Some questions regarding pipework

[st07]

Hi,

I have a few questions regarding the plumbing at my mums place.


1.) She's looking at getting a new shower fitted, and while we're at it I thought it would be nice to conceal the pipework so it isn't on show. The shower sits on plasterboard and I'm 99% certain there's a gap big enough behind it so we could run a pipe to the loft directly above. I've read that it's not advisable to have joints hidden behind walls, so what would you suggest I do here? Can you buy plastic piping with moulded 90 degree angles (the angle being where the pipe comes through the wall to meet the shower unit)?





2.) There is no gas available at the flat so her heating is supplied by an E7 combination cylinder (direct). I understand that the hot water side is essentially gravity-fed and that because the 'cold water tank' is directly on top of the cylinder this is the reason for her poor hot water pressure at the taps. We're looking to improve on this and I see only two options; either a.) replace the combination tank with a standard immersion where the cold water tank resides in the loft (1 metre above, would this really make much difference to flow?) or b.) fit an electric pump on the hot water outlet to provide extra pressure. The pump would be the cheaper option but is there anything else I can try?


3.) The hot water pump goes from the tank, under 1 metre of floor, 1.5m to the bath then from there another 3-or-so metres to the sink in the kitchen. None of it is lagged. Would it be worth lagging the accessible internal pipework, being that heat energy would be lost dissipating to the air after running the hot water taps etc? It can't hurt can it?

Any help appreciated

 

[DIYDave2]

I am NOT a qualified plumber....

In reverse:

1. Lag everything!
2. 1 meter extra head will not provide much extra pressure re the work involved
3. I have plumbed a fair bit (DIY that is) and always go for soldered joints in hidden areas and vacuum test. That said, the modern push fit stuff is excellent.... You should not have any leaks...

But then... I am not a plumber

 

[DeltaT2]

Why not just stick with the an electric shower mate? Conceal the cable & pipe behind the plasterboard & upgrade the cable/supply to give your Mum a better shower.
A 6mm cable will be OK on a shower up to 8.5KW, anything bigger, then upgrade to 10mm.
HTH

 

[st07]

I am NOT a qualified plumber....

In reverse:

1. Lag everything!

Interesting. Lagging is fairly cheap so yeah I think I'll go for that I'll look in to plastic push-fit stuff then, though I'd still really rather not have a join behind the wall if I could help it.

Why not just stick with the an electric shower mate? Conceal the cable & pipe behind the plasterboard & upgrade the cable/supply to give your Mum a better shower.
A 6mm cable will be OK on a shower up to 8.5KW, anything bigger, then upgrade to 10mm.
HTH

Yeah she's sticking with electric. We have some 10mm in the shed so will be replacing her 6mm with it. Just worried about having pipe joins behind plasterboard, what do you think?

 

[st07]

Lagged all the pipework, just wondering about the shower pipe now.

At the moment the pipework for the shower runs through the loft. I've had a look and think it's probably easier just to run behind the plasterboard and down to the cold tap supply under the bath - what do you think? Are plastic push-fittings the way to go, how would I join to the existing copper pipe?

Thanks

---

 

[TicklyT]

Low water pressure isn't a problem if you select taps designed for the pressure you have available.

Fitting brassware designed for mains pressure systems to a gravity system will always give disappointing results.

Low pressure taps have much larger internal waterways, giving high flow rates at low water pressures.

 

[PrenticeBoyofDerry]

If you are fitting an electric shower you must have RCD protection on that circuit. The cable size not only depend on the output of the shower but also depend on the route the cable is taking.
For example if you are using 10mmT&E it can carry a maximum of 64A when clipped direct if run in through thermal insulation the current carry capacity can be reduced to 32A. There are also de-rating for runs within conduit/trunking and also the distance the cable is run can result in voltage drop which will also effect the size of cable needed. all things to be considered.
But saying all that if there are no de-rating factors a 6mm cable can supply a 10.5kW shower with a 45A MCB but must have RCD protection.
It is also considered a special location (BS7671 and part p of building regulations) So work if done by none scheme registered tradesmen must be notified prior to start of work and a fee will be requested!