Pool Returns Weak and Intermittent

[alam2p]

Hello,

Long time lurker, first time poster and also a new pool owner trying to get it up and running for the first time.

I had a pool company come in and do some new valve work, as well as install a new variable speed pump. I got all new Praher ball valves for my pool and spa returns, my skimmer, main drain and spa drain lines, and also on either side of the pump. The only problem that arose was the pipework tying all the suction lines together was not glued well, so there is a (seemingly) small air leak. When the system is off, that drips water and I can hear it hissing. The company is coming back to fix that joint later.

In my excitement, after filling the pool halfway, I draw from the main drain to prime the pump and noticed that while the return jets eject water, it was quite weak and also very intermittent. I figured the main drain was probably not generating enough suction and the water level is too low so I gave up and waited. In the meantime, I installed some new 1" eyeballs to help lessen the pressure at the filter.

The pool is finally filled up (halfway up the skimmer door) and I go to turn on the system. The pump seems to prime well via the skimmer and main drain line and I can feel water moving through the pipes through the pump, to the filter and at least from the filter to the heater. However, at the return jets for the pool, it still takes some time for water to come out and when it does, it seems fairly weak. The water comes out intermittently as well in a smooth column for about 30 seconds. From what I can tell, the in-ground cleaning system seems to work alright -- I can see debris being moved and I believe they are tied to the return system as I don't see any additional piping for it from the pool room. The return jets are not bubbling, just weak. The spa jets appear to work fine (which is weird to me because the return line is one pipe that splits off into the pool return and the spa return via valves).

I've tried the multi-port in filter and recirculate. The results seem to be the same.

I've been trying to figure this out and determine what's actually wrong with the system. Here are my thoughts and I appreciate if you check my logic:

1) The small leak just after the drain ball valves is actually the one causing all this problem even though it is extremely minor. However, I don't see air bubbles in the returns when they work... maybe the leak is just so small that it isn't negatively affecting the pump, but still causing the returns to not perform well? A lot of what I've been reading from here and on YouTube seem to suggest that suction side leak (which I think this is) is the main cause for weak pool returns.
2) There may be a clog in the line to the return jets, although I can't really imagine how that could be if the jets work fine for about 30 seconds at a time.
3) There is a leak at the pressure side, but I don't really understand how that could be as well if water comes through intermittently only. I am not losing any water in the pool from what I can see, and it would be impossible for me to notice any wet patches as the deck is all concrete.
4) The spa jets work fine because the returns there are all high-pressure jets, whereas the pool has big eyeballs. It still doesn't answer why the spa returns work okay but the pool returns are so intermittent and weak.

I'm at my wits end and trying to just understand how all of this works. How can it be that the spa jets work but pool jets don't?!

Thank you all kindly. This community is awesome!

 

[Jimrahbe]

A,

What speed are you running your VS pump?

At that speed, what is your filter pressure?

Water can't really travel through part of the system and then stop when it gets to the heater. Your flow is the same throughout the system unless there is some other path the water can take.

Show us a bunch of pics of your equipment pad.

Thanks,

Jim R.

 

[alam2p]

Thank you so much for the quick reply, J. I'm at work so just scrolled through my phone and this is some older pictures that I found so hopefully that works for a rough idea. The pump is different, as are all the valves but the layout remains largely the same.

There is an old solar system that I had entirely plumbed out because it was broken. The pool company installed a 90 elbow to get rid of the solar diverter and shutoff valve.

The heater piping is basically the two verticals. Where it comes off the cross junction is the supply for the heater, and the other one is the return.

On pump start up, I think the pump is in self-prime mode so it runs on max at approximately 3400 RPM. The pressure goes up to approximately 20-25 psi.

When the pump is on low at approximately 1800 RPM, pressure comes down to 15 psi.

Thanks!

 

[Jimrahbe]

A,

Thanks for the pics...+

Is this the first time you have used the new VS pump? I ask, because the amount of flow at 1800 RPM will be significantly lower than your old single speed pump.

Increasing the eyeball sizes just makes the flow feel that much lower.

I am surprised that running in the "Recirculate" mode did not increase the flow of your returns. If your filter pressure is 15 lbs. when in the filter mode, I would have thought you have seen a much better flow when the filter was bypassed.

Let's see what some of our other members have to say.

Thanks,

Jim R.

 

[alam2p]

A,

Thanks for the pics...+

Is this the first time you have used the new VS pump? I ask, because the amount of flow at 1800 RPM will be significantly lower than your old single speed pump.

Increasing the eyeball sizes just makes the flow feel that much lower.

I am surprised that running in the "Recirculate" mode did not increase the flow of your returns. If your filter pressure is 15 lbs. when in the filter mode, I would have thought you have seen a much better flow when the filter was bypassed.

Let's see what some of our other members have to say.

Thanks,

Jim R.

Yes it is! I came from a 2 HP pump which, by everyone I've talked to tells me that it's way overpowered for my system. The pool was closed for all summer and uncirculated because of a bad solar diverter switch so this is the first time it's been running since last summer. My biggest fear is that we had one or two weeks of very cold weather for Vancouver and that there's a chance of freeze damage to the lines... what are some telltale signs of a broken return line? I'm not seeing any leaks or anything right now. I tried winterizing it, but the old return eyeballs and rings were basically stuck on. There was one that I couldn't get at in the deeper end (returns arranged vertically by the steps up to about 3.5' deep, which is an odd layout too), but as far as I'm aware, the freezing shouldn't have gotten that far down.

Also, I'm wondering if it takes some amount of time for a pool that was drained to slowly push all the air out of the lines on its way back to the pool returns. There is movement in the returns but very intermittent. If that is the case, I guess I would just need to let the pump run but I'm just not sure.

 

[Jimrahbe]

A,

So, you had a 2 HP pump that you are used to and then replaced it with a 1.5 HP pump that only produces 1.5 HP when running at about full speed.

What was your normal filter pressure when your old single speed pump was running?

It is possible that you have some broken pipes, but I doubt it. The water has to go somewhere. If you had a broken pipe, you'd think that the water level in the pool would go down as the water was pumped out.

Air in the lines has nothing to do with your problem.

Thanks,

Jim R.

 

[alam2p]

A,

So, you had a 2 HP pump that you are used to and then replaced it with a 1.5 HP pump that only produces 1.5 HP when running at about full speed.

What was your normal filter pressure when your old single speed pump was running?

It is possible that you have some broken pipes, but I doubt it. The water has to go somewhere. If you had a broken pipe, you'd think that the water level in the pool would go down as the water was pumped out.

Air in the lines has nothing to do with your problem.

Thanks,

Jim R.

Yes, the 2 HP pump was necessary at the time because of an existing solar system that is now plumbed out. The first pool guy who came out said that it was probably the right size pump for the equipment IF it were to all work, but since I got rid of the solar, it's probably overpowered now.

I've only had the house for less than a year and the pool hasn't run reliably because of the faulty diverter and broken solar (sent water to where I didn't water), so I left the system off. In the past when I did see it run, I believe the filter pressure was on the higher side (closer to 25-30). I'm guessing that pressure was due to a high HP pump paired with a 24" sand filter.

Maybe I'll give it another run today to see what happens... driving me crazy though because I thought the pool would be up and running and good to go!