The Importance of underfloor heating control

It is a fair statement to say that any underfloor heating system is only as good as the control system attached to it.  At Begetube we place a huge importance on the controls which we specify and use.  Underfloor heating is more difficult to control than a high temperature convection heating system because of the longer response time associated with underfloor heating.  This is why it is imperative that the correct controls are always specified and used.  The control system is an integral part of any underfloor heating system and should certainly never be considered as an 'optional extra'.

There are three main elements of control to consider with underfloor heating:

• Water temperature control of the underfloor heating pipe.
• Individual room temperature control.
• Time control for night setback.

1. Water temperature control of the underfloor heating pipe:
   Underfloor heating works at a much lower flow temperature (typically 50°C) than a traditional radiator system.  This means that you must have a mixing device in place before the manifold(s) to blend down the high temperature boiler flow.  There are two accepted methods of doing this:
   
   
   • By the use of a mechanical blending valve, this method is used in our standard control Combimix system and delivers a fixed water temperature as set on the valves head.
     
     
   • By the use of an electro-mechanical 3 or 4 port blending valve, this method is used in our Intelligent Control system and delivers a variable water temperature governed by the prevailing climate conditions inside and outside the building.  The Intelligent Control also has the benefit of self learning individual room sensors.  These sensors provide the most precise control available in the underfloor heating industry.
     
     
   The latter of these two options gives finer and more economical control and should be considered in any project over 80 square metres.
   
   
2. Individual room temperature control:
   Individual rooms or areas within a building have different uses and varying influences acting on them (e.g. Amount of glazing, North or South facing, auxiliary heat sources, etc.)  The temperature requirement for each room/area can also be slightly different.  For these reasons we always recommend and specify an accurate digital room thermostat for every room/area.  This is linked to the electric actuator which either opens or closes the valve(s) on the manifold serving that room/area.  Wet areas where it is not allowed to put a mains operated thermostat are controlled using a thermostat which employs a low voltage remote sensor.  This sensor can be used to sense the air temperature or the floor temperature.  This level of individual room control is supplied with our standard control Combimix system.  The Intelligent Control option utilises self learning sensors giving even finer control.
   
   
3. Time control for night setback:
   Because it is uneconomical to run any heating system at the full comfort settings 24 hours a day there has to be a method of setting back the temperature during the night.  With the standard control system a programmable clock thermostat is used along with all the individual room thermostats.  The clockstat has time control along with two different temperature settings.  One of the temperature settings is used to run the system at the room stat settings and the second temperature setting is used to provide a night setback setting (this allows the overall temperature to drop back overnight or when the building is not being used).  With the Intelligent Control option one or more fully programmable sensors are used within the system, this gives the ability to have a wide programme of time and temperature settings in all areas.
   
   

Linking all these room thermostats back to the manifold and integrating them with the other parts of the control system can be a confusing and costly exercise for any electrician.  At Begetube all our control systems are supplied with purpose made wiring centres with simplifies and speeds up the electrical installation.

IMPORTANT POINT: The cost of wiring the Intelligent Control system is considerably cheaper than normal underfloor heating control systems as it utilises a 5 volt bus system to connect all the room sensors together.