Shower issue

[McNulty]

Hi there,

just a little issue im dealing with on a bathroom re-fit and after some advice. Heres a little understanding of whats happening.

Customer had gravity fed hot and cold to the bath taps in the main bathroom, now they want a shower put in and shower tray.

At the moment the cold feed from the CWS tank in the loft runs across the loft a few meters in 22mm down to the bathroom where the new shower will go which is fine, doesnt tee off anywhere so nice and straight forward.

Now the hot from hot water cylinder currently tees off under the floor boards in the bathroom whilst it goes on and feeds all other hot outlets in the house.

The customer in the future would like a shower pump, but for the time being gravity fed water is fine by them as they have an ensuite next to the bathroom, which also has a sepperate cold feed to that shower from the CWS tank in the loft, and hot feed teed off from under floor boards up to the shower.

Both bathrooms are 1st floor, normal house, CWS tanks in loft, Hot water cylinder 1st floor next to bathroom.

Im going to keep cold feed from CWS in loft in 22mm to shower in the main bathroom, but my question is I want to tee off the hot water cylinder as close as I can to the bend coming out the top, run that up the wall into the loft in 22mm, tight against the top of the joists, run in about 2 meters across the joists and back down into bathroom where shower will be. The CWS tank is about a foot off the ground in the loft and its a 50 gallon tank.

So then in the future when they want a pump i can just configure pipework in the airing cupboard, instead of re routing a lot of pipes.

Do you think the pressure will be ok not great obviously? or is this too close to a negative head? Meaning they will need a negative shower pump in the future?

Ive added a diagram i drew up on the pc to give u an idea, now please bare with me I know its terrible but just thought it would be good if you could see it (or not lol)

Sorry for long message but would like any oppinions,

Thanks

 

[thompsonbrown]

with a low pressure shower valve you will get water through but your looking at about .5psi and the lowest shower i know of is .1 i would fit a Stuart turner neg head 3bar whole house pump on the hot. the tanks big enough and it would seem a shame to fit all this then someone runs the tap downstairs and you loose your hot supply to shower

 

[PlumbBobBob]

another option would be to fit a power shower utilising hot and cold gravity feeds

 

[McNulty]

They will get a low pressure shower valve, when the pump is fitted do you think this will this effect it at all?

At the moment the ensuit shower has really poor flow, so in the future they will get me to fit a pump and deal with the rubbish pressure atm.

But my real question is with the hot and cold pipework being taken into the loft after the shower pump and back down to the shower, is this a negative pump or a positive pump? In theory it should be a positive pump as the outlet of the shower and all pipework isnt above the CWS tank right?

Just want to make sure im right is all before going ahead with it. Because after i fit this bathroom the ensuite shower needs doing and i was thinking of just teeing of hot and cold in the loft in 22mm and running to other shower, then they will both be pumped with the correct sized pump.

Again any info would be great, cheers

 

[Paulus]

Most shower pumps require 2 metres head of water. Provided the bottom of the CWS tank is 2 metres above the shower head then you want a shouldn't need a negative head pump. I have done the same as you many times to run 2 showers from the one pump and used a 2 bar stuart turner.

I spoke to stuart turner a couple of years ago to ask if it was possible to put their pumps in the loft and tee into the expansion pipe for the hot supply. They said it would work fine provided the tee was below the bottom of CWS tank as the head of water required is from CWS tank to shower head not the pump. I've done it loads of times now and never had a problem.