how do you drain a vented heating system

6 steps to drain and refill a central heating system

• Step 1. Switch the heating system off First things first, as a safety measure it is important to switch off the heating system. ...
• Step 2. Cut the water supply ...
• Step 3. Locate the radiator with the drain-off valve ...
• Step 4. Open the drain-off valve ...
• Step 5. Bleed the radiators and allow water to drain ...
• Step 6. Refill the central heating system ...

Full Answer

How do I drain my central heating system?

To drain a central heating system you first need to switch your heating system off for safety reasons as well as cut the water supply, which can be done at the mains or by isolating your boiler. Next, you need to locate the main radiator which has the drain-off valve, this is usually located on the ground floor of your home.

How do you drain a radiator without a drain valve?

Isolate the radiator from your heating system 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.

Can you drain down a sealed or unvented central heating system?

This guide explains how to drain down and refill a sealed or unvented central heating system. For vented systems see Draining Down Vented Central Heating System. On a sealed system, as the name implies, there is no new water being added to the system on demand.

Why is my drain off not draining my central heating system?

If your drain off is not draining your central heating system and your wondering why, this will most likely be due to the age of the drain off valve and the muck that is stuck behind the draining valve.

How to drain central heating without a drain valve?

Why Draining a Central Heating System is Necessary?

How to prevent limescale build up on radiator?

How long does it take to drain a radiator?

How to make water run faster in a radiator?

How do I drain a combi boiler?

How to speed up draining?

See 2 more

How do I empty my heating system?

Go around your house ensuring that all the radiator valves are open, then go back to your radiator with the attached hosepipe and open up the valve. All the water will start to drain out. To get the water to drain out more quickly and effectively, go upstairs and open the bleed valves on all of your upstairs radiators.

How do you drain a heating system without a drain valve?

Isolate the radiator from your heating system If you don't have a drain valve, you need to separate the radiator from the system by closing the two valves on each end of the radiator. On one end is the regulator or thermostatic radiator valve (TRV). All you need to do here is rotate it in a clockwise direction.

How do you drain a radiant heat system?

How To Drain A Central Heating SystemSwitch off the boiler.Shut the water intake valve.Locate the drain-off valve.Drain the radiators.Open the bleed valves.Complete the drainage process.

Do you need to turn water off to drain central heating?

If you do not have a radiator with a drain-off valve then the process is slightly different. Steps 1 and 2 will be the same. You will still need to turn off your heating system and make sure that all of the radiators and pipes have properly cooled down and that the water supply has been cut off.

How do I find my drain valve?

The drain off point for draining central heating system, will be found at either the lowest point of the plumbing pipes, almost the lowest point next to the radiators or if your very lucky, you may find it on the outside wall.

Where is the drain valve on central heating?

The drainage valve is usually located at the lowest point of your heating system, typically to one side of a downstairs radiator, however, it may also be located outside your property, in which case you won't need to worry as much about any spillages.

How do I winterize my radiant heating system?

Winterizing a radiant heat system is done by replacing water with antifreeze. Winterizing a radiant heat system keeps it from freezing when not in use or when exposed to temperatures that may cause freezing of regular water. A radiant heat system can be winterized with a special type of antifreeze.

How do you drain and refill a heating system?

Close all bleed & drain valves Go round each radiator and close every bleed valve and drain valve and, if you have a feed and expansion tank, release the ball valve. You can then switch the mains water supply back on. After a short while, your central heating system will start to refill with water.

Can I flush my central heating system myself?

There are a couple of ways that you can clean the sludge out of your heating system. The first is called a powerflush, which is both the name of the method and also a physical device that your heating engineer will use. Alternatively, you can take every radiator off one at a time and flush it yourself.

Is there always water in central heating pipes?

Your central heating system moves in a constant circle which pushes hot water from your boiler, to the heating elements and back again to accumulate more heat. The same water is locked within your system, and loops around again and again, unless you flush your heating system.

Can I drain my heating system and still have hot water?

As a result, if you have a combi boiler, you may want to take steps to ensure you can still use hot water while the system is drained down. To do this, you'll need to cap the pipes and isolate the boiler from the system. Then, you'll need to pressurise the boiler to 1.5 bar and switch your boiler back on.

How often should I drain my central heating system?

If you want to keep your system in tip-top shape then power flushing every 5 to 6 years is a good idea. Still, you should be able to get away with power-flushing your radiators every 8 to 10 years depending on the quality of the materials used in your system.

How do you bleed an old radiator without a valve?

Bleeding a Radiator With a Towel Rail or Compression JointTurn off your heating and give the radiators time to cool down. ... With a towel to hand, loosen the compression joint where the towel rail joins the radiator. ... Once the hissing stops, retighten the valve with the wrench. ... Turn the heating back on.More items...

How do you drain a hot water heater without a hose?

Remove the aerator from your kitchen faucet. Open the hot water side on your faucet. Opening the faucet will allow air into the water heater so it can drain. Tip: If your system has an older style pressure relief valve, you can use it to let air into the tank.

How do you drain a 20 gallon water heater without drain?

