Central heating, but no hot water

Discussion in 'UK DIY' started by Daniel, Nov 23, 2004.

  1. Daniel

    Daniel Guest

    Hi, I wonder if someone can shed some light on this. I live in a 5 year old
    Bryant home. There is a boiler downstairs and the tank upstairs.

    When I turn on the hot water via the boiler (On teh electronic keypad
    downstairs) The water does not get hot, but the radiators do. It was all
    working fine last year. However, in the summer, I stopped using the boiler
    completely and used the electricity to power the water tank for hot water.
    I believe this isn't good cos it costs a fortune - I know for next time now
    though.

    Anyhow, before I pay some guy a fortune, does anyone have any suggestions as
    where to start looking? I'm a completely numpty on central heating, but I'm
    not too bad at diy.

    Kind regards,

    Daniel
    Daniel, Nov 23, 2004
    #1
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  2. Daniel

    Daniel Guest

    Hi Paul,

    Thanks for the reply. Ok, to be honest I don't know the diff between a
    combi or plain boiler. It's an "Ideal Minimiser SE". The keypad to control
    it is a Donfuss FP715. Upstairs in the airing cupboard there is a Donfuss
    Motorised Valve.

    I'm definately putting on the HW and not the CH. The keypad is easy to use,
    and I made sure CH was on "OFF" and I put HW to "ON". I've been reading in
    the Google newsgroup archive of uk.d-i-y and some guys say the motorised
    valve could be gone (Thats why I mentioned it above) but I am not sure how
    to test it. It has a metal lever on it labeled Auto/Manual, and I moved it
    over, but it didn't help so I moved it back to Auto. I've noticed then even
    with the hot water on, the radiators are on as I mentioned, and on one side
    of the motorised valve (labelled "Central Heating") the pipe is hot, but the
    other side (Labelled "Hot Water") the pipe is luke warm.

    Any more suggestions? I see a new motorised valve is around £31.00 so I
    want to be sure it's that, and if it is, can I fit one myself?

    "Paul King" <> wrote in message
    news:p...
    > Daniel wrote:
    >> Hi, I wonder if someone can shed some light on this. I live in a 5
    >> year old Bryant home. There is a boiler downstairs and the tank
    >> upstairs.
    >> When I turn on the hot water via the boiler (On teh electronic keypad
    >> downstairs) The water does not get hot, but the radiators do. It was
    >> all working fine last year. However, in the summer, I stopped using
    >> the boiler completely and used the electricity to power the water
    >> tank for hot water. I believe this isn't good cos it costs a fortune
    >> - I know for next time now though.
    >>
    >> Anyhow, before I pay some guy a fortune, does anyone have any
    >> suggestions as where to start looking? I'm a completely numpty on
    >> central heating, but I'm not too bad at diy.
    >>
    >> Kind regards,
    >>
    >> Daniel

    >
    > Some idea as to what make/type of boiler we are aiming at wouldn't go
    > amiss. Combi or just a plain boiler?
    > Using 'leccy to heat water is a bad idea (it's the most expensive form of
    > fuel). When you say "When I turn on the hot water via the boiler (On teh
    > electronic keypad downstairs) The water does not get hot, but the
    > radiators do" are you certain you are "turning on" the DHW or the CH
    > instead?
    > --
    >
    > Reply address is spamtrapped. Remove theobvious for valid e-mail address
    >
    Daniel, Nov 24, 2004
    #2
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  3. Daniel

    Set Square Guest

    In an earlier contribution to this discussion,
    Daniel <> wrote:

    > Hi Paul,
    >
    > Thanks for the reply. Ok, to be honest I don't know the diff between
    > a combi or plain boiler. It's an "Ideal Minimiser SE". The keypad
    > to control it is a Donfuss FP715. Upstairs in the airing cupboard
    > there is a Donfuss Motorised Valve.
    >
    > I'm definately putting on the HW and not the CH. The keypad is easy
    > to use, and I made sure CH was on "OFF" and I put HW to "ON". I've
    > been reading in the Google newsgroup archive of uk.d-i-y and some
    > guys say the motorised valve could be gone (Thats why I mentioned it
    > above) but I am not sure how to test it. It has a metal lever on it
    > labeled Auto/Manual, and I moved it over, but it didn't help so I
    > moved it back to Auto. I've noticed then even with the hot water on,
    > the radiators are on as I mentioned, and on one side of the motorised
    > valve (labelled "Central Heating") the pipe is hot, but the other
    > side (Labelled "Hot Water") the pipe is luke warm.
    >
    > Any more suggestions? I see a new motorised valve is around £31.00
    > so I want to be sure it's that, and if it is, can I fit one myself?
    >


    First, a bit of education . . .

