Air in pump

[basjke]

Hi I have an in ground pool with Zodiac Tri, Hayward 1.5 Hp super pump II and hayward filter.

I have a check valve between pump outlet and filter, and a closed tap on the filter waste pipe.

I checked the check valve and it is not blocked.

When I finish a filter cycle, there will come one big air bubble into the chlorinator, enough to have the dry cell light go on. So more then half of the cell housing is air.

When I look at the pump lid it will show water to the top.

I manually start the pump again, and lot of air will show under the pump lid, which will last for about 10 seconds.

After 15 seconds I shut down the pump again, and now the cell housing will be full of water, and will still be so 12 hours later.

I don't notice any air in the pump or cell housing during the filter cycle.

Any idea where the air may come from?

 

[ajw22]

What model filter do you have?

Post pics if your equipment and plumbing.

 

[basjke]

What model filter do you have?

Post pics if your equipment and plumbing.

Bit complicated to make pictures right now, but thanks for trying to help.

My filter is a Hayward S310T2. As said I have a return valve between pump outlet and filter and a cl;osed tap on the waste pipe

I also have added now a check valve on the filter outlet pipe., right at the flter.

I still get the air when a filter cycle finishes, and now took a close look.

The big air bubble comes up from the return lines. The chlorinator cell is mounted right above the return lines.

So if after the filter cycle has finished, and the cell housing is only half full with water, I let the pump run for 1 minute

Chances are that again a small bubble comes up from the return lines. If that happens I let it run again for 1 minute, and then there will be no air at all.

 

[basjke]

I want to add, the pump draws water from bottom drain, skimmer and vacuum. So since it are 3 separate feeds I doubt it the water supply is insufficient.

 

[basjke]

Another update since the problem still persists.

I have removed the check valve on the return pipe of the filter, because it would constantly make noise, as if it was opening and closing constantly.

The check valve is of the spring type and mounted horizontal right at the outlet of the filter.

I still have the big air bubbles come up out of the return lines below the cell housing when the filter cycle ends.

When the filter cycle is active I also can clearly hear water flow in those return lines below the cell housing, though I don't see any air bubbles or whatever in the cell housing or under the pump lid.

I don't hear that water flow noise anywhere else in the piping system.

When I run the pump for a minute to get rid of the air in the cell housing, I don't hear that water flow, it only starts after the pump has been running for an extended period of time.

 

[basjke]

What model filter do you have?

Post pics if your equipment and plumbing.

Managed to make some picks

 

[ajw22]

So the problem is you have an air leak that when the pump stops you lose pressurization in your system and get air bubbles? Is it causing any operational problems?

You have so many twists and turns and joints in your pipes the leak could be anywhere. If the pump clears the air in the pipes when it turns back on you are fine.

 

[basjke]

So the problem is you have an air leak that when the pump stops you lose pressurization in your system and get air bubbles? Is it causing any operational problems?

You have so many twists and turns and joints in your pipes the leak could be anywhere. If the pump clears the air in the pipes when it turns back on you are fine.

The big air bubbles rise from the return line that goes to the pool below the cell housing.

I do not think there is a leak in the piping in the pump house, as that would create bubbles in the pump or the cell housing during filtering, or maybe even some water leaks, but none of that is visible.

My biggest concern is that unless I each time run the pump manually for 30 seconds after a filter cycle, the chlorinator cell will be dry until the next filter cycle.

Could this damage the cell?

 

[ajw22]

The chlorinator cell should be powered off when the pump is off. It can be dry when it is powered off. It should not turn on until the pump power is on and you have water flow through its flow switch.

 

[basjke]

The chlorinator cell should be powered off when the pump is off. It can be dry when it is powered off. It should not turn on until the pump power is on and you have water flow through its flow switch.

Thanks for the reply, and what you say is correct.

I worried that the coating on the cell might get damaged when not soaked in water for long time

 

[basjke]

The chlorinator cell should be powered off when the pump is off. It can be dry when it is powered off. It should not turn on until the pump power is on and you have water flow through its flow switch.

Please see if you can explain this.

A filter cycle is 3 hours. The pump get activated by the timer in the Zodiac Tri, so cell and pump get switched on and off simultaneously.

When a filter cycle ends, immediately a few big air bubbles will rise from the return line into the cell housing, rendering it almost empty.

These are know facts which I have explained before.

Now this is new.

Twice now I have let the pump run for 3 hours without the cell powered up. So it is a 3 hour filter cycle with no chlorination.

