I have recently bought a house with a new sealed combination boiler
installed. All is well with the thing until we decided to have a
thermostatic mixer shower installed in the bathroom upstairs. It has
transpired that the cold water pressure isnt sufficient to open the
non-return valve on the cold water side of the mixer, which means that
the pressure is low and sometimes only dribbles out until the mixer is
thumped. Taking out the non-return valve is an option but it does
mean that there is a risk of the hot water feeding back into the cold
water tank. The reason the cold water pressure is low is that it is
still fed to the bathroom via a cold water tank in the attic. Logic
dictates that with a sealed combi boiler the need for a water tank is
done away with, however one still exsists!
My question is, can I get rid of the water tank in the attic and feed
the bathroom with the rising mains that feeds the tank?

"David Tate" wrote in message
om...

I have recently bought a house with a new sealed combination boiler
installed. All is well with the thing until we decided to have a
thermostatic mixer shower installed in the bathroom upstairs. It has
transpired that the cold water pressure isnt sufficient to open the
non-return valve on the cold water side of the mixer, which means that
the pressure is low and sometimes only dribbles out until the mixer is
thumped. Taking out the non-return valve is an option but it does
mean that there is a risk of the hot water feeding back into the cold
water tank.

With a combi boiler the cold to the shower should be off the mains and the
hot off the combi which is supplied from the same cold mains. Then equal
high pressure on bothe hot and cold. No need for a non-return valve.

The reason the cold water pressure is low is that it is
still fed to the bathroom via a cold water tank in the attic. Logic
dictates that with a sealed combi boiler the need for a water tank is
done away with, however one still exsists!
My question is, can I get rid of the water tank in the attic and feed
the bathroom with the rising mains that feeds the tank?

Just take the cold for the shower off the mains. Leave the tank if it is
doing no harm and it will supply the toilets and other cold supplies.



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In message , David Tate
writes
I have recently bought a house with a new sealed combination boiler
installed. All is well with the thing until we decided to have a
thermostatic mixer shower installed in the bathroom upstairs. It has
transpired that the cold water pressure isnt sufficient to open the
non-return valve on the cold water side of the mixer, which means that
the pressure is low and sometimes only dribbles out until the mixer is
thumped. Taking out the non-return valve is an option but it does
mean that there is a risk of the hot water feeding back into the cold
water tank. The reason the cold water pressure is low is that it is
still fed to the bathroom via a cold water tank in the attic. Logic
dictates that with a sealed combi boiler the need for a water tank is
done away with, however one still exsists!
My question is, can I get rid of the water tank in the attic and feed
the bathroom with the rising mains that feeds the tank?

Yes, you can. The normal way is indeed to remove the cold water cistern
as well. You should find that it all works fine after that.

--
Chris French, Leeds

"David Tate" wrote in message
om...
I have recently bought a house with a new sealed combination boiler
installed. All is well with the thing until we decided to have a
thermostatic mixer shower installed in the bathroom upstairs. It has
transpired that the cold water pressure isnt sufficient to open the
non-return valve on the cold water side of the mixer, which means that
the pressure is low and sometimes only dribbles out until the mixer is
thumped. Taking out the non-return valve is an option but it does
mean that there is a risk of the hot water feeding back into the cold
water tank. The reason the cold water pressure is low is that it is
still fed to the bathroom via a cold water tank in the attic. Logic
dictates that with a sealed combi boiler the need for a water tank is
done away with, however one still exsists!
My question is, can I get rid of the water tank in the attic and feed
the bathroom with the rising mains that feeds the tank?

You might find the cold was left on a tank supply cos the mains can't supply
an adequate amount of water if more than one tap is turned on and the tank
ball valve supply could be restricted to reduce its effects.

Rgds

Andy R