Where the bleed valve is on a towel radiator
On most heated towel rails the bleed valve is at the very top of one of the two upright side bars, not on a top corner face as on a panel radiator. It usually points straight up out of the top cap of the upright, or sits on the side of the upright just below the top, facing outwards or towards the wall.
Look at both uprights. The valve is normally on the opposite side to where the pipes come in, but not always. On some designer rails it is hidden behind a decorative cap that pulls or unscrews off by hand, and a few have it on the back face, so you may need a mirror or a phone camera to find it.
The fitting itself is usually the same as on a radiator: a small square spindle for a standard key, a slot for a flat-head screwdriver, or both. Some rails use a small hex or a plastic fitting with the maker's own key. The fitting instructions that came with the rail show where the valve is and what opens it. If you have no key, our guide on bleeding a radiator without a key covers each type of valve.
Check what type of towel rail you have
How you bleed a towel rail, and whether you should at all, depends on how it is heated. Look for a cable or a wall switch next to it, and for pipes coming up from the floor or wall.
| Type of rail | How to recognise it | Bleed it? |
|---|---|---|
| Central heating only | Two pipes with a valve on each, no cable | Yes, like any radiator |
| Dual fuel | Pipes and valves, plus an electric element with a cable at the bottom of one upright | Yes, with the element switched off and the rail cool |
| Electric only, liquid filled | Cable and switch, no pipes, sealed at the factory or on fitting | No, unless the maker's instructions say so |
| Electric only, dry element | Cable and switch, no pipes, no liquid inside | No, there is nothing to bleed |
In older homes with a hot water cylinder, a towel rail is sometimes plumbed into the pipes that heat the cylinder, so it warms whenever the hot water is on. It still bleeds the same way as a central heating rail.
How to bleed a towel radiator, step by step
- Turn the heating off at the programmer or thermostat, and switch off the element at the wall switch on a dual fuel rail. Wait until the rail is cool enough to hold.
- Find the bleed valve at the top of an upright and remove any decorative cap.
- Wrap a cloth around the top of the upright and under the valve. Because the valve points upwards or sideways at the top of a narrow bar, water that comes out tends to run straight down the rail and onto the floor or the towels, rather than dripping in one spot.
- Open the valve anticlockwise a quarter to half a turn. Air should hiss out.
- Close it clockwise as soon as water appears in a steady trickle. Hand tight is enough.
- Wipe the rail dry, especially on chrome, where heating water leaves marks if it dries on.
- Check the boiler pressure on a combi or system boiler before turning the heating back on.
A towel rail holds much less water than a panel radiator, so the hiss of air is usually short. If you are bleeding the whole house, do the towel rail in the same order as the other radiators, starting on the lowest floor and working up. Our main guide on how to bleed a radiator explains that order.
Never bleed a towel rail while it is hot, and never touch the element, its cable or its wall switch with wet hands. On a dual fuel rail, switch the element off at the fused spur and let it cool before you open the bleed valve.
Why is my towel rail cold at the top?
A towel rail that is cold at the top and warm at the bottom almost always has trapped air, and bleeding it should fix it. Towel rails are tall and narrow, and the bleed valve sits at the highest point, so air collects in the top bars first. Bathroom rails are also often the highest or last radiator on a floor, where air from the rest of the system ends up.
If bleeding does not help, check these before calling anyone:
- Water came out straight away. Then there was no air, and the rail is simply not getting enough flow. Check both valves are open. If the rail has a thermostatic valve, turn it to its highest setting.
- The whole rail is only lukewarm. Towel rails often sit at the end of a pipe run and lose out to radiators nearer the boiler. The system may need balancing, which our guide to one radiator not heating explains.
- The bottom bars are cold instead. That points to sludge settling in the lowest bars, covered in our guide to radiators cold at the bottom.
- It never gets as hot as the panel radiators. That is often normal. Chrome towel rails give out noticeably less heat than a painted steel rail or panel radiator of a similar size, and the rails feel warm rather than hot.
Can you bleed an electric towel rail?
You should not bleed an electric-only towel rail unless the manufacturer's instructions tell you to. These rails are not connected to your heating pipes. A liquid-filled electric rail is a sealed unit filled with water and an additive, or a special fluid, and many are deliberately left with a small air space at the top so the liquid can expand as it heats. Opening a valve on it can let fluid out that you cannot easily replace, and on some models it affects the warranty.
So a slightly cooler top bar on an electric rail is not necessarily a fault. If an electric rail has gone cold or much cooler than it used to be, switch it off and check the fused spur and any timer or thermostat on the element first. If those are fine, contact the manufacturer or the installer. The element, its wiring and the spur are electrical work, so anything beyond changing a fuse is a job for a qualified electrician.
A dry element electric rail has nothing inside to bleed at all.
Dual fuel towel rails: bleeding and summer use
A dual fuel rail is a central heating rail with an electric element added, so it fills with the same water as your radiators and can collect air in exactly the same way. Bleed it with the heating off and the element switched off.
The element lets you warm towels in summer without running the whole heating system. Rail makers usually say to close one or both valves when running on electric so the heat does not escape into the pipework. Check the instructions for your rail before doing this, because water expands as it heats. If both valves are closed and the rail is running on its element, the expanding water needs somewhere to go, so follow the maker's guidance on which valve to leave open. Open both valves again when the central heating goes back on. For how the valves work, see our guide on how to turn off a radiator.
After bleeding: check the boiler pressure
On a combi or system boiler, bleeding lowers the system pressure slightly. A single towel rail rarely lets out enough to matter, but check the gauge anyway. If it has dropped below the cold pressure in your boiler manual, top it up following our guide to repressurising a boiler. Homes with a feed and expansion tank in the loft refill automatically.
When to call a plumber or engineer
Call a plumber or heating engineer if the towel rail keeps filling with air every few weeks, the bleed valve is seized or leaks after closing, or the rail stays cold after bleeding with both valves fully open. Call a qualified electrician, not a plumber, for any fault with the element, its cable or the fused spur on a dual fuel or electric rail. If you have to top up the boiler pressure regularly as well, mention that when you book, because it suggests a leak somewhere in the system rather than a problem with the rail itself.