When after 3 hours I switch off the pump not even the tiniest air bubble will rise from the return line, and the cell housing will be full of water

 

[ajw22]

I cannot get a mental picture of your plumbing and water flow from the jumbled set of pictures you posted. I need to be able to follow the pipes and water flow from the pump suction through the return pipes.

What problem does the air bubble cause?

 

[basjke]

I cannot get a mental picture of your plumbing and water flow from the jumbled set of pictures you posted. I need to be able to follow the pipes and water flow from the pump suction through the return pipes.

What problem does the air bubble cause?

Yes the pictures are not really clear.

A 2" pipe which feeds from up to 3 different feeds goes to the 1.5Hp pump all in the back of the pump house.

The feeds are Skimmer - vacuum and main drain.

From the pump a 2" pipe with a vertically mounted check valve goes to the filter.

From the filter a 2" pipe goes to the cell housing all to the left in the pump house, which is right above the location where all pipes ( feeds and returns ) enter the pump house.

From the cell housing it goes to a a 2" return line, which is split into 4 returns that all are open.

Don't take notice of all the other pipes and pumps as they are not engaged at any time.

I hope this will give you a clearer picture of the installation

The air bubble renders the cell housing almost empty, but the fact is that this ONLY happens when chlorinator is activated.

1 . I can run the filter cycle with chlorinator deactivated, as short or as long as I want, and there will be no air bubble. I have tried from 2 minutes up to 3 hour cycles.

2 . If I run the filter cycle with chlorinator enabled, there will always be an air bubble rising, but only as soon as the cycle is finished.

The size of the air bubble depends on the length of the cycle, where the longer the cycle the bigger the bubble, but there is already that bubble even when running for 15 minutes only.

So it is clear that the bubble is related to the chlorination, and not the piping structure, because the only difference between the two scenarios is that the cell is activated or not.

Pump get controlled by the chlorinator, so chlorination and pump on/off happen at the exact same time, but of course I can also manually switch on the pump only.

 

[ajw22]

That may be a hydrogen bubble not an air bubble in your cell. Hydrogen gas is generated by the SWG process. Most cells water passes straight through. Your cell the water flow takes two 90 degree bends. The water flow may not be strong enough to flush all the hydrogen gas out of the cell m

 

[basjke]

That may be a hydrogen bubble not an air bubble in your cell. Hydrogen gas is generated by the SWG process. Most cells water passes straight through. Your cell the water flow takes two 90 degree bends. The water flow may not be strong enough to flush all the hydrogen gas out of the cell m

Not sure if I understand your explanation correctly, but to be clear there is no air bubble in the cell housing during the cycle, the air bubble is clearly visible rising from under the cell housing as soon as the pump stops running.

It has worked fine for 7 years, and only started a few weeks ago. I don't dispute your explanation though.

When you look at the filter, you will notice a horizontal mounted check valve housing, but the internals have been removed for the past 7 years.

Then when you read post #3 and #5 I posted I temporarily mounted the internals in that check valve again, but removed them again because it would constanly make noise, as if the valve was moving all the time.

All check valves are of the spring operated kind.

So your explanation that there is not enough water pressure makes sense, as was probably the reason for the noise of the valve.

What can be the reason for the lack of pressure, and how to solve it?

p.s. The vertical operated check valve on the inlet of the filter never makes any noise and is operating correctly.

 

[ajw22]

When did you last backwash your filter or do a deep clean?

Have you done a Perform the Overnight FC Loss Test (OCLT) - Trouble Free Pool to rule out algae clogging your filter?

 

[ajw22]

Not sure if I understand your explanation correctly, but to be clear there is no air bubble in the cell housing during the cycle, the air bubble is clearly visible rising from under the cell housing as soon as the pump stops running.

This gas bubble has to be accumulating at some corner in your plumbing and not being purged with the water flow.

 

[basjke]

When did you last backwash your filter or do a deep clean?

Have you done a Perform the Overnight FC Loss Test (OCLT) - Trouble Free Pool to rule out algae clogging your filter?

To do this test I assume a Taylor test kit should be used. I don't have this, and I have also never seen one available in Thailand, so i use the Aquachek 7 test strips.

I don't notice any irregularities in my chlorine levels, and I test about once every 2 weeks.

Last backwash was about 6 weeks ago and currently the pressure gauge shows 11 psi.

Does the noise of the check valve on the return line tell you anything?

Is it normal that this makes a " clacking" sound all the time during filtering, or does this mean lack of pressure on the return pipe of the filter?

 

[ajw22]

Open up the check valve and examine it for breakage.

 

[basjke]

Open up the check valve and examine it for breakage.

I did check the valve, in fact I used a valve I removed from the jacuzzi pump, which has no issues there.