hi everybody plumbers and d i y ers been a little handy myself i have a little problem and sure you can help i have a baxi combi boiler and i want to change my bath taps from brass to chrome i have changed my taps before but i did not have a combi then i just turned off the hot at the tank and cold off at the mains but do i just turn it off at the mains and if i do does the pressure on the combi drop when the water drains off i would be gratefull for some advice