In my 14 years of advising plumbers, landlords and homeowners at Elegant Radiators, the most frequent support question we receive is surprisingly simple: “Which valve do I turn, and which way does it go?”
Those two valves at the bottom of your towel rail aren’t just for show. One controls your comfort; the other balances your entire home’s heating system. Turning the wrong one can disturb your boiler’s efficiency and leave other radiators cold. Here is exactly how to adjust them safely — backed by over a decade of hands-on heating experience.
⚡ Quick Answer: Which Way to Turn?
To turn ON or increase heat: turn the adjustable valve anti-clockwise (to the left) to open it and allow hot water to flow.
To turn OFF or reduce heat: turn the valve clockwise (to the right) to restrict the flow.
Rule of thumb: Lefty-loosey (open & hot), Righty-tighty (closed & cold).
🔧 Understanding Your Two Valves
Your towel rail is connected to your central heating system by two distinct valves. Knowing which is which is the key to a healthy heating system.
1. The Wheelhead / TRV Valve
This is the one YOU adjust. It controls how much hot water enters the rail, and therefore how hot it gets.
- Usually on the left side (depends on your pipework)
- Has a twistable cap, a distinct handle, or a numbered dial (TRV)
- Anti-clockwise = more heat
- Clockwise = less heat
2. The Lockshield Valve — do NOT touch
This valve is pre-set by your heating engineer during installation to balance the system, so water flows evenly to every radiator in the house.
- Usually on the right side
- Covered by a blank plastic cap that spins freely
- Leave it alone — it controls water flow rate
- If you close it, the rail stops heating entirely and may need re-balancing by a plumber
📋 Step-by-Step: How to Turn On Your Towel Rail
Locate the adjustable valve
Find the valve with the twistable top or numbered dial (usually the left side). This is your temperature control — the one you’re allowed to touch.
Turn it anti-clockwise to open
Rotate the valve cap to the left. If it hasn’t been moved all season you may feel some initial resistance — this is normal.
Make sure the heating is calling for heat
Your central heating must be on and the room thermostat calling for heat before any hot water can reach the towel rail.
Wait and check the spread
Give it 10–15 minutes. Carefully touch the bottom bars first — heat should enter from the open valve and rise up to the top.
Expert tip: if the bottom bars get hot but the top stays cold, that is not a valve problem — you have trapped air. Bleed the radiator with a radiator key. See our guide on how to bleed a radiator.
🔄 Which Way to Turn?
Anti-Clockwise
OPEN = More Heat
Clockwise
CLOSE = Less Heat
💡 Remember: “Lefty loosey, righty tighty”
🎥 Manual vs Thermostatic (TRV) Valves
The way you interact with your valve depends on the technology inside it.
Manual Valves
These work like a simple tap. They are either open, closed, or somewhere in between, and they do not react to room temperature. You set the heat once and leave it. Best for towel rails where you want consistent drying. Shop manual valves →
Thermostatic (TRV) Valves
These feature a numbered dial (usually 1–5). A built-in liquid or wax sensor reads the room’s ambient temperature. Set to “3” (around 20°C) and the valve automatically shuts off the flow once the bathroom reaches that temperature — saving energy while you dry your towels. Do TRVs save money?
☀ Dual Fuel Systems: Summer vs Winter Mode
If you have a dual fuel towel rail (connected to both your central heating and the electrical mains), your valve management changes with the seasons:
- Winter (central heating mode): leave the manual/TRV valve OPEN (anti-clockwise) and switch the electric element OFF at the fused spur.
- Summer (electric-only mode): turn the manual/TRV valve completely CLOSED (clockwise) so the element does not push heated water back into your cold central heating pipes. Switch the electric element ON at the wall.
New to dual fuel? Read the complete dual fuel towel rail guide or view our heating elements guide.
⚠ Valve Turns, But No Heat? Troubleshooting
Run through this checklist before calling a plumber:
- Is the internal pin stuck? On a TRV, unscrew the numbered head and look for a small metal pin. If it sits in the “down” position the valve is closed. Gently tap the side of the valve body or press the pin with the flat side of a spanner until it springs back up.
- Is the lockshield closed? If a decorator or cleaner recently removed the rail, they may have closed the lockshield and forgotten to re-open it. What is a lockshield valve?
- Is the radiator full of air? Bottom hot, top cold usually means trapped air — bleed it.
- Is the system unbalanced or blocked? If the pipes are hot but the rail is cold, see our guide on why your towel radiator is cold.
- Is the valve faulty? If it turns freely but nothing changes, the valve may need replacing — see how to change a towel radiator valve.
🎫 Types of Radiator Valves
Manual Valve
From £8.99
- Simple twist to adjust
- No temperature settings
- Compact & minimal design
- Best for: Towel rails
Thermostatic (TRV)
From £24.99
- Set exact temperature
- Auto cut-off when warm
- Saves energy
- Best for: Living spaces
Corner Valve
From £19.99
- Pipes from wall
- Clean, hidden look
- Ideal for tight spaces
- Best for: Wall-mounted pipes
📐 Straight vs Angled Valves
Straight Valves
Use when your pipes come up from the floor. The valve connects in a straight line.
Angled Valves
Use when your pipes come from the wall. The valve has a 90° angle.
❓ Frequently Asked Questions
Should towel rail valves be fully open?
If you have a manual valve, yes — keeping it fully open gives maximum heat for drying thick towels. If the room becomes uncomfortably hot, throttle it back by turning the valve halfway clockwise. If you have a TRV, set it to 3 or 4 (around 20–22°C) and let the sensor regulate the flow for you.
Can a stuck radiator valve be fixed without draining the system?
If the TRV pin is merely stuck, yes — gently freeing the pin with pliers requires no draining. However, if the internal valve gland is leaking or the valve is completely seized, that section of the system will need to be drained to fit a replacement valve.
Does it matter if the valve is on the left or right?
Most modern designer radiators and towel rails are bi-directional, so water can flow in from either side. However, the adjustable TRV or wheelhead valve should always be installed on the flow pipe (where the hot water enters), and the lockshield on the return pipe. If yours are the other way round it will still work, but the temperature control will feel less accurate.
Why does my towel rail have two valves?
One valve controls the heat (the adjustable wheelhead or TRV you use every day). The other — the lockshield — is pre-set by your heating engineer to balance water flow across every radiator in the house so they all heat evenly. That balance is why you should leave the lockshield alone.
Old Valves Looking Tired?
New valves can transform the look of your towel rail. Available in Chrome, Black, White, Anthracite and Brushed Brass — a perfect match for our chrome towel radiators.
Shop Radiator Valves →Need Help Choosing the Right Valves?
Tell us your pipe position and we’ll recommend the perfect match.
📚 Related Reading
🔌 Looking for an Electric Towel Rail?
If you are considering upgrading to an electric towel rail you can control independently of your central heating, we have over 200 pre-filled models ready to install.
About the Author — Ibrahim Kalay
Ibrahim has been supplying, testing and advising on radiators and heated towel rails since 2012. Based at Elegant Radiators in Coventry, he works directly with heating engineers, plumbers and homeowners across the UK every week. His troubleshooting advice is rooted in over a decade of practical, on-site heating experience.
Questions about your own setup? Get in touch with our team →
Last updated: 25 September 2026
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