Pressurizing a conventional boiler

Discussion in 'Plumbers' Talk' started by Colin Finney, May 19, 2019.

  1. Colin Finney

    Colin Finney New Member

    I have a conventional gas boiler probably installed when house was built back in the late 70's. It has a hot water tank in the airing cupboard and two tanks in the loft.

    I would like to get rid of the two tanks in the loft as part of a loft conversion and thought I had to get a whole new boiler system but my architect says I can just get my current boiler switched to a pressurized system.

    Is that as simple as he make out and his indicated cost is about £1000 to £1200 which is a lot less than a new boiler.
     
  2. ESPlumb

    ESPlumb Member

    It’s not quite as simple as that. In theory you could make the boiler work on a pressurized system by sealing the vent and adding an expansion vessel and blow off valve etc. The problem would be the hot water side. If you removed your header tank from the loft you would need to replace your cylinder with an unvented cylinder. This could be quite costly. How many bathrooms does your house have?
     
  3. Mike83

    Mike83 Screwfix Select

    The boiler may also require an overheat stat.
     
  4. Colin Finney

    Colin Finney New Member

    Two bathrooms and a downstairs wc.
     
  5. Mike83

    Mike83 Screwfix Select

    If your going the the hassle of getting the loft converted this may be the time to get a new heating system anyway.
     
    The Teach likes this.
  6. Colin Finney

    Colin Finney New Member

    Its the cost as I think It may be too much for me to afford so am looking for cost savings I can realistically make.

    Paying £1200 for a pressurised update as opposed to £3500 for a new system will save me £2300 so I might be able to afford the three Velux windows I am thinking of removing.

    I am also told my boiler is considerable more reliable than a new one but not as efficient but the extra efficiency will take 20+ years to offer any real pay back.
     
  7. rogerk101

    rogerk101 Screwfix Select

    I had a top of the range Worcester-Bosch gas combi boiler fitted in my rental home 4 years ago and it came to a whole lot less than £3500. At the same time I also had some radiators changed and 2 underfloor heating zones installed along with programmable thermostats, wiring centres, and zone valves. The entire bill was just over £3000 ... and that's in expensive Oxford ! How is your bill so expensive? BTW if the installer is WB-certified you get an 8 year warranty .
     
  8. joinerjohn1

    joinerjohn1 Screwfix Select

    Whatever you do, do it before gas boilers are extinct as a heating source. Time is running out.
     
  9. Colin Finney

    Colin Finney New Member

    I have been warned to expect cost any where up to £1500 for combi boiler installation including removal and disposal of old water tanks in loft and storage tank in cupboard. The boiler could be up to £2K for one big enough, 42KW, to run my house or I could compromise and only use one bathroom at a time for either shower or bath.
     
  10. The Teach

    The Teach Screwfix Select

    Many vintage gas boilers are not suitable for sealed systems,some are.

    Which gas boiler do you have ?
     
  11. Colin Finney

    Colin Finney New Member

    I don't know but will have a look tonight to see if there is a label inside the hatch that covers the controls.
     
  12. rogerk101

    rogerk101 Screwfix Select

    My 29kW WB boiler is easily powerful enough for a 5 bedroom 2 bathroom house with both showers being used at the same time.
     
  13. Colin Finney

    Colin Finney New Member

    my boiler is a

    Stelrad Group - WLx
     
  14. Colin Finney

    Colin Finney New Member

    I had three plumbers round over the weekend and two have now quoted. Neither quoted for what I asked which was an unveted conversion although both said it was OK to do. Both quoted combi conversion for over £3k with the highest £3.3k.
     

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