Keeping your pond pump working well results in your having healthy fish and water in the pond. The pond also looks beautiful because the pump removes dirt and debris from the water and circulates clean water that is better for the pond and its denizens. A malfunctioning pump can be diagnosed by following a few tips, which helps you determine whether the pump is fixable or if you need a new one.
Look for the source of the power supply to your pond pump. Check the circuit breaker to see if it is in the "On" position. If not, flip it on.
Check to see that the circuit breaker running from the electrical source to the pond pump remains on and does not shut off. If it does keep shutting off, check the pump seal. If it is damaged, water has entered the motor and the pump needs replacing.
Check the cords from the electric supply to the pond pump. See if any of the wires or cords are torn, broken or frayed. Replace or repair any that might be. Check the circuit breaker to see if it is faulty. You might have to replace the breaker.
Check the pond pump to see if it is submerged correctly. There is a thermostat that forces the unit to shut down when it gets too hot, which it does if it is not submerged sufficiently.
Look for clogs or twists in the impellers and hoses. If you have a filter that works correctly, this should not be a problem, but some stray piece of debris might be clogging the works.
Inspect and check any wiring, hoses and the water pH at least once a week.
Cut off the power supply when accessing any internal elements of the pump.