Shower pump, pumped hot water and flange/cylinder options

29 Jan 2011
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United Kingdom
I currently have a conventional boiler/indirect hot water cylinder setup. I have a number of things I want to sort out together as follows:

1. The 2 bar Stuart Turner power shower pump which is currently just teed downwards from the hot water outlet from the tank rather than being fed from a Surrey flange.

2. Replace the hot water cylinder with a larger one to give a bit more capacity to the power shower.

3. The house mostly has modern taps, and although these are for low pressure systems and have the correct open strainers fitted, the flow still isn't that good through narrow tap tails - so I want to add a Grundfoss home booster pump to the hot output to wind it up a bit.

I was looking at stainless steel hot cylinders, but they tend to all come with 22mm compression outlets - albeit usually with a secondary shower outlet already built in. Ideally I was thinking I'd want a secondary shower outlet for the shower pump AND a Surrey flange in the top to give an air free supply for the Grundfoss - but no one seems to do a stainless tank with a 1" BSP at the top unless anyone knows different?

The only other option I can think of with a stainless cylinder is feeding the shower from the shower outlet, and the Grundfoss from the 22mm at the top - but finding some other way to vent the system so air can't be drawn into the pump. Any ideas?

Failing that, I guess I have options around copper cylinders as follows so I'd appreciate any thoughts:

1. Put in a Surrey flange and feed BOTH the shower pump and Grundfoss off the flange shower output - and use the normal house connection as a vent. Just wasn't sure the flow would be enough if both pumps are running together.

2. Feed the Grundfoss off a Surrey flange (normal outlet used as vent) and add an Essex/Techflange further down the tank for the shower.

TIA, Midge.
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Any reason why you can't get an unvented (mains pressure) cylinder fitted?
lots of stainless cylinders have a secondary draw off, RM stelflow do im pretty sure
I guess its a no-brainer on a new install Muggles. Cylinders are more expensive, but no need for shower pump, no need for booster pump, no pump noise, no electricity consumed by pumps, no cold tank, reduced overall maintenance etc. - so they obviously make sense.

The main downer for me though was the fact our cylinder is bang smack in the middle of the house - and getting the discharge pipework in would be the biggest pain of the lot by a considerable margin. Might give it another thought today though.....thanks.
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Thermal store will give you mains pressure without having to run discharge pipework.
Thermal store will give you mains pressure without having to run discharge pipework.

I must admit I'm more comfortable with the concept than I am with a mains pressure cylinder with all its safety gubbins. Just not sure I could justify the cost at around four times that of a conventional cylinder - but its an interesting thought, thanks.

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