Underfloor heating extension pack commissioning

This system utilises a manual 3 port mixer to control the temperature of the water in the underfloor heating system.

The plant layout and wiring diagrams also show how to connect this type of floor heating system in with a radiator system and domestic hot water system.  If one or both of these systems are not in the installation simply ignore the plumbing and wiring for the non-relevant part.  Before starting the checks detailed below, ensure the power is on and the clockstat is switched down (not calling for heat).  Switch off the DHW and Radiator circuit.

• Set the clockstat to call for heat (a flame symbol will appear on the clockstats screen).
  
  
• This will put power to the motorised valve and the manifold pump.
  
  
• Once the motorised valve has opened, this in turn will put power to the boiler and boiler pump.
  
  
• Set the mixer valve to give a flow temperature of 25-30°C.  The system should be left to run at this low temperature until the screed/concrete has dried.  It can then be raised to its full operating temperature depending on what type of floor construction it is.
  
  
• Screeded floor full operating flow temperature is 55°C.
  
  
• Check the correct operation of the Radiator and/or the DHW circuits and that each of these systems can independently bring on the boiler and boiler pump.
  
  
• Set the clockstats two temperature settings. The lower one to 16°C (night setback) and the higher one to 21°C.  These settings can be altered to suit the clients own preferences.
  
  
• Set the times on the clockstat, bring the system on (high temp setting) two hours before they want the house up to temperature and switch it to its low temp setting two hours before they retire at night.
  
  
• Once the floor has cured (normally 2-3 weeks at low temperature) the 3 port mixer can be set to its correct operating temperature.
  
  
• For most of the heating season this temperature can be reduced by up to 20°C depending on the outside air temperature.  This will aid overall comfort levels and increase the economy of your floor heating system.

Thus typical settings are:

1. Going into heating season set mixer to 30°C - 40°C.
   
   
2. During the coldest spell set mixer to maximum for floor construction.
   
   
3. Coming out of heating season set mixer to 30°C - 40°C.
   
   
4. One of the main points to remember when controlling your system is that switching your system on and off several times a day is false economy.  Keeping your floor at a constant temperature is more economical and will give you better comfort level.