Description
This is a simple, practical thermostatic radiator valve (TRV) and lockshield twin pack intended for conventional hot-water central heating. The pack contains a straight (inline) thermostatic radiator valve with a white thermostatic head and a matching manual lockshield; the valve body is chromed. It’s designed to give individual temperature control at a radiator, automatically throttling flow as the room reaches the set temperature so each room stays closer to the level you choose.
Underlying the product is a liquid-filled sensor head and a reversible valve body, so the same pack can be installed on the flow or the return and mounted horizontally or vertically. That reversibility, plus standard 1/2″ tails and compatibility with 10–15 mm pipework, makes it a straightforward choice for both replacement jobs and new installations where you want per-radiator control without any electronics.
Key specifications
- Temperature range: 7°C to 28°C
- Pipe size / fittings: suited to 10–15 mm pipe, 15 mm compression for lockshield
- Thread / tailpiece: standard 1/2″ BSP tail
- Maximum working pressure: 10 bar; maximum differential pressure: 1 bar
- Sensor type: liquid-filled thermostatic element; hysteresis ~0.2 K
- Maximum water flow temperature: 110°C
- Pack contents: straight TRV + matching lockshield (pack code TRVPACKST)
How it behaves and where it suits
The valve head is manually set using the numbered scale (approximate temperature markings run from a frost/isolation position up to position 5). Once set, the liquid sensor expands or contracts to open/close the valve, keeping the room near the chosen temperature without any external controls. That makes this pack best for people wanting simple, reliable room-level control and installers who need a standard mechanical TRV rather than a motorised or smart head.
Because the body is fully reversible it’s convenient for straight pipe runs where the supply and return approach the radiator in-line. The chromed body with a white head works visually with most modern radiators where white trim is preferred, while the lockshield provides the manual balancing function for the return side.
Installation and practical notes
Installation is typical for radiator valves but a few points are worth emphasising. The pack uses 1/2″ tails and is supplied to suit 10–15 mm pipe – if your installation is strictly 10 mm you may need the small reducer/adapter often supplied for 10 mm systems. The product is intended for fully pumped systems; the maximum working pressure is 10 bar and the differential pressure guidance (maximum differential pressure 1 bar) is relevant where high-pressure pumps or pressure surges can cause valve instability or noise.
The lockshield included is a manual device used to balance the radiator against the rest of the system. It’s supplied with a protective cap and a small ‘witches-hat’ fitting for lockshield applications; installers will normally set the lockshield once system commissioning is complete and leave it at the required position.
Limitations and straightforward tips
This pack is purely mechanical: it does not include a motorised or wireless head. If you plan to retrofit a smart TRV head from a third-party brand, check mechanical compatibility first — smart heads rely on pressing down the valve pin and often need a specific adapter to fit other manufacturers’ bodies. The valve is not designed to provide complete shut-off; it uses a frost/‘off’ position for protection but the system design should still include an isolation valve where full shut-off is required.
For reliable operation, have a competent heating engineer fit and commission the valves, particularly when multiple radiators are being balanced. Observe the differential pressure limits and note that very high flow temperatures or conventional system faults (sludge, excessive system pressure, debris) will reduce long-term reliability of any TRV unless the system is properly maintained.
Overall, the TRV Pack Inline (white) is a no-nonsense, low-cost twin pack for standard UK radiator installations: straightforward to fit, reversible for different pipe layouts and suitable where simple mechanical thermostatic control — rather than smart or programmable control — is the requirement.
