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Solar panels and legionella risk?

Discussion in 'Plumbing and Central Heating' started by ericmark, 10 Aug 2018.

  1. ericmark

    ericmark

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    Father-in-law had solar panels fitted to roof, it seems they simply fitted a second hot coil below the central heating one in the cistern and removed the immersion heater using the feed for immersion heater to power solar panels.

    The latter caused a problem as he turned off immersion in kitchen which in turn resulted in no pump for solar panels, so they all needed refilling and recommissioning, net result was they never really worked in his life time.

    House now up for sale, so is the fact that the hot water is gravity fed and not heated to over 60°C going to cause a problem selling house?
     
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  3. foxhole

    foxhole

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    NO, have you ever heard of a hot water temp check in relation to buying a property, house use means the risk is very low since the turnover of both hot and cold water is fairly high so nothing sits there long enough to cause a problem.
    A typical instantaneous water heater will run at only 50 degrees.
     
  4. Nige F

    Nige F

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    Personally I would get them taken off the roof and remove the gubbins, leaving the heating/hot water running off the boiler. I wouldn't buy a house with anything but tiles on it's roof;) An Estate Agent who knows the area might have a different view.
     
  5. Instantaneous water heaters have nothing to do with legionnella. There not stored water content. So an old couple that still has a house with say a shower room ensuit not used, and another second bathroom not used. Are ok? Not being used daily. Ps that’s a risk.
     
  6. ericmark

    ericmark

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    I have only heard of legionnella once, that was on the building of terminal 5 Heathrow, There was a huge tank that should have heated water to around 80°C, but so much water was being used it was never reaching cut off temperature, the water was to make concrete with it was mixed with cold to get it at correct temperature, but also it had been tapped into to feed the high pressure vehicle washers, and it was the guy using the washer who caught it, water was a fine mist so breathed in.

    As to instantaneous water heaters I know two types, one that is local to taps, this only heats water as required so unlikely to ever be a problem, the other mainly used in hotels is where a pump circulates the hot water again so when you turn on tap you get hot water instantly, this does involve storing water however although water circulated in pipes could well be below 60°C the water in tank is above that. I know the combi boiler in this house and the independent main 7 boiler in my house are not instant, in both cases it takes time for boiler to warm up, and for pipework to warm up. The combi boiler can be programmed to retain a small store of hot water, but it still has to warm pipes and results in shower starting cold then going hot then cold then hot again which I must admit causes an instant reaction, lucky a wet room so there is room to stand aside.

    Normally the central heating would be left on in father-in-laws house, the solar panels only pre-heat the water, however since up for sale and empty central heating has been turned off, so only solar panel heating so tank hot but not at 60°C so wondered if some thing needs adding to cold water tank?
     
  7. foxhole

    foxhole

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    Does not have to be stored water, just little used feed.
     
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  9. Come back to me with what you Just quoted and make some sense. Iv got my ticket etc for this . So crack on.
     
  10. ericmark

    ericmark

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    If there was only a bath I would not worry so much, but bath removed and only a shower which means far higher chance to catch it, you breath in the fine shower mist. And since house not in use so water just siting there in tank this also increases risk, as to if all I need to do is turn on central heating once before new owners move in, or if somthing needs adding to header tank, or if I really have nothing to worry about I don't know?

    Who would carry the can, installers of solar panals, my late father-in-law, his children, the surveyor, or new owners once sale complete is clearly of interest.
     
  11. AdrianUK

    AdrianUK

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    I have a mothballed house that belonged to my late aunt. The water in the cold & hot water tanks has stood for almost two years now. Obviously the heating has been run over the winter months but with the thermostat set at 16 deg C so I guess the hot water tank (primatic copper cylinder ) never really gets hot.

    I've been think about what to do. I guess I need to change the water in the tanks. I read that one way to deal with this is to place the shower head in a bucket of water, this prevents any airborne mist forming. I guess another way would be to drain via the kitchen hot tap using a hose & place the end of the house under the water line in a gulley? Obviously fresh water will enter the cold water tank was the level drops but this will contain chlorine. Will this 'disinfect' the tanks if I allow things to flush through for a while?

    Adrian
     
  12. JohnD

    JohnD

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    For a simple amateur job, you can (probably) empty the cold tank by running the cold bath tap. If the tank is dirty you can clean it with a new nylon sweeping brush and household cleaner. Clean the lid as well (or fit one, if not present). Using the cold tap will prevent the grime or cleaning products getting into the cylinder. When refilled with clean water you can use chlorine water purifying tablets. These work better when you have removed all the dirt, because dirt neutralises them (instructions should be on the tablets). You will need to let it stand for a while before running it through the pipes. As this is not drinking water, I would be happy if it was rinsed enough to wash in.

    BTW the cold tank (and pipes) should be well insulated. The main purpose is to prevented it getting excessively warm in sunny weather which promotes biological growth. A tank in the UK will not usually get cold enough to freeze.

    You can get powerful biocides that are used in feed and expansion tanks which sometimes get disgusting bacterial jelly and moulds.
     
  13. foxhole

    foxhole

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    Not sure what you mean, Southwark park had legionella in its changing room showers [using instaneous water heaters] shower were unused for long periods.
     
  14. flameport

    flameport

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    That.

    The new owners can turn on the water heating, flush the pipes, have the gas appliances checked and do all the other things which are required for any property.

    You are fussing over nothing. Just sell the house.
     
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