Lay the other end of the garden hose in either a floor drain, a tilted 5-gallon bucket, a toilet at similar or lower elevation, or a sump pump pit. If none of these options work for your situation, connect the hose to a pump and run a second hose out of a window to drain on the ground.

How do I drain my central heating system and refill?

Close all bleed & drain valves Go round each radiator and close every bleed valve and drain valve and, if you have a feed and expansion tank, release the ball valve. You can then switch the mains water supply back on. After a short while, your central heating system will start to refill with water.

How to drain central heating without a drain valve?

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.

Why Draining a Central Heating System is Necessary?

Draining central heating, in order to remove the accumulated sludge and limescale, is also a good practice. And let’s not forget that some heating or boiler repair works can’t be dealt with without draining the whole system down.

How to prevent limescale build up on radiator?

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 .

How long does it take to drain a radiator?

The entire process may take around 20 minutes to more than an hour, based on the type of system you have.

How to make water run faster in a radiator?

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.

How do I drain a combi boiler?

Step 1. Turn off your system and cut the water supply. 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.

How to speed up draining?

Open the bleed valves to let the air out of your system, as this will speed up the process of draining.

How do you drain a central heating system?

To drain a central heating system you first need to switch your heating system off for safety reasons as well as cut the water supply, which can be done at the mains or by isolating your boiler. Next, you need to locate the main radiator which has the drain-off valve, this is usually located on the ground floor of your home.

How to release water from radiator without drain off valve?

Place a bucket and towels underneath this coupling nut and with the support of an adjustable spanner rotate the nut anti-clockwise until the water starts to pour out. Monitor this and tighten the coupling nut when the bucket is full. Empty the water and continue. Alternatively, attach a hose using a speed fit tap to drain the radiator.

Why do you need to bleed your radiator?

In a nutshell, bleeding your radiator is to release air that has become trapped in the system. It is common to need to bleed your radiators as air can get trapped in the system and cause your radiator to distribute heat un-evenly as the areas with trapped air remain cool.

How to isolate a radiator from a heating system?

To isolate the radiator, you will need to close the two valves on either side of it. You close the regulator valve by rotating it clockwise. You close the lockshield valve by removing the plastic cap and using pliers to tighten the valve. A top tip is to take a note of how many turns you have made, as you will need to re-tighten it the same amount when you are refilling it.

How to check if radiator is bleed?

Double-check that every radiator has its bleed valves closed. When you detach the hosepipe from the drain-off valve, you will be able to see if you have closed it properly. Switch the mains water supply back on and after a moment your central heating system will start to refill.

What to do if you don't have a drain off valve?

Steps 1 and 2 will be the same. You will still need to turn off your heating system and make sure that all of the radiators and pipes have properly cooled down and that the water supply has been cut off.

What controls the temperature of a radiator?

Make sure that all the radiator valves in the house are open. Every radiator will have two main valves, one that controls how much water is traveling through the radiator called the regulator, and the other is a thermostatic valve called the lockshield which controls the temperature.

How to drain a radiator that has no drain off valve?

To drain a radiator, as mentioned in one off the above paragraphs, you can either freeze the pipes at both ends and fit a drain off valve to drain down or just open a nut nearest to the radiator at both end and drain down.

Why is it important to drain radiators?

It is very important to keep all the radiator valves in the open position to ensure there is no water left behind when draining, allowing air pockets to form.

Why does water come out of the radiator?

The reason central heating water will come out slowly of the drain off valve is most likely because the drain off valve may be full of muck.

Why does my central heating system leak water?

Why does the drain valve leak water when draining down the central heating system. The drain off valve leaks when draining down due to there being no washer or the washer is worn but, most likely due to no washer as the old valve tend not to have one. As shown in the picture here is the new type of drain off valve, ...

What is the difference between an unvented and an open vented system?

The difference between draining an open vented combination systems and an un-vented system is a question asked to me from another plumber and the answer is: the open vented system is a gravity pressure, where the un-vented is pressurised meaning in the un-vented system you do not need to turn the water off, when draining central heating system.

Why isn't my central heating drain draining?

If your drain off is not draining your central heating system and your wondering why, this will most likely be due to the age of the drain off valve and the muck that is stuck behind the draining valve. There is a very slight possibly that if you stick something thin down the valve, such as solder wire, you may get rid of the blockage once the valve is in the full open position. There are other possibilities as mentioned in the paragraph below.

How long does it take to drain a central heating system?

How long does it take to drain the central heating system. To drain the central heating system, it takes on average 20-minutes, however a more complicated system depending on the draining down process can take as much as 2-hours leaving the plumber very frustrated.

Why do you need to drain a central heating system?

A central heating system may need to be drained down to carry out a repair or maintenance work or to make a modification to the system such as fitting a new radiator.

What happens if water stops flowing in my house?

Once the water has stopped flowing, the heating system will be empty and you can now carry out whatever repairs or maintenance work is required .

Why Would I Need to Dain Down my Heating System?

This may be because you need to introduce an agent to clean it and flush it through, removing sludge etc or simply to change a radiator.

What to do when no water comes out of hose?

