I want to install a direct un-vented hot water cylinder in a flat. The install
instructions call for 22mm diameter water supply line, the main riser supply
to the building is 22m and then reduces to 15mm before the stop valve. Do i
need to isolate the main riser into the building in order to replace the 15mm
stop valve with 22mm or can I step up the pipe diameter back to 22m after
the 15mm stop valve without affecting the performance of the cylinder.

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On Friday, 13 April 2018 21:44:06 UTC+1, Jonno wrote:
I want to install a direct un-vented hot water cylinder in a flat. The install
instructions call for 22mm diameter water supply line, the main riser supply
to the building is 22m and then reduces to 15mm before the stop valve. Do i
need to isolate the main riser into the building in order to replace the 15mm
stop valve with 22mm or can I step up the pipe diameter back to 22m after
the 15mm stop valve without affecting the performance of the cylinder.

15mm is likely to give unsatisfactory flow.

If the unvented cylinder is over 15 litres you must have an Unvented Hot Water certificate to do this work.

Owain

wrote:

On Friday, 13 April 2018 21:44:06 UTC+1, Jonno wrote: I want to install
a direct un-vented hot water cylinder in a flat. The install
instructions call for 22mm diameter water supply line, the main riser
supply to the building is 22m and then reduces to 15mm before the stop
valve. Do i need to isolate the main riser into the building in order to
replace the 15mm stop valve with 22mm or can I step up the pipe
diameter back to 22m after the 15mm stop valve without affecting the
performance of the cylinder.

15mm is likely to give unsatisfactory flow.

If the unvented cylinder is over 15 litres you must have an Unvented Hot
Water certificate to do this work.

Owain

I rather like the idea of an unvented certificate. Is that really it's
name?

--

Roger Hayter

I'd have thought that this was a little academic, unless the person is
incredibly stupid and sets thermostats to try to make the tank into a steam
engine. also does not say how far this 15mm runs for and what the cylinder
is supposed to be feeding either.

Yes I've not come across unvented certificates, only the people issuing
things tend to vent a lot...:-)

Brian

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"Roger Hayter" wrote in message
...
wrote:

On Friday, 13 April 2018 21:44:06 UTC+1, Jonno wrote: I want to
install
a direct un-vented hot water cylinder in a flat. The install
instructions call for 22mm diameter water supply line, the main riser
supply to the building is 22m and then reduces to 15mm before the stop
valve. Do i need to isolate the main riser into the building in order
to
replace the 15mm stop valve with 22mm or can I step up the pipe
diameter back to 22m after the 15mm stop valve without affecting the
performance of the cylinder.

15mm is likely to give unsatisfactory flow.

If the unvented cylinder is over 15 litres you must have an Unvented Hot
Water certificate to do this work.

Owain

I rather like the idea of an unvented certificate. Is that really it's
name?

--

Roger Hayter

On Saturday, 14 April 2018 01:12:09 UTC+1, Roger Hayter wrote:
I rather like the idea of an unvented certificate. Is that really it's
name?

https://www.gledhill.net/trade/g3-un...aining-course/

It was called G3 Unvented Hot Water but it's now been overtaken by changes in Building Regs and the certificate now covers all hot water systems.

England/Wales covers Approved Document G3, Part L1 and Part P of the Building Regulations, while the one for Scotland references Part J of the Building Standards

http://bpec.org.uk/qualification/dom...orage-systems/

Also, if not a member of a Competent Persons scheme, notification to Building Control is required.

Owain

wrote:

On Saturday, 14 April 2018 01:12:09 UTC+1, Roger Hayter wrote:
I rather like the idea of an unvented certificate. Is that really it's
name?

https://www.gledhill.net/trade/g3-un...aining-course/

It was called G3 Unvented Hot Water but it's now been overtaken by changes
in Building Regs and the certificate now covers all hot water systems.

England/Wales covers Approved Document G3, Part L1 and Part P of the
Building Regulations, while the one for Scotland references Part J of the
Building Standards

http://bpec.org.uk/qualification/dom...orage-systems/

Also, if not a member of a Competent Persons scheme, notification to
Building Control is required.

Owain

Do you actually need a sustificate to work on such a system, or just to
sign it off for BC?



--

Roger Hayter

On Saturday, 14 April 2018 18:27:01 UTC+1, Roger Hayter wrote:
Do you actually need a sustificate to work on such a system, or just to
sign it off for BC?

AIUI both, a sustificate to comply with Water Regulations, and to sign it off for BC (or membership of a scheme to self-certify it to BC)

Owain

On 14/04/2018 01:12, Roger Hayter wrote:
wrote:

On Friday, 13 April 2018 21:44:06 UTC+1, Jonno wrote: I want to install
a direct un-vented hot water cylinder in a flat. The install
instructions call for 22mm diameter water supply line, the main riser
supply to the building is 22m and then reduces to 15mm before the stop
valve. Do i need to isolate the main riser into the building in order to
replace the 15mm stop valve with 22mm or can I step up the pipe
diameter back to 22m after the 15mm stop valve without affecting the
performance of the cylinder.

15mm is likely to give unsatisfactory flow.

If the unvented cylinder is over 15 litres you must have an Unvented Hot
Water certificate to do this work.

Owain

I rather like the idea of an unvented certificate. Is that really it's
name?


Yes, it comes in a sealed container. g
--
Cheers,
Roger
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checked.

On Sat, 14 Apr 2018 23:25:32 +0100, Roger Mills wrote:

On 14/04/2018 01:12, Roger Hayter wrote:
wrote:

On Friday, 13 April 2018 21:44:06 UTC+1, Jonno wrote: I want to
install a direct un-vented hot water cylinder in a flat. The install
instructions call for 22mm diameter water supply line, the main
riser supply to the building is 22m and then reduces to 15mm before
the stop valve. Do i need to isolate the main riser into the
building in order to replace the 15mm stop valve with 22mm or can I
step up the pipe diameter back to 22m after the 15mm stop valve
without affecting the performance of the cylinder.

15mm is likely to give unsatisfactory flow.

If the unvented cylinder is over 15 litres you must have an Unvented
Hot Water certificate to do this work.

Owain

I rather like the idea of an unvented certificate. Is that really it's
name?


Yes, it comes in a sealed container. g

g === groan /

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On Sat, 14 Apr 2018 13:50:45 -0700 (PDT),
wrote:

Do you actually need a sustificate to work on such a system, or
just to
sign it off for BC?

AIUI both, a sustificate to comply with Water Regulations, and to sign
it off for BC (or membership of a scheme to self-certify it to BC)

Do you need one to do such work in your own property? ie not for
reward.

--
Cheers
Dave.

On Sunday, 15 April 2018 11:42:39 UTC+1, Dave Liquorice wrote:
Do you need one to do such work in your own property?

Again AIUI, yes.

Owain

On Sun, 15 Apr 2018 05:26:55 -0700 (PDT),
wrote:

Do you need one to do such work in your own property?

Again AIUI, yes.

So not like gas then? Which just requires a "competent person" unless
working for reward.

--
Cheers
Dave.