Description
Astralpool C71 mechanical flange 1/2–3/4–1–1.25 HP 4405010424
The Astralpool C71 mechanical flange 1/2–3/4–1–1.25 HP 4405010424 is the original interface piece between the motor and the hydraulic
body on selected Astralpool pool pumps. It centres the motor, supports the mechanical seal and keeps the impeller at the correct distance
from the diffuser, which is essential for smooth, efficient filtration in residential pools.
Main features of the Astralpool C71 mechanical flange
- Original Astralpool flange for C71 frame motors from 0.5 to 1.25 HP.
- Houses the stationary part of the mechanical seal and shaft passage.
- Machined surfaces for accurate motor and pump body alignment.
- Fixing points matched to compatible Astralpool pump housings.
Function in the pump assembly
The mechanical flange is a structural link between the electric motor and the pump body. The Astralpool C71 mechanical flange
1/2–3/4–1–1.25 HP 4405010424 positions the motor shaft in line with the impeller and maintains the precise spacing needed for the impeller
and diffuser to work together correctly. It also provides the recess for the stationary seal seat, forming a key element of the shaft
sealing system.
- Aligns the motor shaft with the impeller for efficient power transfer.
- Supports and centres the mechanical seal to prevent water ingress to the motor.
- Provides a rigid connection that helps limit vibration and operating noise.
Compatibility and typical applications
This mechanical flange is designed for Astralpool circulation pumps that use a C71 frame motor in the 0.5, 0.75, 1 or 1.25 HP range and
that specify reference 4405010424 in their exploded view or spare parts list. It is commonly used in residential filtration systems with
sand, glass or cartridge filters where the pump runs many hours per day.
- Suitable for Astralpool pumps with C71 frame motors from 0.5 to 1.25 HP.
- Recommended when replacing the motor or rebuilding the hydraulic section.
- Direct replacement for worn or damaged flanges that no longer align correctly.
When to replace the mechanical flange 4405010424
Although the flange is not in constant contact with pool water, it is subjected to mechanical loads, occasional moisture and handling
during maintenance. Damage or deformation can compromise alignment and reduce the life of the mechanical seal and bearings.
- Cracks, broken ears or visible deformation of the flange body.
- Corrosion or wear around the mechanical seal seat or shaft opening.
- Thread damage in the fixing holes that prevents safe tightening.
- Repeated seal failures or unusual vibration after other causes have been excluded.
Replacing a compromised flange with the original Astralpool C71 mechanical flange 1/2–3/4–1–1.25 HP 4405010424 helps restore correct
alignment and stable, quiet pump operation.
Installation recommendations
Installation of the Astralpool C71 mechanical flange 4405010424 is normally done during a major pump service or motor change. The system
must always be isolated electrically and hydraulically before work begins.
- Switch off the power supply, close isolation valves and drain the pump housing.
- Separate the wet end from the motor and remove the existing flange and mechanical seal.
- Clean the contact faces on the motor and pump body to remove rust and deposits.
- Press the new mechanical seal seat into the flange, following the correct orientation.
- Bolt the flange to the motor, then to the pump body, tightening screws evenly in a cross pattern.
- Refit the impeller and remaining parts, checking that the shaft turns freely by hand before priming.
After reassembly, prime the pump, start filtration and monitor the seal area and general noise level to confirm that alignment and
sealing are correct.
Good practice for long term reliability
With the Astralpool C71 mechanical flange 1/2–3/4–1–1.25 HP 4405010424 correctly installed, a few simple habits help extend the life of
the flange, seal and motor.
- Mount the pump on a solid, level base with properly supported pipework.
- Avoid overtightening fixing screws to prevent stress in the flange body.
- Replace the mechanical seal whenever the flange or motor is renewed.
- Inspect the flange area during annual maintenance for early signs of corrosion or distortion.
Using the original Astralpool C71 mechanical flange 4405010424 helps compatible pumps maintain precise motor alignment, reliable shaft
sealing and quiet, efficient filtration over many swimming seasons.
