Introduction
The PROFLO PF91655 Descaler Pump Kit is designed for the efficient removal of scale, lime, mineral deposits, and rust from tankless water heaters. Regular descaling is essential to maintain optimal heat transfer and energy efficiency of your tankless water heater. This manual provides detailed instructions for the safe and effective use of your descaler pump kit.
Safety Information
- Always wear appropriate personal protective equipment (PPE), such as gloves and eye protection, when handling descaling solutions.
- Ensure the work area is well-ventilated to avoid inhaling fumes from descaling chemicals.
- Disconnect power to the tankless water heater before beginning any descaling procedure.
- Follow the specific safety instructions provided by the manufacturer of the descaling solution you are using.
- Keep children and pets away from the work area during the descaling process.
- Do not operate the pump with flammable liquids.
Package Contents
Verify that all components are present before beginning the setup:
- PROFLO Descaler Pump
- 3.5 Gallon Pail with Screw Top Lid
- Hoses and fittings (as supplied)
Setup Instructions
Follow these steps to set up the PROFLO PF91655 Descaler Pump Kit:
- Prepare the Tankless Water Heater: Turn off the power and water supply to the tankless water heater. Close the cold water inlet valve and the hot water outlet valve. Open the service valves (flush valves) on the cold and hot water lines.
- Position the Pail: Place the 3.5-gallon pail on a stable, level surface below the tankless water heater.
- Connect Hoses:
- Connect one hose from the pump's discharge port to the cold water service valve of the tankless water heater.
- Connect the second hose from the hot water service valve of the tankless water heater, directing its open end into the 3.5-gallon pail.
- Submerge the Pump: Place the PROFLO descaler pump into the 3.5-gallon pail, ensuring it is fully submerged.
- Add Descaling Solution: Pour the recommended amount of descaling solution into the pail, ensuring the pump remains submerged. Refer to the descaling solution manufacturer's instructions for proper dilution and volume.

Image: The PROFLO PF91655 Descaler Pump Kit set up for descaling a tankless water heater. The pump is submerged in the white bucket, and hoses connect it to the water heater's service valves.
Operating Instructions
Once the kit is set up, follow these steps to operate the descaler pump:
- Start the Pump: Plug the pump into a grounded electrical outlet. The pump will begin circulating the descaling solution through the tankless water heater.
- Circulation Time: Allow the solution to circulate for the duration recommended by the descaling solution manufacturer, typically 45 minutes to 1 hour. Monitor the process for any leaks.
- Drain and Flush: After the recommended circulation time, unplug the pump. Disconnect the hoses from the tankless water heater service valves. Drain the descaling solution from the water heater and the pail. Flush the tankless water heater thoroughly with fresh water until all traces of the descaling solution are removed.
- Restore Water Heater: Close the service valves, open the cold water inlet and hot water outlet valves, and restore power to the tankless water heater.
Maintenance
Proper maintenance ensures the longevity and performance of your descaler pump kit:
- Clean After Use: After each use, thoroughly rinse the pump, hoses, and pail with clean water to remove any residual descaling solution.
- Inspect Hoses and Fittings: Regularly inspect hoses and fittings for signs of wear, cracks, or damage. Replace any damaged components immediately.
- Storage: Store the pump kit in a clean, dry place, away from direct sunlight and extreme temperatures. Ensure the pump is completely dry before storage.
Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| Pump does not start | No power; clogged impeller; airlock | Check power connection; clean impeller; prime pump by ensuring it's fully submerged and free of air. |
| Reduced flow rate | Clogged hoses or pump; low descaling solution level | Check and clear hoses/pump; add more descaling solution to ensure pump is fully submerged. |
| Leaks from connections | Loose fittings; damaged hoses | Tighten all hose connections; inspect hoses for damage and replace if necessary. |
Specifications
| Feature | Detail |
|---|---|
| Brand | PROFLO |
| Model Number | PF91655 |
| Power Source | Electric (55 watt mag drive pump) |
| Item Weight | 10.5 Pounds |
| Pail Capacity | 3.5 Gallons |
| UPC | 781889401989 |
Warranty and Support
For warranty information, please refer to the documentation included with your purchase or contact your retailer. For technical support or inquiries regarding the PROFLO PF91655 Descaler Pump Kit, please visit the official PROFLO website or contact their customer service department.


