm not complaining

Then don't whinge then.

But everyone I know who has one has
exactly the same complaints.

You are dumb. Read what I wrote. They got the wrong models with the wrong
flowrates.

They can't all have cheap 'crap' with poor flow rates!

They obviously have. For every dope who bought a cheap and nasty combi with
a poor flowrate, there are 1000s of satisfied owners of good quality combi's
with decent flowrates.

Now read what I wrote and understand.

"Doctor Drivel" wrote:

For every dope who bought a cheap and nasty combi with
a poor flowrate, there are 1000s of satisfied owners of good quality combi's
with decent flowrates.

So one in a thousand combi's sold is cheap and nasty?

Lies, damn lies and Dribble's made up statistics.


--

"Doctor Drivel" wrote in message
eenews.net...

"Uno Hoo!" wrote in message
...

Combi boilers heat the cold water as it passes through the device. For
that
reason the water-flow is restricted because if it passed through at
normal
'speed' it would not be heated up enough. Personally I wouldn't touch
a
combi boiler with a barge-pole. Several relatives and friends of mine
have
them, and they do nothing but complain about the unreliability,
frequent
need to call out plumbers, and the excessively long time it takes to
fill
a
bath.

More old wives tales.

Not at all. They are not imagining the problems that they have!

Did you read what I wrote. More combi's are sold in the UK, and the EU,
than any other type of domestic boiler. They don't all fail every other
week.

I've never stated that they do. But the experience of every owner of combi
boilers that I know is that they break down far more often than conventional
boilers. My central heating boiler is now thirty years old, It has been
serviced about twice and has had one replacement thermo-couple. That's it.
My son's Worcestor Bosch combi has caused him endless problems and my
Mother-in-law's Baxi combi has required plumber attendance three times in
four years. Both say they would never even consider a combi-boiler again.

They bought cheap crap combi's that break down.

Worcestor Bosch? Baxi?

W-B did make the odd dog, and Baxi? Forget it.

What you forget is that probably 99% of householders don't have the
knowledge to make an informed choice - many buy new/second hand houses in
which the combis are already installed. Those who decide to switch from
conventional to combis rely on the advice of so called 'expert' plumbers.

What you seem to be arguing is that you agree with me that the majority of
combis are useless - and you only get a good one if you are prepared to pay
the earth. Bit like telling the driver of a troublesome Focus/Punto/Astra
etc that they have only themselves to blame for not buying a Merc!

In short:

1. Get the combi with the flowrate you need
2. Get a good quality model.

It would appear that the only combi with a flow-rate even approaching that
of a conventional system is the Alpha CD50 - and that is comparatively
extremely expensive. I take it you agree with me then that the majority of
combis are pathetically useless?


If you don't fulfil Nos 1 & 2 above then don't complain.

I'm not complaining

Then don't whinge then.

I'm not whingeing - I'm merely pointing out an absolute fact - that everyone
I know who has a combi boiler tells me that they are crap.

You are dumb. Read what I wrote. They got the wrong models with the
wrong
flowrates.

Yes - they should have bought a Mercedes!!

They can't all have cheap 'crap' with poor flow rates!

They obviously have. For every dope who bought a cheap and nasty combi
with
a poor flowrate, there are 1000s of satisfied owners of good quality
combi's
with decent flowrates.

I would suggest that your statistics are arse about face. For every 1
satisfied combi owner there are thousands who think they are rubbish!

Now read what I wrote and understand.

I have and what you are suggesting is that out of all the combi boilers on
the market - only one or two are any use!

Kev

In message , Uno Hoo!
writes
In short:

1. Get the combi with the flowrate you need
2. Get a good quality model.

Worcestor Bosch? Baxi?

If you don't fulfil Nos 1 & 2 above then don't complain.

I'm not complaining - because I don't have one of the wretched things.
But everyone I know who has one has exactly the same complaints. They
can't all have cheap 'crap' with poor flow rates!

All the ones you have heard complaints about could have low flow rates.

Most Combis that I have seen have flow rates of 9 or 11 l/m with a 35C
temp change. They tend to be 24K or 28K BTU which, in theory, is enough
to heat a medium 3 bed semi. However, the flow rate is crap.

Spend more money, and a much greater flow rate can be obtained, but
plumbers tend to suggest the cheapest to compete with competitive
quotes, and the customer tends to know no different.

