plumbing help, ideas needed?

rossyl · 11 Dec 2006 at 18:10

Right.

Got a combi boiler and two bathrooms.

One bathroom has an electric shower, which runs off the cold water feed.
Other bathroom has a standard shower using the regular hot and cold coming from the combi.

You cannot run the two at the same time.

What can i do so that i can?

Thanks

rossyl · 11 Dec 2006 at 18:23

from doing som internet research it would appear that the situation might be better if i took out the electric shower and installed a thermostatically controlled shower.

But i am not sure whether this would result in two low flow showers.

I'm not sure where the electric shower was getting its feed. if it was to get the cold water before the combi bolier got it, would this make a difference?

whitecrook · 11 Dec 2006 at 18:36

Who says you can't run both at the same time? Is the shower running of the cold feed, by that you mean the cold water tank upstairs, and the shower is a pump shower? The shower running off the combi uses the combi to heat the water? Is that second shower running of the pressure from the combi or is it pumped as well?

Chabsy · 11 Dec 2006 at 18:41

Is it due to low water flow (pressure) is you stop **** fully open?

I assume both are coming of the rising main

RatsPom · 11 Dec 2006 at 20:19

"Who says you can't run both at the same time? Is the shower running of the cold feed, by that you mean the cold water tank upstairs, and the shower is a pump shower? The shower running off the combi uses the combi to heat the water? Is that second shower running of the pressure from the combi or is it pumped as well"

Ok shower 1 does not need to have a pump, it can be fed by mavity from the water tank provided the water tank is higher than the shower, the higher the tank the higher the water pressure to the shower will be. As for the combi, mains water pressure will have to be sufficient so that the boiler heats up the water and then through the shower,temperature at the shower being controlled via a mixer valve (usually) in built in the shower.

I'm not a plumber but work in the building services industry and at work there are 4 Triton electric showers all fed from the rising main, pressure at about 2 bar ish and they work ok, if low water pressure is detected by the showers' in built pressure switch then they will not heat up.

Hope that helps

Hedge · 11 Dec 2006 at 20:32

Its because there isnt sufficent flow to supply both. Bear in mind that a combi is drawing from the cold feed, and obviously the shower is cold fed too.

In order to remedy this you need a cold water storage cistern for one of your showers

rossyl · 12 Dec 2006 at 12:38

Hi,

Sorry it seems I created some confusion.

Shower one is an electric shower. It runs off the mains, not a water storage tank.

Shower two runs off the combi, and is a standard mixer shower.

Now i think that the electric shower being on just consumes the pressure of the system and as a result the combi doesn't have enough pressure to run anything.

So the solution would be to get a tank with a pump for the electric? How much is that likely to cost???

thanks

Cybermyk · 12 Dec 2006 at 13:02

I seem to remember someone getting a larger bore mains feed pipe fitted to cope with a shower problem. Was a while ago so not sure what the regulations or standards are now.

Guigsy · 12 Dec 2006 at 13:07

Tanks aren't expensive (guess £50???) and pumps are about £200. It's the plumber that'll cost you the cash.

The tank has to be pretty big. You'll have to set the filler valve to quite a low flow or you'll be in the same situation as now. The tank will need the capacity to last the length of a long shower. I think the pump will have an automatic shut-off when it runs out of water, I guess the electric shower will be OK if it suddenly gets no water? You don't want to have the water cut-off while you're taking a shower though.

SeriousPigeon · 12 Dec 2006 at 13:43

A larger bore (25 mm) water mains feed in, would reduce the amount the pressure drops by when the electric shower is turned on. This may then allow the combi boiler to operate at the same time. The only problem with this is that it needs to be a larger bore pipe all the way back to the main stopcock/water meter, or it is of little use.

Another alternative is to use your combi boiler to run 2 showers at once.
If it cannot do this, then you need to ask yourself, is this the right heating solution for my house.
You can either have something bodged together that might work, or get it done properly.

I got my heating system replaced with a new gas conventional boiler and Megaflo unvented hot water cylinder, becuase of the poor showers in my house. Never looked back since - 3.8 bars and 25 litres per minute of skin flaying power shower!

The_blue · 12 Dec 2006 at 14:24

rossyl said:
Right.

Got a combi boiler and two bathrooms.

One bathroom has an electric shower, which runs off the cold water feed.
Other bathroom has a standard shower using the regular hot and cold coming from the combi.

You cannot run the two at the same time.

What can i do so that i can?

Thanks

Tank in loft to feed cold to the electric. Stops pressure dip when both on.

Mr_White · 12 Dec 2006 at 14:48

When was your combi-boiler last serviced?

And what is the pressure at?

The combi-boiler in my old house had no problem powering a standard shower, and a power shower at the same time, no problem with all the taps on at once either.

So it sounds like you've got a bad pump or you've not been maintaining the pressure.

You really shouldn't need to fit a water tank just to feed a shower, it defeats one of the points of having a combi, no tanks.