Heating Wiring....

Discussion in 'UK DIY' started by Lee Nowell, Aug 10, 2009.

  1. Lee Nowell

    Lee Nowell Guest

    Hi,

    I have a relatively complex setup and was wondering if anyone had any
    views on the best way to wire it all up... Also, any advice on whether
    a wiring centre is a good idea as they seem to be very expensive given
    what they appear to be....

    Setup is....
    -----------------
    3 x radiator heating zones timed centrally and operated by 2 port
    motorised valves
    1 x towel rail heating zone timed centrally and operated by 2 port
    motorised valves
    1 x hot water tank heating timed centrally and operated by 2 port
    motorised valves
    1 x secondary hot water loop timed centrally.
    2 x underfloor heating zones with 2 wire actuators, pump, manifold,
    controlled by a prog room stat
    zone 1 has 1 actuator
    zone 2 has 5 actuators

    All ideas appreciated.

    thanks

    Lee.
     
    Lee Nowell, Aug 10, 2009
    #1
    1. Advertising

  2. On Mon, 10 Aug 2009 04:01:11 -0700 (PDT), Lee Nowell wrote:

    > Also, any advice on whether a wiring centre is a good idea as they seem
    > to be very expensive given what they appear to be....


    A normal wiring center won't cope with that number of zones.

    For the system here (just four zones 2 x HW, 2 x CH, with shared
    circulators for the two HW zones and two CH zones). I bought a small
    (three row) DIN rail enclosure and lots of terminals. All the wires
    from the valves, thermostats, timers, etc come back to that box so
    and config changes are just jumper changes in the box not house
    rewire jobs.

    The logic for the pump, boiler and pump over run control is done with
    half a dozen DIN rail mount minature relays. If I was doing it again
    I'd find a large enough PLC, even easier to adjust the logic. I'd
    retain the normal programmers as they have nice simple buttons and
    displays that ordinary people can understand.

    --
    Cheers
    Dave.
     
    Dave Liquorice, Aug 10, 2009
    #2
    1. Advertising

  3. Lee Nowell

    Lee Nowell Guest

    On Aug 10, 12:27 pm, "Dave Liquorice" <>
    wrote:
    > On Mon, 10 Aug 2009 04:01:11 -0700 (PDT), Lee Nowell wrote:
    > > Also, any advice on whether a wiring centre is a good idea as they seem
    > > to be very expensive given what they appear to be....

    >
    > A normal wiring center won't cope with that number of zones.
    >
    > For the system here (just four zones 2 x HW, 2 x CH, with shared
    > circulators for the two HW zones and two CH zones). I bought a small
    > (three row) DIN rail enclosure and lots of terminals. All the wires
    > from the valves, thermostats, timers, etc come back to that box so
    > and config changes are just jumper changes in the box not house
    > rewire jobs.
    >
    > The logic for the pump, boiler and pump over run control is done with
    > half a dozen DIN rail mount minature relays. If I was doing it again
    > I'd find a large enough PLC, even easier to adjust the logic. I'd
    > retain the normal programmers as they have nice simple buttons and
    > displays that ordinary people can understand.
    >
    > --
    > Cheers
    > Dave.


    Hi Dave,

    Thanks for your reply. I don't suppose you have a wiring diagram do
    you or a link to a suitable PLC?

    The guy I bought the timers etc. from recommended this...

    http://randall.danfoss.com/Product/088H012801_MNU17433646.html

    But I couldn't see how it would support what I have.

    thanks

    Lee.
     
    Lee Nowell, Aug 10, 2009
    #3
  4. Lee Nowell

    fred Guest

    In article
    <>, Lee
    Nowell <> writes
    >Hi,
    >
    >I have a relatively complex setup and was wondering if anyone had any
    >views on the best way to wire it all up... Also, any advice on whether
    >a wiring centre is a good idea as they seem to be very expensive given
    >what they appear to be....
    >
    >Setup is....
    >-----------------
    >3 x radiator heating zones timed centrally and operated by 2 port
    >motorised valves
    >1 x towel rail heating zone timed centrally and operated by 2 port
    >motorised valves
    >1 x hot water tank heating timed centrally and operated by 2 port
    >motorised valves
    >1 x secondary hot water loop timed centrally.
    >2 x underfloor heating zones with 2 wire actuators, pump, manifold,
    >controlled by a prog room stat
    > zone 1 has 1 actuator
    > zone 2 has 5 actuators
    >
    >All ideas appreciated.
    >

    When I set up my system I did it with 9 zones (1 per room) but was
    frustrated with the lack of multizone controls available at a reasonable
    (or unreasonable) price.

    In the end I have grouped rooms into 3 zones and used Honeywell
    programmable stats to control the zones with TRVs in rooms not currently
    directly stat controlled. The system is not without its problems however
    as the demand from the stats is not synchronized[1], meaning that one
    zone can call for heat and be satisfied just in time for another zone to
    call for heat. The staggering of the zones can cause repeated light load
    firings of the boiler which are inefficient and wasteful[2].

