On 27 Oct 2005 03:31:12 -0700, "Jon" wrote:

I'm new to all this so please bare with me...

I'm having a problem with a combi-boiler and need help trying to
identify the problem -

The boiler appears to be working fine - i.e. it's able to heat the
radiators and water. However when heating water for the shower it seems
incredibility sensitive to changes in water pressure, if someone were
to turn the tap on in the kitchen the hot water flow in the shower
completely stops. Also, if the heating is on it seems to frequently
cause the hot water in the shower to fluctuate.

I'm wondering is it possible to control the boiler so that it gives
priority to heating water? Also, is it possible to prevent the affect
of turning on a tap in another room?

TIA
Alas one of the major drawbacks of many combis is finally revealed.
Many combis just arent up to the job of supplying two taps at once
with decent flow rate. As others have stated, check if the mixer vavle
is thermostatic,if not then fit a thermostatic mixer,thats about all
you can do apart from fitting a water storage cylinger to ensure a
decent bulk hot water supply.



Remove antispam and add 670 after bra to email

http://www.no2id.org/

"tarquinlinbin" wrote in message
...
On 27 Oct 2005 03:31:12 -0700, "Jon" wrote:

I'm new to all this so please bare with me...

I'm having a problem with a combi-boiler and need help trying to
identify the problem -

The boiler appears to be working fine - i.e. it's able to heat the
radiators and water. However when heating water for the shower it seems
incredibility sensitive to changes in water pressure, if someone were
to turn the tap on in the kitchen the hot water flow in the shower
completely stops. Also, if the heating is on it seems to frequently
cause the hot water in the shower to fluctuate.

I'm wondering is it possible to control the boiler so that it gives
priority to heating water? Also, is it possible to prevent the affect
of turning on a tap in another room?

TIA
Alas one of the major drawbacks of many combis is finally revealed.
Many combis just arent up to the job of supplying two taps at once
with decent flow rate. As others have stated, check if the mixer vavle
is thermostatic,if not then fit a thermostatic mixer,thats about all
you can do apart from fitting a water storage cylinger to ensure a
decent bulk hot water supply.

Bzzzt Wrong. A higher flowrate combi would solve it too.

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

Alas one of the major drawbacks of many combis is finally revealed.
Many combis just arent up to the job of supplying two taps at once
with decent flow rate. As others have stated, check if the mixer vavle
is thermostatic,if not then fit a thermostatic mixer,thats about all
you can do apart from fitting a water storage cylinger to ensure a
decent bulk hot water supply.

Bzzzt Wrong. A higher flowrate combi would solve it too.

It's my understanding that Combi's can only ever supply hot water at the
maximum flow rate of the mains supply. Which I think mine certainly can. So
putting a higher flowrate boiler on wouldn't necessarily help

It's my understanding that Combi's can only ever supply hot water at the
maximum flow rate of the mains supply. Which I think mine certainly can.
So
putting a higher flowrate boiler on wouldn't necessarily help

If your mains is that bad, then a mains pressure hot water system is
probably a bad idea in the first place.

Christian.

In message , Mark Hewitt
writes

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

Alas one of the major drawbacks of many combis is finally revealed.
Many combis just arent up to the job of supplying two taps at once
with decent flow rate. As others have stated, check if the mixer vavle
is thermostatic,if not then fit a thermostatic mixer,thats about all
you can do apart from fitting a water storage cylinger to ensure a
decent bulk hot water supply.

Bzzzt Wrong. A higher flowrate combi would solve it too.

It's my understanding that Combi's can only ever supply hot water at the
maximum flow rate of the mains supply.

And/or the maximum rate at which they can heat it. The mains flow in my
old house with a combi the mains flow rate was a fair bit more than the
boiler could heat. So the rate of heating was the limiting factor (as it
is in most combi installations I suspect.


Which I think mine certainly can.

If you shower really does stop (as opposed to just get bit slower) when
another tap is turned on then it suggests to me that the mains flow
isn't up to the job maybe. In the above mentioned installation, (with a
100,000 btu combi) if someone tuned on the tap in the kitchen or the
bathroom the shower flow would reduce, but it was still usable. 15mm
water supply, bath or kitchen teed off of the same pipe to the shower.


