I am just about to embark on upgrading my old oil fired gravity hot water /
pumped central heating system to a gas fired fully pumped system and am
unsure what arrangement of valves to use. What are the advantages /
disadvantages of using a 3 port valve instead of two 2 port valves to
control a fully pumped hot water and (single zone ) central heating system?

"EMC" <(E-Mail Removed)> wrote in message
news:9gqVa.133$(E-Mail Removed)...

> I am just about to embark on upgrading
> my old oil fired gravity hot water /
> pumped central heating system to a
> gas fired fully pumped system and am
> unsure what arrangement of valves to use.
> What are the advantages / disadvantages
> of using a 3 port valve instead of two 2 port valves to
> control a fully pumped hot water and (single zone )
> central heating system?

Go for a 3-way throw over valve with an end switch (3 port) and a quick
recovery cylinder (part L is not quick recovery). The cylinder will take
"all" of the boilers output, reheating in a matter of minutes, and be
cheaper to run. The system will be a "priority" system. These valves are
generally to order, but come fast. A few have the end-switch, like Drayton
and others. The end switch makes it easy to wire up.

The now common 3-port mid-position valve can be temperamental. If going
this route, which I suggest you do not. Use two 2-port valves, unless space
is a problem.

A quick recovery cylinder can be downsized. So a normal 114 litre cylinder
can 80 litres. The 80 litre Telford Typhoon from Travis Perkins is approx
£100. Albion and Range do them too

http://www.albion-online.co.uk




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IMM,

Thanks for the information. By throw-over valve, do you mean a diverter
valve? I assume that by using this arrangement all hot water from the
boiler will be diverted to the cylinder when demanded. If several baths,
washing machine and shower are used in succession (probably unlikely I
know), would that mean the radiators may not be supplied for some time?

On the subject of quick recovery cylinders, what is Part L? I am also
considering an unvented cylinder and a sealed system boiler. Which unvented
cylinders would you recommend as quick recovery?

Eric

"IMM" <abuse-(E-Mail Removed)> wrote in message
news:bg5hof$dsv$(E-Mail Removed)...
>
> "IMM" <abuse-(E-Mail Removed)> wrote in message
> news:bg5dnp$j6h$(E-Mail Removed)...
> >
> > "EMC" <(E-Mail Removed)> wrote in message
> > news:9gqVa.133$(E-Mail Removed)...
> >
> > > I am just about to embark on upgrading
> > > my old oil fired gravity hot water /
> > > pumped central heating system to a
> > > gas fired fully pumped system and am
> > > unsure what arrangement of valves to use.
> > > What are the advantages / disadvantages
> > > of using a 3 port valve instead of two 2 port valves to
> > > control a fully pumped hot water and (single zone )
> > > central heating system?
> >
> > Go for a 3-way throw over valve with an end switch (3 port) and a quick
> > recovery cylinder (part L is not quick recovery). The cylinder will
take
> > "all" of the boilers output, reheating in a matter of minutes, and be
> > cheaper to run. The system will be a "priority" system. These valves
are
> > generally to order, but come fast. A few have the end-switch, like
Drayton
> > and others. The end switch makes it easy to wire up.
> >
> > The now common 3-port mid-position valve can be temperamental. If going
> > this route, which I suggest you do not. Use two 2-port valves, unless
> space
> > is a problem.
> >
> > A quick recovery cylinder can be downsized. So a normal 114 litre
> cylinder
> > can 80 litres. The 80 litre Telford Typhoon from Travis Perkins is
approx
> > £100. Albion and Range do them too
> >
> > http://www.albion-online.co.uk
>
> http://www.telford-group.com
> http://www.range-cylinders.co.uk
>
>
>
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>
>

Thanks Bill, I'm coming to the same conclusion as the lack of reliability of
the 3 port valves seems to be a widespread opinion.

