Need help with air in system

[basjke]

My setup is Zodiac Tri SWG - Hayward Superpump II 1.5Hp and 28" top mount Hayward filter
Equipment is at pool level and right at the pool. The feeding tubes go vertical for about 80 cm, then connect to the tube that feeds the pump, which is horizontal for about 1 meter, then goes down 45° to the pump. The SWG cell is about 20 cm above the tubing to the pump.
All tubing is 2" and the pump feeds from skimmer and vacuum which are both way below water level.
I have a check valve between pump outlet and filter, which is functioning, and a closed ball valve on the waste pipe.
There is a ball valve on each feed, and when I close 1 of them, there is no change in my experience described below.
When the pump is running, I hear a clattering sound in the filer head, as if air is circulating.
I don't see any air bubble in the returns to the pool, and very little champagne sized bubble under the pump lid, but really so little that you have to focus on to see them. I suspect they come from the lid.
When the pump stops after 3 hours, I hear like a large air bubble moving from the filter, and my SWG cell sucks half empty. Though the air bubble looks like it is coming up from the pipe that goes from the SWG to the pool.
The Pump strainer remains completely full.
I let the pump run for another 30 seconds, and then the SWG cell is full as is the pump strainer.
When I come back after 1 hour, both SWG cell and pump strainer as still completely full, haven't even dropped 1 cm.
But when I start the pump, the strainer sucks completely empty, and the pump has to prime again, which actually takes only like 10 seconds, but a lot of air enters the pump during that process, and lasts for another 20 seconds, until everything runs normal again, other than the clattering under the filter head.

Any suggestions on this?

 

[JohnT]

Have you checked out the Pool School article on air leaks? Suction Side Air Leaks - Page 2 of 2 - Trouble Free Pool

Might Point to some possibilities.

 

[basjke]

Have you checked out the Pool School article on air leaks? Suction Side Air Leaks - Page 2 of 2 - Trouble Free Pool

Might Point to some possibilities.

Yes I did, but my understanding is that if there are leaks at the suction side, there will be visible bubbles under the pump lid, which I don't have.

It is also a mystery to me how an air bubble can build up somewhere in the system, which is obvious when I restart the pump after an hour, while pump strainer and SWG cell housing remain full.

 

[basjke]

Let me add this, as it can be useful info.

It happens for a while that the cell housing turns half empty at the end of a filter cycle, but there is no real problem with the pump sucking are on restart.

The problem started a few days ago when I decided to shock the pool.

I cleaned the pool, backwashed the filter and cleaned the pump basket.

After that there were quite some bubbles under the pump lid. So I changed the o-ring and the bubbles were gone, but then the issue started that the pump would suck a lot of air, after being shut down for an hour, while cell housing and pump strainer basket remain full

 

[basjke]

I had air in the system earlier this week, where after ending a pool cycle, within 1 hour the feeding pipes would run empty, while pump and cell housing would remain full.

Thread is here Need help with air in system

I got that sorted, by greasing the o=rings from all ball joints - check valves and pump lid.

Now no air under the lid any more, and no pipes losing water, but now the next issue started.

In about 30 minute after a pump cycle the cell housing will be completely empty.

I see a bubble rising from the pipe that goes to the filter every few seconds.

Since this is a pressure pipe, I assume if there was a leak, it would also leak water during operation, but everything is dry. By the way, after this issues started, I have greased also all valves after the pump, but to no avail.

Any suggestions where I should look.

 

[PoolGate]

Can you post a pic of your setup and list equipment types? SWGs do create hydrogen gas and if your pump doesn't flow enough could lead to a buildup of that gas.

 

[basjke]

Can you post a pic of your setup and list equipment types? SWGs do create hydrogen gas and if your pump doesn't flow enough could lead to a buildup of that gas.

When the pump cycle ends the cell housing is full. It drains slowly over the period of 30 minutes. It also happens if I do a cycle without chlorinating

I can also hear a sound under the lid of the multi port valve

This started today, on a 10-year-old system, right after I had solved the air issue at suction side

 

[PoolGate]

Need to see a pic of the system. Do you get air/gas coming out of your return jets? If you turn off the SWG, do you also get the air/gas buildup? Multiport valves do wear out.

 

[basjke]

Need to see a pic of the system. Do you get air/gas coming out of your return jets? If you turn off the SWG, do you also get the air/gas buildup? Multiport valves do wear out.

Yes of course I get some gas coming out of the return jets, but I think you are overlooking something.

This has nothing to do with the SWG.

If I just let the pump only run for a few minutes, the cell housing is full when I turn of the pump. Thirty minutes later, the cell housing is empty.

The SWG is a Zodiac Tri, and it is just a straight pipe from filter to SWG, and then to the pool.

The pump strainer and the feeding pipes are still completely full. I switch on the pump and within 1 second cell housing is full again, and everything running fine.

My point is if there was a leak after the pump or filter outlet, I would see water somewhere, as that is all on pressure side of the pump.

I have a functioning check valve on the outlet of the pump and a closed ball valve on the waste pipe of the filter

 

[PoolGate]

When it is running you are saying there are no leaks or air bubbles showing up? Have you air-bled the filter housing? It would really help to see a pic of your setup to see where a possible leak point may be.

 

[basjke]

When it is running you are saying there are no leaks or air bubbles showing up? Have you air-bled the filter housing? It would really help to see a pic of your setup to see where a possible leak point may be.

Sorry I don't have pictures.

Please read the OP of this thread for more clarity on my setup and the previous issue.

I had a problem with air leaks at suction side for the past week, though when I had that issue the SWG would not drain at all.

I fixed the previous issue this morning by greasing all the O-rings from every ball and check valve between pool and pump, and I have no air at suction any more. Also, no more clattering sound in the filter valve either.

There are now no bubbles at all in either in the pump, or the cell housing or the return jets, not even the champagne sized bubbles. The pool house is tiled, so I would notice any water leak, but I have also been with my hands over all the piping, and everything is completely dry.

A Hayward filter has no option to bleed. It was immediately after I had fixed the air issue at suction side, that the SWG would drain. So I then greased also the valves at the pressure side. There is only ball valve and 1 check valve at the pressure side which are both between pump and filter, and I have checked the no-return valve already several times that it's working properly. I also have a ball valve on the waste pipe of the filter.

Like I said already, when the pump is switched off, I hear a whispering sound of escaping air in the filter valve. Then after a few minutes I see an air bubble rising in the SWG from the pipe that connects to the filter. Only 1 bubble every 15 seconds or so.

The system at the suction side is airtight, because when I start the pump, the pump is fully primed.

 

[basjke]

Issue seems to have resolved on its own in the meantime.

I still hear the remote sound of air escaping in the filter valve when pump is off, but everything stays 100% primed.

Any suggestions of what may have been the cause are welcome. The sound of air escaping, means air must go somewhere. Valve on waste pipe is closed