Bradford-White Corp D38T155 service manual Service Procedure D24-II, Pilot Operation Testing

SERVICE PROCEDURE D24-II

Pilot Operation Testing

DANGER

120 volt exposure. To avoid personal injury, use caution while performing this procedure.

CAUTION

Be Careful When Making Voltage

Measurements or Jumping Terminals

Not to Damage or Deform Connectors or

Connector Pins.

		Condition:							11
	Pilot will not light,
	Ignition module LED is “ON”								Check across
									“MV/PV” & “PV”
									terminals
	Reset heater by turning power
“OFF”. Wait 5 seconds and turn
	power “ON”. When LED of				N		Replace ignition
ignition module turns “ON” does							module		Check across “MV/PV”
	ignition module send “spartk”								& “PV” Wire leads to
signal (buzzing or clicking sound)									gas valve
			Y					Check for:
	Is there spark at the			N			Loose or damaged ignition wire		12
		pilot?					Grounded pilot electrode
			Y					Damaged pilot.
Is there 22-27 volts AC output across
terminals “MV/PV” & “PV” of Ignition						N		Replace ignition
	Module? Disconnect wires & check
								module
	across terminal of module.

(see photo 11)

Y

Is there 22-27 volts AC input			Loosen pilot tubing connection at				Check for clogged or kinked
across wire leads
		Y	the gas valve and soap test.			Y	pilot tube, clogged pilot orifice.
“MV/PV” & “PV”
			Is there pilot gas flow out of the				Clean or replace as needed.
at Gas Valve?
				gas valve?			(see page 13)
(see photo 12)
	N				N
			Tighten pilot tube connection at
			the gas valve. Check incoming
			gas pressure to water heater. if
			okay, replace gas valve
				ECO Specifications			13
Check continuity across ECO
(RED) leads of lower thermister N			Opens between 181°F/201°F
(see photo 13)			Closes between 160°F/100°F

Is continuity okay?

Y

Check wire harness for damage or loose connections. Repair or replace as needed.

Check across RED wire leads of lower thermister (ECO).

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