How to bleed a towel radiator: 3 simple steps to keep it hot

Close up of gloved hand bleeding a chrome towel radiator
(Image credit: Getty Images)

Cold towel radiator? Then you need to know how to bleed a towel radiator to bring it back up to piping hot to keep your towels toasty. When air gets trapped in the heating system you'll notice your towel radiator isn't warming up properly — ordinarily being hot at the bottom and cold at the top.

Bleeding a radiator is the easy way to remove trapped air. A heating system is pressurised, so when the bleed valve is opened it forces the air out allowing the water to fill the radiator. 

But it is worth noting the reasons why air is getting into your system. There might be a leak somewhere, or your radiators need replacing. If it happens regularly you will need to call in a professional to help identify any issues.

But until then follow out quick and easy guide to stay warm.

How to bleed a towel radiator quickly 

To bleed a towel radiator you will need the right tool to help undo the bleed valve. For this job you can use a standard radiator key or a flat head screwdriver. 

1. Turn off the heating and switch on the radiator valves

The first step is to ensure your heating is turned off and the towel radiator has cooled down.

A towel radiator will need to be filled with water to bleed properly. Typically there will be two valves on the bottom which allow water into the radiator. You need to make sure that these are both open.

If your towel radiator is equipped with a TRV (Thermostatic Radiator Valve) turn it up to the max (typically number 5). If you have valve caps that twist, turn anti-clockwise. If the caps are just covers, pop off and use a pair of pliers to turn the valve anti-clockwise.

2. Open the bleed valve
First locate the bleed valve. This is typically on top of the radiator and will have a small square screw in the centre with a slot on top. There will also be a small hole in the bleed valve where the water comes out when you open it. 

Get a towel or cloth and wrap around the bleed valve and get a small container to capture the water

Now get your radiator key – or if you don’t have one, a slotted screwdriver – and slowly turn the screw until you hear air hissing out. As soon as this happens get ready to catch any water. Quickly close when the hissing stops.

3. Repressurise heating system
After letting air out of the system, the pressure on the heating system will drop. If you have a pressurised boiler you may need to repressurise the system to get it back up to optimum working order. The process is different depending on what system and what manufacturer you have. 

If you don’t know how to repressurise your boiler, locate the instruction manual and see how it's done. If unsure, contact a professional. 

Close up of a towel radiator bleed valve

A towel radiator bleed valve typically sits on top of the radiator (Image credit: Steven Jenkins)

What are the two valves on top of a towel radiator for? 

These are not valves in the same sense that they control the water flow in and out of the radiator. One is a vent valve, which is known as the bleed valve, which releases trapped air.

The other is known as a blanking plug. This effectively seals up the other hole in the top of the towel radiator. This simply screws in the top of the radiator. You will need an adjustable spanner to insert or replace.

How much will a plumber charge to bleed a radiator?

If you follow this guide you wont need to call out a plumber to bleed your towel radiator. However, heating a bathroom is essential when the winter months close in. When bleeding your towel radiator it will be a good time to do all the radiators in your home.

If you are not confident doing this yourself you can call in a plumber, or potentially combine this with your annual boiler service. The price will depend on how many radiators that you have. If you have less than 10 radiators the job should take an hour or two or less. Expect to pay around £80-£100.

If you have more than 10 radiators the job will obviously take longer, maybe around two to three hours expect to pay £100-£150.

Steve Jenkins

Steve is Homebuilding & Renovating's DIY content editor, and has been a writer and editor for two decades. He is an avid DIYer with over 20 years of experience in transforming and renovating homes. He specialises in painting and decorating, but has strong all-round building skills, having previously worked in the industry for 10 years.