.jpg)
.jpg)
|
|
|
|
HOW TO: INSTALL A HOT WATER TANK
INTRODUCTION If you are constantly running out of hot water, a new hot-water cylinder can give you a faster heat-up time and increased capacity. A direct cylinder with an immersion heater has just two connections so it should be very easy to fit. An indirect cylinder, which has a coil inside for transferring heat from the boiler, is a bit more involved because you need to drain down the boiler and heating circuit. If you have an older-style gravity primary hot-water circuit, you might also want to change over to a more efficient pumped system.
SKILL LEVEL Plumbing skills are required and electrical knowledge would be useful. SAFETY FIRST
Turn off the hot water a few hours before you begin draining down. This will
TO COMPLETE THIS PROJECT YOU WILL NEED... Adjustable Plumbers Wrenches Blow Lamp Compression Fitting (28mm or 22mm) Copper Angled Connector Copper Tube (22m or 28mm) Cylinder Cylinder Unions Immersion Heater/Blanking Plate Immersion-Heater Spanner Male Iron Thread (1in) Pipe Cutters 1- CHOOSING A CYLINDER New hot-water cylinders have factory-fitted foam insulation which helps keep the water hotter for longer. A quick-recovery cylinder can also increase the efficiency of your boiler by transferring heat faster. In a family home with heavy demands on the hot water, it is worth fitting a larger cylinder. This can usually be achieved with minimal changes to the pipework.
A hot-water cylinder can be heated by a boiler or with an electric immersion
heater. It is even possible to run them both at once if you want a really
There are also Economy 7 cylinders for use with off peak electricity. These have two immersion heaters; one in the top and one in the bottom. The top heater is wired up to standard rate electricity to give you a daytime top up. The lower heater is wired to the white meter supply for night-time heating of the whole cylinder.
2- PREVENTING FREEZING OF VENT PIPES A very serious explosion can occur if the feed and vent pipes freeze in the loft while the cylinder is heating up. It is essential to insulate the pipes very well and make sure they are within the heated area of the house for as much of their route as possible. 3- DRAINING To remove an existing cylinder you need to drain it down. Even when the water is turned off and no hot water is coming from the taps there is still a full cylinder of hot water which needs to be emptied from the bottom.
Turn off the cold supply to the hot -water cylinder and any heating appliance, including the immersion heater. Turn off the heating and hot-water system by switching off the boiler control's electricity supply. You should find a valve on the supply pipe from the cold-water storage tank(s) to turn off. Check the hot taps aren't running. If they are letting any water through, you will have to turn off the mains water supply to the tank and then drain the cold-water tank. This will cut off the water supply to the cylinder.
The water supply may be off for some time, so ensure there is plenty of If the drain off point won't work, it is probably because the washer has baked on or the outlet is full of limescale. The alternative way to drain the cylinder is through the top connection. You'll need to undo the nut at the top and lift out the pipe. A small amount of water might come out so have a towel ready to mop it up. Poke the hose down through the hole in the top of the cylinder and siphon the water out to a lower point by partially filling the hose from a garden tap and then letting the water go at once. Once the cylinder is completely empty, drain the water from the boiler or a low point on the radiator circuit. Open any motorised valves by sliding the manual lever against the spring to the open position. When the heating and primary hot-water circuits have been drained you can undo all the connections on the cylinder. 4- REMOVING AND REFITTING AN IMMERSION HEATER Turn off the electricity supply to the immersion heater at the consumer unit by removing the fuse or MCB (miniature circuit breaker). Undo the cover on the immersion heater and disconnect the three wires. Loosen the flex clamp and pull the supply flex through.
Use an immersion-heater spanner to loosen the heater. It turns in an anticlockwise direction. If it won't undo, don't force it or the cylinder will buckle. Use a hammer and gently tap the spanner handle. If this doesn't work, use gentle heat from a blowlamp or hot-air gun to warm the brass.