    You have a conventional (not combi) boiler which provides central heating
    and stored (not instant) hot water using a Y-plan setup ( see
    http://content.honeywell.com/uk/homes/systems.htm)

    This uses a mid-position 3-port motorised valve to direct the water from the
    boiler either to the radiators or to the heating coil in the hot water
    cylinder, or to both at the same time.

    In its rest state, the valve gives hot water only. The internal motor inside
    the actuator drives it to the mid or CH position, as required. It has a
    spring return to bring it back to the HW position when motor current is
    removed.

    For one reason or another, your valve isn't returning to the HW position.
    The valve is actually in two parts - the wet bit with a shaft sticking out
    of the top and the actuator (the electrical) bit which rotates the shaft to
    direct the water to the right places. The chances are that the wet bit has
    partially seized up due to lack of exercise during the summer.

    You should be able to remove the actuator from the top of the valve by
    undoing a couple of screws (but leave it connected electrically). You will
    then see the shaft - which is circular in cross section apart from one flat
    bit (making it a bit like a D). You should be able to rotate the shaft
    backwards and forwards with finger and thumb - or at any rate using light
    pressure with a pair of pliers. If you can't, this is your problem. You may
    be able to free it up by turning to and fro with pliers. If you can't, you
    will need to replace the wet part of the valve - which involves partially
    draining the system.

    If the valve is free, but you *still* have no hot water, the actuator could
    be faulty - but that is less likely. With the actuator removed from the
    valve, test the spring return by moving the lever and then releasing it. You
    should see and hear the spring returning it to the rest position. If it
    doesn't, the spring is duff. These actualtors do have other modes of
    failure - but these usually result in no heating rather than no hot water.
    --
    Cheers,
    Set Square
    ______
    Please reply to newsgroup. Reply address is invalid.
    Set Square, Nov 24, 2004
    #3
  4. Daniel

    Daniel Guest

    Hi,

    Ok thanks for the info thus far. Tonight i removed the actuator from the
    valve. I can turn the valve easily left and right with my fingers. So it
    looks liek it's the actuator? To test this I went and switched the keypad
    from HW to CH and got someone to watch the actuator to see if it moved - It
    didn't move.

    Would it be worth taking the cover off the actuator and checking this
    spring? I'd like to make sure it's the actuator and not the keypad, or
    something inbetween.

    Thanks for the help so far, you guys are life (and £££) savers :)

    "Set Square" <> wrote in message
    news:...
    > In an earlier contribution to this discussion,
    > Daniel <> wrote:
    >
    >> Hi Paul,
    >>
    >> Thanks for the reply. Ok, to be honest I don't know the diff between
    >> a combi or plain boiler. It's an "Ideal Minimiser SE". The keypad
    >> to control it is a Donfuss FP715. Upstairs in the airing cupboard
    >> there is a Donfuss Motorised Valve.
    >>
    >> I'm definately putting on the HW and not the CH. The keypad is easy
    >> to use, and I made sure CH was on "OFF" and I put HW to "ON". I've
    >> been reading in the Google newsgroup archive of uk.d-i-y and some
    >> guys say the motorised valve could be gone (Thats why I mentioned it
    >> above) but I am not sure how to test it. It has a metal lever on it
    >> labeled Auto/Manual, and I moved it over, but it didn't help so I
    >> moved it back to Auto. I've noticed then even with the hot water on,
    >> the radiators are on as I mentioned, and on one side of the motorised
    >> valve (labelled "Central Heating") the pipe is hot, but the other
    >> side (Labelled "Hot Water") the pipe is luke warm.
    >>
    >> Any more suggestions? I see a new motorised valve is around £31.00
    >> so I want to be sure it's that, and if it is, can I fit one myself?
    >>

