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What is involved in replacing a radiator valve?

Replacing a radiator valve usually means draining down or holding back the water in that part of the heating system, swapping the valve body and refilling, so it is normally a job for a plumber or heating engineer. GOV.UK lists most repairs and replacements as work you do not need to tell building control about [S1].

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What does a radiator valve do?

Most radiators have a valve at each end. One controls how much hot water goes in. The other, often hidden under a plain plastic cap, is the lockshield, which a plumber sets once to balance the system so each radiator gets its share of heat.

The control end is usually one of two types:

  • A thermostatic radiator valve (TRV) has a numbered head that opens and closes the valve as the room warms and cools.
  • A manual valve has a plain wheel head that simply turns the radiator on or off.

QuoteZila is starting in Cheshire, with Crewe, Nantwich and Sandbach among the first towns, and anyone in the UK can post a plumbing job. A valve job is the same work wherever the radiator is.

When does a radiator valve need replacing?

Common reasons to change a valve are:

  • It weeps or drips at the joint or the spindle, leaving marks on the floor or the pipe.
  • The pin is stuck. On a TRV, the small pin under the head can seize, so the radiator stays hot or cold whatever the setting.
  • The head is broken or the numbers have worn off.
  • You want thermostatic control in a room that only has manual valves.
  • The radiator is being replaced and the old valves do not line up with the new one.

A stuck pin or a broken head does not always mean a new valve body. A cold radiator can also have other causes, which our page on a radiator not heating up covers.

How does a plumber replace the valve?

The details depend on the system, but the job usually involves:

  1. Turning the heating off and letting it cool.
  2. Draining down the system, or the part of it that feeds the radiator, or holding the water back with the right equipment.
  3. Undoing the old valve from the pipe and the radiator tail, and fitting the new body and tail.
  4. Refilling, letting out trapped air and checking for leaks.
  5. Bringing a sealed system back to the right pressure and setting the lockshield so the radiator heats evenly.

This page does not give step-by-step DIY instructions. Hot water, a sealed system under pressure and inhibitor in the water make it a job for someone with the right tools. If the boiler needs anything beyond being switched off and on, that is gas appliance work. HSE says anyone employed to work on gas appliances in a home must be a Gas Safe registered engineer, competent in that area of work [S3].

Do you need building control for a valve change?

GOV.UK's guide to building work says most repairs, replacements and maintenance work do not need to be reported to a building control body. The exceptions it lists are replacements of combustion appliances, oil tanks, electrical fuse boxes and glazing units [S1]. A like-for-like valve swap is ordinary repair work.

Adding a new radiator is a different job. The same GOV.UK guide lists adding a radiator to an existing heating system among work to tell building control about, though it says this may not need notifying in some circumstances [S1]. If you are thinking of moving a radiator rather than repairing a valve, our guide to the cost of moving a radiator explains what changes that price. Replacing the whole radiator is covered in radiator replacement costs.

What to ask before you hire

Ask each plumber the same questions so the quotes can be compared:

  • How many valves are included, and are they TRVs, manual valves or lockshields?
  • Who supplies the valves, and which type or brand?
  • Will they drain the system or hold the water back?
  • Will they add inhibitor when they refill, and is that in the price?
  • Will they balance the radiators afterwards?
  • Is there a call-out charge, and is VAT included?

Citizens Advice says to try to get written quotes from at least 3 different traders, and that a quote is a fixed price while an estimate is just a rough guess [S2]. Our plumber cost guide explains how call-out and hourly prices are usually set out.

Jobs you might post

These are examples, not taken from real job posts.

  • "Two radiator valves weeping in the lounge. Please replace both with thermostatic valves and check the rest of the system."
  • "TRV pin stuck on the bedroom radiator. Happy to have just the head or the whole valve changed, whichever is needed."
  • "Six manual valves upstairs. Please quote to change them all to thermostatic valves and balance the system afterwards."

Post the job to plumbers or heating engineers. Your job goes to up to five matched local businesses [QZ2]. QuoteZila is free for customers and local businesses [QZ1].

Honest status: QuoteZila is new. We're starting in Cheshire, beginning with Crewe, Nantwich and Sandbach, and growing area by area. Anyone in the UK can still post a job or register a business. How fast you get quotes depends on how many local businesses have joined near you. Businesses can register and receive jobs straight away. We don't check insurance, qualifications or registrations, so please check these yourself before you hire.

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Questions about replacing a radiator valve

Do I need to drain the whole system to replace a radiator valve?

Not always. A plumber may drain only part of the system, or use a method that holds the water back while the valve is changed. It depends on the pipe layout, the type of system and the tools they carry. Ask how they will do it, and whether the boiler will need to be off and refilled afterwards.

Can I change just the thermostatic head?

Often, yes. The head on a thermostatic valve is usually a separate part that sits on the valve body, and a matching replacement head can be fitted without touching the water. The valve body has to match, so take the old head and a photo of the body when you buy one.

Does replacing a radiator valve need building regulations approval?

GOV.UK says most repairs, replacements and maintenance work do not need to be reported to a building control body, with exceptions such as combustion appliances, oil tanks, fuse boxes and glazing units. A like-for-like valve swap falls under ordinary repairs. Adding a new radiator is different and may need approval.

Who should I ask to do it?

A plumber or heating engineer. If the boiler itself needs adjusting, refilling through its controls or any gas work, HSE says anyone employed to work on gas appliances in a home must be Gas Safe registered and competent for that work. Say in your job post which valves need changing and how many.

Does QuoteZila check plumbers?

No. We don't check insurance, qualifications or registrations, so please check these yourself before you hire. You can report a quote or a business from your job page.

This page is general information, not professional or legal advice. QuoteZila does not check Gas Safe, WaterSafe, NFRC, NICEIC or other registrations against the register on your behalf: look them up yourself.

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Sources

  1. QZ1: QuoteZila product fact. QuoteZila home and FAQ copy.
  2. QZ2: QuoteZila product fact. QuoteZila FAQ How does getting quotes work.
  3. S1: Building work, replacements and repairs to your home, GOV.UK. Accessed 2026-10-31. https://www.gov.uk/government/publications/building-work-replacements-and-repairs-to-your-home/building-work-replacements-and-repairs-to-your-home
  4. S2: Before you get building work done, Citizens Advice. Accessed 2026-10-31. https://www.citizensadvice.org.uk/consumer/getting-home-improvements-done/before-you-get-building-work-done/
  5. S3: Domestic gas: frequently asked questions, Health and Safety Executive. Accessed 2026-10-31. https://www.hse.gov.uk/gas/domestic/faqs.htm