Bradford-White Corp Commerical 24 Volt Flue Damper series Water Heater, D38T155 service manual - page 8

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.
DANGER
120 volt exposure. To avoid personal injury,
use caution while performing this procedure.
Condition:
Pilotwill not light,
Ignition module LED is “ON”
Isth ere 22-27 volts AC output acro ss
terminals “MV/PV” & “PV” ofIgnition
Module?Disconnect wires&check
across terminal of modu le.
(see photo 11)
N
Y
Loosen pilot tubing connection at
the gas valve and soap test.
Isthere pilot gas flow out of the
gas valve?
Tighten pilot tube connection at
the gas valve. Check incoming
gaspressure to waterheater. if
okay, replace gas valve
Checkf or clogged or kinked
pilot tube,clogged pilotorifice.
Clean or replace as needed.
(see page 13)
Isthe re 22-27 volts AC input
across wire leads
“MV/PV” & “PV”
atGas Valve?
(see photo 12)
Check continuity across ECO
(RED) leads of lower thermister
(see photo 13)
Is continuity okay?
Check wire harness for damage
or loose connections. Repair or
replace as needed.
Resethea ter by turning power
“OFF”. Wait 5 seconds and turn
power “ON”. When LED of
ignition module turns “ON” does
ignition module send “spartk”
signal (buzzing or clicking sound)
11
Replace ignition
module
12
Check across
“MV/PV” & “PV”
terminals
Check across “MV/PV”
&“PV” Wire leadsto
gas valve
13
Check across RED
wirele ads of lower
thermister (ECO).
ECO Specifications
Opens between 181°F/201°F
Closes between 160°F/100°F
N
Y
YY
NN
Y
N
Replace ignition
module
Isth ere spark at the
pilot?
Check for:
Loose or damaged ignition wire
Grounded pilot electrode
Damaged pilot.
Y
N
Page 8
8