LMV Series    Technical Instructions 
  Document No. LV5-80
00 
SCC Inc.  Page 11  Appendix A 
Hot Standby on a Steam Boiler with an RWF50 or RWF55 (continued) 
 
4.  Set the following parameters in 
the RWF55 controller.  For more information, obtain 
Siemens Document No. U7867 for the RWF55 at www.scccombustion.com. 
 
ConF > Cntr > CtYP = 2 
ConF > Cntr > SPL = setpoint range lower limit 
ConF > Cntr > SPH = setpoint range upper limit 
OPr > SP1 = normal operation setpoint 
PArA > HYS1 = burner on for normal operation 
PArA > HYS3 = burner off for normal operation 
ConF > InP > InP1 > Sen1 = pressure sensor type 
ConF > InP > lnP1 > SCL1 = 0 
ConF > InP > InP1 > SCH1 = high end of the range of the pressure sensor 
ConF > InP > InP3 > Sen3 = temperature sensor type 
ConF > AF > FnCt = 12 
ConF > AF > AL = hot standby setpoint 
ConF > AF > HYSt = burner on / off for hot standby 
ConF > OutP > SiGn = 2 
Operation 
1.  When the hot standby switch is set for hot standby, the LMV5 system is in hot standby 
mode.  The burner will turn on and off based on the temperature limits set in the 
RWF55 controller for hot standby (ConF > AF). Since the signal to LMV5 terminal X62 is 
broken by the hot standby switch, the LMV5 stays at low fire until the burner turns off 
based on the burner off point set in the RWF55. 
 
2.  When the hot standby switch is set for normal operation, the system is in normal 
operation mode and not in hot standby.  The burner will turn on and off based on the 
pressure limits set in the RWF55 controller for normal operation (PArA > HYS1 and PArA 
> HYS3). The signal to LMV5 terminal X62 determines the firing rate of the burner. 
 
Important Notes 
 
1.  An RWF55 controller must be used for this hot standby option (not RWF50). 
 
2.  The RWF55 is operating as the load controller during normal operation as well as 
controlling the hot standby.