With plumbing, as with many DIY situations, the golden rules, are:
BE SAFE, and BE IN CONTROL
The first one is mostly common sense, in terms of working well away from any electrical wiring, if there might be some water leakage. If you HAVE to work close to any electrical wiring, or supply point, make sure you can isolate it by throwing the appropriate circuit breaker. Also, don’t forget that in Bathroom plumbing, any earth bonding clamps must be replaced, if rerouting pipework. For radiators, don’t be tempted to put the wire and clamp under the floor. Regulations state they MUST BE VISIBLE. Obviously this does not apply to the ones on the bath frame.
BEING IN CONTROL: for plumbing, this really means knowing where the valves are to isolate YOUR part of the system you are working on, and ensuring they are operative. Just turning off the water at the mains supply in the kitchen IS NOT ENOUGH. The cold water loft tank can hold up to 100 GALLONS, The hot water tank 30 to 50 gallons, and the central heating header tank plus radiators can be around 20 to 40 gallons, depending on the number of radiators.SO, ensure you know WHERE THE SHUT-OFF TAPS/VALVES ARE FOR THESE, AND ENSURE THEY ARE WORKING. They are USUALLY in the airing cupboard, and there is sometimes a shut-off (service valve) where the cold water “rising main” goes into the large loft tank. The airing cupboard ones are usually the “gate-valve” type, with red hand-wheels. There should be 2 on the inlet and outlet of the CENTRAL HEATING PUMP, don’t touch those, unless you are changing it.If draining the central heating system, you MUST turn you boiler off, and the timer controls to off positions, to ensure that the boiler will not try to fire up while the system is empty. Otherwise, although there ARE safety overtemperature sensors, you MIGHT damage the heat exchanger. NEVER ATTEMPT TO MAINTAIN OR CHANGE ANYTHING RELATED TO THE GAS SUPPLY OR GAS VALVE, OTHER THAN TURNING OFF THE GAS FOR SAFETY REASONS. ONLY CORGI REGISTERED TRADESMEN CAN REPLACE OR MAINTAIN THESE.
If you have to turn the water off completely at the main supply or loft tank to replace something, like a tap, or a cistern, think about including a SERVICE VALVE at an appropriate place that is easy to reach. They are quite cheap.
If fitting an outside tap, get a full kit that includes a non-return valve, to cover new WATER BY-LAWS. Try kit 10101 from SCREWFIX, at around £9.
If you need to change or update your cold water loft tank, and you have not already got the extra seperate indpendent outlet for a power shower, fit an extra tank connector (15MM), and add a short piece of pipe connected to a full-flow ball valve. Leave it in the OFF position until you are ready to fit the shower (fit a stop-end for safety). This will save having to drain that big tank at a later date.
If you DO need to fit an extra cold shower connector (best if you do not want loo flushing to effect the cold pressure, and therefore the temperature!), to an existing tank, shut off the supply to the tank for a couple of days before you need to do the job, then there is less water wasted. If you are not a big water user, with a smaller family, then make it longer.
If you have a problem that requires one of the supply pipes from the cold-water tank to be off to fix, and you cannot locate a service valve or gate valve (or if it has stuck/siezed up), then you can get hold of a large cork, or rubber bung (or better still, the proper bung kit that plumbers use, see SCREWFIX PART 81203, in the PLUMBING TOOLS section of the latest cataloge). You will have to reach down into the tank, and block off the appropriate pipe from the inside before starting the work. BEAR IN MIND THAT THERE COULD STILL BE QUITE A BIT OF RESIDUAL WATER IN THE PIPEWORK BETWEEN THE TANK AND THE PROBLEM AREA, EVEN IF YOU HAVE SEALED IT WELL.HOWEVER, IF NO AIR GETS IN THE PIPE TO DISPLACE THE WATER, IT MAY STAY THERE UNTIL YOU HAVE FINISHED THE WORK.