Showers

[Magrah]

Hi All

Not sure where to post this, plumbing or electrics!

I currently have two electric showers. The way the system is set up they both run of the tank via a booster pump. This means there is no loss of pressure if someone turns a tap on. I want to add a third one but this is not advisable on a 100amp fuse on the main consumer unit. I am concerned that using the Combi boiler I have, with a thermostatic shower will struggle if there is demand for hot water elsewhere. The only options that have come up are;

1) New three phase supply (costly).
2) A priority board which only allows two to be on at any one time.

Can anyone think of a plumbing solution where hot water demand will not be effected? This can't be an uncommon issue!

Any help / thoughts would be great.

Thanks

 

[Johntheo5]

You are worried about the water pressure with 3 showers in service?.
Electric showers use very little water simply because the can't heat it sufficiently due to their low thermal output.
Even in the summer with a mains temp of 15C, a 9.5kW shower will only require a flowrate of 5.5LPM at 40C, so present 2 electrics on together require a flowrate of 11.0LPM just about the minimum flowrate of one tthermostatic shower, total of two electrics+ one thermostatic, ~ say 11+15, 24LPM, if you wish to add another electric then total flow required 31.5LPM but 3 X 9.5kW electrics require 124A where as 2 "only" require 82A. Do you really need 4 showers on together, option 2 above, seems the easiest and obvious one to go for.

 

[denso13]

Hi All

Not sure where to post this, plumbing or electrics!

I currently have two electric showers. The way the system is set up they both run of the tank via a booster pump. This means there is no loss of pressure if someone turns a tap on. I want to add a third one but this is not advisable on a 100amp fuse on the main consumer unit. I am concerned that using the Combi boiler I have, with a thermostatic shower will struggle if there is demand for hot water elsewhere. The only options that have come up are;

1) New three phase supply (costly).
2) A priority board which only allows two to be on at any one time.

Can anyone think of a plumbing solution where hot water demand will not be effected? This can't be an uncommon issue!

Any help / thoughts would be great.

Thanks

A power shower has an integral pump and is connected with hot and cold gravity supplies. It only uses about 150w for the pump therefore it could be an option.

 

[denso13]

Just noticed you have a combi, a power shower won't work. Just fit a hot and cold thermostatic valve off the mains.

 

[Johntheo5]

Yes, something like a Triton Novel SR (SR=Silent Running) gives up to 14LPM, quite a few of its equivalent here around me, a excellent choice IMO.

 

[Johntheo5]

Just noticed you have a combi, a power shower won't work. Just fit a hot and cold thermostatic valve.

Why won't it work, it would be fed from the CWSC.

Of coure not, no HW Cylinder!!!

 

[Magrah]

Thanks for all the replies.

The issue is not water pressure as the existing 2 showers run of a pump which is fed by the 50g water tank. It's the load on the electricity supply. The input is combi hot and pumped water cold. To add a little bit more colour, the shower is in the loft as loft conversion and so is the tank so gravity fed is out the window as is a thermostatic shower as that has to run hot from a cylinder and not a combi.

 

[denso13]

as is a thermostatic shower as that has to run hot from a cylinder and not a combi.

A high pressure thermostatic shower will work straight from the mains/combi.

 

[Johntheo5]

As long as the cold is the pumped cold

 

[endecotp]

As long as the cold is the pumped cold

What is that in reply to?

A thermostatic mixer shower will work connected to mains cold and combi hot, with no pumps anywhere.

 

[Johntheo5]

It will, but the two electric showers would as well as they have flow stabilizing valves to allow for someone opening a cold tap somewhere so mains pressure must/ might be on the low side, the lowest pressure will then determine the flowrate from the thermostatic shower.

 

[Madrab]

If you have gravity cold water, that would suggest that there may have been a hot water cylinder at one time?

2 electric showers? Why? That seems to be a very strange way to service, what I can only presume is multiple bathrooms/en suites? Have you had you mains water surveyed? Given you want 3 showers I'd be looking at an alternative HW supply TBH

 

[Magrah]

I think you guys are missing the point, or maybe I am. The whole house, bar the kitchen sink, runs off the tank. I have ran this system on multiple houses, the idea is that electric showers run of a pump fed by the tank. This means no matter who turns what cold tap on the showers will maintain constant pressure. You can have two running and every single cold tap, or hot, in the house and they are not effected. You can't feed a thermostatic shower from a combi, gravity fed is out the window as the tank would not be high enough for the feed. I never needed 3 showers but this is a 6 bedroom house. A mega flow system would not be able to cope substantially. This can't be an uncommon problem. The boiler is a pretty new 42k WB, if you have the kitchen sink hot water on and say another hot tap in one of the other bathrooms the pressure is naff and a thermostatic shower, if possible would just pee on your head, pardon the french.

Hope that makes sense.

Thanks

 

[denso13]

I think you guys are missing the point, or maybe I am.

A thermostatic shower fed from a combi/mains is perfectly normal and generally works well.

The boiler is a pretty new 42k WB, if you have the kitchen sink hot water on and say another hot tap in one of the other bathrooms the pressure is naff and a thermostatic shower, if possible would just pee on your head, pardon the french.

Using a 42kw combi? There must be something wrong with your set up, a boiler that size can easily feed more than one hot water outlet at the same time. I have an old 28kw combi and the thermostatic shower is only slightly affected if someone opens a hot tap elsewhere.

 

[Magrah]

Outlet is 22mm radiator and 15mm hot water, there is only so much 15mm can do. . .