Abrupt loss in return pressure

[Beez]

Any ideas what might cause this? I didn't actually observe it happening, but Saturday all was normal, then while I was swimming in the pool Sunday I noticed the significant loss in pressure. It happened to coincide with the addition of salt to the water, but I don't see how the two could be connected.

Thanks,
Dave

 

[Beez]

Oh, BTW, I meant to add that filter pressure seems normal. Gauge reads zero when pump not on, then goes up to the normal operating pressure when pump is turned on.

 

[mdhwoods]

Blockage in the impeller can cause pressure to drop. if some salt got sucked in an temporarily clogged it that could be your issue.

 

[Beez]

Blockage in the impeller can cause pressure to drop. if some salt got sucked in an temporarily clogged it that could be your issue.

OK, if that's the case then it should resolve itself. However, it is an old pump. Let me ask an ignorant question: What are the signs that the impeller needs to be replaced apart from a blockage?

Thanks,
Dave

 

[waste]

If the impeller is clogged, it only needs to be cleaned out.

Very rarely an impeller will snap off it's stem - could be what's happening with your pump, more likely if it's the original impeller on an old motor. Changing out an impeller is as easy as changing a shaft seal (there a a number of posts here on changing the seal) - but that's only because it's the exact same thing Speaking of the seal, if you do need a new impeller, change the seal, they don't like being taken off and put back on!

There's only 1 thing the gauge reads normal, if it was a bad impeller, you'd need to have some sort of obstruction to jack the pressure up to normal. Are you loosing water? It's starting to sound like a broken return line