Concealed Thermostatic
Shower Mixers

A manual mixer blends hot and cold water in a fixed ratio set by the user. If the incoming water temperature changes — because someone runs a tap elsewhere in the building — the outlet temperature changes too. A thermostatic mixer uses a wax element cartridge that continuously senses and adjusts the blend to maintain the set temperature within ±2°C, regardless of supply fluctuations. It also includes an automatic shut-off if the cold supply fails, preventing scalding.

The rough-in stage requires more planning because the valve body must be positioned correctly before the wall is tiled. However, the trim-out stage — fitting the plate and handle after tiling — is straightforward. The key requirement is accurate positioning during rough-in and a pressure test before closing the wall. For new builds and full bathroom renovations, concealed installation adds minimal complexity. Retrofitting into an existing tiled wall is more involved and typically requires opening the wall.

Yes, provided you have a minimum of 1m head pressure (approximately 0.01 MPa) at the valve inlet. Most gravity-fed systems in two-storey homes meet this requirement when the cold water tank is in the loft. For very low-head installations — typically where the tank is less than 1m above the shower head — a pump-assisted supply is recommended. Ensure hot and cold pressures are balanced; a significant imbalance will affect thermostatic accuracy.

The maximum temperature stop is a mechanical limiter on the handle that prevents the user from turning the temperature above a set point. The factory default is 38°C, which is within the safe bathing range for adults. It can be adjusted during commissioning — typically to 43°C for adult-only households, or left at 38°C where children or vulnerable users are present. UK Building Regulations and NHS guidance recommend a maximum of 38°C in care settings and homes with young children. The stop does not affect the thermostatic safety shut-off, which operates independently.

The simplest check is to measure dynamic pressure at both inlets using a pressure gauge before connecting the valve. On unvented and combi systems, pressures are usually naturally balanced. On gravity-fed systems, the cold supply comes from a tank and the hot from a cylinder — both fed by gravity — so pressures are typically equal. Problems arise when one supply is mains-fed and the other is gravity-fed, creating a large imbalance. If the ratio exceeds 2:1, fit pressure-balancing valves on the supply lines before the mixer.

Thermostatic cartridges should be inspected and descaled every 12–18 months in hard water areas, and every 2–3 years in soft water areas. The inlet filters (supplied with the valve) should be cleaned annually. Cartridge replacement is straightforward — remove the handle and trim plate, unscrew the cartridge retaining nut, and swap the cartridge. No specialist tools are required. The concealed design means the valve body itself never needs to be accessed for routine maintenance; only the cartridge and filters are serviceable from the front.

Yes. This valve has two outlets, allowing you to connect two separate water outlets — for example, an overhead shower and a handset, or a shower head and body jets. A diverter or sequential flow control allows you to switch between or run both simultaneously, subject to your system's flow rate capacity. If running multiple outlets at once, ensure your boiler or hot water system can sustain the combined flow demand. A single-outlet version is also available if only one outlet is required.

The valve is WRAS approved (Water Regulations Advisory Scheme), confirming it meets UK water regulations for use in potable water systems. It also carries CE marking and complies with BS EN 1111 (thermostatic mixing valves for sanitary purposes) and BS EN 1287 (low-pressure thermostatic mixing valves). WRAS approval is a requirement for any fitting connected to the mains water supply in the UK and is increasingly specified by local authorities and housing associations.