    Your life will be made a lot easier if you have some kind of thermal
    store on the heating side of the system, that way if one of your small
    zones kicks in it doesn't need to fire the boiler to get heat. The last
    thing you want is your boiler (which I assume is large) to be short
    cycling repeatedly to satisfy the demand of a towel radiator. If you do
    this, you don't need to synchronise your controls meaning you could
    break the system down into smaller and more manageable blocks. You could
    use a PLC to control those sub-blocks but I don't know of a controller
    that will do the job as a whole.

    If you don't have the hot water linked to your store then you can still
    have the heating side flow at a temperature that suits best efficiency
    for a condensing boiler.

    I think your system is too complex for a single wiring centre to handle,
    I would wire all your controls back to a single point and grow your own
    wiring centre using a large shallow electrical installation panel filled
    with DIN rails and rail mounted terminals, leaving plenty of space for
    other DIN rail goodies to be added at a later date. Document the system
    very well.

    [1] Up to 4 Honeywell wireless programmable stats can be synchronised in
    one of their moderate systems but there was I reason I didn't like it. I
    think it was an insistence that you use RF controlled radiator valves to
    control the heat.
    [2] Made worse by Honeywell's (compulsory) proportional control system
    which forces the boiler to be cycle at least 3 times an hour when the
    temperature is in the proportional zone.
    --
    fred
    BBC3, ITV2/3/4, channels going to the DOGs
     
    fred, Aug 11, 2009
    #4
  5. Lee Nowell

    Lee Nowell Guest

    Thanks very much for the reply.

    The trouble I have is that I am not confident enough to grow one from
    scratch. Whilst I think I understand the basics and logic, the wiring
    bit (e.g. use of PLC/ relays) is a bit beyond my comfort zone...

    Also, from what I can see, I have an additional problem to yours in
    that I need to run the UFH with seperate pump and actuators in
    addition to all the zones.

    Maybe I could split the problem into 2
    - UFH
    - Non-UFH

    and wire the demand from each in parallel to the boiler? Not sure
    whether that resolves the relay problem though - I'm not sure why I
    need them at all to be honest...

    thanks
    Lee.
     
    Lee Nowell, Aug 12, 2009
    #5
  6. Lee Nowell

    fred Guest

    In article
    <>, Lee
    Nowell <> writes
    >Thanks very much for the reply.
    >
    >The trouble I have is that I am not confident enough to grow one from
    >scratch. Whilst I think I understand the basics and logic, the wiring
    >bit (e.g. use of PLC/ relays) is a bit beyond my comfort zone...
    >
    >Also, from what I can see, I have an additional problem to yours in
    >that I need to run the UFH with seperate pump and actuators in
    >addition to all the zones.
    >
    >Maybe I could split the problem into 2
    >- UFH
    >- Non-UFH
    >
    >and wire the demand from each in parallel to the boiler? Not sure
    >whether that resolves the relay problem though - I'm not sure why I
    >need them at all to be honest...
    >

    You'd might be surprised at how simple the wiring can be.

    Yes, you can separate that UF and conventional heating, that would be a
    sensible place for a break but unless you use a truly synchronised
    controller for the 3 conventional zones you are likely to run into short
    cycling problems which may not be obvious but will stress the boiler
    unnecessarily.

    As I said, you could make this a lot easier with a bit of thermal
    storage in the heating loop but it sounds like you have it already built
    and aren't keen for that kind of change.

    Relays can be a handy way to combine demands that need to be otherwise
    isolated eg. in your case, where you have a pump for UFH and one for
    conventional, using relays would let you combine those 2 demands to call
    for heat at the boiler without switching on the pump on the other
    circuit at the same time. Shout if you want a circuit.

    Have you had a look at the uk.d-i-y heating wiki?
    http://wiki.diyfaq.org.uk/index.php?title=Category:Heating
    --
    fred
    BBC3, ITV2/3/4, channels going to the DOGs
     
    fred, Aug 12, 2009
    #6
  7. Lee Nowell

    Lee Nowell Guest

    On 12 Aug, 17:13, fred <> wrote:
    > In article
    > <>, Lee
    > Nowell <> writes
    >
    >
    >
    > >Thanks very much for the reply.

    >
    > >The trouble I have is that I am not confident enough to grow one from
    > >scratch.  Whilst I think I understand the basics and logic, the wiring
    > >bit (e.g. use of PLC/ relays) is a bit beyond my comfort zone...

    >
    > >Also, from what I can see, I have an additional problem to yours in
    > >that I need to run the UFH with seperate pump and actuators in
    > >addition to all the zones.

