How big a cold water tank can I put in my loft?

[SimonD]

Following on from my thread here about my upcoming power shower installation, I'm thinking about putting a larger cold water tank in the loft. I've a 'challet' style 70's house with dormer roofs, and in the loft the joists I'd say are load bearing (it's one big span internally with no 'ties', just joists.

How big (and therefore heavy) a storage tank can I put up there without worrying about the weight? If 1l of water = 1kg then 200litres= 200kg, but what's a good size to get?

Thanks,

Simon

[Simpo Two]

Seems on odd request - are you running the current one dry faster than the mains can refill it?

[SimonD]

Simpo Two said:

Seems on odd request - are you running the current one dry faster than the mains can refill it?

I haven't fitted it yet, but the installation guide recommends at least a 225 litre tank, and what with the fact that the cold tank will be emptying both to the hot water tank, and the shower when the showers in use, I'm worried that even with the 'fresh' water going into the tank that the tank won't last very long (effectively having 2 x 22mm going from it at full bore when the pumps running (1 via the hot tank, 1 straight to the pump))...

[Grandad Gaz]

Take out the existing ball valve seat (white plastic cone thing) and replace with a medium seat (red) or even a full way (green)

Change the 4" plastic float for a 6".

You will get twice as much water filling the tank

Worth trying before you consider changing tanks

[SimonD]

Grandad Gaz said:

Take out the existing ball valve seat (white plastic cone thing) and replace with a medium seat (red) or even a full way (green)

Change the 4" plastic float for a 6".

You will get twice as much water filling the tank

Worth trying before you consider changing tanks

That's top advice! What do the colours represent and why swap for a larger float? It a while old so I could just fit a whole new ball valve...?

[Grandad Gaz]

SimonD said:

Grandad Gaz said:

Take out the existing ball valve seat (white plastic cone thing) and replace with a medium seat (red) or even a full way (green)

Change the 4" plastic float for a 6".

You will get twice as much water filling the tank

Worth trying before you consider changing tanks

That's top advice! What do the colours represent and why swap for a larger float? It a while old so I could just fit a whole new ball valve...?

The larger float is to compensate for the extra pressure the arm will be under. A standard float might not be enough to cut off the water supply.

[SimonD]

Grandad Gaz said:

SimonD said:

Grandad Gaz said:

Take out the existing ball valve seat (white plastic cone thing) and replace with a medium seat (red) or even a full way (green)

Change the 4" plastic float for a 6".

You will get twice as much water filling the tank

Worth trying before you consider changing tanks

That's top advice! What do the colours represent and why swap for a larger float? It a while old so I could just fit a whole new ball valve...?

The larger float is to compensate for the extra pressure the arm will be under. A standard float might not be enough to cut off the water supply.

Thanks! What do the different colours represent then? Are they for 'low pressure' systems?

[JR]

SimonD said:

I've a 'challet' style 70's house with dormer roofs, and in the loft the joists I'd say are load bearing (it's one big span internally with no 'ties', just joists.

I see that the thread has moved on from this now so as an aside this type of construction is one of the worst for carrying heavy loads because it is not very stiff. Things can be done to stiffen up the structure but the way suggested above sounds like a better solution.

[SimonD]

JR said:

SimonD said:

I've a 'challet' style 70's house with dormer roofs, and in the loft the joists I'd say are load bearing (it's one big span internally with no 'ties', just joists.

I see that the thread has moved on from this now so as an aside this type of construction is one of the worst for carrying heavy loads because it is not very stiff. Things can be done to stiffen up the structure but the way suggested above sounds like a better solution.

Why do you say that? The joists in the loft look as big as those supporting the upstairs, and the current tank is right next to the dormer wall. Additionally, all the internal walls are block built, with only one exception. Should I be worried?

[Ferg]

Grandad Gaz said:

Take out the existing ball valve seat (white plastic cone thing) and replace with a medium seat (red) or even a full way (green)

Change the 4" plastic float for a 6".

You will get twice as much water filling the tank

Worth trying before you consider changing tanks

But be aware that a ballvalve so modified may well overcome a standard 3/4" overflow if it fails.