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Worcester Boiler - Pressure Problems On-going

Discussion in 'Plumbing and Central Heating' started by sara64, 1 Feb 2006.

  1. sara64

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    Please help, I am now at my wits end, I have spent just over £500 on having my boiler 'fixed' over the past 3 weeks and it still doesn't work. The problem is the boiler keeps losing pressure, I have had the pump replaced, the pressure release valve replaced and the expansion vessel replaced and bleed all the rads to make sure there is no air in the system. The plumber has isolated one part from another to ascertain whether I have a leak but pressure remained constant indicating that this was not the case. The system works fine for a while but then needs refilling and reseting, I tried to do this this morning and I couldn't reset it - I am so fed up of having no hot water or heating and I am running out of money to keep having it repaired! I am also greatly concerned as to where the water is escaping as it isn't through the prv. Any advice greatly appreciated.
     
  2. bobw1956

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    We need more info to give any constructive help.
    ie; boiler model, how old is the boiler,
    how much pressure loss,over what period,etc;
     
  3. scatmanjohn

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    You have paid someone £500 to sort your problem
    You need to have a serious word with them.

    How much pressure are you losing over how long.
    Leak sealer may work if its not too bad.
     
  4. pierrot

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    it could be a tiny leak inside the combustion chamber from the heat ex, the heat from which is evaporating it. thereby no physical sign of a leak.
    500 pounds is a lot of money sweety, I think you may have had your arse felt as we say up north.
     
  5. kevplumb

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    go further north marra ;)
     
  6. sara64

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    thanks for all reploes - Its a Worcester Bosch 240, I think its 5 - 6 years old. The pressure loss started about 3 weeks ago. The plumber came over again this morning with another guy for a second opinion, the other guy is certain it must be a leak but when the plumber isolated the heating from something else and pressurised the system it didn't show a leak. I think we're no going to try putting something in the system to hopefully block any leak that may be there. When I re-fill the boiler the pressure is at 1.2 and it rises to 2 when its on, the boiler seems to loose pressure (back to 0) when its cold. Someone mentioned leaving the tap near the boiler on slightly so it is constantly filling - is this an option? I'm actually in the process of selling this property and need a quick fix that won't cost me a fortune as I've spent enough.
     
  7. sara64

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    oh and I forgot to say the pressure loss usually happens over night (from 1.2 to 0) or during the course of the day - if I re-fill the boiler before I go to work say 8am, its dropped to 0 by the time i get home at 5/6pm. The water isn't coming out of the prv as I've checked. Do you think it would work if I kept the heating on constantly??
     
  8. tazza_no1

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    Hi, i have a worcester 230 which started haveing the same problem about 2 week ago. constantly losing pressure over night and evenings and and trigering the the over heat switch.
    The other thing i noticed was that if i pressurized the system to 1 bar when cold, it would rise excessively over a very short time when switched back on.
    Here is what i did.
    1) i swiched off the power to the boiler.
    2) i had water dripping from the PRV which had been triggered. i presurized the system to 2.5 bar and then released it out or the PRV to clear the dirt. ( do not do this if u do not have any water being expelled from the external pipe.
    3) drained some water out of the system and left the drain valve open under the boiler.
    4) got a digital guage and foot pump from halfords and pupped the vesal to 0.8 bar. ( the presure on the boiler guage should bo show this as it is the vesal u are presurizing and not the boiler)

    5) closed the drain valve.

    6) represured the system to 2 bar and removed air from radiator bringing it back down to about 1.2 bar.

    7) turned the power on and let it run for about an hour . checked to see if the pressure is rising above 2.5bar and checked all radiator valves.

    8) the heating was fine for a whole 24 hours but noisy.

    9) partially drained system and and put some Ferox ds-40 into the system via bathroom radiator.

    10) repressurized and run. I have had it running for two days without problems and the system has become very quite (i accually had to go to the garage where the boiler is to see if it was still running it was that quiet)

    11) have to keep removing the air from the system as the fernox created are bubbles. I will leave it in for a week as recommended and flush out.


    Basically what was happening was at night the boiler is working harder because its cold and am in the house so have the heating on. Due to the lack of pressure in the expansion vessal it could not be compressed anymore when the system heated up. This would rase the pressure in the boiler to above the 3bar threshold of the PRV and release the excessive water. when the system switch off and the water cooled down it brought the pressures down to zero and thus the boiler would not fireup.

    if u do not have a leak then you expansion vesal may need pressurizing.

    hope this helps..

    my first post.
     
  9. Bryan King

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    hi

    There are a few possible causes of pressure loss.


    a) a leak on the system.

    b) Pressure relief valve faulty

    c) Air in your system (water pressure deficiecy valve will produce inacurate readings and possibly zero reading)

    d) Expansion vessel to small for your system. This would normally be indicated by pressure relief valve running water at high temperatures)

    e) Damaged expansion vessel(neopren diaphragm split)


    f) lost nitrogen or air from vessel
     
  10. scatmanjohn

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    sara64 wrote

    :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL: :LOL:

    Whoever said that is having you on
     
  11. COG

    COG

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    You said "the plumber isolated the heating from something else " if he isolated the boiler from the system to check for pressure loss he would have to have used the isolateing valves (bulkhead) under the boiler when the system was cold and left it for at least 8 hours to see if the loss was on the boiler or system side . The bad thing about this test is that 9.9 times out of ten one or both the valves will leak when turned back on.
     
  12. anurbandog

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    Its just leaking. Ask for your money back. These things are not the answer to global warming. Just a money machine for cowboy service engineers. Brit Gas top of the heap. If the service people had no mobile phones they could not mend anything!!!!
     

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