Maintaining your Whitlock DNFT-PRG (Digital No-Flow Timer) is essential for ensuring the continuous protection of your reciprocating compressors and lubrication systems. When the LCD screen fades or the unit fails to trigger, it is usually time for a battery replacement.
Below is a step-by-step guide on how to safely and effectively replace the battery in a DNFT-PRG unit.
1. Safety and Preparation
Before performing any maintenance, you must address the environment. The Whitlock DNFT-PRG is typically installed in Class I, Division 1, Group C & D hazardous locations.
- Area Classification: Ensure the area is non-hazardous (de-classified) or obtain a “hot work permit” before opening the enclosure.
- Tools Needed: You will generally need a small hex (Allen) wrench to loosen the set screw and a replacement battery.
- Replacement Part: Use only 3.6V Lithium battery. Using an incorrect battery type may compromise the intrinsic safety of the device.
2. Accessing the Battery Compartment
The DNFT-PRG features a rugged, explosion-proof housing. Follow these steps to open it:
- Loosen the Set Screw: Locate the small hex set screw on the side of the housing cover. Use your Allen wrench to loosen it (you do not need to remove it entirely).
- Unscrew the Cover: Turn the large circular housing cover counter-clockwise. Since these units are often exposed to the elements, you may need a specialized wrench or a firm grip to break the initial seal.
- Inspect the O-Ring: Once the cover is removed, inspect the rubber O-ring for cracks or debris. A damaged O-ring can lead to moisture ingress, which will shorten the life of the electronics.
3. Replacing the Battery
With the internal electronics exposed, you can now proceed with the swap:
- Remove the Old Battery: Carefully pull the old 3.6V battery out of its clip. Avoid using metal screwdrivers to pry it out, as this could short-circuit the board components.
- Observe Polarity: Look for the + and – markings on the battery holder.
- Install the New Battery: Slide the new lithium battery into the clip, ensuring it is seated firmly.
- Verify the Display: Upon installation, the LCD should power up. The DNFT-PRG is programmable; verify that the “Pre-set” and “Elapsed Time” remain accurate or re-program them according to your system requirements.
Closing and Testing
Properly sealing the unit is just as important as the replacement itself.
- Clean the Threads: Wipe down the housing threads to remove any grit or old lubricant.
- Thread the Cover: Screw the cover back onto the housing clockwise until it is hand-tight.
- Secure the Set Screw: Tighten the hex set screw to lock the cover in place. This prevents the housing from vibrating loose during compressor operation.
- Functional Test: Cycle the lubrication system to ensure the DNFT-PRG is correctly sensing the magnet’s movement and that the countdown timer resets as expected.
>>>Battery replaces 000505 for Whitlock DNFT-PRG Tadiran
Conclusion
Replacing the battery in a Whitlock DNFT-PRG is a straightforward process that significantly extends the life of your monitoring equipment. By following these steps and prioritizing safety, you ensure that your machinery remains protected against costly “no-flow” conditions. Always keep a spare 3.6V lithium battery in your maintenance kit to minimize downtime.