Temperature Control and Bypass for Floor Heating Systems

  • Discount Kit Floor Heating-Direct Pressure Relief Valve
    Save 55%

    Pressure Relief Valve

    £54.17 £24.58 £29.50 incl. VAT
    15mm or 22mm
  • Discount Kit Temperature Control Unit

    Blending Valve

    £270.83 £216.67 £260.00 incl. VAT
    With A Rated Pump


Many central heating systems make use of temperatures between 70°C and 90°C. These temperatures are too high for a floor heating system because these types of systems usually make use of water with a temperature around 40°C. Therefore, manifolds for high temperature systems are assembled with a blending valve and pump unit that mix the return water from the system with the hot water supply from the boiler. Should you prefer a stainless steel manifold you can use this blending valve (also called mixing shunt or temperature control unit) to make the manifold suitable for a heating system with high supply temperatures.

Blending Valve for Open Modular Manifolds

Stainless Steel Blending Valve

This blending valve makes the open stainless steel manifold suitable for high temperature systems. The blending valve mixes the hot supply water from the boiler with the return water of the system to the correct temperature for underfloor heating.
The blending valve is assembled with an A rated Grundfos UPS2 pump and is designed to work with manifolds of all types, on 210mm centres.
Blanking plug and pump can be changed so the complete blending valve can be reversed.


An important consideration when installing underfloor heating is whether or not to use a pressure relief valve (also called bypass). When floor heating is the only form of heating at a certain floor level and no wall mount radiators are present (anymore) then the use of a bypass is always recommended. Also when only radiators with thermostatic heads are availabe using a bypass must be considered.

Spring-loaded Bypass

Spring-loaded Bypass

A spring-loaded bypass valve prevents the increase of pressure in the supply pipe that could cause damage or malfunction. This bypass valve is a proportionally operating valve that is controlled by difference in pressure. A reduction in the hot water supply could result in a rising differential pressure in the flow and return pipes of your heating system. When this is the case, the pressure relief valve opens and a too high pressure in one of the pipes is prevented.