Pump Not Running
Make sure the power is on. Next, check the fuses/breakers and switches. If your pump came equipped with a timer, make sure the timer is functioning properly. This could make it seem like your pump has failed, when it's actually just the timer malfunctioning.
Pump Runs Hot/Shuts Off
This can actually be caused by a low power supply or undersized power wires. Or perhaps the wires running between the power source and the pump are too long. Always follow the specs provided in your manufacturer's instructions and follow local code requirements.
The "problem" could also be that your pump has a thermal overload switch. This is fine. However, the pump will shut off if the motor gets too hot and will restart after it has cooled a bit.
Pump Is Noisy
This might be normal. Pumps have fans to help cool the motor, and you'll hear it running.
A low water level, improper suction line size (which will cause cavitation), a leak in the piping, or a blockage in the suction line may cause a high level of noise.
If you don't think this is the problem, you might check the motor bearings. The chemical tablets that are normally added to swimming pools also corrode the pump seal over time. Water leaks in and damages the motor bearings. These must be replaced by a motor repair shop.
Pump Cuts In/Out Every 5 to 10 Seconds
You have the motor wired to the wrong voltage. Most pumps can be wired to 115v or 230v. You should shut off the pump immediately and call a licensed electrician to check and correct the problem.
It's not advisable to do this type of electrical work yourself unless you're a licensed electrician. You may seriously damage your pump or seriously injure yourself or your family.
Bubbles Forming In Pool
The strainer cover has come loose or the gasket is damaged. Check and replace those parts as necessary.
Other possible problems include:
The pool water level might be too low. The air is mixing with the water in the skimmer and causing bubbles to form in the pool. Add water to the pool.
The skimmer weir might be stuck. If it is, air is mixing with water in the suction line. You can fix this by opening the weir or "flap" so that water can flow freely again.
There might be a leak in the suction line or piping, or in the suction-side valve at the O-ring. Check and replace these parts as necessary.
Pump Is Running, But There Is No Pressure
The pressure might be fine, but the water flow is low. This is caused by a dirty or clogged filter. It can also be caused by a blocked return line, or a closed or partially closed valve on the return piping.
Alternatively, the pump's impeller might be dirty or clogged with debris.
In either case, shut off the pump and remove the basket. Check with your hand to see if there's anything clogging the impeller or piping.