Radiator Valves: Angled, Straight, and Corner — A Trade Guide to Selection, Connection, and Balancing

The right radiator valve starts with the route of the pipe and radiator connection—not simply the finish. A thermostatic radiator valve (TRV) controls room temperature, while the valve at the opposite end is normally used as the lockshield to set flow during balancing. APM offers verified 15mm angled and straight options for common UK heating layouts.

Use the quick selection guide and product cards below, then confirm the existing pipe size, valve orientation and radiator-tail arrangement before ordering. For an alteration or a system with uncertain flow direction, seek advice from a competent heating professional.

Angled, straight or corner: match the pipe route

• Angled valve: changes direction through 90 degrees. It is commonly used where a pipe rises vertically from the floor and meets a horizontal radiator tail. Both the EDEN angled TRV and Taurus angled set suit this geometry as a starting point.
• Straight valve: keeps the two connections in line. The EDEN straight TRV is the relevant choice where wall-fed or skirting-level pipework aligns directly with the radiator connection.
• Corner valve: is a distinct compact geometry often used to keep the valve head facing forwards with concealed wall pipework. Do not substitute an angled or straight body merely because the connections appear close: check the inlet, outlet and head orientation. No corner model is included in the verified shop selection above.

Photograph the existing installation and look at the route through the valve body. Allow for the finished floor or wall surface and enough clearance to operate the TRV head. “15mm” describes the stated pipe connection on these products; it does not prove that existing pipework, radiator tails, reducers or decorative covers are compatible.

TRV and lockshield: different jobs

A TRV senses the air temperature around its head and varies flow through the radiator. It is not a boiler control and its numbered setting is not a precise room-temperature measurement. Keep the head exposed to representative room air; curtains, furniture, radiator covers and direct heat can cause misleading sensing.

The lockshield at the other end is normally adjusted during commissioning to restrict flow to the design requirement, then capped to discourage casual alteration. The Taurus product above is supplied as a TRV-with-lockshield set. For either EDEN TRV, check the live product page and order details rather than assuming a matching lockshield is included.

How to balance after valve work

1. Complete the installation, refill and vent the system, then check every disturbed joint for leaks.
2. Open TRVs for commissioning and establish that the pump and boiler controls are operating correctly.
3. Starting from a known commissioning position, regulate each radiator at its lockshield—not at the TRV—to obtain the design flow or target temperature drop specified for the system.
4. Use suitable measuring instruments and make small adjustments, allowing readings to stabilise. Recheck earlier radiators because adjustments interact.
5. Record settings where practical and refit lockshield caps. Persistent cold spots, noise or poor circulation need diagnosis; balancing cannot cure sludge, trapped air, incorrect pump settings or undersized pipework.

There is no single universal temperature-drop figure for every heating system. Follow the boiler, heat-source and system designer’s commissioning data, particularly on lower-temperature or heat-pump systems.

Safe installation checklist

• Turn off the heat source and circulator, isolate electrical supplies where required, and allow the water and radiator to cool fully.
• Isolate and drain the relevant part of the system safely. Heating water may be hot, dirty or chemically treated; protect people, floors and finishes and dispose of it appropriately.
• Confirm the pipe size, radiator connection, flow direction requirements and valve geometry before dismantling. Support pipework and radiator connections so they are not twisted or strained.
• Use the correct radiator tail, nut, olive and sealing method specified by the manufacturer. Do not mix parts from unrelated valves or overtighten compression fittings.
• Position a TRV head where air can circulate and where it remains accessible. Follow the product instructions for body direction and head orientation.
• Refill to the system manufacturer’s requirements, restore inhibitor where required, vent air, repressurise if applicable and test hot as well as cold. Inspect again after thermal cycling.

If isolation will not hold, the system layout is unclear, pipework must be altered, or you are not competent to drain, refill and commission the heating system, use a qualified heating engineer. Work involving the boiler, gas appliance or fixed electrical supply must be undertaken only by a person with the appropriate competence and legal authorisation.

Order radiator valves online or collect in Acton

Choose the EDEN 15mm angled TRV, the Taurus angled TRV and lockshield set, or the EDEN 15mm straight TRV. Check the product page for live availability before travelling. For help choosing the correct geometry, call APM Plumbing & Electrical on 020 8702 8080 or bring a photo and measurements to our trade counter at 24 Western Avenue, Acton, W3 7TZ.

APM Electricals — Plumbing, Electrical & Heating Supplies
Unit 5, Alperton Lane, Wembley, HA0 1HH
📞 020 8900 4959
Browse our full product range at apmi.uk