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    Boilers How to Replace a Leaking Radiator
  • Leaking Radiator

    If you have a leaking radiator on your central heating system then it will need to be replaced.

    They can sometimes be repaired but it’s really quicker just to replace than trying to find someone who can weld it up, and will be cheaper to replace.

    If the leaking radiator is leaking badly then you will need to isolate it to stop it causing any damage to your property, on each radiator you should have a valve each side, you need to close both valves, this will stop the flow of water going to the radiator.

    Once the water has stopped you can now decide if you are going to replace it yourself or call in a professional.

    If you are going to try and replace the leaking radiator yourself then you will need to take yourself off to the local plumbing and heating merchants to purchase a new one, make sure you have taken the measurements of the leaking radiator.

    Now you have the new radiator you are now ready to replace the leaking radiator.

    If the new radiator is the exact same make and size then it is a simple job to replace.

    To change the radiator you need to undo the valves on each side, the nuts closest to the radiator not the ones that the pipe goes in.

    Make sure you have turned the valves off first though.

    If the nuts are a little tight then just give it a little force, make sure you don’t let the valve move as it could cause the pipe side to leak.

    Once you have released the valves you will still have some water inside the radiator, drain this off into a bowl then remove the radiator.

    If you have problems undoing the valves then you will need to drain down the whole central heating system down.

    Now you have the radiator removed you need to remove the valve tails and refit them to the new radiator, make sure you use PTFE on the thread otherwise it will leak. Now refit the new radiator to the wall and tighten the valves.

    You are now ready to refill your new radiator with water.

    If you have a tank feed heating system then as soon as you open the radiator valves then the tank will start to refill, if you have a sealed or pressurised system then you need to refill the system via the fill-up loop.

    Open the fill-up loop and check the pressure gauge this is normally located close to or on the boiler.

    Take the pressure to 1.5 bar then close.

    Now go and remove the air from the new radiator via the air vent, once full close the vent, check the pressure to make sure it hasn’t dropped below 1.2 bar.

    If you had to drain the whole heating system then you need to vent all the radiators.

    Now your heating system is full of water you are ready to heat test, switch your heating on and check that all the radiators are heating up.

    If you find some get hot and some stay cold then close the ones that are hot and you should find the other ones will start to heat up.

    A leaking radiator is caused by corrosion within the heating system.

    To stop the corrosion you will need an inhibitor to the system.

    When you were draining you’re leaking radiator if the water was black then you need to flush your heating system out with a flushing agent and add an inhibitor otherwise you may have more leaking radiators in the future.

    If you would like to know more about a leaking radiator then just enter your name in the box below…