    >
    > First, a bit of education . . .
    >
    > You have a conventional (not combi) boiler which provides central heating
    > and stored (not instant) hot water using a Y-plan setup ( see
    > http://content.honeywell.com/uk/homes/systems.htm)
    >
    > This uses a mid-position 3-port motorised valve to direct the water from
    > the
    > boiler either to the radiators or to the heating coil in the hot water
    > cylinder, or to both at the same time.
    >
    > In its rest state, the valve gives hot water only. The internal motor
    > inside
    > the actuator drives it to the mid or CH position, as required. It has a
    > spring return to bring it back to the HW position when motor current is
    > removed.
    >
    > For one reason or another, your valve isn't returning to the HW position.
    > The valve is actually in two parts - the wet bit with a shaft sticking out
    > of the top and the actuator (the electrical) bit which rotates the shaft
    > to
    > direct the water to the right places. The chances are that the wet bit has
    > partially seized up due to lack of exercise during the summer.
    >
    > You should be able to remove the actuator from the top of the valve by
    > undoing a couple of screws (but leave it connected electrically). You will
    > then see the shaft - which is circular in cross section apart from one
    > flat
    > bit (making it a bit like a D). You should be able to rotate the shaft
    > backwards and forwards with finger and thumb - or at any rate using light
    > pressure with a pair of pliers. If you can't, this is your problem. You
    > may
    > be able to free it up by turning to and fro with pliers. If you can't, you
    > will need to replace the wet part of the valve - which involves partially
    > draining the system.
    >
    > If the valve is free, but you *still* have no hot water, the actuator
    > could
    > be faulty - but that is less likely. With the actuator removed from the
    > valve, test the spring return by moving the lever and then releasing it.
    > You
    > should see and hear the spring returning it to the rest position. If it
    > doesn't, the spring is duff. These actualtors do have other modes of
    > failure - but these usually result in no heating rather than no hot water.
    > --
    > Cheers,
    > Set Square
    > ______
    > Please reply to newsgroup. Reply address is invalid.
    >
    >
    Daniel, Nov 25, 2004
    #4
  5. Daniel

    Set Square Guest

    In an earlier contribution to this discussion,
    Daniel <> wrote:

    > Hi,
    >
    > Ok thanks for the info thus far. Tonight i removed the actuator from
    > the valve. I can turn the valve easily left and right with my
    > fingers. So it looks liek it's the actuator? To test this I went
    > and switched the keypad from HW to CH and got someone to watch the
    > actuator to see if it moved - It didn't move.
    >
    > Would it be worth taking the cover off the actuator and checking this
    > spring? I'd like to make sure it's the actuator and not the keypad,
    > or something inbetween.
    >
    > Thanks for the help so far, you guys are life (and £££) savers :)
    >


    My guess is that the actuator is stuck in the CH position, and the spring
    return isn't working. Sometimes, they can just get confused - and need to be
    reset.

    The first thing to do is this: With the actuator removed from the valve, but
    still connected by its wires, get someone to observe what it does when you
    remove *all* power to the heating system. [You should have an isolator
    switch somewhere for the heating - switch *that* off, not just the
    programmer].

    If when you do this, you see and hear it return to the HW position, you may
    have fixed it. Refit it to the valve, switch on and see what happens.

    If it does *nothing* when all power is removed, see whether you can move the
    actuator with the manual lever. You should feel some resistance from the
    gearbox as it moves - and when you release it, it should move back under
    spring return.

    It the lever flops about without moving anything and/or if the spring
    doesn't return it, the chances are that it's shot. They can sometimes be
    repaired - but for the sake of 30 quid or so it's usually best to replace
    them.

    Make a careful note of the wiring before disconnecting it. There are 5
    coloured wires, and the replacement must be connected exactly the same.
    --
    Cheers,
    Set Square
    ______
    Please reply to newsgroup. Reply address is invalid.
    Set Square, Nov 25, 2004
    #5
  6. Daniel

    Daniel Guest

    Hi,

    Ok, I've opened up the actuator to find the Syncron motor. The unit is
    warm, and you can feel a slite "humm" in it. Are the Syncron units all the
    same, I found one on Screwfix for 7.99

    "Tony Bryer" <> wrote in message
    news:...
    > In article <41a61444$0$755$>,
    > Christian McArdle wrote:
    >> Heads often don't cost much less than the complete valve, so you
    >> might consider buying the whole thing, so that if it turns out
    >> that the valve itself is knackered, you've already bought the bit
    >> and can reunite the new head and valve.

