MCQUAY Service Guide Book    Controller Configuration 
 
34 
   
SB125 Heatpump with Auxiliary Heater 
 
To convert SB125 heatpump PCB to auxiliary 
heater application, only need to add one heater 
relay as shown below:  
 
1.  Place the JM Relay (240V/20A) on the 
RY_HTR location 
2.  Solder all the relay pins. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Re 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
SB125 Heatpump with Auxiliary Heater 
 
RY_HTR