--
Richard Faulkner

Richard Faulkner wrote:
Most Combis that I have seen have flow rates of 9 or 11 l/m with a 35C
temp change. They tend to be 24K or 28K BTU which, in theory, is enough
to heat a medium 3 bed semi. However, the flow rate is crap.

Spend more money, and a much greater flow rate can be obtained,

But only if the incoming mains flow rate is sufficient.

MBQ

"Richard Faulkner" wrote in message
...
In message , Uno Hoo!
writes
In short:

1. Get the combi with the flowrate you need
2. Get a good quality model.

Worcestor Bosch? Baxi?

If you don't fulfil Nos 1 & 2 above then don't complain.

I'm not complaining - because I don't have one of the wretched things.
But everyone I know who has one has exactly the same complaints. They
can't all have cheap 'crap' with poor flow rates!

All the ones you have heard complaints about could have low flow rates.

Most Combis that I have seen have flow rates of 9 or 11 l/m with a 35C
temp change. They tend to be 24K or 28K BTU which, in theory, is enough
to heat a medium 3 bed semi. However, the flow rate is crap.

Spend more money, and a much greater flow rate can be obtained, but
plumbers tend to suggest the cheapest to compete with competitive
quotes, and the customer tends to know no different.

Very true. The sad thing is that most people, like this poster, think that
all combi's are all the same. Even on his second post, after being put
right, he was still insistent that all combis can only fill a bath in 15
minutes and break down every week, the indoctrination was so complete.

Katya Robin wrote:

we've just moved into new house last week, and there's a long list of
jobs to be done...
but top of the list is get the hot water/central heating working.

I've read the instruction manual but maybe I've misunderstood as still
can't set the combi boiler (it's a Vokera excell 80SP)
to provide decent flow of hot water for baths or shower.
The temp varies from cold - tepid to hot (just briefly), and flow rate
is poor.

As you may have noticed you have just asked the "holy war" question - so
you may find rather more (not too useful) responses than you need to
this question!

With regard to your boiler, there are a few possibilities. One may be
that it has a fault and needs fixing, however it is also possible that
you just need to understand its quirks to get anything useful out of it!

The model listed is quite ancient, and in common with many combis of the
era they are more quirky than current models.

The first thing to note is that with any instantaneous water heater the
thing that will determine the performance more than anything else is the
power available from the boiler - since it needs to heat water on the
fly. More power = more hot water.

Your boiler is probably just under 24kW input - this is about the
smallest you can get today. To make matters worse, it is also only just
over 70% efficient. So of those 24kW, 7 of them will go straight out of
the flue and not do anything to heat your bath. That leaves you 17kW to
play with.

Doing some quick sums suggests that this time of year you can have a
maximum of just over 9L of water per min at bath temperature. That is
not much. In the winter when the ground water is 10 degrees cooler, that
will fall to under 7L per min. So don't expect a bath in less than 15
mins if you like it full.

So the first thing to realise is that if you turn the hot tap on hard,
the water will come through the boiler too fast, and it won't have
chance to heat it enough. So you need to turn down the tap to have less
flow, but of hotter water.

The other trick that some old combis played was that they needed the tap
to initially be turned on quite hard to start them running. So the
procedure is turn the tap on hard, but then turn it down until the
required temperature is reached. Some people prefer to tweak the cold
input isolation valve on the boiler down so that the maximum flow
through it will not exceed its capacity - that way you can turn on the
tap harder and not need to be so delicate with adjustments. (it won't
give you any more hot water thought!)

With showers you have another potential problem. The boiler will have a
water temperature thermostat, that will set the maximum temperature of
water it can produce. If you demand too little hot water than the
temperature will rise to the point where it gets too hot and the
thermostat will cause the boiler to turn of its burner. Your shower now
goes cold, it turns the burner on again, it gets too hot, and so on!

To fix this try turning the shower on harder if you can. If that does
not work, see if leaving the hot tap in the basin running a little while
having your shower is enough to keep the demand for hot water up to the
point that will keep the boiler firing.

Modern combis are better in these respects since they tend to be more
powerful (and efficient) and are also able to better control their
burners to actually match the demand for water. If you replace it with
another, then you really need to look at the top end of the power inputs
(i.e. 35kW and better) to get decent bath filling performance.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

John Rumm wrote:
Katya Robin wrote:

...it's a Vokera excell 80SP
to provide decent flow of hot water for baths or shower.
The temp varies from cold - tepid to hot (just briefly), and flow rate
is poor.