    >
    > >Maybe I could split the problem into 2
    > >- UFH
    > >- Non-UFH

    >
    > >and wire the demand from each in parallel to the boiler?  Not sure
    > >whether that resolves the relay problem though - I'm not sure why I
    > >need them at all to be honest...

    >
    > You'd might be surprised at how simple the wiring can be.
    >
    > Yes, you can separate that UF and conventional heating, that would be a
    > sensible place for a break but unless you use a truly synchronised
    > controller for the 3 conventional zones you are likely to run into short
    > cycling problems which may not be obvious but will stress the boiler
    > unnecessarily.
    >
    > As I said, you could make this a lot easier with a bit of thermal
    > storage in the heating loop but it sounds like you have it already built
    > and aren't keen for that kind of change.
    >
    > Relays can be a handy way to combine demands that need to be otherwise
    > isolated eg. in your case, where you have a pump for UFH and one for
    > conventional, using relays would let you combine those 2 demands to call
    > for heat at the boiler without switching on the pump on the other
    > circuit at the same time. Shout if you want a circuit.
    >
    > Have you had a look at the uk.d-i-y heating wiki?http://wiki.diyfaq.org.uk/index.php?title=Category:Heating
    > --
    > fred
    > BBC3, ITV2/3/4, channels going to the DOGs- Hide quoted text -
    >
    > - Show quoted text -


    Thanks for the reply. A circuit diagram would be very useful -
    thanks.

    I had a further thought and was wondering if this would work????

    Zone 1 – Under floor heating with 1 actuator – controlled by prog room
    stat
    -----------------------------------------------------------------------------------------------------------
    Connect room stat demand to actuator, UFH motorised valve and UFH pump
    in parallel

    Zone 2 – Under floor heating with 5 actuators – controlled by prog
    room stat
    -------------------------------------------------------------------------------------------------------------
    As for Zone 1 but wiring all 5 actuators in parallel with connection
    to UFH pump in parallel with Zone 1


    Timed secondary return pump
    ---------------------------------------------
    Wired to the on/ off terminals on the timer

    Remaining 5 zones – controlled by timers
    ------------------------------------------------------------
    Connect the on/ off terminals for the zone to motorised valve


    Connect the micro switches from all motorised valves together in
    parallel and to the demand on the boilers

    Finally, we have 2 boilers. Can they be wired together in parallel or
    do we need any relay etc.?

    Thanks again for all your help.

    Lee.
     
    Lee Nowell, Aug 13, 2009
    #7
  8. Lee Nowell

    fred Guest

    In article
    <>, Lee
    Nowell <> writes
    >
    >Connect the micro switches from all motorised valves together in
    >parallel and to the demand on the boilers
    >
    >Finally, we have 2 boilers. Can they be wired together in parallel or
    >do we need any relay etc.?
    >
    >Thanks again for all your help.
    >
    >Lee.


    You can wire demands in parallel in a simple system but where you have
    separate pipe circuits with eg separate pumps then you have to find a
    way of combining the demands (to feed the boiler 'call for heat') while
    keeping the pumps separate (or you will turn on the pump for a circuit
    that is meant to be off). This can be done with relays.

    I've uploaded a couple of sketches which give the basics of how this is
    done: http://i26.tinypic.com/2yzejko.jpg (first sketch).

    Secondly, it wouldn't be that clever to run 2 boilers to service a
    demand from a single small zone. To overcome this problem you can use
    relays to create a demand to the second boiler only when a number of
    conditions become active ie when condition (or demand) 1 AND condition
    (or demand) 2 are met. I've shown a basic example of this in the second
    sketch. Another option would be to only fire the second boiler when
    there is a certain level of demand AND the temperature outside is lower
    than a certain level, ie. when full power is really needed.

    A clever 2 boiler design would also have provision for swapping the
    control of the boilers round so that they aged at the same rate and an
    option to remove a faulty boiler from the circuit.

    Some manufacturers have helpful notes on the design of 2 boiler sytems,
    here's a link to info from Keston which is for their pre-fabricated rigs
    but the information should read across to other designs too:
    http://www.keston.co.uk/multi-rig.html
    http://www.keston.co.uk/downloads/manuals/rigcntrl.pdf

    Or google for "dual boiler" +heating +system +design ( -coffee -espresso
    )
    --
    fred
    BBC3, ITV2/3/4, channels going to the DOGs
     
    fred, Aug 16, 2009
    #8
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. chrisc
    Replies:
    3
    Views:
    713
    Lurch
    Dec 30, 2004
  2. D.M. Procida
    Replies:
    6
    Views:
    294
    tonytrans
    Mar 10, 2006
  3. Replies:
    2
    Views:
    208
    SQLit
    Nov 15, 2005
  4. Carl
    Replies:
    15
    Views:
    438
  5. Lobster
    Replies:
    22
    Views:
    1,789
    george [dicegeorge]
    Dec 8, 2010
Loading...

Share This Page