Low hot water pressure

[muggo]

I've just fitted a new thermostatic shower (made sure I bought a low pressure type) but there's still not enough pressure for me to get wet with hot water without running around.
I figure that the only way forward is to raise the cold water tank in the loft. Due to the roof height, I can't raise it too much so I wonder if you can give advice on if a larger tank will also help.
Is the surface area (so gravity can act on it) the only important point or will a deeper tank also make a difference (extra weight of water)?
I imagine I just need to extend the feed in & the overflow pipe & reuse the existing ballcock type valve assembly.
Any advice gratefully received.
Cheers
Paul
PS Where's the best place to get some plastic milk crates to raise it all?

 

[PlumbBobBob]

what about a pump? where does the cold water come from? don't use plastic crates to raise the tank won't be nearly strong enough to hold that sort of weight 200 litres=200 kilos or more if you increase the size of the tank imho.

 

[Simon F]

it is the height of the water that acts with gravity to give more pressure,
a larger tank at the same height will only give the same pressure.
raising the tank by 1m will give an increase of 0.1 bar of pressure.

 

[Whn1]

it is the height of the water that acts with gravity to give more pressure,
a larger tank at the same height will only give the same pressure.
raising the tank by 1m will give an increase of 0.1 bar of pressure.

I was thinking about this the other day, I can't argue because I don't know but surely a larger volume of water would create more weight causing more pressure no?

 

[PlumbBobBob]

no it's the height not the volume

 

[Simon F]

:iagree: Thanks Steve B

 

[stevetheplumber]

a larger tank will only add preasure if its taller therefore raising the hight of water level

 

[Paulus]

As steveb says, the only way you're going to get a decent shower is to fit a pump unless you can raise the cold water tank by a couple of metres or more.

 

[muggo]

If that's the only way, I could consider a pump. Is there such a thing as a pump that can be fitted into the HW outlet on the cylinder that automatically actuates when a tap is switched on & vice versa ie flow actuated? That would be ideal.

 

[ecowarm]

If the cold comes from the same cistern you will need to pump both supplies, so would need a twin impeller pump.

 

[PlumbBobBob]

If that's the only way, I could consider a pump. Is there such a thing as a pump that can be fitted into the HW outlet on the cylinder that automatically actuates when a tap is switched on & vice versa ie flow actuated? That would be ideal.

yes pumps of the type you would require are flow actuated.

 

[mountainman]

If the pump is fitted in the loft and the flow is too poor to actuate the flow sensors then you may need to use a negative head pump .

 

[MP plumb]

PS Where's the best place to get some plastic milk crates to raise it all?[/QUOTE]


thats a scary thought!!!