1. Visiting from the US? Why not try DIYnot.US instead? Click here to continue to DIYnot.US.
    Dismiss Notice

need advice on fitting combi boiler

Discussion in 'Plumbing and Central Heating' started by diydad888, 12 Aug 2011.

  1. monoxide62

    monoxide62

    Joined:
    1 Jul 2011
    Messages:
    873
    Thanks Received:
    103
    Country:
    United Kingdom
    Your always sittin on that fence Transam. ;)
     
  2. Sponsored Links
  3. bengasman

    bengasman

    Joined:
    28 Jan 2005
    Messages:
    34,181
    Thanks Received:
    3,124
    Location:
    London
    Country:
    United Kingdom
    Off course not; a legionella victim needs either a doctor or a corroner to check him out, not a plumber.
    Legionaires disease numbers are verifiable to anyone who cares to look at ONS archives.

    According to my information from ACS training, fully pumped became the standard about half a century ago.
    Apart from that, to heat gravity fed cylinder to remain above 65C, the boilerstat would have to be on or very near max. Any RGI worth his keep has the experienced most boilerstats NOT to be at max.
     
  4. bengasman

    bengasman

    Joined:
    28 Jan 2005
    Messages:
    34,181
    Thanks Received:
    3,124
    Location:
    London
    Country:
    United Kingdom
    Probably do, but is irrelevant. Legionella only becomes a threat above certain levels apparently.
     
  5. monoxide62

    monoxide62

    Joined:
    1 Jul 2011
    Messages:
    873
    Thanks Received:
    103
    Country:
    United Kingdom
    Take it from me gravity fed hot water cylinders were heated to above 70k , minimum boiler stat temp was 65K & most housholds set the stat to around #3 which was 'around' 75K , boiler stat max temp was in the region of 82k although most calibrated to around 90K ;) ...........think about this , most hot water cylinders with hot water temperature control (cyl stat) are set to around 65K , the old gravity system would have hot water temperatures in excess of 70K , so which is better regards killing the bacteria that legionella thrives on , 65K or 75K?
     
  6. bengasman

    bengasman

    Joined:
    28 Jan 2005
    Messages:
    34,181
    Thanks Received:
    3,124
    Location:
    London
    Country:
    United Kingdom
    Never looked into the details about those temperatures, but at a guess I'd say that both 65K and 75K will kill legionalla stone dead in seconds.

    Something tells me that you are trying to be a bit too clever with the figures you quoted.
     
  7. monoxide62

    monoxide62

    Joined:
    1 Jul 2011
    Messages:
    873
    Thanks Received:
    103
    Country:
    United Kingdom
    I used to calibrate boiler stats when sub contracting for Islington council (1980) ;)

    Ideal temp for legionella bacterium is about 37K , below 20K & above 55K the bacterium is dormant , as you can see hot water heated by gravitys will never fall below 60k due to minimum temp @ boiler stat (back end corosion being the issue) , this is not the case when hot water is controlled via cyl stat , i've seen these set as low as 50K , borderline temps being the case for legionella. ;)
     
  8. bengasman

    bengasman

    Joined:
    28 Jan 2005
    Messages:
    34,181
    Thanks Received:
    3,124
    Location:
    London
    Country:
    United Kingdom
    Subcontracting for CALIBRATING boiler stats on council stock???? First time I ever heard of council spending money on that. In fact, I've never heard of open vent boiler stats being calibrated period.

    But even if, since when is social housing heating work known for it's great standards? Did a brief stint assesing in social housing, and I don't think a day went buy where I didn't cut somebody off due to immediately dangerous situation.

    You are miles off. Like I said: you are trying to be a bit too clever.
     
  9. gasafengineer

    gasafengineer

    Joined:
    23 May 2011
    Messages:
    314
    Thanks Received:
    34
    Location:
    Wigtownshire
    Country:
    United Kingdom
  10. Sponsored Links
  11. bengasman

    bengasman

    Joined:
    28 Jan 2005
    Messages:
    34,181
    Thanks Received:
    3,124
    Location:
    London
    Country:
    United Kingdom
    I am pretty sure that below 55K legionella is stone dead, and certainly below 20K.

    Not that it matters; when your cylinder goes below 20K, legionella is the least of your worries.
     
  12. monoxide62

    monoxide62

    Joined:
    1 Jul 2011
    Messages:
    873
    Thanks Received:
    103
    Country:
    United Kingdom
    Whenever we installed the boilers we had to calibrate the stats , simples , nothing clever in my postings , those who think it's clever are the ones who don't know. ;)
     
  13. transam

    transam

    Joined:
    20 Nov 2009
    Messages:
    31,090
    Thanks Received:
    3,698
    Location:
    Surrey
    Country:
    United Kingdom

    Best place to be , providing it's not to high :)
     
  14. Gasman77

    Gasman77

    Joined:
    18 Jan 2009
    Messages:
    1,340
    Thanks Received:
    149
    Location:
    Berkshire
    Country:
    United Kingdom
    So the statement was correct then, a combi is better for a shower, not as good for filling a bath.

    Do you want some salt and vinegar to go with that chip?
     
  15. namsag

    namsag

    Joined:
    12 May 2004
    Messages:
    9,909
    Thanks Received:
    324
    Country:
    United Kingdom
    My bath is 240 litres and my combi fills it quite easily...After its heated the water in the cylinder attached :LOL:

    I like the way people say a combi can fill 4 or more baths in a row without running out yep they can but in the winter it would leave the house quite cold with no heating during that time
     
  16. Agile

    Agile

    Joined:
    26 Jun 2004
    Messages:
    64,017
    Thanks Received:
    4,591
    Location:
    London
    Country:
    United Kingdom
    I think that at either of those cryogenic temperatures the legionella would be well frozen !
     
  17. ChrisOxford

    ChrisOxford

    Joined:
    25 Nov 2007
    Messages:
    491
    Thanks Received:
    60
    Location:
    Oxford
    Country:
    United Kingdom
    You were thinking what I was thinking :LOL:
     
Loading...

Share This Page