The Davey Silensor SLS100 uses a mechanical shaft seal for a 5/8″ shaft (about 15.9 mm), Davey part number 49771SP. This CapacitorsNZ seal is an aftermarket replacement for 49771SP to suit pumps labelled SLS100 or SLS100E. The same seal is also listed for the Silensor SLS75, SLS150, SLS200, SLS300, SLL150, SLL200, SLL300 and SLL400, and the Davey HS50 and HS60.
Pumps that share the Davey Silensor SLS100 seal
The 49771SP seal is listed for a group of Davey pumps. These have their own seal listings: Davey Silensor SLS75, Davey Silensor SLS150, Davey Silensor SLS200, Davey Silensor SLS300, Davey Silensor SLL150, Davey Silensor SLL200, Davey Silensor SLL300, Davey Silensor SLL400, Davey HS50 and Davey HS60.
The Davey HS60-08 and Davey ProMaster are listed with the same seal but don’t have their own listing here. It is also sold on its own as our Davey HS50 / HS60 / Silensor / ProMaster pump seal.
How to spot a worn SLS100 seal
A mechanical seal works by holding two very flat faces together: one spins with the shaft on a spring, the other is fixed in the pump housing. Grit, scale, age or a dry run wears or cracks those faces and water starts to get through.
- A steady drip or wet patch between the pump housing and the motor.
- Rust marks or white crust on the motor end or the pad underneath.
- Air being drawn in at the motor end, which can show as bubbles in the pump basket or trouble holding prime.
- Noisy, rough-running motor bearings, which can follow once water has got past the seal and along the shaft.
Swapping the SLS100 seal: general steps
These are the usual steps for this style of pump; follow the pump maker’s instructions where they differ. Isolate the power, shut the suction and return valves, and drain the pump. Separate the motor from the wet end, then hold the shaft still while you unscrew the impeller; the spinning half of the old seal comes off the shaft and the seat pushes out of the housing.
Before fitting, compare the old seal with the new one and measure the shaft, which should be 5/8″. Seat the new stationary part evenly, keep the polished faces clean and dry of oil, and use a little soapy water to slide the rotating part on. Fill the pump with water before switching on, because even a short dry start can damage new seal faces.
If the motor has also been slow to start, the Silensor SLS100 service kit pairs this seal with a run capacitor, and the SLS100 capacitor guide explains how to read the old one. Seals for other Davey pumps are listed on our Davey service kits page.
Before you order
Check the old part before fitting: match the size of your old seal.