try reading my posting to "water not flowing from cold water tap? in box below but keep smudges advice in mind
Kenny F, November 2008
With the problem you describe I am assuming that when you say a dual tap it is most likley a mixer tap.
Some mixer taps will not work with a difference in pressure between hot and cold supplies.
ie: If cold water is mains and hot water comes from a gravity feed hot water tank.
Please check the instructions for your tap and check your type of system is suitable. The instructions may offer ways around the problem eg reducing pressure on cold water or putting both supplies through a dual pump to equal supply pressure etc. It may also be that you have to change the tap as it is not suitable for your supply.
If this does not cure your problem it would be best to repost your problem listing type of supply you have, make and model of taps & all you have done to try to make it work. Hopefully someone will have used that type of tap and be able to advise further.
