Advertisement
If you have a new account but are having problems posting or verifying your account, please email us on hello@boards.ie for help. Thanks :)
Hello all! Please ensure that you are posting a new thread or question in the appropriate forum. The Feedback forum is overwhelmed with questions that are having to be moved elsewhere. If you need help to verify your account contact hello@boards.ie

Cold water tanks

  • 13-09-2007 5:58pm
    #1
    GreeBo
    Registered Users, Registered Users 2 Posts: 27,182 ✭✭✭✭


    Hey,
    I have two cold water tanks in my attic, interconnected at the base.
    Only one of them has a ballcock off the mains, the other is fed/balanced from the first one.

    The one with the ballcock is grand, no problems with the water. From what I can see it feeds all the (non mains) cold taps in the house.
    The other tank is purely to drive the hotwater from the cylinder.
    This tank is manky, it has what I can only describe as a crust on it and is not very pretty. Considering that I (eventually) wash myself in this water Im a little concerned.

    I'm guessing the problem is that the water is too still, it drains from the bottom and fills from the bottom so there is no agitation on the surface.
    Is this a normal setup?

    Im considering installing another ballcock off the mains to fill the second tank, means quicker filling and also will move the water about a bit.

    Comments?


Comments

  • #2
    Avns1s
    Registered Users, Registered Users 2 Posts: 3,422 ✭✭✭Avns1s


    I can't see any major problem in doing this. You could leave the interconnector in place also so you will still have the store of water available to both systems in the event of an outage.

    Even with it in place, a lot of the water going to your hot taps, would come into the tank via the ballvalve and hence you would get replacement of the water.

    I do think this would help with the reduction of the stagnation of the water in this tank.


  • #3
    ircoha
    Closed Accounts Posts: 2,290 ✭✭✭ircoha


    GreeBo wrote:
    Hey,
    I have two cold water tanks in my attic, interconnected at the base.
    Only one of them has a ballcock off the mains, the other is fed/balanced from the first one.

    The one with the ballcock is grand, no problems with the water. From what I can see it feeds all the (non mains) cold taps in the house.[ How many? ]
    The other tank is purely to drive the hotwater from the cylinder.
    This tank is manky, it has what I can only describe as a crust on it and is not very pretty. Considering that I (eventually) wash myself in this water Im a little concerned.

    I'm guessing the problem is that the water is too still, it drains from the bottom and fills from the bottom so there is no agitation on the surface.
    Is this a normal setup?

    Im considering installing another ballcock off the mains to fill the second tank, means quicker filling Not really as the pressure will be halved so the increased flow will be incremental and create less aeration in eachand also will move the water about a bit.

    Comments?

    If I were u i would move the colds to the back tank as per _brian_ : not a big job? u can get a bimetal core drill the exact size and just blank off the old ones.
    HTH


  • #4
    GreeBo
    Registered Users, Registered Users 2 Posts: 27,182 ✭✭✭✭GreeBo


    Hey, there are 3 basin taps, dishwasher, washing machine, ensuite shower, bath/shower and 2 toilets coming from the "main" tank.


    Are you suggesting filling into one tank and draining from the other?
    I dont get how this will resolve my stagnation though? The water in the back tank will still not get agitated...

    Also, will the flow of water actually be halved for an additional ballcock?
    The pressure will be reduced alright but will the flow be actually halved?
    Im trying to remember my physics but broadband terminology is confusing me.
    i.e contention (a loss of flow) doesnt kick in until you pass a certain threshold... but Im open to correction!


  • #5
    10-10-20
    Registered Users, Registered Users 2 Posts: 7,184 ✭✭✭10-10-20


    Grebo, mine is the same setup and I have a limited amound of 'scum' on the top of the second tank.
    From reading the install guide for the plastic attic tanks, the ideal setup is to have the water-in (mains feed) directly opposite to the feed to the second tank, meaning that the water entering the second tank doesn't collect the sunken crud which gets raised by the incoming water.
    My feed is setup incorrectly.

    In terms of the second BC, flow won't half as the output of most BC's is less than the max flow available. It will only reduce the flow, unless there are background mains water pressure issues.


