Please check for the following possible causes before contacting your Selwood supplier.
1. Is the strainer fully submerged in the liquid and not blocked?
2. Is the drain cock under the pump volute closed? If not, close valve? Note: Use drain in cold weather to ensure liquid in volute does not freeze.
3. Ensure all ‘O’ rings on the suction side of the pump are in place. If they are damaged - replace. This includes all suction hoses.
4. Ensure non-return valve seat is clear of any debris. This can be done by opening the inspection plate. Warning: Pump must be drained down before carrying out this procedure