How to fit a heated towel rail

Inspired by a helpful YouTube guide. This walk-through is based on “How To Fit A Heated Towel Rail” by the Tommy’s Trade Secrets channel, a long-running UK plumbing and trades tutorial series that has helped DIYers get jobs done properly for well over a decade. The video is clear on valve connections and bleeding, which are the two stages most people get wrong first time.

1. Choose the right position and valve type

Most heated towel rails connect to the central heating system via two 15 mm copper pipes — one flow, one return. Before you buy anything, decide where the pipes will run and whether they come up through the floor or out through the wall. That determines the type of angled or straight valves you need.

Standard towel rail valves come in manual, thermostatic, or lockshield pairs. A manual valve one side and a lockshield the other is the most common setup. Mind you, if you want individual temperature control, a thermostatic head is worth the extra couple of pounds.

2. Gather tools and materials

You will need: a pipe cutter or junior hacksaw, compression or push-fit fittings (or solder if you prefer), PTFE tape, a spirit level, wall plugs and screws rated for your wall type, and the brackets supplied with the towel rail. Check the bracket centres against the holes on the rail before you drill anything — they are not always the same as the dimension on the box.

Have a small bowl and a towel handy for when you drain the section of pipe. There will always be a bit of water left even after the system drains.

3. Drain down the relevant section

Turn the central heating off and let it cool. Isolate the section of pipework you are working on using the nearest lockshield valves, then attach a short hose to the drain-off cock and run it to a bucket or outside. Open the drain-off cock and let the water out.

If you do not have convenient isolation valves, you may need to drain the whole system from the lowest drain-off cock. It is worth fitting isolation valves at this point if there are none — it saves time on every future job.

4. Fix the wall brackets

Offer the towel rail up to the wall and mark the bracket positions with a pencil. Use a spirit level across the top rail to make sure it sits horizontal. Drill and plug the wall, then screw the brackets in firmly. In a tiled bathroom, use a tile drill bit to start the hole cleanly.

Hang the rail on the brackets before connecting any pipework, just to check it sits flat and level. Easier to adjust it now than after the pipes are soldered.

5. Connect the valves and pipework

Wrap the valve tail threads with PTFE tape — three to four turns, wound in the direction the thread tightens. Screw the valves into the bottom of the towel rail hand-tight, then snug them up with a spanner. Do not over-tighten or you risk cracking the rail body.

Cut the supply pipes to length and connect them to the valve bodies using compression or push-fit fittings. Check both connections are square before you tighten. A fitting pulled slightly off angle will weep once the system is under pressure.

6. Fill and check for leaks

Slowly open the isolation valves and let the system pressure up. Watch every joint carefully for the first minute. Any weeping compression fitting can usually be cured by a quarter-turn tightening with a spanner — no need to drain again.

Check the valve bodies, the union nuts, and the connections at the back of the towel rail. A drip from the rail threads usually means the PTFE needs re-doing.

7. Bleed the towel rail

Heated towel rails trap air at the top where there is no bleed valve on the rail itself. Open the manual valve fully, then hold a cloth under the cap on the top of the angled valve and crack it open briefly to release any air pocket. You will hear a brief hiss and then water will push through. Close it back up.

Run the heating and check the rail heats evenly top to bottom. Cold patches at the top usually mean air is still trapped. A cold bottom usually means the flow direction is the wrong way round — swap the flow and return connections.

When to call a handyman

Call Richard if the pipes are in an awkward position, if the wall is tiled all the way across and you are not confident drilling tiles, or if you want the system drained and refilled properly without the risk of an airlocked boiler afterwards. Heated towel rails are a satisfying job when they come together, but getting one small connection wrong can mean a damp bathroom floor.