Step 7. Fuel pump and ignition drive motor stops after only two minutes of operation.
a. Check for 24 vdc at HEATER ON/PURGE ON switch (S4) between terminals 2 or 3. Place heater control switch to PURGE ON and allow
to operate for two minutes. If 24 vdc was indicated, and burner fails again after restarting, flame switch (S2) is faulty. Replace faulty
flame switch (S2).
b. Check for 24 vdc between terminal K2-X2 and ground and terminal K2-A1 and ground.
(1) If no voltage at X2, replace S4 switch.
(2) If no voltage at A1, replace K2 relay.
(3) If no voltage at X2 or A2, notify intermediate direct support maintenance.