shower pump pipework design

[Thornwhite]

Hi

I am looking for a bit more pressure out of our en-suite shower (on an old gravity based system) so am thinking about getting a shower pump.

Our En-suite backs on to our main bathroom. there are 22mm feeds for the hot and cold which have offshoots for all different units.
Bathroom toilet
Bathroom basin
Bathroom bath
En-suite toilet
En-suite basin
En-suite Shower

All of the different branches are quite short and my concern is that if we had a shower pump installed, then the pump might suck water back from another unit e.g. bathroom basin if it someone was using it.

Is this possible or am i being paranoid?
If so will we need to run separate pipes back to the hot and cold water tanks?

Any info or advice would be appreciated.

 

[kbdiy]

AFAIK the normal recommendation is dedicated hot and cold supplies if only pumping the shower. However you could consider just pumping the whole lot I would have thought?

 

[Madrab]

You could pump the shower and possibly the taps though the taps can affect the flow to the shower, depending on the power of the pump, if opened when the shower is being used, not ideal. Avoid feeding the toilet from a pumped circuit. Do you really want the pump kicking in at 3am when someone uses the toilet, also the short cycles to fill a toilet isn't very good for the pump.
The ideal is only pump the shower. This would be supplied by dedicated feed from the cold tank and the hot using a flange of one type or another to minimise air bubbles being drawn in and damaging the pump's impeller.
Whatever you decide there will be a fair bit of work involved

 

[Thornwhite]

Thanks,

I was wondering if something could be done with non-return valves or similar.

Not easy to run dedicated lines, but not impossible I guess.

I appreciate your input.

 

[Madrab]

Not sure what you mean - non return (Check) valves are designed to stop backflow but you couldn't use them on your setup to allow everything to be pumped. They wouldn't stop flow variations in the shower feed if a tap was opened nor would it remove the toilets from the pumped circuit I'm afraid.

 

[Thornwhite]

My ideal is for the shower pump to only feed the shower.

What I meant was - Could I fit the shower pump on the short branch (off the main bathroom/ensuite supply) that only feeds the shower if I put non return valves on the other branches (to prevent draw back from the basins/toilets if they are being used at the same time).

I was thinking it might be an easier option to routing in a spearate feed for the shower. In hindsight, it probably isn't

 

[Madrab]

Ah I see where you are coming from and it's a fair thought but still not ideal for a pump Thorn and it would still be affected by fluctuations when a tap was opened. A pump really needs a dedicated feed.
There is the option of an 'on the wall' power shower setup rather than a pumped shower.
It does mean a new shower unit rather than retaining what you have now and you would still be affected by someone opening a tap if it's on the same circuit though a thermostatic power shower would alleviate most of the fluctuation.
Food for thought or another option to further confuse the issue

 

[HERTS P&D]

You could fit a T40 pump to boost the shower:

http://www.ebay.co.uk/itm/Triton-T4..._Bathroom_Shower_Units_PP&hash=item257daef15d

Or pump all the hot and cold and fit the power supply with a timer so that it can run from 6am to 11pm, this is so that if anyone goes to the toilet at 2am the pump wont come on.


I have a 2 bar stuart turner pump fitted to my shower, I must say it is very quite.

Andy

 

[Sydneytoo]

I'm planning on installing a Stuart Turner pump for a shower as well, but I'm struggling to find a suitable route to get a dedicated cold feed to the pump. Is it really a no no to tee into the existing 22mm cold supply to the bathroom? Afterall the H/W supply to the pump will be affected by the hot water taps being turned on because the H/W tank has a shared supply.

 

[Madrab]

The supply from the hot water cylinder to the pump needs to be a dedicated supply through a feed pipe that minimises air bubbles getting into the pump. This is achieved by fitting a flange into the cylinder. this could be a surrey, or essex flange but the pump then has it's own supply pipework and doesn't use the shared supply.
It is not advisable, using the existing cold feed from the tank could starve the pump of cold water if other outlets draw too much and cause internal damage, that's why it's recommended to have it's own feed.

 

[Sydneytoo]

Hi Madrab, I was afraid that might be the case. I've had another look and may be able to dismantle a stud wall to hide a dedicated C/W pump feed behind.

I was planning on taking the H/W feed from a blanked off fitting about 6" below the top of the hot tank. I think the tank is old as other tanks I've seen don't seem to have this fitting.

Regarding the shared H/W tank feed, I meant that there is a single cold feed from the loft into the hot tank. If the there is a high demand for H/W from the taps or washine machine, then the hot tank pressure will drop and the pump could be starved of H/W, even if it has its own hot feed from the hot tank.

 

[Tibbot]

A twin (hot and cold) shower pump requires;

* A cold supply direct from a dedicated connection on the cold water tank.
* A de-aerated hot supply from the cylinder (from a purpose made flange or tee'd off the underside of a rising hot water outlet from the cylinder).

Anything else can be described as shoddy, slapdash or a bodge.

 

[Madrab]

That will be an essex flange 6" down and perfect for a shower pump, other tanks do have them but you usually have to ask for them to be fitted.
As long as the cylinder has an un-interupted 22mm feed from the cold water cistern and the cold water tank is large enough (50 gal) and at least a meter above, then experience says that should be ok. If not then the option would be to alter the cold feed to the cylinder to a 28mm pipe.
You can make rough estimates given the size of cylinder and a typical days hot water use and average out from there to gauge if it will be adequate.
The other consideration is how quickly the hot water cylinder recovers, especially if it's old as you mention, but it is all supposition until put into practice and used.

Does you washing machine use hot feed? A lot of them only use a cold feed these days.

 

[Sydneytoo]

Thanks guys. I'm not sure what size the essex flange on the tank is and it will be a while befoe I get to drain the tank. I found a 3/4male to 22mm compression which looks about right, will that fit?

We shouldn't have any issues regarding hot water pressure, I was just making a point really. The base of the hot tank is about 12 feet below the base of the cold tank so there should be plenty of pressure. There is a hot feed for the washing machine but I never connected it up. I felt that by the time hot water had reached the machine, the machine would have stopped filling.

 

[Madrab]

It may be 3/4" or 1" though chances are it will be 3/4" and your fitting will be ok.