Pilot Operation Testing - Bradford White D-38T-155 Service Manual

DANGER
120 volt exposure. To avoid personal injury,
use caution while performing this procedure.
Condition:
Pilot will not light or stay lit,
Error codes 62, or 63 shown on Water
Heater Display
Reset control by pressing the lower
right button under "reset" on the
display for 3 seconds. Does control
board start ignition sequence and
start sparking (sparking noise at pilot
or at board)
Y
Is there spark at the pilot?
Y
Is there 22-27 volts AC output across
terminal pins 8 & 2 on "Control" plug
of Control Board? Carefully insert
meter probe in wire plug to check pin
terminals. Make sure control is in the
trial for ignition sequence (see
Sequence of Operation).
(see photo 13)
Y
Is there 22-27 volts AC input across
wire leads
"MV/PV" & "PV" (yellow & red wires)
at Gas Valve?
(see photo 12)
N
Check wire harness for damage or
loose connections. Repair or replace
as needed.
Turn on power to the water heater
and verify proper operation
N
Replace control board
Check for:
N
Loose or damaged ignition wire
Grounded pilot electrode
Damaged pilot.
N
Replace control board.
Loosen pilot tubing connection at
the gas valve and soap test.
Y
Is there pilot gas flow out of the
gas valve? See pilot illustration
for pilot inspection. (Wires must
be connected to gas valve during
this test).
N
Tighten pilot tube connection at
the gas valve. Check incoming
gas pressure to water heater. if
okay, replace gas valve
11
13
Checking for 24
volts output to
pilot valve
(yellow and red
wire pin
terminals) on
control board
"control" plug.
Page 27
SERVICE PROCEDURE D24-II

Pilot Operation Testing

CAUTION
Be Careful When Making Voltage
Measurements or Jumping Terminals
Not to Damage or Deform Connectors or
Connector Pins.
Check across "MV/PV" & "PV" Wire
leads to gas valve
12
Check for clogged or kinked pilot
Y
tube, clogged pilot orifice. Clean
or replace as needed.
(see "Pilot Burner Inspection")
27