Honeywell PDX50S60F(B,S,C)*(N,X) Safety Circuit Voltage Trace, Pdx Service Procedure, PDX Series

PDX Series

PDX SERVICE PROCEDURE VIII

Safety Circuit Voltage Trace

Safety Circuit Voltage

Trace

NOTE: This procedure assumes a cool tank.

WARNING

120 volt potential exposure. Use caution

making voltage checks to avoid personal injury.

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Step 2. Remove three screws (Phillips Screw driver) from control access cover on blower and remove cover (see photo 24).

Position gas control switch to the “ON”
position and adjust thermostat dial to call
for heat, Is there 10 to 13 VAC between red		N	Is LED on gas valve flashing the
wire leading to blower temperature switch					Y		No voltage from gas control,
			“heartbeat” code (alternating
and green ground wire?							call for technical support.
			bright/dim)
Blower must be running during this
voltage check.				N
(see photo 25)
	Y
			Verify 120VAC to gas
			control (see page 30)
Is there 10 to 13 VAC between yellow wire						Is there continuity				Check for loose or
leading from pressure switch and green		N				through blower			Y
										broken wire connection
ground wire?						temperature switch?
										at switch terminals
(see photo 25)							(see page 21)
	Y							N
						Determine cause of blower
			Correct igniter/			temperature switch activation
			sensor problem.				and correct.

Do you hear or can you see N the igniter sparking?

Y

Safety circuit voltage is OK.

If burner does not light, observe LED flash code on gas valve and refer to troubleshooting section on page 13

Check igniter/sensor	Y	Faulty cord set or
(see page 17)
		gas control.
is igniter/sensor OK?
		Green ground wire
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		Red wire leading to
		blower temp. switch

Yellow wire leading from pressure switch

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