Hayward 2.70 THP VS Problem

[TucsonRob]

I've watched a dozen YouTube videos, sent many emails back and forth with Hayward support and spent almost $1K on local "experts" but my problem persists and nobody seems to be able to correct it.

My in-ground pool is 7500 gallons. It is 17 years old. Last June, I replaced the original single speed pump with a new Hayward 2.70 THP VS model #SP32950VSP. (The filter was also replaced with a Hayward C4030). Since the new pump was installed, I've been experiencing air bubbles entering the pump basket chamber from the suction line. The suction line is 2" PVC and runs to the skimmer without any intermediate valves. The skimmer is a two port type, one to the pump and one to the main drains. I also have a Caretaker in-floor cleaning system and patio roof-mounted solar heat, both of which are on the pressure side of the pump with no suction connections.

When the pump was first installed, the installer took a "shortcut" and placed the pump so that its suction inlet was connected to the pool plumbing by a very short length of 2" PVC. Pump cavitation was frequent. The installation instructions call for a minimum pipe length of 10", so I had the installer return and replace the connection pipe. . .now 19". This significantly improved matters but did not totally eliminate the ingress of bubbles. If I run the pump at low speed, around 1200-1500 RPM with the floor and solar systems off, I get no bubbles. However turning the floor and/or solar on and bumping the pump RPM up to around 2500 (required to run these systems) results in intermittent small bubbles entering the pump. If left runningthat way, the pump gradually fills with more and more air and begins to surge. Closing the floor and solar valves and bumping the pump up to Quick Clean for thirty seconds or so, clears the air.

I had the solar system checked for leaks and it is tight, so the air isn't getting in from there. I had the suction line pressure tested and it appears tight. A pool service tech, pressurized the suction line and pump with water using a water sock in the skimmer suction inlet and said he did not see any water coming from the pump housing, cover, plugs or exposed plumbing. He was stumped just like the others I've had over.
Can anyone suggest any other possibilities or diagnostic steps to be taken? Is a 19 inch run of straight pipe from the pump inlet to the pool plumbing long enough? Should I repeat the suction line pressure test? Is it a design characteristic or flaw in the pump, as some people on various internet pool forums suggest? All input very much appreciated.

 

[mknauss]

Welcome to the forum.
Post a picture of the suction side connections to the pump.
Also, have you used proper Pool Lube - Further Reading on the pump lid gasket and drain plug orings?

 

[TucsonRob]

Welcome to the forum.
Post a picture of the suction side connections to the pump.
Also, have you used proper Pool Lube - Further Reading on the pump lid gasket and drain plug orings?

Hi Marty. Thanks for the reply. Yes, the o-rings/seals on the pump lid, drain plugs and unions have been inspected and lubed. The male threads on the pump inlet union have been covered with teflon tape. I've checked the glued pipe joints as well, coating them with an RTV sealant just to be sure. There are no air bubbles in the pool returns, the air relief in the filter has been handling that. Please see attached photos as requested. Best, Rob.

 

[1poolman1]

Hi Marty. Thanks for the reply. Yes, the o-rings/seals on the pump lid, drain plugs and unions have been inspected and lubed. The male threads on the pump inlet union have been covered with teflon tape. I've checked the glued pipe joints as well, coating them with an RTV sealant just to be sure. There are no air bubbles in the pool returns, the air relief in the filter has been handling that. Please see attached photos as requested. Best, Rob.

If no air is returning to the pool, there is no suction leak. That's how the air-relief screen inside the filter works, it allows the air to go to the pool through it before it fills the tank with air. No need to tape the threads on the union fittings, but shouldn't hurt.
Usually, the higher the rpm more, not less, air will be sucked into any area that may leak as there is more suction in the entire line from the skimmer to the pump. It also takes a bit higher rpm just to clear any air in the basket.
Those Hayward TriStar/EcoStar pumps have always had that "air in the pump" appearance. Pump is the same, only a name change. Mine has for 13+ years. Then, sometimes, it goes away. Has never been an issue, just something you get used to.
Even the single-speed 1/2hp TriStars (I probably installed a hundred of those) would not always fill the pot with water initially, and then, mysteriously, would as the system aged a bit. They were the only brand that I ever used that had that "not a problem," but a disconcerting at first, appearance.

 

[TucsonRob]

If no air is returning to the pool, there is no suction leak. That's how the air-relief screen inside the filter works, it allows the air to go to the pool through it before it fills the tank with air. No need to tape the threads on the union fittings, but shouldn't hurt.
Usually, the higher the rpm more, not less, air will be sucked into any area that may leak as there is more suction in the entire line from the skimmer to the pump. It also takes a bit higher rpm just to clear any air in the basket.
Those Hayward TriStar/EcoStar pumps have always had that "air in the pump" appearance. Pump is the same, only a name change. Mine has for 13+ years. Then, sometimes, it goes away. Has never been an issue, just something you get used to.
Even the single-speed 1/2hp TriStars (I probably installed a hundred of those) would not always fill the pot with water initially, and then, mysteriously, would as the system aged a bit. They were the only brand that I ever used that had that "not a problem," but a disconcerting at first, appearance.

