Maintenance; Precautions Before Maintenance - Lennox LNINVE052 Service Manual

9. Maintenance

9.1 Precautions before Maintenance

There are high-capacity electrolytic capacitors on the outdoor mainboard. Thus, even the power is cut off, there is high voltage
inside the capacitors and it needs more than 20min to reduce the voltage to safety value. Touching the electrolytic capacitor within
20min after cutting the power will cause electric shock. If maintenance is needed, follow the steps below to discharge electricity of
electrolytic capacitor after power off.
(1) Open the top cover of outdoor unit and then remove the cover of electric box.
(2) As shown in the fig below, connect the plug of discharge resistance (about 100ohm, 20W) (if there is no discharge resistance,
you can use the plug of soldering iron) to point A and B of electrolytic capacitor. There will be sparks when touching them. Press
them forcibly for 30s to discharge electricity of electrolytic capacitor.
outdoor mainboard(AP1)
(3) After finish discharging electricity, measure the voltage between point A and B with universal meter to make sure if electricity
discharging is completed, in order to prevent electric shock. If the voltage between the two points is below 20V, you can perform
maintenance safely.
50
electric box
outdoor mainboard(AP1)
B
A
discharge resistance or
plug of soldering iron
B
A
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