When installing a new towel rail/radiator, the first thing to consider is whether this new item will give the same heat output as the one being removed. To gauge the output of your existing radiator you will need to measure the width and height, as well as taking note of the radiator type. For example is it just the panel only? Single or double, without connector fins attached at the back of the panel(s)? These run top to bottom on the back of the radiator, and look similar to the corrugated sections.
With this information on hand you would be able to find out from a plumbers' merchant, or alternatively go online and check radiator sizing to get the output - which will be measured in watts/Btus. Once you have this reading, you can then either find a towel rail/radiator to give equal output as a replacement or decide it will be an additional feature to the bathroom, because those cute little towel rails/radiators don't usually give the required heat output to keep the room warm enough. If you're replacing the radiator completely, then make sure you have the appropriate wall space for the new item.
Once you have made your choice you will need to look at what type of heating system you will attach it to. You may have a combination boiler (a sealed heating system), filled by either a metal braded hose detachable from the valves it's connected to, or a knob/lever valve built into the boiler and usually found underneath. This is what you will use to refill your boiler and heating system after the new rail/radiator has been fitted, but first you must get a few fittings to be able to reconnect the new item.
These can be done by soldered or compression fittings. Once you have these fittings you can drain the heating system of the water/chemicals that should be in there, and connect a hose pipe to a drain-off valve found at the lowest points of the pipe work going to the radiators. There could be more than one of these, depending on the design of the pipework. Put the other end of the hose in a foul drain gulley only (due to the chemicals in the water from the system), and turn the electric supply off at the power point the boiler is connected to. Take the fuse out to make sure no one accidently turns the boiler back on while you're draining the water out of the heating system, then you can start by opening the draining valve the hose is connected to until the initial pressure that was in the system has come out.
You can now start to bleed the individual radiators by opening the air bleed valve sited at one top end or the backside of the panel with a radiator air bleed key. Start with the top radiators first, and when they have stopped draining do the lower ones. With the system drained you can lift the flooring under the existing radiator to expose the pipework. If you don't feel competent enough to solder the pipework and fittings, you can use compression fittings to alter and connect the new item.
When the new item has been both hung and piped up, you will need to go around closing all the air bleeds on the other radiators and shut the drain-off valve before filling the system. You'll require someone else at the new radiator so they can tell you if there is a problem before you put too much water in when filling the system. Pressure the system to 1.5 bar on the boiler gauge, shut off the filling point and check your new pipework and fittings. Leave things at that pressure for about 10-15 minutes to see if it is holding, and if it is after that period then it is safe to start bleeding the radiators until the pressure has gone. Go back to the boiler to re-pressurise to 1.5 bar and shut off the valve again, repeating this filling and bleeding until you have to radiators left to fill and bleed. With only two left only pressure them to 1 bar before bleeding, and again to 1 bar after the radiators have been bled. Replace the fuse in the fused spur, turn the electric on and put the controls for the boiler onto constant, allowing you to check your new installation is heating up okay. When the system is up to full temperature and there are no problems the flooring can be replaced.
However if you have an open vented system, you should find a small header tank in your loft connected to the heating pipework in the airing cupboard. There will be a stop valve on the pipework feeding that tank - you should shut this off (turning off your boiler's electric first), and then drain down the same way as previously mentioned. This time when you turn the valve back on, you will have to keep an eye on the new pipework and item for leaks. If you hear air leaking out of your new work as it is filling, stop and fix before continuing. If no air is leaking keep filling until the tank is full. When it stops you can then bleed the radiators, starting downstairs and working up. Turn the power back on to the boiler and put the controls on constant like previously mentioned, allowing it to heat up and then replacing the flooring once full heat has been achieved.
- Mark Lewis
If after reading this you still feel like you might need a little bit of extra practice before taking on such a DIY task, have you considered one of Access Training's intensive plumbing courses? Not only to we offer them at a variety of difficulty levels suited to whatever renovation plans you may have, but also professional qualifications should you choose to take things further and become a fully trained plumber. For more information on our courses and to discuss your needs call us on 0800 345 7492.