Burnham Series 5B - Manual (Page 60)

60
When the operating control (A) calls for heat, it energizes the main gas valves (B) in both gas trains
starting burner operation. The burners will operate until the operating control is satisfied. The high limit
control (C) will stop burner operation in case of excessive steam pressure (steam boiler) or excessive
boiler water temperature (water boiler).
The low water cut-off (D) will stop burner operation if the water level in the boiler drops below the low-
est safe level.
Should one of the pilot flames become extinguished the pilot safety switch (E) to which it is connected
would shut off the gas supply to that pilot and to the main gas valves and burners it is serving (100%
shut-off). Operation of the burners supplied by the second gas train will be unaffected.
FIG. 51
WIRING DIAGRAM - 5015B THRU 5024B SECTION BOILERS
THERMOCOUPLE CONTROL SYSTEM
CANADA ONLY
SecTiON iV - OPeRATiON (continued)