A.O. Smith BTR 201, Service Handbook

Page: 29 / 40

27
Servicing should only be performed by a Qualified Service Technician
TEST 6
–
INDUCER ON
–
NO IGNITION
TEST 6 24 VAC Check of Blower Prover/Low Gas Pressure Circuit
IF......... THEN............
Ignition board receptacles E1, Pin
7 to ground shows no voltage.
Replace ignition board.
E1, Pin 7 has 24 Volt to ground Check wire connection to and from inducer.
Voltage check of each blower
switch terminal to ground shows
voltage to only 1 terminal.
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 (draft) proving switch.
NATURAL GAS ONLY
24V is present from each switch
terminal to ground.
Check wiring from blower switch to low gas pressure switch.
Voltage check to each terminal
of low gas pressure switch and
ground shows only voltage on 1
terminal
Switch is open - test for a minimum of 5.2 ± " W.C. Natural Gas or
10.5" Propane, flowing supply gas pressure (should also see 3 Flash
LED code). Replace low gas pressure switch.
Voltage is present to each
pressure switch terminal and
ground
Check wiring from low gas pressure switch to ignition board
receptacles E1, Pin 10.
CONDITIONS:
• Power On.
• Plugs in Receptacles.
• Inducer operating.
• No power to Hot Surface Igniter (HSI)
Note LED flash code.