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 26).
Position gas control switch to the “ON” |
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position and adjust thermostat dial to call |
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for heat, Is there 10 to 13 VAC between | Is LED on gas valve flashing |
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red wire leading to blower temperature N | Y | ||||
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| the “heartbeat” code |
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switch and green ground wire? |
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(alternating bright/dim) |
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Blower must be running during this |
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voltage check. |
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(see photo 28) |
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| Y | Verify 120VAC to gas |
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| control (see page 30) |
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No voltage from gas control,
call for technical support.
Is there 10 to 13 VAC between yellow | Is there continuity |
| Check for loose or | |||
wire leading from pressure switch and N | through blower | Y | broken wire | |||
green ground wire? |
| temperature switch? |
| connection at switch | ||
(see photo 28) | (see page 21) |
| terminals | |||
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| N |
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| Determine cause of blower |
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| Correct igniter/ | temperature switch |
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| sensor problem. | activation and correct. |
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Do you hear or can you N see 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 12
Check igniter/sensor | Y | Faulty cord set or | |
(see page 16) | |||
| gas control. | ||
is igniter/sensor OK? |
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| Green ground wire | ||
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28 |
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| Red wire leading to | |
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| blower temp. switch |
Yellow wire leading from pressure switch
Page 30
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