APL-3 Series Limit Switch Box
Installation Operation & Maintenance Manual
Doc No. : HumG-APL3-21 Rev1 Page 9 / 10 Valve Automation Leader, HKC
9. Maintenance
Caution :
-Shut off incoming power or air supply on the valve actuator before maintenance limit switch box.
-Be sure that the area is clean before disassemble and maintenance limit switch box. Clean all parts and
housing before re-assemble.
-Refers to the part list when ordering replacement or spare parts.
9.1. Maintenance, under normal conditions at six month intervals or 100,000 cycle operation. But when
conditions are more severe, more frequent inspections may be required.
9.1.1. Ensure valve actuator alignment. [If the alignment is not correct, the shaft may be damaged by metallic
fatigue during operation. --- 20 r0]
9.1.2. Ensure wiring is insulated, connected and terminated properly
9.1.3. Ensure all screws are present and tight
9.1.4. Check the cleanliness of the internal electrical system.
9.1.5. Ensure conduit connections are installed properly and are dry
9.1.6. Check internal devices for condensation
9.1.7. Check enclosure O rings seals and verify that the O ring is not pinched between housing
9.1.8. Visually inspect during open/close cycle
9.1.9. Inspect identification labels for ware and replace if necessary
Warning ;
Before opening, you must ensure that there are no flammable gases and electrical power is off.
Treat cover with care. Gap surface must not be damaged or dirtied in any way
10. Inspection
10.1. Check the item and quantity of products with packing list or related documents.
10.2. Check the limit switch box o-ring. Where a damage on it. It caused the corrosion of internal parts.
10.3. Check the adjustment of cams. Cams shall be released when those have been used for a long period of
operating. If do so, they don’t work correctly with switches.
11. Storage
The products must be stored in a clean, cool and dry area. The unit shall be stored with the cover installed and
the cable entry openings sealed. Storage must be off the floor, covered with a sealed dust protector.
12. Trouble Shooting
The following instructions are offered for the most common difficulties encounter during installation and start-
up.
Signal fails to main control room.
① Check the wiring of limit switch box in accordance with wiring diagram.
② Check whether the cams or switches are damaged or broken.
③ Check the main signal wire from the terminal strip.
④ Re-set the limit switch box
⑤ Check resistance value of the potentiometer.
⑥ Check potentiometer gear jamming
⑦ Check the zero and span calibration
⑧ Check whether the card is damaged or not.
13. Tools
① 1 Set Metric Allen key (Hex Wrench)
② 1 Set Screw driver
③ 1 Set Metric spanner
④ 1 Wire Stripper long nose
⑤ 1 Needle nose pliers
⑥ 1 Multi Meter (AC, DC, Resistance)
⑦ 1 Ohm Meter (0~25mA) : IF APL - . 16 adapted
14. Installation and Maintenance Tips
For any installation and maintenance work, the following should be observed :
Caution :
A regular inspection and maintenance performed by qualified and trained personnel
