
HOT
3A(FUSE)
NEUTRAL
FROSTSENSING
SWITCH
ARRESTER
VARISTOR N
GND
IGNITION
J
®
i SW,TC......i,se__F_
, 
J
  | WATERFLOW  | Q  | MODULATING  | 
  | SOLENOID  | ||
  | SENSOR  | 
  | |
  | (_  | ATERFLOW  | VALVE  | 
  | 
  | SENSOR  | 
  | 
  | 
  | CiRCUiT  | 
  | 
  | WATERFLOWCONDEVtCE  | Q  | 
  | 
  | (_  | WATERFLOW  | 
  | 
  | 
  | CONTIROLDEVICE  | 
  | 
r  | 
  | CIRCUIT  | 
  | 
  | 
  | 
  | |
!  | 
  | COMBUSTION  | |
I  | CONTROLDEVICE  | 
  | |
  | FAN  | 
I
DRMNG
CIRCUIT
FLAMEROD
DRIVING
CIRCUIT
T
GND
OUTGOINGWATER
_,THERMISTOR HEATEXCHANGER
r_) , THERMISTOR
I
__IT_'_TTU RE
I1_THERMISTOR
L
INDOORMODELONLY
Figure 15
305 & 505 Outdoor Manual  | 31  |