What size cover pump do I need?
Bigger than you think, and read the flow rate with its lift attached. An inch of rain on a 16 by 32 ft pool is 319 gallons weighing over a ton, so a pump rated near 1700 gallons an hour clears it in about eleven minutes and one rated 300 takes most of two hours. The catch is that every flow rate is quoted at a stated lift. Ask the same pump to push the water ten feet uphill to a drain and it moves far less than its headline figure, so read the curve, not the box. Match the pump to the rain you get rather than to the size of the pool.
Should I get an automatic pump or a manual one?
Automatic if it is going to live on the cover all winter, manual if you will be standing over it. An automatic pump carries a float: it starts itself when the water reaches a couple of inches and stops before the cover is dry, so the rain that falls while you are at work is gone by the time you get home. A manual pump runs from the moment it is plugged in until you unplug it, which is fine when you are there and a problem when you are not.
Can I leave a cover pump out all winter?
An automatic one, yes, and that is what it is for. Keep the cord and the plug clear of standing water and off the ground, check on it after a hard freeze, and lift it before the cover goes into ice it cannot get out of. A manual pump should not be left running unattended at all, for the same reason it should not be left running on a dry cover: there is nothing to stop it.
Why does running it dry matter?
Because the water is what cools it. A submersible pump has no fan; it sheds its heat into the water around it, so a pump that keeps running after the cover is clear is cooking itself. That is the real argument for a float switch, and it is not about saving you a trip outside. It is a protection device that happens to also be a convenience.
Can I use a sump pump or a utility pump instead?
It will move the water, and plenty of people do it. Two things make it a worse tool for the job. A sump pump is built to sit in a pit and needs several inches of water before it will pick up, where a cover pump is built to work in about two and to stop near one, so the sump pump leaves behind the last of what you were trying to remove. And its float is set for a pit, not for a cover, so it will cycle badly or not switch at all on a shallow puddle.
My cover pump will not start. What should I check?
Work from the outside in. Confirm the outlet has power and the breaker or the ground fault plug has not tripped, because a wet extension lead outdoors trips one often. Then lift the pump and clear the intake screen, which fills with leaves and silt and is the usual answer. On a pump with a float, check the float moves freely and is not jammed against the cover or wrapped in its own cord. If it hums but moves nothing, the impeller is blocked or gone, and that is a part rather than a new pump.
