Pool physics

[philwire]

Hi all,

2 years ago I had my inground built and it went great. Then last year we installed a heatpump for heating the water. It still went fine, but near the end of summer it started cutting off with HP error messages. I cleaned the filter, dipped it overnight, let it dry, it did the same. I even remember I took it out again to clean it with the shopvac and it still did it!

So I call the heatpump guy, he comes, and tells me the HP is caused by low flow, usually because cartridge filters restrain water too much. He even tells me to run the pool with no filter for a few days, and call him if it HP again. So it does it again, he comes again, now tells me my pump might now be able to pump fast enough. So I call my buddy that has his pool car company, he checks into it and tells me it's running ok. So the heatpump guy comes back and now tells me something like: Look, I'm a heatpump tech, not a pool tech. However, I don't think it's normal that the water is so low in your motor.

Effectively, you can see the water flowing into the motor. So I called the pool guy and now he says it's normal because it's pressure and it's boiling and blah blah blah. However, I tried running the motor without the basket into it for a few minutes and now the motor keeps its water! All I see is a bubble the size of a quarter!

Now, is it possible the motor basket is restraining the water flow by itself? or is it restraining the cover from being able to go back into is place? I was also thinking of eliminating all 90 degree angles and either install flexible pipes or 45 degree angles. Also, would I win something if I changed my whole apparent plumping for clear pvc instead of white?

thanks for the help!

 

[JohnT]

You shouldn't be able to see any bubbles in the basket before the pump. A loose lid will cause that to happen, so removing it and putting it back on may have been what you needed to fix it. It's a good idea to keep the O-ring lubed with pool lube.

Welcome to TFP!

 

[Bama Rambler]

Welcome to TFP.

What you have is a suction side air leak. It's possible that the basket is preventing the lid from sealing. Have you cleaned and lubed the lid o-ring? I'd start there.

 

[philwire]

Hi John and Dave,
Thanks for the quick replies, it's really appreciated to have support so quickly!
I'll check into the ring part on my lunch break, thanks for the suggestion.

Will changing the 90 degrees elbows for 45 degrees help in water flow?

 

[JohnT]

Will changing the 90 degrees elbows for 45 degrees help in water flow?

Probably not. Two 45s isn't much better than a 90. Maybe post a picture and we could evaluate any issues that might not be obvious.

 

[Bama Rambler]

Not enough that you'd even be able to tell.

As JT said, post a pic and we'll take a look at it.

 

[philwire]

Ok guys here are pictures

on the first picture as you can see I'm thinking of correcting from the motor to the filter with either 45s or a flexible that will loop to the right then under the motor intake to go straight to the filter.

on the 3rd one it was to show the bubbling.

 

[Bama Rambler]

Clean and lube the o-ring good and see if that helps.

 

[philwire]

Hi again,
So I replaced the o-ring of the motor, and of the cartridge filter. this morning I still had the problem, but then I remembered the heatpump guy told me to try without the cartridge in the filter. So I gave it a new try, removed the cartridge, restarted the whole thing, and BAM the motor got all filled up! I put the cartridge back, and since then I cant get the motor to fill up completely. The highest I got it to was to about over the handles of the glass. right now you don't see the water flowing like Niagara falls, it just flows quite nicely with some space on the top.

Now what should I try?
Also, I found out that when I put the filter in backwash the motor tends to fill up but it wont last long. then I figured my filter was emptying so maybe my backwash pipe should be higher than the filter? I'm so confused!

 

[btolley]

philwire - did the heatpump work okay when you removed the cartridge and got good suction? also, do you know what the filter gauge reads with and without the cartridge installed?

 

[harleysilo]

I didn't think people had cartridge filters set up to backwash? Is the filter clean? Do you have a spare or new one?

 

[philwire]

Hi guys - the filter is brand new (one week old) and it gives a reading of about 20 psi. I'll go check without the filter to make sure again.

 

[philwire]

ok guys without the cartridge in it's also at 20 psi so it should be working ok

Side question... If the heatpump's output is higher than the motor or slighty, wont gravity have an effect on it?

 

[philwire]

ok guys I put the cartridge back in, put the cover back, turned on the motor and..... quickly reopened the skimmer and bottom drains valve (forgot to open them before the motor) and now the glass is full. or almost, now it has a bubble like when the cartridge was not there. is there a risk for me to damage my motor if I start it that way??

wanted to attach a file of the motor glass with just a bubble about one quarter the size of the glass but there seem to be server problems.

 

[mas985]

If the filter is reading 20 PSI with or without the filters, then I am pretty sure that you have enough pressure at the heat pump. However, it could be that the pressure switch in the heat pump is not set properly or maybe not working properly. Normally, you shouldn't have to change that but there is no telling what the installer did. Also, is the equipment pad elevated above the pool and if so by how much?

 

[philwire]

well the concrete of the equipment pad is level with the pool's sidewalk so the water might have about a foot to lift up. would it help if the motor was lower than the skimmers level? I could dig a place for it between the concrete pad and the fence...

 

[philwire]

oh btw I havent had any trouble with the heatpump since I changed the filter. Now I really want my motor glass to fill up with water and have a minimum of bubble in it. I think fixing this will fix all my problems once and for all.

 

[mas985]

ok guys I put the cartridge back in, put the cover back, turned on the motor and..... quickly reopened the skimmer and bottom drains valve (forgot to open them before the motor) and now the glass is full. or almost, now it has a bubble like when the cartridge was not there. is there a risk for me to damage my motor if I start it that way??

wanted to attach a file of the motor glass with just a bubble about one quarter the size of the glass but there seem to be server problems.

A quarter sized bubble is not an issue. So are you saying with the skimmer and main drains open (full flow), that there is still an issue with the heat pump? The problem may not have anything to do with the filter. It just might have been a coincidence.

 

[philwire]

ok I just went back and the bubble got bigger. any other suggestions ?

 

[mas985]

The bubble is not an issue unless the water level in the pump basket drops below the inlet pipe. But to my other question, is the heat pump still having a problem or did you solve that issue?