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Different opinions from plumbers - who is right?

Discussion in 'Plumbing and Central Heating' started by dave_y, 12 Jun 2008.

  1. dave_y

    dave_y

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    Hi there. We've recently noticed some problems with our heating system and, having spoken to a couple of plumbers, we're none the wiser as to what the answer is.

    We have a back boiler system with hot water cylinder and the main problem is that we have no hot water when the central heating is off. If we move the thermostat to 20+ then this obviously kicks in the radiators and we do get hot water too.
    Possibly unrelated to this our cold water tank in the loft will always overflow when the heating is on.

    Our first plumber explained that the valve to (or in) the cylinder is faulty and will need replacing, this will fix the lack of hot water. They then said that the expansion pipe going into the cold tank is not high enough, therefore the dripping. Added to this the ballcck is loose.

    Another plumber tested the system and simply diagnosed that a new cylinder was needed as well as a de-sludge of our system. We have been quoted around £650 for this including the boiler service.

    We've yet to hear back from the original plumber for a quote but one sounds like a lot more work than the other. Is there any way to know who could be right?

    Thanks in advance..
     
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  3. Agile

    Agile

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    Without seeing the system its not possible for me to guess exactly whats wrong.

    A type number or photo of this valve would help. ( Clytrol ? )

    However, virtually all of the senarios where the vent pipe is discharging into the F&E tank are as a result of sludging or a blockage.

    The vent pipe should be at least 450mm at the top above the water level but the effect will depend on how the pipework has been arranged.

    Power flushing is usually about £350 upwards but £650 sounds very expensive but perhaps special aspects may apply.

    The conclusion is that I cannot be sure but perhaps the foregoing will be of some help.

    Tony
     
  4. DP

    DP

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    Pump-over in my opinion is cause of incorrect plumbing.

    Continuous pump over will adversely effect the system as corrosion will be accelerated and ultimately need removal with chemicals or another method.

    If the cylinder is in a position where water can rise to it, then HW heating by gravity can be achieved. In this case, you will not be able to select CH by itself on the programmer.

    If you can select CH and HW channel on timer stays off, look for a motorised valve jammed open.
     
  5. seco services

    seco services

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    hw is called for from the cylinder stat not motorised valve.
    so even if jammed in mid position and cyl stat calls that will still activate the boiler/pump.
     
  6. namsag

    namsag

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    Seco not on an S plan, cylinder stat only provides power to valve motor . It is the permanent live to microswitch that when its made gives power to pump and boiler.
    OP has not confirmed what system he has
     
  7. seco services

    seco services

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    i agree yes your correct.
    but my mind just had y plan for some reason.
     
  8. dave_y

    dave_y

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    Thanks for all the answers. What information is needed as to what system I have?
    I had a look last night and took some pics, hopefully these will help to understand our system.

    http://img396.imageshack.us/my.php?image=12062008052kk6.jpg
    http://img151.imageshack.us/my.php?image=12062008054jl4.jpg
    http://img145.imageshack.us/my.php?image=12062008053vr6.jpg

    Both pipes coming up into the cylinder were warm when the central heating was on.

    In the loft the water is overflowing into the smaller one of the two tanks and before it overflows the level is only just below the overflow pipe - does this mean that the ballcck is knackered too?
     
  9. DP

    DP

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    the image http://img145.imageshack.us/my.php?image=12062008053vr6.jpg shows two pipes connected to side of cylinder. Upper should be hot and lower not as hot when calling for HW only.

    Can you turn down the setting on the roomstat and see if water is heated?

    I have been to houses where there is no saperation between heating and hot water. In summer months, rads have to be isolated at the valves to get HW to heat.

    Gravity HW system would normally fire the boiler for HW and run the pump as well for CH
     
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  11. seco services

    seco services

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    We have a back boiler system with hot water cylinder and the main problem is that we have no hot water when the central heating is off
     
  12. Agile

    Agile

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    Tie up the ball valve and empty most of the water and see if the valve drips and if the pumping over ceases.

    Unfortunately I cannot see anything which gives me any clue about the HW problem. If there are no valves to have failed or jammed then it must be a blockage but I expect there is a valve somewhere. What was it that the plumber said was failed?

    Tony
     
  13. seco services

    seco services

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    tony
    how do we know that the programmer is giving out power on hw only ?
     
  14. Agile

    Agile

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    We dont know anything and I did not see any motor valves in the pictures but perhaps I missed one?

    Tony
     
  15. seco services

    seco services

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    no nor did i.

    i just see a post on another forum and he said.

    hw on its own on the programmer is kicking the boiler in but not heating the hw.

    soon as he selects heating as well the cylinder will heat.

    strange.
     
  16. Agile

    Agile

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    Based on what he has said and what we see its a gravity hot water and a pump powered for heating.

    Bit odd that the gravity no longer works unless the heating is on UNLESS the programmer is not starting the boiler on HW only ???

    BUT this plumber said that a VALVE had failed ???

    I think he needs a competent person to visit!

    Tony
     
  17. doitall

    doitall

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    I said that about 12 hours ago Tony :rolleyes:
     
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