Novus Blog

At least in the short term, it looks like many of us are going to be working from home over the winter period and spending much more time indoors. So perhaps this year more than any year previously, it is important that your central heating is working correctly.

Over the colder autumn and winter months, you might have noticed your heating switching on.

If not, it might be time to test whether your central heating is working ahead of the temperature dropping outside.

After a summer of neglect and under use, issues with central heating are quite common in autumn when the system begins to be called upon once more.

Before you call the landlord or a Gas Safe Registered Engineer, there are some common issues with radiators and central heating that you can check and potentially fix yourself:

My heating hasn’t come on and the radiators are cold

The heating is off, and the radiators are cold.

There are numerous things that could be causing your heating to have gone off but the first check might seem fairly obvious; make sure that your thermostat is on and calling for heat by adjusting the settings above the current room temperature.

Then wait to see if that makes a difference…

Check that your thermostat is not on a timer that you don’t recognise, especially the case if you have moved into a new house. Changes in the clocks going forward/backwards at different times of year might throw some people too.

A second check is to make sure that central heating and hot water settings are selected on programmer or boiler.

All fine?

If this doesn’t work, you can check the supplies to your heating system –

Electricity – check your heating system has power by making sure the display screen on your thermostat, programmer or boiler is lit up (if they have them).

If they aren’t, there is usually a switch in the surrounding area of the boiler which controls the power supply, make sure it is on and has not been switched off accidently.

Gas – You can make sure you have gas to your property by checking other gas appliances such as the gas cooker, try lighting one of the hobs.

If there is no gas at the cooker and you have a prepayment meter, ensure you have sufficient funds on it.

Any issues with the gas supply to the property will need to be rectified by your gas supplier.

If you have gas and electric and the heating system controls are correctly set the next two most common problems should be checked –

• Central heating water pressure
• Blocked or frozen condensate pipe

My central heating has low pressure

If you have a combination boiler, low pressure in the system can cause the heating to not work effectively or even switch off altogether.

As with most of the issues raised here, there are once again numerous reasons why your heating system may have lost pressure; water leakage or the removal of air through radiator bleeding are the common ones.

You can check your system’s pressure by taking a quick look at the pressure gauge on the boiler (if it has one).

Even when you haven’t necessarily noticed an issue, we recommend that you check the pressure approximately once a month as good practice.

On a digital gauge if the reading is lower than 1 bar, then this is considered to be low pressure.

If the boiler is slightly older with a hydraulic gauge and a dial, there will be upper and lower limits marked out by red and green sections on the face of the dial.

How to re-pressurise your boiler

In the case of a low pressure reading, re-pressurising is something that you can without the assistance of a professional. However, if you are not confident, don’t attempt it.

Although most boilers are quite similar, there will be slight variations between each depending on the manufacturer. Before you start, we recommend that you read and understand the manufacturer’s user instructions first.

Re-pressurising with a filling loop

• Switch off your boiler and leave the system to cool down fully.
• Locate the filling loop and check to make sure that both ends are securely attached.
• Open the two valves and listen for the mains cold water entering the system.
• Keep a close eye on the pressure gauge until the pressure reaches 1.5 bar.
• Close both valves one at a time when it reaches this pressure.
• Turn the boiler back on and press the reset button on the boiler (if it has one).
• Undo the filling loop and catch any excess water.

If you find yourself having to re-pressurise the central heating system on a regular basis, there may be a water leak and it is important to address this issue as soon as possible to prevent damage to your property.

Your condensate pipe may be blocked or frozen

Check the condensate pipe is not blocked where is enters the drain, if the water has no where to drain it can back up which will stop the boiler from working.

At really cold times, condensate pipes situated in exposed locations can freeze, again causing the water to back up.

This can be readily rectified by defrosting the pipe using warm water.

If you have tried all of these and still have no heating, it is time to call in a Gas Safe registered Engineer to further investigate.

My radiators are warm at the bottom but cold at the top

This is a very common complaint and is sure sign that there is air trapped inside the radiator that has risen to the top, therefore displacing the hot water.

To fix this issue, the radiators will require bleeding.

How do you bleed a radiator?

It’s actually pretty straight forward but you will need a radiator bleed key or with newer radiators, a small flat head screwdriver.

• Switch off the heating and wait for the radiators to cool down completely.
• Find the bleed value, which you will find at the top of the radiator on one of its ends (it looks like a round hole with a square inside it).
• Place a container directly beneath the valve on the floor to catch any spillages when the radiator is being bled. Also, have on old kitchen towel or rag ready.
• Attach the radiator key to the square bit in the centre of the bleed valve or insert the screwdriver into the groove of the valve screw.
• Turn it anti-clockwise; one quarter to a half turn will be fine (not fully!). A hissing noise should indicate that the trapped air is escaping from the radiator. Hold the rag or kitchen towel over the hissing to avoid any excess water splashing up the wall.
• Once all the air has been released, the valve will start to trickle water (hence why you put a container to protect the floor). Wait until there is a steady stream of water and any sputtering has stopped to ensure all the air has gone.
• Finally, tighten the bleed screw (clockwise) ensuring that you do not tighten it too much as this could damage the valve.
• Wipe down any spillages and turn your heating back on.

Some of my radiators are not getting warm?

This is a common problem and is usually caused by a minor blockage or an unbalanced system where the water in the pipework follows the easiest route. There are a few things we can check –

Ensure the radiator valves are open on the faulty radiator and the TRV is on its highest setting.

If it doesn’t warm up you can force the water in the heating system through the pipework by closing the lock shield valves on all other radiators, leaving the faulty one open.

If this works and the faulty radiator heats up you can reopen all other valves by half a turn. This will restrict the amount of water they are taking and ensure the faulty radiator stays warm.

If this doesn’t work, it’s time to call in a professional as your heating system may need flushing.

Your safety is the priority

As always, your safety is the number 1 priority here.

Please do not attempt any of the fixes mentioned in this article unless you are absolutely confident that you can complete them safely and, if you are renting, within the boundaries of your rental agreement with your landlord.