2 port Vs 3 port central heating valves

Discussion in 'UK DIY' started by EMC, Jul 29, 2003.

  1. EMC

    EMC Guest

    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, Jul 29, 2003
    #1
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  2. EMC

    IMM Guest

    "EMC" <> wrote in message
    news:9gqVa.133$...

    > 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, Jul 29, 2003
    #2
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  3. EMC

    EMC Guest

    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" <> wrote in message
    news:bg5hof$dsv$...
    >
    > "IMM" <> wrote in message
    > news:bg5dnp$j6h$...
    > >
    > > "EMC" <> wrote in message
    > > news:9gqVa.133$...
    > >
    > > > 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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    EMC, Jul 29, 2003
    #3
  4. EMC

    EMC Guest

    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$9.net...
    > 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, Jul 29, 2003
    #4
  5. EMC

    IMM Guest

    "EMC" <> wrote in message
    news:CivVa.1040$...

    > 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, Jul 29, 2003
    #5
  6. EMC

    IMM Guest

    "IMM" <> wrote in message
    news:bg60bc$ah8$...
    > "EMC" <> wrote in message
    > news:iSuVa.1026$...
    > > 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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    IMM, Jul 29, 2003
    #6
  7. EMC

    Ed Sirett Guest

    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, Jul 29, 2003
    #7
  8. EMC

    IMM Guest

    "Ed Sirett" <> wrote in message
    news:...

    > 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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    IMM, Jul 29, 2003
    #8
  9. EMC

    Andy Hall Guest

    On Tue, 29 Jul 2003 23:16:14 +0100, "IMM" <> wrote:

    >
    >"Ed Sirett" <> wrote in message
    >news:...
    >
    >> 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, Jul 30, 2003
    #9
  10. EMC

    IMM Guest

    "Andy Hall" <> wrote in message
    news:eek:...
    > On Tue, 29 Jul 2003 23:16:14 +0100, "IMM" <> wrote:
    >
    > >
    > >"Ed Sirett" <> wrote in message
    > >news:...
    > >
    > >> 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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    IMM, Jul 30, 2003
    #10
  11. EMC

    Andy Hall Guest

    On Wed, 30 Jul 2003 00:17:19 +0100, "IMM" <> wrote:


    >> >
    >> >> 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.
    >

    IIRC, the original was made by Switchmaster? (had a blue motor head),
    there were then I think a Danfoss and two Honeywells, with the latter
    two lasting about 4 years each. I wouldn't call Danfoss and
    Honeywell poor makes as such.

    The fitting position was on the return in one of the recommended
    positions so no clue there either.

    I even went to the trouble of exercising the heating at least weekly
    during the summer months so that the valve wouldn't stick. The
    failures weren't at any particular time of year.



    ..andy

    To email, substitute .nospam with .gl
    Andy Hall, Jul 30, 2003
    #11
  12. EMC

    IMM Guest

    "Andy Hall" <> wrote in message
    news:...
    > On Wed, 30 Jul 2003 00:17:19 +0100, "IMM" <> wrote:


    > >> >> 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.
    > >

    > IIRC, the original was made by Switchmaster? (had a blue motor head),
    > there were then I think a Danfoss and two Honeywells, with the latter
    > two lasting about 4 years each. I wouldn't call Danfoss and
    > Honeywell poor makes as such.


    On a far simpler valve you have a failure rate far higher than the more
    troublesome mid-position 3 port valve. Sounds like the system was faulty
    somewhere.

    > The fitting position was on the return in one of the recommended
    > positions so no clue there either.
    >
    > I even went to the trouble of exercising the heating at least weekly
    > during the summer months so that the valve wouldn't stick. The
    > failures weren't at any particular time of year.


    Correct and sufficient inhibitor can lubricate valve mechanisms. A two pump
    casting Grundfoss Tee setup can be used instead of any 3-port valve,
    mid-position or diverter.




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    IMM, Jul 30, 2003
    #12
  13. EMC

    Andy Hall Guest

    On Wed, 30 Jul 2003 00:42:45 +0100, "IMM" <> wrote:


    >
    >On a far simpler valve you have a failure rate far higher than the more
    >troublesome mid-position 3 port valve. Sounds like the system was faulty
    >somewhere.


