Why Is My Radiator Still Cold After Bleeding?

Radiators are designed to cause as little hassle as possible. With systems that are supposed to run for years, and with warranties to match, it can be irritating when a problem continues to persist, even after attacking from all angles.

One such problem includes cold radiators. As an accessory and tool designed specifically and solely to warm up and provide heat for a room, when a radiator remains cold or has cold patches, it’s unsurprising that the homeowner might be just a little frustrated. Usually rectified through radiator bleeding, a relentless cold shoulder from your radiator needn’t spell doom and gloom for the oncoming autumn and winter period.

Whilst many electric radiators promise strong BTU outputs and no central heating problems, the majority of heating units out there run on hot water. This can trigger problems that are outside of the radiators control, affected instead by the homeowner and the environment around them. So, if you’re radiator has a cold patch and radiator bleeding hasn’t fixed the issue, these points might help you to find a solution.

Why Should I Bleed My Radiator?

If your radiator has cold patches, it’s probably because of air bubbles getting trapped in your system. Radiators use gravity and water pressure to push the hot water through the central heating system and pipes, and so when there’s not enough internal pipe pressure or a build-up of residue, hot water won't reach that specific section of the heating unit. Whether chrome radiators or coloured radiators, this will always be a problem with central heating based radiators.

What Is Radiator Bleeding?

Before we explore the alternatives to radiator bleeding, let’s take a look at what it actually is. Every central heating radiator in the world should come with a bleed valve installed. The reason for this is that radiator cold spots are unfortunately common occurrences, regardless of whether they’re top of the range designer radiators or not.

First off, make sure your radiator system and central heating are switched off. You don’t want boiling hot water dripping onto your skin. Once it’s turned off, find your radiators bleed valve, usually on the top corner of your radiator, and use a bleed key or similar tool to open it. Make sure you have put a bucket or towel under the valve, as it will almost certainly drip water. Once you’ve opened the valve, you should hear a hissing, which will indicate the air bubbles leaving the system. This will eventually stop, replaced by the dripping water. This is the signal to tighten up the bleed valve. Once you’ve done this, turn on your radiator and find out if the cold patch has gone.


What Are the Alternatives to Radiator Bleeding?

If you’re faced with a cold horizontal radiator, bleeding is the simplest solution. Even if it doesn't work, it’s a good litmus test to see if the problem is more serious than first thought. It’s never a waste of time to bleed a radiator, it will at least rule out the simplest ailment a radiator can encounter, meaning you can focus on other potential causes.

Check Your TRV Valves

Your TRV valves might be to blame for your cold radiator. With it’s gaging and controlling of the radiator units water content, the TRV valve plays an important part in regulating the temperature of your room. The pin can get stuck and can be easily get shut in the shut position. You can use an adjustable spanner to gently shift the pin into the open position, loosening it to allow water in again.

Check your TRV Valves

Flushing Your System

Flushing your radiator system can be used to get rid of any blockages inside. Chemical inhibitors are available at all good hardware and homeware shops and are used to shift any residue in your radiator system that could block the pipes. Turn off your central heating system and add the chemical inhibitor to your system. Turn on your central heating again and heat up your radiators. This will allow the chemical inhibitor to run through your radiator and get rid of any residue.

Radiator Balancing

An unbalanced radiator system is another reason why your radiator may have cold patches. Central heating radiators work through water running through the closest radiator to the boiler, and into the next. This can lead to less pressure reaching the last radiator in the system, which is why you should regulate the TRV valves pressure to be slightly more open for each radiator in the system.

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