--
Chris French

"chris French" wrote in message
...
In message , Mark Hewitt
writes

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

Alas one of the major drawbacks of many combis is finally revealed.
Many combis just arent up to the job of supplying two taps at once
with decent flow rate. As others have stated, check if the mixer vavle
is thermostatic,if not then fit a thermostatic mixer,thats about all
you can do apart from fitting a water storage cylinger to ensure a
decent bulk hot water supply.

Bzzzt Wrong. A higher flowrate combi would solve it too.

It's my understanding that Combi's can only ever supply hot water at the
maximum flow rate of the mains supply.

And/or the maximum rate at which they can heat it. The mains flow in my
old house with a combi the mains flow rate was a fair bit more than the
boiler could heat. So the rate of heating was the limiting factor (as it
is in most combi installations I suspect.

Unless you have 76kW MAN boiler

Which I think mine certainly can.

If you shower really does stop (as opposed to just get bit slower) when
another tap is turned on then it suggests to me that the mains flow
isn't up to the job maybe. In the above mentioned installation, (with a
100,000 btu combi) if someone tuned on the tap in the kitchen or the
bathroom the shower flow would reduce, but it was still usable. 15mm
water supply, bath or kitchen teed off of the same pipe to the shower.


--
Chris French

On Thu, 27 Oct 2005 12:54:27 +0100, "Doctor Drivel"
wrote:


"tarquinlinbin" wrote in message
.. .
On 27 Oct 2005 03:31:12 -0700, "Jon" wrote:

I'm new to all this so please bare with me...

I'm having a problem with a combi-boiler and need help trying to
identify the problem -

The boiler appears to be working fine - i.e. it's able to heat the
radiators and water. However when heating water for the shower it seems
incredibility sensitive to changes in water pressure, if someone were
to turn the tap on in the kitchen the hot water flow in the shower
completely stops. Also, if the heating is on it seems to frequently
cause the hot water in the shower to fluctuate.

I'm wondering is it possible to control the boiler so that it gives
priority to heating water? Also, is it possible to prevent the affect
of turning on a tap in another room?

TIA
Alas one of the major drawbacks of many combis is finally revealed.
Many combis just arent up to the job of supplying two taps at once
with decent flow rate. As others have stated, check if the mixer vavle
is thermostatic,if not then fit a thermostatic mixer,thats about all
you can do apart from fitting a water storage cylinger to ensure a
decent bulk hot water supply.

Bzzzt Wrong. A higher flowrate combi would solve it too.

Yes i know your a Combi evangelist doctor and i do know about higher
flow rate combis. You tend to pick things like that up after 25 years
in the industry.



Remove antispam and add 670 after bra to email

http://www.no2id.org/

"tarquinlinbin" wrote in message
...
On Thu, 27 Oct 2005 12:54:27 +0100, "Doctor Drivel"
wrote:


"tarquinlinbin" wrote in message
.. .
On 27 Oct 2005 03:31:12 -0700, "Jon" wrote:

I'm new to all this so please bare with me...

I'm having a problem with a combi-boiler and need help trying to
identify the problem -

The boiler appears to be working fine - i.e. it's able to heat the
radiators and water. However when heating water for the shower it
seems
incredibility sensitive to changes in water pressure, if someone were
to turn the tap on in the kitchen the hot water flow in the shower
completely stops. Also, if the heating is on it seems to frequently
cause the hot water in the shower to fluctuate.

I'm wondering is it possible to control the boiler so that it gives
priority to heating water? Also, is it possible to prevent the affect
of turning on a tap in another room?

TIA
Alas one of the major drawbacks of many combis is finally revealed.
Many combis just arent up to the job of supplying two taps at once
with decent flow rate. As others have stated, check if the mixer vavle
is thermostatic,if not then fit a thermostatic mixer,thats about all
you can do apart from fitting a water storage cylinger to ensure a
decent bulk hot water supply.

Bzzzt Wrong. A higher flowrate combi would solve it too.

Yes i know your a Combi evangelist doctor and i do know about higher
flow rate combis. You tend to pick things like that up after 25 years
in the industry.

It seems you never picked it up over 25 years.

tarquinlinbin wrote:

Alas one of the major drawbacks of many combis is finally revealed.
Many combis just arent up to the job of supplying two taps at once
with decent flow rate.

Even with boiler powerful enough to handler more than one tap at a time
there is still the problem that the change in flow rate will in many
cases also cause a change in output temperature of the combi.



--
Cheers,

John.

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