Operation Manual
5
  Prior to mounting the unit should be set in either ON/OFF or 
chrono-proportional control mode (see below).
ON/OFF - boilers switches ON when below set temperature 
and OFF when above.
Chrono-Proportional - energy saving feature which  res 
the boiler at regular intervals to maintain a set temperature, 
achieving a constant ambient environment for the user. 
Some existing thermostats will have a Neutral wire and/or 
Earth wire connected. These are not required by the RT51/52 
and must NOT be connected to any RT51/52 terminals. Instead 
they should be made electrically safe and coiled in the recess at 
the back of the RT51/52. 
 ON/OFF CHRONO   
!
Installation Instructions
GB










