Pressure drops inexplicably

[IceShadow]

Having an issue carrying over from the end of last year - my water pressure will suddenly drop from around 15 to about 10 with no reason I can find. Turning the pump off and on again corrects it.

Here’s a short video I made of the low pressure turning it off and correcting it to the high pressure.

https://www.facebook.com/100000182950095/posts/3500692639946800

 

[Texas Splash]

You don't have anyway to bypass the heater do you? What about running on ricirculate? Does it change pressures then too?

 

[duraleigh]

It sounds like you have a suction side air leak. Is the water frothing around inside your pump basket when the pressure is low?

 

[IceShadow]

You don't have anyway to bypass the heater do you? What about running on ricirculate? Does it change pressures then too?

No way to bypass without replumbing.

I haven’t tested on recirculate. Will do tomorrow!

It sounds like you have a suction side air leak. Is the water frothing around inside your pump basket when the pressure is low?

Nope, no air in the basket at all.

 

[JamesW]

Maybe the gauge is sticking. Try tapping it when it's low.

 

[JamesW]

Maybe the heater flow valve is defective?

 

[markayash]

what does your pressure normally run, 10 or 15?

 

[IceShadow]

Maybe the gauge is sticking. Try tapping it when it's low.

Brand new gauge, and the old one recorded the same thing. The flow on the pool drops a lot too. I can feel it go down when it does this.

Maybe the heater flow valve is defective?

How do I test?

what does your pressure normally run, 10 or 15?

Normal is 15.

Maybe my pump is dying? It looks pretty old.

 

[markayash]

Brand new gauge, and the old one recorded the same thing. The flow on the pool drops a lot too. I can feel it go down when it does this.

How do I test?

Normal is 15.

Maybe my pump is dying? It looks pretty old.

Have you backwashes the filter? Maybe the sand is clumping together and allowing it through somehow?
Just a thought, weird how rebooting the pump fix’s it

 

[IceShadow]

Have you backwashes the filter? Maybe the sand is clumping together and allowing it through somehow?
Just a thought, weird how rebooting the pump fix’s it

I just deep washed the sand today, and have backwashed a few times after as I had to clean out my pool after the winter.

It was doing this last year at the end of the year as well.

 

[JamesW]

If the flow goes down when the pressure goes down, I think that points to a suction restriction or maybe something clogging the impeller.

Maybe check the impeller.

Maybe put a vacuum gauge in the front drain plug to see what that shows.

Be careful not to crack the front drain plug hole when screwing in the gauge.

 

[markayash]

I just deep washed the sand today, and have backwashed a few times after as I had to clean out my pool after the winter.

It was doing this last year at the end of the year as well.

I will be interested to see what you find! I like Pat's idea running on recirculate and see what happens

 

[IceShadow]

If the flow goes down when the pressure goes down, I think that points to a suction restriction or maybe something clogging the impeller.

Maybe check the impeller.

Maybe put a vacuum gauge in the front drain plug to see what that shows.

Be careful not to crack the front drain plug hole when screwing in the gauge.

How do I check the impeller? I reached into the pump opening with the basket out and didn’t feel anything. Do I need to take apart the pump somehow?

What is a vacuum gauge and what front drain plug hole?

Another oddity is that my heater isn’t always firing up - sometimes I have to turn the pump off and on a few times to get it to fire. But it is also very old and finicky (millivolt heater).

 

[wireform]

Not sure this can diagnose the motor but possibly putting an amp probe on the the L1 or L2 wires and see if amperage drops off with the psi gauge.

 

[IceShadow]

Not sure this can diagnose the motor but possibly putting an amp probe on the the L1 or L2 wires and see if amperage drops off with the psi gauge.

I'm sorry, but this is a bit beyond me. I don't have any sort of electrical probes except one of those pen-style ones you use to test if wires are live. >.>

I'm going to try to pull the pump apart a bit to access the impeller. Maybe there's something partially blocking it? Dunno.

I'll also pull the in and out unions off the heater and see if I can spot any sort of blockage around the unions. I have no idea where the flow valve in the heater is located, so that would make that hard to diagnose. Heater was on last night but off again this morning, so I'm starting to think I should replace the whole thing anyway.

 

[markayash]

I don't know how he insides of a heater work but if there a internal bypass so if it thinks pressure is too high it bypasses at the in/out? If so that might explain the pressure drop.
I know my hayward looks like it has some sort of pressure type valve where the unions fit..
That also might explain why it works and stops, does the pressure stay at 15 when the heater is working?

 

[JamesW]

It's definitely an odd situation. A vacuum gauge looks exactly like a pressure gauge except it measures vacuum. It has the same 1/4" npt threads as the pressure gauge. You can screw it into the front drain plug of the pump.

Refer to the manual or parts diagram if you're not sure what the drain plugs are.

Measuring the current and voltage at the same time is a good idea so that we can see if they are the same or different at different filter pressure.

 

[IceShadow]

I don't know how he insides of a heater work but if there a internal bypass so if it thinks pressure is too high it bypasses at the in/out? If so that might explain the pressure drop.
I know my hayward looks like it has some sort of pressure type valve where the unions fit..
That also might explain why it works and stops, does the pressure stay at 15 when the heater is working?

It's a millivolt heater so any bypass would likely be mechanical in nature. I doubt it has one - it seems pretty rudimentary. I don't know a ton about heaters either, but I know it has some sort of valve to check water pressure to make sure it's not running when the pressure is low - perhaps that's getting jammed somehow and restarting the water flow is loosening it?

I have no idea how to get at it, though, so I can't see if anything is impeding it.

It definitely turns off when the pressure drops, but if the water flow is low that could be an effect and not a cause, due to the safety of it not going when water flow is low. This morning I went and checked it and the gauge was at 15 after running all night, which is good, but the heater was not running at all.

It's definitely an odd situation. A vacuum gauge looks exactly like a pressure gauge except it measures vacuum. It has the same 1/4" npt threads as the pressure gauge. You can screw it into the front drain plug of the pump.

Refer to the manual or parts diagram if you're not sure what the drain plugs are.

Measuring the current and voltage at the same time is a good idea so that we can see if they are the same or different at different filter pressure.

OK, front drain plug = thing that I opened on the bottom of the impeller housing to leave open for the winter, and then plugged again when I started the pool up Friday.

I don't have a vacuum gauge or any sort of way to measure current/voltage. Do you have recommendations of what to get so I can self-diagnose? (Model/make, perhaps source?)

Going to go open up the impeller housing and see if I can see anything. I'll take photos and post them since I probably have no idea what to see if anything is wrong.

 

[IceShadow]

So - checked the heater in and out. Didn’t see any obstructions.

 

[IceShadow]

Next I pulled the pump housing apart. I noticed some pine needles wedged between what I assume is the impeller and the impeller housing / cover. Took that off, cleaned them out, put it back together....and now it won’t even prime.

Did the pine needles destroy the impeller or housing?