Does this sound like I need a new pump??

Hi, opened the pool yesterday but having issues and not quite sure what the problem is. I have an inground 18,000 gallon pool and a self priming hayward 1.5 hp pump that is 4 seasons old. The pump sits 4' above water level. First off I have to say that I changed the sand in my filter for the 1st time and forgot the step to put water in the filter before adding the sand but I don't think that is causing the issue.

We cannot seem to sustain a flow through the pump without force priming each time after we turn it off. I checked for leaks in the intake, and any other leaks and can't find anything. Switched it over to waste to bypass any potential problem with the way I changed the sand and it still won't sustain suction.

Does this sound like I need a new pump or is there another issue I might be missing?

Thanks very much,
Tom

Tom,
I doubt it is a pump problem as there are very few things that can go wrong with a pump. Electrically it usually works or doesn't. Mechanically bearings can fail or the seal can leak. Another possibility is hair and crud is tangled in the impeller which would cut down the pumping ability. By force priming do you mean pouring water in the pump basket then closing the lid to get it going? If so then it sounds like it does pump for a while then enough air gets sucked in somewhere to cause a loss of suction. The 4' lift above water level is high so this would cause additional suction side resistance. My best guess at this time is a crudded up impeller causing low flow.
Re-reading your post, I'm now not sure if it stops pumping while it is running or it won't pump after you turn it off for some time. If the latter, any kind of air leak anywhere, even on the pressure side, would let water drain back into the pool.
Post again to try and clarify things but in the meantime, relax for now...a new pump doesn't seem necessary.
Al

Thanks very much for your reply. Now today, I cannot even get it sucking the water up at all even with priming. It only sucks the water I primed with. Yesterday I did get it running one time after pouring in buckets of water and closing the lid. The pump is running but it just doesn't seem to have enough strength. I will check to see if it is clogged with hair etc.
Haven't had any other issues with it in the last 4 years and this is all new to me.
Thanks again for your time,
Tom

Hi, checked the impeller and it was clean...any other thoughts?
Thanks,
Tom

Tom, a lonely thought, putting a 'backflow prevention valve' or check valve on the suction line would prevent the re-priming problem. If you have valves on the suction lines, close them before opening the pump lid, of course you'll have to open the valves again when restrting the pump - also, only open one line when restarting the pump, then crack the other valve (just enough to draw the air out of the other line without loosing prime) and open it when you are drawing only water.

Tom,
That 4' elevation is certainly not helping the problem but since the system was working for several seasons, says something has changed. My best guess is you have a very small air leak in the suction side and because of the additional suction required to handle the 4' rise, a small leak can definitely cause the problem you are seeing. Another best guess is the leak would be at the highest point, the pump, because this is the point of maximum suction or vacuum. Don't know what your system looks like but here are my guesses and remember, we're talking a very small air leak::
--Pump basket lid. Give the gasket and seating channels a good visual and don't spare the silicone grease when putting it back together.
-- drain plug(s)
-- Any pipes with hose clamps on the suction side? Those barbed fittings can leak easily.
There is another highly unlikely possibility and that is the clearance between the impeller and the pump chamber. I don't know what this clearance typically is but I suspect on the order of mils. This lets the pump creat enough of a vacuum when wet to be 'self priming'. If this clearance open up just a little, then there won't be enough suction to sustain the 4' water column. If something got past the pump basket and damaged the impeller edges or the chamber then it could be a problem. Again , highly unlikely. Only way I know to find out if to disassemble and inspect.
Gotta run.
Best I can think of now.
Al

Believe it or not, I am having the same problem. My pool is also in it's fourth year. I am not sure of the height difference between the water line and the pool. I ran out of daylight today. I am going to look at all my connections to check for leaks.

tom

Since both pumps in question are 4 years old, let me ask a few questions here...
Any and all quick disconnects on your system have rubber O rings to seal them, has anyone bothered to clean the dirt that deposits around them and the surfaces they sit on, then lube it up with some silicone pool lube?
This also goes for your Pump lid and O ring seal on it.
If that does not work, have you tried removing all teh air out of your sand filter?
I just found a great way to do that recently, place filter on rinse setting, hold your discharge hose above top of filter and fill it with the garden hose, it fills up your filter quickly.
Also, has anyone bothered checking the basket in the sand filter, many people don't ever bother taking the selector valve body off their filter, when they do, the basket's full of leaves because somewhere along the line, someone ran the system without a skimmer or pump basket thinking they can discharge the leaves by vacuuming to waste and pugging the hidden basket. (top mount valve unit - not sure about others)

All good suggestions--thanks. I will try all this when I get home tonight.

One other thing, is there a special pool silicone?

yes, probably many brands, it's silicone based, you don't want any petroleum based product.