Combi Boiler with low mains preasure

[raxlar]

Hi guys I could really use some help.

I have just got my first house and the previous owner has put a combi boiler in but the mains preasure is so low that i can not turn on a cold tap at the same time as a hot water tap without the hot water turning off compleatly.

I wanted to fit a shower but i dont see how i am going to be able to do this.

Is there any way I can get around this. I dont have much cash and i dont know what to do as the flow even with just the hot is only just enougth to allow the boiler to work.

A combi should never have been used.

Is it possible to feed the combi boiler from a cold water storage tank or to feed the cold water seperatly from a tank and only take the hot from the mains directly.

Any help would be greatly appreciated as i love showers but dont see how i can get one to work without resorting to an electric one.

 

[corgiman]

You could pump the water from a tank through the combi.

Grunfoss do a nice one

 

[simond]

An accumulator could provide the best option (no break tanks, no noise, no electricity) but we would need to know a bit more detail; primarily, what your highest typical standing pressure reading is.

Alternatively, TWS manufacture a product called Charger which would be useful if the pressure is very low indeed.

 

[raxlar]

It takes about 6 seconds to fill a 1ltr bottle from the cold tap and a little less to do this from the hot tap.

The problem is that the flow from the hot tap compleatly stops when any cold tap in the house is turned on.

It was my impression that when people say you can only use one tap at a time with a combi they mean one hot tap and not one hot or cold tap.

P.s what is an accumulator can you both give me links?

 

[simond]

So you have around 10 litres per minute

This will give the cross modulation effects you describe.

My profile contains details of our web site, but whilst it gives more detail on water boosting accumulators I should add we will not be able help you in your geographical area. The forum prohibits advertising.

The products we use are supplied by GAH Ltd, www.gah.co.uk, I'm sure they could put you in touch with a local specialist.

 

[raxlar]

Took a look at this. How much is this likly to cost me for a system that is sutable to run two baths / long showers from per day including fitting? I have a sutable location where the old hot water tank used to be.

 

[simond]

Somewhere around £1K, but it is something to talk to a local specialist about. And of course, you need to get the pressure checked.

 

[bengasman]

I have just got my first house and the previous owner has put a combi boiler in but the mains preasure is so low that i can not turn on a cold tap at the same time as a hot water tap without the hot water turning off compleatly.

that is a flow problem, not pressure. try to open your stopcock completely

Is it possible to feed the combi boiler from a cold water storage tank or to feed the cold water seperatly from a tank and only take the hot from the mains directly.

combi must be on mains, and all tanks removed

 

[Agile]

combi must be on mains, and all tanks removed

Not necessarily!

Its acceptable if the source is designed for potable water supply like most of the pumped storage boosters like the Grunfoss and similar products.

Many of the tall council blocks have a potable cistern on the roof and feed to the flats by gravity with pressure reducing valves every few floors down.

Tony