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13
BASO POWER UNIT
BA SOT RON
ACTUATOR
DIAGRAM IV
_- B300
THERMOCOUPLE
THERMOSTAT
TEST RIT
Thermocouple connected,
Thermostat wires connected. Clip cable plugged into MV jack. Red clip attached to
bellows side of thermostat (Bare wire). Black clip attached to contact side of thermo-
stat (Black insulation).
Selector switch set to 0-30 MV range.
PROCEDURE No. IV (See Diagram IV)
Closed Circuit MV Test of Thermostat
Push down reset, light
pilot, and turn plug valve knob to ON.
Set thermostat dial to highest setting to turn on main burner and attach clip
lead to thermostat.
If
the main burner ignites, THE MAXIMUM READING AT THIS POINT
SHOULD BE 2 MV. A higher reading would indicate high contact resistance,
requiring replacement.
If
the main burner does not ignite, and no MV reading
is
obtained,
it indicates a disconnected or broken thermostat wire.
If the main burner does not ignite, and a very high MV reading (within the
open circuit MV range of the thermocouple as specified in Procedure 1A) is
obtained, it indicates open thermostat contacts and ruptured bellows. Replace
thermostat.
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