IMPORTANT DISCLAIMER - leaking water can cause substantial damage and cost to your home, if you are unsure or not competent to work with any of the listed tools, or carryout any of the advice in the guides, you should not take a risk and call a qualified plumber to complete the work. Any work with pressurized systems such as expansion vessels, any gas related appliances such as boilers and any electrical work should only be carried out by qualified registered engineers as these are extremely dangerous and could lead to injury or death.