Thanks for the input!

 

[TucsonRob]

If no air is returning to the pool, there is no suction leak. That's how the air-relief screen inside the filter works, it allows the air to go to the pool through it before it fills the tank with air. No need to tape the threads on the union fittings, but shouldn't hurt.
Usually, the higher the rpm more, not less, air will be sucked into any area that may leak as there is more suction in the entire line from the skimmer to the pump. It also takes a bit higher rpm just to clear any air in the basket.
Those Hayward TriStar/EcoStar pumps have always had that "air in the pump" appearance. Pump is the same, only a name change. Mine has for 13+ years. Then, sometimes, it goes away. Has never been an issue, just something you get used to.
Even the single-speed 1/2hp TriStars (I probably installed a hundred of those) would not always fill the pot with water initially, and then, mysteriously, would as the system aged a bit. They were the only brand that I ever used that had that "not a problem," but a disconcerting at first, appearance.

Hi, I've spent some free time experimenting and have the following findings to share with you and ask for your comments/suggestions. I have turned the solar off and closed both isolation valves to its inlet and outlet. I have closed the diverter valve which controls pressure flow to the in-floor system. So now, I have a simple skimmer --> pump --> filter --> returns flow, right? I've tried running the pump at varying speeds and see the following:

3000 rpm - some micro bubbles in pump basket, no bubbles in returns

2500 rpm - somewhat larger but occasional bubbles in basket that tend to grow together over time so that after five or six hours the pump basket chamber water level is down approx 1/2 inch, No bubbles in returns. Sliight "rattle" sound from pump (not motor noise).

1200 rpm - no appreciable bubbles in basket but now there is a steady stream of small bubbles in the returns.

1000 rpm - no bubbles in basket but slight increase in returns.

Does this make any sense to you? It is driving me absolutely nuts.

 

[mknauss]

How do you chlorinate?

 

[TucsonRob]

Hi, I've spent some free time experimenting and have the following findings to share with you and ask for your comments/suggestions. I have turned the solar off and closed both isolation valves to its inlet and outlet. I have closed the diverter valve which controls pressure flow to the in-floor system. So now, I have a simple skimmer --> pump --> filter --> returns flow, right? I've tried running the pump at varying speeds and see the following:

3000 rpm - some micro bubbles in pump basket, no bubbles in returns

2500 rpm - somewhat larger but occasional bubbles in basket that tend to grow together over time so that after five or six hours the pump basket chamber water level is down approx 1/2 inch, No bubbles in returns. Sliight "rattle" sound from pump (not motor noise).

1200 rpm - no appreciable bubbles in basket but now there is a steady stream of small bubbles in the returns.

1000 rpm - no bubbles in basket but slight increase in returns.

Does this make any sense to you? It is driving me absolutely nuts.

If no air is returning to the pool, there is no suction leak. That's how the air-relief screen inside the filter works, it allows the air to go to the pool through it before it fills the tank with air. No need to tape the threads on the union fittings, but shouldn't hurt.
Usually, the higher the rpm more, not less, air will be sucked into any area that may leak as there is more suction in the entire line from the skimmer to the pump. It also takes a bit higher rpm just to clear any air in the basket.
Those Hayward TriStar/EcoStar pumps have always had that "air in the pump" appearance. Pump is the same, only a name change. Mine has for 13+ years. Then, sometimes, it goes away. Has never been an issue, just something you get used to.
Even the single-speed 1/2hp TriStars (I probably installed a hundred of those) would not always fill the pot with water initially, and then, mysteriously, would as the system aged a bit. They were the only brand that I ever used that had that "not a problem," but a disconcerting at first, appearance.

Another update. After running for an hour @ 1200 rpm with solar and floor off, minor bubbles in basket and return streams have no bubbles.

 

[TucsonRob]

How do you chlorinate?

Chlorine generator. Outflow of filter to generator input.

 

[mknauss]

SWCG produces hydrogen gas.

 

[TucsonRob]

SWCG produces hydrogen gas.

Yes, I'm aware of that. Do you think reduced flow rate @ 1200 rpm would make H2 bubbles more apparent?

 

[mknauss]

Yes, I'm aware of that. Do you think reduced flow rate @ 1200 rpm would make H2 bubbles more apparent?

Yes. Slower velocity of water from the returns.