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Owning a central heating system, it is essential that you maintain it regularly for it to last a long time. Consistent upkeep is vital for your central heating systems’s performance, and from time to time, you need to drain it and clean it. We have noted a stop by step guide on all you need to know for this!
Sometimes maintenance is not the only reason to drain your central heating. This will be also necessary when you’re up to remove a radiator or fit a new one. Draining central heating, in order to remove the accumulated sludge and limescale, is also a good practice. And let’s not forget that some repair works can’t be dealt with without draining the whole system down.
Your central heating system is an important addition to your home, as it provides hot water and heating (essential for this cold winter!). That’s why you need to know how to handle the task properly and safely with the following steps:
Before you start draining, switch off the system as a safety measure. Then wait until the pipes cool down completely, and if you are about to do a replacement or restoration job on your radiators, let them cool down, as well.
If your boiler operates with solid fuel, better make sure to extinguish the fire, and wait until the boiler is entirely cold.
Before draining the central heating system, stop the water supply to your unit, which will prevent the water from entering it while you work. There should be a separate stop tap for that, however, if there isn’t one or you find it hard to turn it, simply stop the water flow by tying up the ball valve to a wood laid on top of the cistern.
Remember, there is a difference between the draining methods with conventional and combi boilers. When you want to drain a central heating system with a combi boiler, switch off the boiler, wait for it to cool down completely and proceed with the draining process. Anyway, the method you should follow with a sealed central heating system is a bit different. Firstly, isolate the water flow to the water tank and then switch the boiler off.
The right radiator, in this case, is located somewhere on the first floor in your house. Look at the bottom of the radiator, as most of the time the drain valve is located there. Grab a garden hose and clip it with the help of a clip to the outlet, so the water runs outside. The clip will prevent the hosepipe from slipping off and ending up with the water making a mess. Just in case, you can also tighten the clip with a flat-head screwdriver.
Remember, there are chemicals in the inhibitor, so locate the hosepipe somewhere away from plants and your lawn. If you don’t have a hosepipe, a bucket will also do the trick. Except, you should shut off the valve every time you need to empty the bucket.
Now it’s time for the actual work. open the bleed valve, so the water runs through the system freely. To make the water run faster, start with the radiators at the top of the building. Wait for about 15 minutes and open the bleed valves on the radiators downstairs.
Sometimes, some air has got into the system, which prevents the water from running. If so, fill the tank with about 15 cm of water and loosen the valve you previously tied up. The water should start running out of the hose in a few seconds. If that doesn’t work, then you have locked air and should join the other end of the hose to the cold tap and give a blast of water back into the radiator you are draining.
Make sure that all the radiator valves in your house are open and if necessary check twice. Next, open the radiator valve, to which the hosepipe is attached and drain your central heating down. The entire process may take around 20 minutes to more than an hour, based on the type of system you have. Open the bleed valves of all your radiators to speed the process up.
Of course, once you’re done with your work, you have to refill the system. Start by closing all the valves you’ve previously opened, as well as the drain cock on the radiator. Let the water fill up the system by uniting the string in the feed tank. Once the tank is completely filled up, start bleeding the radiators downstairs. Then, repeat the latter with these upstairs and with that, your system should be filled.
We recommend that you add an inhibitor to your system to limit corrosion and limescale build-ups. Check if you’ve tightened all the valves and switch on the power supply. Wait for the system to heat and bleed the radiators once again. Check all joints and valves to ensure there are no visible radiator leaks.
Having no drain-off valve? Then, follow along:
Before starting the draining process, switch off the system and wait for the pipes and radiators to cool down entirely. If you deal with a combi-boiler turn it off, wait for it to cool and discharge the water. But if you own a conventional system, then, first, make sure to isolate the water and then turn off the boiler.
When draining central heating without a drain valve, you need to separate the radiator by the system. Here all you need to do is to close the two valves. For the regulator, you need to rotate it in a clockwise direction. When it comes to the lockshield, remove the plastic cap, grab the pliers and close the valve back tightly.
Open the bleed valves to let the air out of your system, as this will speed up the process of draining.
The method by which you drain a central heating system without a drain valve should look something like this:
When the radiator valve is in off position, attach a hose to it and start draining your central heating system. You will need a special fitting to attach the hose itself. That can be speed fit tap or speed fit draining fitting. Once the radiator is empty, take the radiator off the wall carefully, as the water in it can stain. To prevent that, make sure both radiator sides are drained.
As you can see, draining a central heating system is not rocket science, and with the right tools and some skills, anyone can handle the work. Anyway, if you still do not fully understand how to drain a central heating system by yourself and don’t want to risk causing any damage to your heating system, better contact professional heating engineer. Certified and trained specialists will know how to complete the job and ensure that your floor, radiators, pipes and fittings won’t get damaged.