Underfloor heating extension packs overview

The following pages details the plant and wiring diagrams for Extension Packs A & B.  If you are unsure if these are the correct set of plant and wiring diagrams to be using for your installation please contact the supplier of the equipment.  The wiring is as per the wiring diagram shown connecting the clockstat, motorised valve, underfloor pump and boiler.  Please ensure that you read all extra notes on the diagrams as they are important.  It is imperative that both the electrician and heating installer completely understand what they are responsible for as it is very difficult to install cables and pipe work after a certain stage in the build schedule.

The plant layout details the flow and return pipe work needed to correctly connect up the manifold to the heat source.  The plant diagrams also show how to integrate a typical domestic hot water system and high temperature radiator system mechanically and electrically.  As we do not know the length and route of flow and return pipe work, this has to be sized by the on site heating engineer.  Specific manifold loadings are available from your supplier - please ask, do not guess.

Notes for the Heating Installer

• Pay careful attention to flow and return connections onto the manifold.  The flow from the boiler is indicated in RED and the return to the boiler is indicated in BLUE.
  
  
• The automatic by-pass valve is important and must be fitted (supplied by others).
  
  
• The floor heating manifold should be supplied by an uninterrupted flow and return from the boiler.  Definitely not tapped off the end of a radiator system.
  
  
• As with all heating systems, the flow and return pipe work and boiler system should be power flushed to remove any debris before it is connected and opened up to the manifold(s).
  
  
• It is also advisable to install an in-line filter on the main flow from the boiler.  This will protect all equipment attached to the boiler system, in particular the UFH manifold(s).
  
  
• If in doubt please get in touch with your supplier.
  
  

Notes for the Electrician

• Study the wiring diagrams and ensure you have enough cables in place at first fix stage.  It is very difficult to add in cables once the build schedule has passed a certain stage.
  
  
• The clock stat we supply only needs a two core cable to it but it is strongly advisable to use 3 core and earth to all stat positions in case a different stat is used in the future which requires a neutral.
  
  
• It is advisable to fit a small surface mounted joint box at the manifold position. This will provide a termination space for the clockstat, motorised valve, pump and cabling back to the boiler.
  
  

The sequence of operation for this system is as follows:

• The clockstat supplies a switched live to the motorised valve and manifold pump.
  
  
• The motorised valve, using its auxiliary switch, then provides a switched live to the boiler and boiler pump.
  
  
• Please note that all heating controls should originate from a common spur/fuse and should have one point of isolation.
  
  
• If in doubt please get in touch with your supplier.