AdvantagePlus Fault Tree Troubleshooting
1706.doc
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PRESSURE SWITCH; Air pressure switch or blower motor not operating properly; problem with venting.
Explanation; Monitors the positive air pressure
switch. Means there is sufficient combustion airflow.
The LED is ON when the pressure switch is closed.
Fault indicates insufficient airflow thru the venting
and blower system.
At a minimum, check the following:
1. Venting blockage (air in and air out)
2. Blower not operating
3. Pressure switch stuck open
4. Vinyl tubing to pressure switch is kinked
Diagnose and repair venting issue. See list of venting
questions on the next page.
Is the PVC
venting causing
the problem?
Yes
No
Continue to next step
Disconnect both side of the venting and recycle power. If the unit
goes to main burner, the problem is in the venting. If the unit does
not go to main burner, the venting is probably OK.
Replace pressure switch
1. The pressure switch is a normally open, positive pressure
switch. It activates (closes) on +4.75 inches w.c. If you use a
manometer to verify blower motor pressure you can
diagnose venting. IF the pressure drops below normal, then
the problem is the fresh air inlet side of the venting. IF the
pressure increases above normal, then the problem is the
exhaust side of the venting.
2. Verify the pressure switch is open with a continuity test. If
the switch is closed, replace the switch.
3. Remove either the pink or brown wire from the pressure
switch. If the blower runs, then replace the pressure switch
4. If the blower does not run, then go to next step.
Is the pressure
switch OK?
Yes
No
Continue to next step
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