    >
    > IME it's easier to replace the Synchron motor (£10+VAT or so),
    > especially if the lead on the existing head disappears into a rats
    > nest of wires.
    >
    > --
    > Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk
    > Free SEDBUK boiler database browser http://www.sda.co.uk/qsedbuk.htm
    >
    >
    Daniel, Nov 25, 2004
    #6
  7. Daniel

    Daniel Guest

    Hey,

    Ok, reset the system (Found the isolator) Then played around with the
    actuator. Switched back on the system. Selected HW and the actuator moved
    one way. Then selected CH and the isolator moved another way, about 45
    degrees and then keep clicking, I take it this means it's shot and needs to
    be replaced? This is looking good so I know what to replace :)


    "Set Square" <> wrote in message
    news:...
    > In an earlier contribution to this discussion,
    > Daniel <> wrote:
    >
    >> Hi,
    >>
    >> Ok thanks for the info thus far. Tonight i removed the actuator from
    >> the valve. I can turn the valve easily left and right with my
    >> fingers. So it looks liek it's the actuator? To test this I went
    >> and switched the keypad from HW to CH and got someone to watch the
    >> actuator to see if it moved - It didn't move.
    >>
    >> Would it be worth taking the cover off the actuator and checking this
    >> spring? I'd like to make sure it's the actuator and not the keypad,
    >> or something inbetween.
    >>
    >> Thanks for the help so far, you guys are life (and £££) savers :)
    >>

    >
    > My guess is that the actuator is stuck in the CH position, and the spring
    > return isn't working. Sometimes, they can just get confused - and need to
    > be
    > reset.
    >
    > The first thing to do is this: With the actuator removed from the valve,
    > but
    > still connected by its wires, get someone to observe what it does when you
    > remove *all* power to the heating system. [You should have an isolator
    > switch somewhere for the heating - switch *that* off, not just the
    > programmer].
    >
    > If when you do this, you see and hear it return to the HW position, you
    > may
    > have fixed it. Refit it to the valve, switch on and see what happens.
    >
    > If it does *nothing* when all power is removed, see whether you can move
    > the
    > actuator with the manual lever. You should feel some resistance from the
    > gearbox as it moves - and when you release it, it should move back under
    > spring return.
    >
    > It the lever flops about without moving anything and/or if the spring
    > doesn't return it, the chances are that it's shot. They can sometimes be
    > repaired - but for the sake of 30 quid or so it's usually best to replace
    > them.
    >
    > Make a careful note of the wiring before disconnecting it. There are 5
    > coloured wires, and the replacement must be connected exactly the same.
    > --
    > Cheers,
    > Set Square
    > ______
    > Please reply to newsgroup. Reply address is invalid.
    >
    >
    Daniel, Nov 25, 2004
    #7
  8. Daniel

    IMM Guest

    Take it off and see if it spins.

    "Daniel" <> wrote in message
    news:...
    > Hi,
    >
    > Ok, I've opened up the actuator to find the Syncron motor. The unit is
    > warm, and you can feel a slite "humm" in it. Are the Syncron units all

    the
    > same, I found one on Screwfix for 7.99
    >
    > "Tony Bryer" <> wrote in message
    > news:...
    > > In article <41a61444$0$755$>,
    > > Christian McArdle wrote:
    > >> Heads often don't cost much less than the complete valve, so you
    > >> might consider buying the whole thing, so that if it turns out
    > >> that the valve itself is knackered, you've already bought the bit
    > >> and can reunite the new head and valve.

    > >
    > > IME it's easier to replace the Synchron motor (£10+VAT or so),
    > > especially if the lead on the existing head disappears into a rats
    > > nest of wires.
    > >
    > > --
    > > Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk
    > > Free SEDBUK boiler database browser http://www.sda.co.uk/qsedbuk.htm
    > >
    > >

    >
    >
    IMM, Nov 25, 2004
    #8
  9. Daniel

    Set Square Guest

    In an earlier contribution to this discussion,
    Daniel <> wrote:

    > Hey,
    >
    > Ok, reset the system (Found the isolator) Then played around with the
    > actuator. Switched back on the system. Selected HW and the actuator
    > moved one way. Then selected CH and the isolator moved another way,
    > about 45 degrees and then keep clicking, I take it this means it's
    > shot and needs to be replaced? This is looking good so I know what
    > to replace :)
    >
    >

    It may not be shot - it may just have needed resetting.

    There should be 90 degrees between HW and CH, with "both" being at the
    mid-way position at 45 degrees. It may click - that's not necessarily a
    fault. In either the CH or 'both' position, the motor is powered but
    stalled - that's the nature of the beast!
    --
    Cheers,
    Set Square
    ______
    Please reply to newsgroup. Reply address is invalid.
    Set Square, Nov 25, 2004
    #9
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