Combi boiler & Mira Mixer Shower.

[TOGGY]

Have just installed a Combi boiler to replace our old hot water tank and system. Our shower is fed from the cold tank (this is now the only appliance supplied from the cold tank). On trying the shower this evening it appears that due to the increase of hot water pressure this has pushed back up into the cold tank causing it to overflow.

My question obviously pertains in how to remedy this. Is is possible to fit a non return valve to the cold supply to the shower or would supplying the shower direct from the mains cold remedy this, or again would this require a non return valve.

Any help requiring this would be much appreciated

Cheers

tiggy

[EricP]

Simply connect the mains supply to the tank, up to the cold supply from the tank and remove the tank. Mains pressure on H & C, no problems.

[BillV]

That is the simplest solution. When the shower was new there would have been varous flow restrictors in the install kit to balance the flow for various setups e.g. mains cold in + gravity hot, or combi hot + gravity cold. No doubt these restrictors are long gone now though. Maybe the shower is not even suitable for a combi at all..

[BillV]

Just happened to see a Mira 88EV on display today and it said "designed for gravity fed only ... can be used on pump to 1.5bar max". So if its one like that its no good for a use on a combi where you may be getting 3-4 bar pressure.

>