Eric
"BillR" <deepthought@NO_spammers-here.cyberdude.com> wrote in message
news:dfvVa.50684$(E-Mail Removed)...
> EMC wrote:
> > I am just about to embark on upgrading my old oil fired gravity hot
> > water / pumped central heating system to a gas fired fully pumped
> > system and am unsure what arrangement of valves to use. What are the
> > advantages / disadvantages of using a 3 port valve instead of two 2
> > port valves to control a fully pumped hot water and (single zone )
> > central heating system?
>
> I'd recommend two 2 port valves. The normal 3 way ones are a pain in my
> opinion.
> They are always breaking down and its also difficult to tell what mode
> they've failed in.
> My current (3rd) one won't shut off the CH properly. I'm changing it for
two
> 2 ports as soon as I can get round to it.
>
>

"EMC" <(E-Mail Removed)> wrote in message
news:CivVa.1040$(E-Mail Removed)...

> Thanks Bill, I'm coming to the same conclusion as the lack of reliability
of
> the 3 port valves seems to be a widespread opinion.

You mean a 3-port mid-position valve. A 3-port diverter is the most
reliable option. One reliable simple head. With two valves you double the
problem. Diverters and 2 -ports tend to use the same heads.



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"IMM" <abuse-(E-Mail Removed)> wrote in message
news:bg60bc$ah8$(E-Mail Removed)...
> "EMC" <(E-Mail Removed)> wrote in message
> news:iSuVa.1026$(E-Mail Removed)...
> > IMM,
> >
> > Thanks for the information. By throw-over valve,
> > do you mean a diverter valve?
>
> Yes, that is the correct terminology.
>
> > I assume that by using this arrangement
> > all hot water from the boiler will be diverted
> > to the cylinder when demanded. If several baths,
> > washing machine and shower are used
> > in succession (probably unlikely I
> > know), would that mean the radiators may
> > not be supplied for some time?
>
> Yes, but in reality the cylinder is re-heated pronto. The cylinder will be
> well re-heated and well into CH mode by the time another bath is run. A
> largish boiler may be re-heating the cylinder faster than what the shower
> can draw-off the hot water.
>
> As you are buying a new boiler, look at getting a combi to supply the
> showers only. Then no expensive, noisy, vibrating, troublesome power
shower
> pumps. Have the CH section as a conventional system with a 3-way diverter
> valve. As the combi's water section will only be used for showers, once
or
> twice a day, they last quite a time. All the water system, except the
> showers will be at low pressure and high flow.
>
> If you are replacing the cold water tank think about a "combi cylinder".
> Have a 50-50 split of hot water and cold water storage. Have the cold
water
> section 115 litres and take all the cold supplies off the cold water
> section. This way using a combi boiler for the shower side you eliminate
> the cold water tank in the loft, or put the combi cylinder in the loft
(well
> insulated of course) and have a larger airing cupboard. Telford do the
> Trident, which has a 115litre/115litre split. have a look at their web
> site. Combi cylinders are simpler and quicker to install.
> http://www.telford-group.com/trident.htm Some cylinder makers will
provide
> combi cylinders to order, in that if you wanted a 115 litre hot section
and
> 115 litre cold section and appropriate tappings, etc, they will provide
it.
>
> So you would have:
>
> 1. A combi boiler supplying any high pressure showers.
> 2. A combi cylinder with a large cold water section. providing low
pressur
> hot and cold water.
> 3. A DHW priority system.
>
>
> > On the subject of quick recovery
> > cylinders, what is Part L?
>
> In April part L of the building regs came into being. It implemented
energy
> regs to water and heating systems. Part L cylinders means that all
cylinder
> must take no more than 30 minutes to heat up. This obviously is
depending
> on the boiler temp being on max, which it should be, and the flow through
> the coil. Quick recovery are far superior to Part L cylinder. So, in a
> plumbing shop the man may say these are all quick re-heat because they all
> conform to Part L. I have heard that being said by counter men.
>
> > I am also considering an unvented cylinder
> > and a sealed system boiler. Which unvented
> > cylinders would you recommend as quick recovery?
>
> An unvented cylinder needs to be fitted by a BBA approved fitter. They
are
> not DIYable. Consider the suggestion I made above, which is cheap and
easy
> and give lots of flow and high pressure showers. Otherwise fit a heat
bank,
> rather than an unvented cylinder which requires large bore blow-off pipes
to
> outside, tundishes, etc. Some heat banks don't even require overflows.
>
> A sealed system boiler is fine. But many combi's are cheaper and you get
the
> high pressure DHW section for showers for free and a very high output that
> modulates. Many wise installers buy cheap combi's and ignore the DHW
> section, just connecting it to the mains and capping the hot water
draw-off
> pipe off.
>
> When fitting a new boiler to an existing system always insert a strainer
on
> the return next to the boiler to catch ant crud floating around. In fact
> some Alpha combi's have a cyclone in the return pipe inside the boiler to
> catch the debris.

