Policy Statement by UHMA Technical Committee

The Control of floor heating systems in conjunction with heat Pumps
Heating systems that use heat pumps as their heat source and UFH as the heat emitter should be capable of providing a variable heating power to match the systems heating load.
 Members should clearly state

• The water flow temperature, water flow rate, and delta T used at specified design condition
• The control strategy applied (e.g. individual room control with setback provided, water temperature controls by others)

UHMA does not recommend open zones because they could lead to lower comfort & control levels and lower efficiency.

UHMA recommends individual room and / or zone temperature control with setback.

UHMA recommends using a buffer tank1 or heat store2 in systems using heat pumps with fixed speed compressors. 

UHMA makes no recommendation with regards to weather or load compensation; however system designers may wish to incorporate these.

A member should notify the customer of any limitations of the overall heat system that they can foresee. 
Members should consider their role in the overall system design, their responsibilities including post-supply, and should ensure that they clearly state any limitations of their service

1. A BUFFER TANK is defined as a tank of water heated by the Heat Pump and is commonly used as a system reservoir to enlarge system content to extend water temperature changes and thus reduce compressor cycling. Refer to BS.EN 15450:2008
2. A HEAT STORE is defined as a tank of water that is heated by the heat pump and other heat sources. The water is taken from the heat store to feed the UFH system. It is also commonly used to reduce the compressor cycling.