Description
R355621 Backplate Screw For Pump Pinnacle And Superflo Pentair
The R355621 backplate screw for pump Pinnacle and Superflo Pentair is the original fixing screw used to secure the rear backplate of the pump wet end to the motor assembly. It is designed with the correct thread, length and head profile to match the factory housing, ensuring that the pump body is held together firmly and remains correctly aligned under filtration pressure.
Main Features Of The R355621 Backplate Screw
- Original style Pentair backplate screw for Pinnacle and Superflo pumps.
- Correct thread and length to match the original motor and housing fixing points.
- Designed for continuous use in the humid environment of pool technical rooms.
- Suitable for replacing missing, corroded or damaged factory screws.
Function In The Pentair Pinnacle And Superflo Pump
The backplate screws are critical fasteners that hold the pump housing to the motor face. Together with the sealing gasket and mechanical seal, they keep the wet end correctly compressed against the motor flange so that water cannot escape between both parts. Using the correct R355621 screw helps maintain pump alignment and preserves the integrity of the shaft seal area.
- Clamps the backplate securely to the motor adaptor or motor flange.
- Maintains even pressure on the housing gasket to prevent leaks.
- Helps the pump run quietly by reducing unwanted play between components.
Compatibility And Typical Applications
The R355621 backplate screw for pump Pinnacle and Superflo Pentair is used on a range of Pentair pool pumps that share a similar rear housing layout. It is the correct replacement whenever the parts diagram for your Pinnacle or Superflo model lists R355621 as the backplate screw reference.
- Compatible with selected Pentair Pinnacle circulation pumps.
- Compatible with Pentair Superflo pumps that specify R355621 in the exploded view.
- Ideal for restoring full sets of identical screws when some have been lost or replaced by unsuitable hardware.
When To Replace The Backplate Screws
Backplate screws work under vibration and in a moist, chemically active atmosphere. Over time, they can corrode, seize or lose their head profile, making it difficult to remove or reinstall the housing during maintenance.
- Visible corrosion or rust on existing screws around the backplate area.
- Damaged or rounded heads that no longer accept the correct tool.
- Missing screws or non original screws of incorrect length or thread.
- Refurbishment of an older pump where all fixings are being renewed as a preventive measure.
Installation Guidelines
Replacing backplate screws is usually done when the pump is opened for seal replacement, motor work or housing refurbishment. All work should be carried out with the electrical supply isolated and the hydraulic system depressurised.
- Switch off and isolate the power supply to the pump before starting work.
- Close isolation valves and drain the pump housing to relieve pressure.
- Remove the existing backplate screws and carefully separate the wet end from the motor.
- Complete any required maintenance on the seal, diffuser or housing and reassemble the wet end on the motor.
- Install new R355621 screws in the original positions and tighten them evenly in a cross pattern.
- Avoid overtightening, which can distort the housing or damage the screw threads.
After reassembly, reopen the valves, prime the pump and check that there are no leaks around the joint between the pump housing and the motor face when the system is running under normal pressure.
Good Practice For Reliable Fixing
Using the correct original specification screws and following some basic good practice helps ensure the pump remains structurally sound and easy to service.
- Use identical R355621 screws on all backplate fixing points to maintain uniform clamping pressure.
- Apply a light, suitable anti seize compound on the screw threads if recommended, especially in corrosive environments.
- Inspect the condition of all fixings whenever the pump is opened for internal maintenance.
- Replace any screw that shows signs of corrosion, damaged threads or a deformed head.
With original R355621 backplate screws correctly installed, Pentair Pinnacle and Superflo pumps retain their mechanical stability, helping to protect the shaft seal, maintain correct alignment and prolong the overall service life of the filtration system.