Heat banks:
http://www.heatweb.com
Also from Range cylinders under "thermal storage" on their web site. Albion
don't do heat banks.



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EMC wrote:
>
> I am just about to embark on upgrading my old oil fired gravity hot water /
> pumped central heating system to a gas fired fully pumped system and am
> unsure what arrangement of valves to use. What are the advantages /
> disadvantages of using a 3 port valve instead of two 2 port valves to
> control a fully pumped hot water and (single zone ) central heating system?

IMHO using 2 (or more) 2 port valves is better in every respect than a 3
port valve except that the 3 port (either mid-position or diverter
variants) is marginally lighter on material costs.

If you decide to go the 3 port way - be strongly advised that the
diveter valve variant (either but not both CH and HW) - has been found
wanting by many.

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at 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

"Ed Sirett" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...

> If you decide to go the 3 port way - be strongly advised that the
> diveter valve variant (either but not both CH and HW) - has been found
> wanting by many.

This new to me. A 3 port diverter is as simple as a two port. They use the
same heads.



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On Tue, 29 Jul 2003 23:16:14 +0100, "IMM" <abuse-(E-Mail Removed)> wrote:

>
>"Ed Sirett" <(E-Mail Removed)> wrote in message
>news:(E-Mail Removed)...
>
>> If you decide to go the 3 port way - be strongly advised that the
>> diveter valve variant (either but not both CH and HW) - has been found
>> wanting by many.
>
>This new to me. A 3 port diverter is as simple as a two port. They use the
>same heads.
>

I had diverter valves of this type in my system from when the house
was built until I ripped it out with the rest of the abortionate
plumbing that they had done in the airing cupboard.

There were four replacements over a 15 year period which I don't think
is impressive. Typically, either the mechanism would stick in the
base or a leak would develop.

Using 2 port versions and having the boiler do the priority control
seems to be a much better solution.


..andy

To email, substitute .nospam with .gl

"Andy Hall" <(E-Mail Removed)> wrote in message
news(E-Mail Removed)...
> On Tue, 29 Jul 2003 23:16:14 +0100, "IMM" <abuse-(E-Mail Removed)> wrote:
>
> >
> >"Ed Sirett" <(E-Mail Removed)> wrote in message
> >news:(E-Mail Removed)...
> >
> >> If you decide to go the 3 port way - be strongly advised that the
> >> diveter valve variant (either but not both CH and HW) - has been found
> >> wanting by many.
> >
> > This new to me. A 3 port diverter is as
> > simple as a two port. They use the
> > same heads.
>
> I had diverter valves of this type in my system from when the house
> was built until I ripped it out with the rest of the abortionate
> plumbing that they had done in the airing cupboard.
>
> There were four replacements over a 15 year period which I don't think
> is impressive. Typically, either the mechanism would stick in the
> base or a leak would develop.

Sounds like a poor make and compounded by a poorly installed system. They
can be fitted on the cooler return pipe which enhances longevity.


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