As you may have noticed you have just asked the "holy war" question - so
you may find rather more (not too useful) responses than you need to
this question!

thanks very much for helpful reply )

With regard to your boiler, there are a few possibilities. One may be
that it has a fault and needs fixing, however it is also possible that
you just need to understand its quirks to get anything useful out of it!

The model listed is quite ancient, and in common with many combis of the
era they are more quirky than current models.

I'm a bit thrown that it has an integral mecahnical timer ...surely this
is the job of the thermostat/programmer?



The first thing to note is that with any instantaneous water heater the
thing that will determine the performance more than anything else is the
power available from the boiler - since it needs to heat water on the
fly. More power = more hot water.

Your boiler is probably just under 24kW input - this is about the
smallest you can get today. To make matters worse, it is also only just
over 70% efficient. So of those 24kW, 7 of them will go straight out of
the flue and not do anything to heat your bath. That leaves you 17kW to
play with.


oh :-(

does this mean it won't be up to stratch for running the CH?

it's a big stone built 4 bedroom house on 4 floors

Doing some quick sums suggests that this time of year you can have a
maximum of just over 9L of water per min at bath temperature. That is
not much. In the winter when the ground water is 10 degrees cooler, that
will fall to under 7L per min. So don't expect a bath in less than 15
mins if you like it full.
....

The other trick that some old combis played was that they needed the tap
to initially be turned on quite hard to start them running. So the
procedure is turn the tap on hard, but then turn it down until the
required temperature is reached. ....

thanks very much for sugegstions for bath + shower _ I'll experiment
before calling out engineer.

Modern combis are better in these respects since they tend to be more
powerful (and efficient) and are also able to better control their
burners to actually match the demand for water. If you replace it with
another, then you really need to look at the top end of the power inputs
(i.e. 35kW and better) to get decent bath filling performance.

cheers
-
Katya

Katya Robin wrote:

I'm a bit thrown that it has an integral mecahnical timer ...surely this
is the job of the thermostat/programmer?

Some have their own primitive timer - and some users / installers choose
to suppliment this with an external one of more sophistication. The
internal one may allow you to set the heating to Off / Once / Twice and
Continuous, perhaps also enable or disable HW production.

If you have an external programmable thermostat, then you would normally
leave the boiler set to run the CH continously, and leave it to the
programmable stat to actually turn the heating on an off when required.

Your boiler is probably just under 24kW input - this is about the
smallest you can get today. To make matters worse, it is also only
just over 70% efficient. So of those 24kW, 7 of them will go straight
out of the flue and not do anything to heat your bath. That leaves you
17kW to play with.



oh :-(

does this mean it won't be up to stratch for running the CH?

It may be ok on heating unless you have a very difficult to heat house.
(i.e. very poor insulation, exposed position etc). Often 15kW or more
will do the space heating in a three or four bedroom place without much
difficulty. (For example, the worst case heating load on my place is
8kW, and that is with an external temperature of -3)

The time you need loads of power is when you are trying to heat the HW
on a single trip through the boiler.

it's a big stone built 4 bedroom house on 4 floors

Stone built tends to make it harder, four floors tends to help a bit
(i.e. losses up from lower floors are gains for upper ones). If you
wanted you could do heatloss calculations to work out what heating power
you actually require. (Have a google back in this group for explanations
of how - or post again for more detaisl)

thanks very much for sugegstions for bath + shower _ I'll experiment
before calling out engineer.

Let us know how you get on....

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On Thu, 11 Aug 2005 20:14:11 +0000, Katya Robin wrote:

we've just moved into new house last week, and there's a long list of
jobs to be done...
but top of the list is get the hot water/central heating working.

I've read the instruction manual but maybe I've misunderstood as still
can't set the combi boiler (it's a Vokera excell 80SP)
to provide decent flow of hot water for baths or shower.
The temp varies from cold - tepid to hot (just briefly), and flow rate
is poor.

any suggestions much appreciated - thanks
-
Provided the mains supply is good enough to give about 16+ ltrs/min at the
Kitchen Sink and 10+ ltrs/min through the hot taps then the most likely
problem is scaling up of the secondary heat exchanger in the boiler.


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html