Test 6: Blower On, No Ignition - A.O. Smith SERIES 120 Service Handbook

TEST 6: BLOWER ON, NO IGNITION

Conditions:
• Power on
• Plugs in receptacles
• Blower (Draft Inducer) operating
• No power to Hot Surface Igniter (HSI). Note LED flash code.
Check E4 pin 2 to ground
TEST 6
IF.........
ignition board receptacles E1, Pin 7 to ground
shows no voltage
E1, Pin 7 has 24 Volt to ground
voltage check of each blower switch terminal to
ground shows voltage to only 1 terminal
Servicing should only be performed by a Qualifi ed Service Agent
TROUBLESHOOTING
Blower
Prover Switch
Hot Water Outlet
Figure 25
24 VAC Check of Blower Prover Switch Circuit
then............
replace Ignition board.
check wire connection to and from blower (draft inducer).
• switch is open. Check for proper draft (should also see LED 3 flash code).
• check for blocked exhaust.
• check that blower outlet exhaust damper is open.
• replace blower prover switch.
32
Blower
Exhaust
Blower
(Draft Inducer)