When no more water comes out of the hose you must check that the system has completley finished draining before you remove radiators or start work. There is a chance that some air has got into the system and locked the water from escaping.

How to get water out of a drain valve?

Using an adjustable wrench, open up the drain valve and let the water from the system run through.

How to ensure no water comes in when draining a tank?

To ensure no water comes in while you are draining the system down it is an easy job to place a piece of timber across the tank, lift up the valve arm and tie it to the timber. This will close the valve.

Why does my water heater make a knocking sound?

As the water heats up you may hear some knocking sounds as any air expands in the system. The radiators will probably need bleeding again once the system is fully heated.

What happens when the water rises in a toilet cistern?

This valve is the same as the one in your toilet cistern ( see our tanks and cisterns project ), When the water rises it lifts the ballcock. The ball is attached to an arm which closes the valve when it is lifted. When the tank is full of water, no more can get in because the valve is closed.

What is the feed and expansion tank?

In your loft you will have a tank called a feed and expansion tank. Its recognizable by a pipe coming in at the top which is the expansion part of the equation. If the water gets too hot in your system the steam can expand, via the pipe, into this tank.

Why Is Venting Necessary?

Open the vent cap on a plastic gas container and it flows smoothly. That's because the vent hole allows air to enter behind the flowing liquid, producing a quick, glug-free flow. Vent stacks in a household plumbing system work the same way.

What is a true vent?

A true vent is a vertical pipe attached to a drain line that travels through the roof with no water running through it. If a fixture is close to the stack and on the top floor, the upper part of the stack serves nicely as a vent. Many fixtures are not so conveniently located, however, and other solutions must be found.

How to determine critical distance?

The critical distance, or how far the fixture can be from the vent pipe, is determined by three factors: the size of the pipe that codes require, the type of fixture you want to install, and the number of fixtures that are already wet vented on the same line . Measure the length of the pipe s carefully and consult a plumbing inspector ...

How big is a DWV drain pipe?

The centerpiece of a DWV system is the main stack, usually a pipe 3 or 4 inches in diameter that runs straight up through the roof. A secondary stack, perhaps 2 or 3 inches in diameter, serves a branch of the system. Branch drainpipes of smaller diameter (typically 1-1/2 or 2 inches) carry water from specific fixtures to a stack.

How big should a drain line be for a kitchen sink?

Plan drain lines to minimize the possibility of clogs. The general rule is that smaller drainpipes (1-1/4 inches for bathroom sinks and 1-1/2 inches for kitchen sinks, for instance) lead to larger branch drains. These in turn lead to the main stack, which is the largest pipe of all (typically 4 inches). Because the main stack is also vertical, it will rarely clog.

Why does the main stack of water clog?

Because the main stack is also vertical, it will rarely clog. Water travels downward through the stacks to the main drain line, an underground horizontal pipe that leads to the municipal sewage system or to a septic system. In older homes, the main drain might be made of clay pipe or other porous material.

How high should a vent be above flood level?

Other common ways to tie vents into a stack include sanitary crosses, revent alternatives, and loop vents installed at least 6 inches above flood level. Check local codes to see which methods are accepted in your area, then choose the method that requires the least number of holes or notches in studs.

When should I drain my central heating system?

You may need to drain your central heating system if you notice a radiator isn't working efficiently. For example, you may drain your central heating system so you can flush a cleaning agent through your radiators or remove sludge build-up inside a radiator. You will also need to drain your central heating system if you replace an old radiator with a new one.

Why is water still flowing out of my radiator?

Important: If after 10 minutes you notice that water is still flowing out the air vents in your downstairs radiator, it may be because all of your radiators are individually piped. If this happens, you will still be able to drain your central heating system, you will just need to drain each radiator individually.

How to bleed radiators?

Open the air vents Using the key you use to bleed your radiators, open the air vents at the top of the radiator. You should turn the bleed key anti-clockwise until you hear a sucking noise. The sucking noise is air entering the radiator and means you have successfully opened the radiator air vents. 7.

Do electric radiators need plumbing?

Electric radiators are also ideal to include in areas such as garages or outdoor buildings, as they do not require the same extensive plumbing as radiators connected to a central heating system. Another great alternative radiator is a low surface temperature radiator.

Is central heating the best way to heat a house?

If you feel that central heating isn’t the best or most efficient way to heat your home, for example, if you only spend your time in a few of the rooms in your house, there are other options. Electric radiators, for example, can be included alongside a central heating system but operate with their own thermostat and use a different energy source.

How to drain central heating without a drain valve?

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.

Why Draining a Central Heating System is Necessary?

Draining central heating, in order to remove the accumulated sludge and limescale, is also a good practice. And let’s not forget that some heating or boiler repair works can’t be dealt with without draining the whole system down.

How to prevent limescale build up on radiator?

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 .

How long does it take to drain a radiator?

The entire process may take around 20 minutes to more than an hour, based on the type of system you have.

How to make water run faster in a radiator?

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.

How do I drain a combi boiler?

Step 1. Turn off your system and cut the water supply. 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.

How to speed up draining?

Open the bleed valves to let the air out of your system, as this will speed up the process of draining.