  • #6
    GreeBo
    Registered Users, Registered Users 2 Posts: 27,182 ✭✭✭✭GreeBo


    10-10-20 wrote:
    Grebo, mine is the same setup and I have a limited amound of 'scum' on the top of the second tank.
    From reading the install guide for the plastic attic tanks, the ideal setup is to have the water-in (mains feed) directly opposite to the feed to the second tank, meaning that the water entering the second tank doesn't collect the sunken crud which gets raised by the incoming water.
    My feed is setup incorrectly.
    If I understand you correctly doesnt that mean that the first tank has to fill before anything gets to the second tank?
    Or is it directly opposite but still at the base of the tank?
    Are you going to do anything to yours or is this expected behaviour?
    Also, it is recommended to cover the tanks?
    I had some scrap plywood over it but its warped and has a fair amount of green stuff growing on it...:eek:
    10-10-20 wrote:
    In terms of the second BC, flow won't half as the output of most BC's is less than the max flow available. It will only reduce the flow, unless there are background mains water pressure issues.
    Yeah thats what I thought.


  • Advertisement
  • #7
    10-10-20
    Registered Users, Registered Users 2 Posts: 7,184 ✭✭✭10-10-20


    GreeBo wrote:
    If I understand you correctly doesnt that mean that the first tank has to fill before anything gets to the second tank?
    Or is it directly opposite but still at the base of the tank?
    Are you going to do anything to yours or is this expected behaviour?
    Also, it is recommended to cover the tanks?
    I had some scrap plywood over it but its warped and has a fair amount of green stuff growing on it...:eek:
    No, sorry - I should clarify. The feed should be at the bottom of both. While it doesn't fix the scum problem, it's best practice.
    You are also supposed to cover the tank with the fitted lids - mine weren't but I picked up lids in Chadwicks. The reason for covering is to reduce the dust ingress, prevent moisture entering the attic space and to prevent contamination of the tank from dead mammals...
    Yeah thats what I thought.
    I'll see if I can find the document online...


  • #8
    limbovski
    Registered Users Posts: 146 ✭✭limbovski


    Hey Greebo, I have a very similar setup to you. Noticed a really bad smell coming from the hot press and after investigation in the little side attic where the two water tanks are located I see that the one I can get at easily isn't too dirty and has a ballcock. The further away one - I can't get near it without serious effort is full of what looks like mould and fungus and bubbles on top. the two tanks are connected and are both uncovered.

    Should they be covered - officially as part of buying a new house or is this optional for a builder?

    Also, what is the secondary tank normally for? I appreciated your post is quite old, but any help would be great as the missus is going nuts and I'd love to get it sorted asap.


  • #9
    TMC99
    Registered Users Posts: 190 ✭✭TMC99


    Is it possible that one is a header tank for the heating ? In my case I have 2 tanks - one small (25l ?) and one large. Both fed from mains, cold water tank is clean / clear, but the header tank is fairly scummy - not too bad but wouldn't fancy drinking it !!


  • #10
    limbovski
    Registered Users Posts: 146 ✭✭limbovski


    I just tied the ballcock up and drained the tanks until the water was above the release pipe. Both empty at the same pace. So it's all part of the one system. To empty them i just ran the bath.

    The second tank is disgusting. I'm looking at it from about 5 foot away with a torch at an awkward angle but i'd say maybe something like a mouse is dead in it. I can't imagine stagnant water would go like that, or even water where only the lowest water is being drained and the top is static.

    Both tanks are about 5 foot long. probably 60ish litres... I think.

    I'm going to refill it and maybe get in later on and look into the tank. If you don't hear from me again it's because whatever's living in there has had me for dinner. :eek::p


  • #11
    georgejetson
    Closed Accounts Posts: 12 ✭georgejetson


    IMO. You will need to circulate the water and prevent it from becoming stagnant.

    Your hot water has a demand to low for the water to circulate in the second tank.

    The easiest option would be to have the two tanks isolated with its own overflow and mains supply.
    I suggest you dont probably need both tanks. So maybe you could just use one to fill all supplies.This will involve relocating the expansion pipe and filler supply for the hwc and overflow.


  • Advertisement
Advertisement