    There was nothing much else to it so I can't see that that would
    influence anything



    >
    >> The fitting position was on the return in one of the recommended
    >> positions so no clue there either.
    >>
    >> I even went to the trouble of exercising the heating at least weekly
    >> during the summer months so that the valve wouldn't stick. The
    >> failures weren't at any particular time of year.

    >
    >Correct and sufficient inhibitor can lubricate valve mechanisms.


    I did all of that religiously

    >
    >A two pump
    >casting Grundfoss Tee setup can be used instead of any 3-port valve,
    >mid-position or diverter.
    >


    Interesting idea and I believe not much different in cost to a
    conventional set of pump and valve.




    >
    >
    >
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    ..andy

    To email, substitute .nospam with .gl
    Andy Hall, Jul 30, 2003
    #13
  14. EMC

    IMM Guest

    "Andy Hall" <> wrote in message
    news:...

    > >On a far simpler valve you have a
    > >failure rate far higher than the more
    > >troublesome mid-position 3 port valve.
    > >Sounds like the system was faulty
    > >somewhere.

    >
    > There was nothing much else to it so
    > I can't see that that would
    > influence anything


    Then you are just unlucky. Can someone be "that" unlucky using three
    different makes of valves?

    > > A two pump casting Grundfoss Tee setup
    > > can be used instead of any 3-port valve,
    > > mid-position or diverter.

    >
    > Interesting idea and I believe not much different in cost to a
    > conventional set of pump and valve.




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    #14
  15. EMC

    Ed Sirett Guest

    IMM wrote:
    >
    > "Ed Sirett" <> wrote in message
    > news:...
    >
    > > 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 don't mean to imply that there was a reliability issue. As you say the
    heads are the same as a two port unit. What I mean is that people are
    unhappy with a system that cannot simutaneously run the heating and the
    water!
    More than once I have been asked to 'fix' a system with a diverter valve
    that the owners perceived as broken, and as you know, the customer is
    always right.


    --
    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, Jul 30, 2003
    #15
  16. EMC

    IMM Guest

    "Ed Sirett" <> wrote in message
    news:...
    > IMM wrote:
    > >
    > > "Ed Sirett" <> wrote in message
    > > news:...
    > >
    > > > 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 don't mean to imply that there was a reliability issue. As you say the
    > heads are the same as a two port unit. What I mean is that people are
    > unhappy with a system that cannot simutaneously run the heating and the
    > water!
    > More than once I have been asked to 'fix' a system with a diverter valve
    > that the owners perceived as broken, and as you know, the customer is
    > always right.


    I assume they have old fashioned British Standard pig of a cylinder and not
    a quick recovery. If they had a quick recovery they would not complain as
    they would not notice the heating has been off for a few minutes or so.


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    IMM, Jul 30, 2003
    #16
  17. EMC

    Ed Sirett Guest

    IMM wrote:
    >
    > "Ed Sirett" <> wrote in message
    > news:...
    > > IMM wrote:
    > > >
    > > > "Ed Sirett" <> wrote in message
    > > > news:...
    > > >
    > > > > 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 don't mean to imply that there was a reliability issue. As you say the
    > > heads are the same as a two port unit. What I mean is that people are
    > > unhappy with a system that cannot simutaneously run the heating and the
    > > water!
    > > More than once I have been asked to 'fix' a system with a diverter valve
    > > that the owners perceived as broken, and as you know, the customer is
    > > always right.

    >
    > I assume they have old fashioned British Standard pig of a cylinder and not
    > a quick recovery. If they had a quick recovery they would not complain as
    > they would not notice the heating has been off for a few minutes or so.
    >

    Whilst a fast recovery cylinder would cetainly have mitigiated the
    problem it would (at least for one customer) not have fixed it.
    The usage the cusotmer wanted to put the system to was simple: Off for
    days at a time then come home and switch both heating and HW on, a
    completely reasonable way to operate the system for his lifestyle.
    Even a 15 minute delay would really have been unacceptable.


    > ---
    > Outgoing mail is certified Virus Free.
    > Checked by AVG anti-virus system (http://www.grisoft.com).
    > Version: 6.0.488 / Virus Database: 287 - Release Date: 05/06/2003


    --
    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, Jul 31, 2003
    #17
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    Robert Allison
    Jun 25, 2010
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