Using vent pipe in loft for power shower hot water feed?

kingandy2nd · 16 Oct 2012

Hi Everyone,

We’ve bought a pumped Mira Platinum shower to go in our new bathroom. The shower itself is a ceiling fed model, so the logical place for the shower pump unit to go is in the loft.

For the cold water supply to the shower, my plan is to take a T from the cold water pipe that feeds the hot water feed tank in the loft.

Regarding the hot water supply, I was wondering if I could T off from the vent pipe from the hot water cylinder in the loft?

(Forgive me if I’ve used the incorrect terminology, I mean the pipe coming from the top of the hot water cylinder that goes directly upwards into the loft and is open at the end overhanging the hot water feed tank).

My logic is that providing that I put the T piece in the vent pipe below the base of the hot water feed tank that it should provide the hot water I require without the fear of running dry unless the hot water feed tank get totally empty.

Would that work?

Thanks!
Andy

kvsalamander · 16 Oct 2012

Good morning,

as always with these type of appliance its best to read the manufacturers instructions and follow exactly how they say to install it. This will make sure you have a long life and that its covered under warranty.

With regards to the hot water connection i would recommend fitting a suitable flange such as a Surrey or Essex in the cylinder to prolong the life of the appliance.

regards

warmadmax · 16 Oct 2012

hi kingandy2nd

is the shower pumped?

one problem you'll possibly have straight away is mixing low pressure hot water (gravity) with high pressure mains cold water.

second problem, the HW vent pipe in the loft isn't the best place to draw off water as it'll be at the lowest pressure compared to elsewhere and it's also the primary route for air to escape the hot water cylinder to the air (i.e. vent...), so risk of air admittance is highest here.

have a good read at the manufacturers instructions and it'll advise how they want it plumbing.

rjm2k · 16 Oct 2012

As above read the instructions, a flange is better but if you do T off then the vent is just that, a vent, don't T off it, do the join before the vent t's off from the pipe out of the top of the cylinder.

dcawkwell · 16 Oct 2012

Consult the instructions.

You will most likely need a connection near to the outlet of the hot water tank and also a connection into the cold header tank.

Hugh Jaleak · 16 Oct 2012

Please note you cannot pump mains water. The cold connection must be taken from the cold storage cistern, not the pipe feeding it!

Secondly a connection to the vent pipe is likely to drag in as much air as water. Both hot and cold connections must be taken as per the manufacturers instructions, failue to do so may result in a shower that wont work properly, a knackered pump and invalid warranty on both shower and pump!

Whitespirit66 · 16 Oct 2012

Unless you want your pump to pop in about 2 days, and your installation to look like it was done by Jerzy from Warsaw - you need to do it like this

RF Lighting · 16 Oct 2012

So that's an unvented tank then is it?

TicklyT · 16 Oct 2012

Some of the problems :-

For water to flow from the cold cistern to the hot cylinder there must be a pressure differential between the two, so the water level in the vent pipe will drop when you start to draw water, and will probably starve the pump.

Teeing the pump cold feed from the cylinder cold feed will increase the pressure differential required for the increased flow in the cold feed pipe, further increasing the chances of starving the pump.

The vent pipe is intended to release gases held in solution in cold water that are released when the water is heated. Those gas bubbles will get drawn into your pump instead of being released up the vent, and will soon wreck the pump rotor.

Whitespirit66 · 17 Oct 2012

RF Lighting said:
So that's an unvented tank then is it?

You're not making any sense. Who mentioned unvented?

seco services · 17 Oct 2012

Whitespirit66 said:
RF Lighting said:

So that's an unvented tank then is it?

Click to expand...

You're not making any sense. Who mentioned unvented?

Muppet on the video.

diynot

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Using vent pipe in loft for power shower hot water feed?

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