Two showers + one combi boiler = trouble

[sbrough]

I've recently moved into a house where an attic conversion includes an en-suite with a shower. The problem is that it is fed by the same supply as the bathroom via a combi boiler meaning there is not enough pressure to have both showers going at once. With a big family this is a problem.

Is there any way to make an additional rising main? I'm thinking I could have a dedicated cold water supply to an electric shower in the bathroom.
Is it even possible?
I could try to squeeze a water tank in what is left of attic storage but it would only have a drop of a couple of meters.

Any suggestions of how to run two showers at the same time greatly appreciated.
Thanks

 

[kevindgas]

yes you can have a seperate supply to an electric shower so long as your incoming main has sufficient pressure, you wouldn't put a tank in though as an electric shower would normally be fed from the main.

another option would be to upgrade your combi to a larger output model Vaillant ecotec 837 would just about cope or you could look at Worcester Bosch as they have a boiler that is over 40Kw.

there is another option of changing to a unvented cylinder or store keeping some of the taps supplied by the combi and the cylinder heated off the C/H side with a diverter valve

that's some of the options open to you

 

[sbrough]

Thanks very much kevindgas
I'm not sure the boiler change would help as the main problem is the water pressure. A dedicated cold rising main with an electric shower was my first thought, glad to know I'm not barking up the wrong tree.

How much work / cost would another supply be? Are we talking hundreds or thousands??

Thanks

 

[Hugh Jaleak]

One point you may need to consider, if you take another supply from the existing rising main to the loft shower then no problem. If you are thinking of an additional supply into the property Anglian Water are likely to insist both this and exisiting supply are metered. With 2 supplies they will argue you are expecting to use a lot of water, so it has to be metered.

 

[littleleaks]

you don`t really need another rising main you should be able to take a spur off the sink or toliet as they are under mains pressure, in fact if there is already a shower there then the cold supply should be enough for an electric shower. if your mains pressure is so low then try to turn the stopcock up a bit, you`d be amazed how many times people have said they have low water pressure and all i had to do was turn the stopcock on fully

 

[sbrough]

Thanks for all this help
If I can clarify something though...

I've got two showers supplied through a single combi boiler. Both run fine seperately but there is not enough water pressure (through the boiler) to run both at the same time. At the moment it's a matter of timing and shouting "Showers free" or "Im out!"

My thought was a seperate main would allow both to run together if one was heated through the boiler and the other independantly as an electric but don't even know if splitting the mains or adding an extra supply was even possible or if so massively expensive.

Thanks

 

[jeds]

The question is though; do you have sufficient water pressure, and flow, to run both an electric shower and the combi boiler at the same time? If not then you will have to address that problem first.

Check the flow rate of the combi shower alone - and then again with a cold tap running - preferably somewhere near the position of the proposed electric shower. What sort of flow and pressure are you getting when both are on? Does the combi still provide a reasonable shower with the cold tap running?

 

[sbrough]

Thats what I mean John, there is not enough pressure for both showers, hence the query about the second rising main.

 

[mickyg]

Thats what I mean John, there is not enough pressure for both showers, hence the query about the second rising main.

measure how long it takes to fill a vessel with known volume, ie a 10 litre
bucket, with cold tap fully open. From this you can work out your litres per minute flow rate. post back result. Also worth asking neighbours about their pressure, is it low pressure at the street or is it just your house.
you could uprate your main supply only to find the water company is supplying low pressure.

 

[jeds]

Prob simplest solution is an electric pumped shower - Mira Elite or similar. You will need something like a 120...ish litre cold water feed tank but minimum head is virtually nothing.