Bradford White eF Series Service Manual

1
Thermostat calls for heat.
-Prior to energizing blower, ignition module checks safety circuits for normal switch positions:
a) Vent temp switch normally closed.
b) Intake pressure switch normally closed.
c) Exhaust pressure switch normally open.
If the vent temp switch is open, the control waits indefinitely for temp switch to close.
If the exhaust pressure switch contacts are closed (not in normal position), the ignition module will wait 45
seconds for pressure switch contact to open before energizing blower. If after 45 seconds and pressure switch
contacts do not open, the ignition module locks out with the PURGE light flashing indicating pressure switch
fault.
2
Blower energizes.
3
Pressure switch proves blower/vent system operation.
If the N.O. contacts of the exhaust pressure switch do not close within 5 minutes of the blower being on,
the control locks out with the PURGE light flashing indicating pressure switch fault.
4
Blower pre-purge period (5 seconds) indicated by the PURGE LED on the module.
5
Igniter warm up (18 seconds), indicated by the IGNITER LED on the module.
6
Trial for ignition (4 seconds, three trials).
a) Flame establishing period (2.5 seconds) gas valve and igniter on, indicated by the IGNITER and
VALVE LED on the module.
b) Burner on, flame proving period (1.5 seconds, looking for minimum of 1 micro amps), indicated by the
FLAME & VALVE LED on the module.
7
Steady state operation.
Ignition module monitors:
-Thermostat circuit.
-When thermostat opens, gas valve is shut down and post purge begins.
-Safety circuit.
-if vent temp switch opens, gas valve is shut down, system will post purge and wait for
switch to close before attempting reignition.
-If either pressure switch opens, Gas valve is shut down, Blower is shut down for 30
seconds after which blower is reenergized and system attempts reignition starting
at pressure switch proving mode.
-Flame sensor circuit.
-If flame is lost, gas valve is shut down, system will post purge and system attempts
reignition starting at pressure switch proving mode.
Thermostat satisfies.
Burner off.
Blower post purge (15 seconds).
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10
Sequence of Operation
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Bradford White eF Series Specifications

General

Type	Tank
Efficiency	High Efficiency
Vent Type	Power Vent
Fuel Type	Natural Gas or Propane
Recovery Rate	Varies by model
Capacity	40-100 gallons
Warranty	6 or 10 Year Limited Tank & Parts Warranty (varies by model)