Test 7: Blower On, Blower Prover Switch Closed, No Igniter Operation - A.O. Smith SERIES 120 Service Handbook

TEST 7: BLOWER ON, BLOWER PROVER SWITCH CLOSED, NO IGNITER
OPERATION
Conditions:
• Power on, but no power to igniter
• Plugs in receptacles
• Blower (Draft Inducer) on
• 24V at ignition board E1, Pin 10
Check E4 pin 2 to Ground
TEST 7
IF.........
Continuity is not indicated between E4 plug
pin 2 to 4.
Continuity is present
Voltage is not present between E4, Pin 2 to ground
Voltage is present
Voltage is not present between E4, Pin 4 to
ground
Voltage is present
Servicing should only be performed by a Qualifi ed Service Agent
TROUBLESHOOTING
Check E1 pin 10 - 24V
Continuity
Test
4
3
2
1
E4 Plug
Ground
Figure 26
Voltage check and continuity check of hot surface igniter circuit
Continuity check - Power off- Plug removed from E4 receptacles.
Nominal 80 VAC check - Plug in E4- Power on.
then............
• check wiring and connection from E4 plug to HSI receiving plug.
• replace HSI Assembly.
Resistance should be between 11 and 20 Ohms at a temperature of 77°F.
Replace ignition board.
Continue
• check wiring and plug connections to hot surface igniter (HSI).
• replace HSI if needed.
Note ignition board flash code LED. Hot surface igniter (HSI) should work.
33
Check E4 pin 4 to Ground
Ground