Harbor Freight Tools Model 40400 - Manual (Page 5)

SKU 40400 For technical questions, please call 1-800-444-3353. Page 5
Operation (continued)
WARNING! The automatic Pressure Switch (46) is factory set. It should only be adjusted to have the
original settings restored and this should only be done by a qualified technician. Adjustments made
by unqualified personnel or adjusting the pressure valve to other settings will vOID THE WARRANTY
and may cause damage to the compressor or PERSONAL INJURY.
The Safety valve
The Safety Valve (see illustration on page 6 for location) is used as a backup to help prevent the tank
from exceeding its maximum safe pressure. Check before each use as follows: Pull on the Safety Valve ring to
release pressure; the valve is spring-loaded and has resistance, but it should move without sticking.
Empty Air and Condensation
The Petcock (53) release valve is located underneath the Tank Assembly (50). It must be used daily to
release all trapped air and moisture through this valve. It will also get rid of any condensation that may cause
tank corrosion.
Warning: Do not open the Petcock (53) so that more than four threads are showing.
1. Push down on the Power switch to turn the compressor off.
2. Unscrew the Petcock (53) two to three turns only.
3. When all pressure is released, close the Petcock (53) again.
NOTE: IF THE COMPRESSOR SUDDENLY SHUTS OFF, check and reset the unit’s
Overload Protection (59). Ensure that an extension cord is not being used.
REv 06a