This will soften any linseed-oil-based sealant which has been used.
When you fit an immersion heater, make sure the sealing ring is placed on
the underside. If you want to use some additional sealant, make certain it
is a non-setting variety which is suitable for drinking water. This prevents
Again, don't use too much force in tightening the heater or the cylinder will buckle. Once you fill the cylinder with water you can check for leaks and tap the spanner slightly to tighten it. When you are sure there aren't leaks, you can connect the wires. If you connect the wires first and need to tighten the heater, you won't be able to get the spanner on without disconnecting again. The live supply must be connected to the thermostat which fits in a dry pocket. Set the thermostat to 60°C. Make sure the heater is securely connected to the earth wire. If the flexible cable from the wall switch to the heater needs renewing, make sure you use heat-resistant PVC or butyl rubber flex. If you use 1.5mm2, the length should not exceed 1m, otherwise use 2.5mm2. The supply cable from the fuse box to the switch must be 2.5mm2.
5- FITTING THE CYLINDER Try to arrange all pipework so it is easily accessible. If there are awkward connections to be made behind the cylinder try to attach the fittings and fit short lengths of pipe so the cylinder can be moved
into place pre-plumbed. You can then connect 6- COLD FEED The bottom connection must be made with a
threaded elbow or straight connector. Wrap the
The thread should be so tight that a spanner is
You must incorporate a drain cock in the lowest
Secure the pipe to the wall and take it up to the 7- VENT PIPE Wrap the top threaded connector and screw into the hole so the elbow is in the right direction to take the pipe to the vent pipe. It will be either 3/4 in or 1in British Standard pipe thread. The 22mm pipe must rise to the open vent which hooks over the top of the cold-water
tank. Make sure the vent pipe doesn't dip into
the water. Avoid running a pipe over the top of the immersion heater or it will be impossible to change the heater when it burns out.
Don't run the vent pipe directly up from the middle of the cylinder because
the 8- HOT SUPPLY TO TAPS
The branch to the taps is taken from the vent pipe close to the cylinder. It
must 9- SHOWER CONNECTIONS If you have a pumped shower, you might want to fit a separate supply. This can be done with a special dip pipe flange (Surrey Flange) which screws into the top of the cylinder .
10- PRIMARY COIL CONNECTION TO THE BOILER CIRCUIT On a gravity system, which uses the weight difference between hot and cold water to circulate water from the boiler to the cylinder, it is essential that the flow enters the side of the cylinder at the top of the coil. On fully pumped systems it doesn't matter. You can use 1in male threaded connectors to connect the primary pipework to the cylinder, or use purpose-made cylinder unions (which look like large tap connectors). If the system is fully pumped, 22mm pipes will be enough. Where the pump only circulates the radiator water you will need 28mm pipework and connections. Don't reduce the size going into the cylinder. Check that the top primary connection is level or slightly rising from the cylinder to the vent pipe . Some systems have a venting mechanism at this point so the pipework can drop down to a vent elsewhere. The bottom connection returning to the boiler is connected in the same way. On fully pumped systems there is often a valve at this point to balance the water between the radiator circuits and the cylinder. Do not connect copper pipes to galvanized-iron pipes (silver coloured) because an electrolytic action will cause the pipes to corrode and block. If you need to keep old pipework, connect plastic hot-water pipes to it. 11- PREVENTING SCALE If you live in a hard-water area, fit a scale-reducing device to the cold feed of the cylinder . Even a small build-up of scale will add several pounds to your fuel bills and slow down the rate at which your cylinder will heat up. 12- ATTACHING A CYLINDER THERMOSTAT If you have a clamp-on thermostat on your old cylinder, you will need to fit it to the new cylinder. Cut a small rectangle out of the insulation on the opposite side to the boiler primary pipes. The height of the thermostat should be about one third up the cylinder. See illustration (2) for reference. |
Send mail to
info@dynomo.co.uk
with questions or comments about this web site.
|
