Noisy New Pump

[JamesW]

If you changed the three-way valve to a Jandy (4719) 2½" - 3" 3-port valve and all of the manifold and pump piping to 3-inch, then that would help. So, slip a 2.5x3-inch reducer over each of the existing Jandy valves on the individual suction lines and then everything to the pump will be 3-inch. You could probably go 2.5 inch and be fine, especially if you are going to keep the pump speed below 3,000 rpm. However, 3-inch is more conservative and would be best if you intend to run the pump at full speed.

http://www.zodiacpoolsystems.com/Produc ... alves.aspx

You will still be careful not to exceed the flow rate per line. I would say to limit the flow rate to 60 gpm per open 2-inch line. Also, you need to be sure not to exceed the design flow rate of the filter. Check the manual for the design flow rate.

I really don't think that you should ever need to exceed 3,000 rpm at any time. I think that it is just too much flow for your system. You could add a flow meter after the filter to get a better idea of exactly what is happening.

A vacuum gauge would also be helpful in fine-tuning the performance of the system, and is not at all difficult to do. Just drill a 7/16 inch hole in the PVC and then use a 1/4-inch NPT tap to create the threads. Do it at a fitting for double thickness (fitting + pipe wall). Probably not necessary, but more for someone interested in knowing that type of information.

What is the filter pressure when the pump is at full speed?

 

[fyton2v]

when running the pump at full speed with all 3 suction lines open pressure is around 10psi. It's Jandy's biggest cartridge filter (CL model). I think it's max flow rate is around 150gpm. Even if I could push 150gpm I wouldn't. I'm going for low energy here. The only time where it would need to crank up is to provide enough suction to the sweeper line and I'm hoping I figure out a way to do this without exceeding 3000rpm.

 

[JamesW]

10 psi on the return at full speed indicates low return head loss. The flow rate is probably over 130 gpm at full speed.

It probably would not be worthwhile to replumb the suction. The suction cleaner should not need a lot of flow rate. Even if you wanted good skimmer action and cleaner at the same time, I don't think that you would ever need more than 80 gpm at any time.

Even if you improve the ability of that section of plumbing, there might be other elements or components that will limit the flow rate. You have to consider the flow rate ranges of every component of the system: filter, heater, skimmers, main drains, valves, cleaner etc. and make sure that you don't exceed any of them.

I think that you should be able to achieve very good results without ever needing to go to 3,000 rpm. I would try 2400 rpm and then go up incrementally from there.

A vacuum gauge would probably not be necessary. You should be able to tell from the system performance and sound. It might help some if there continue to be unresolved issues. A flow meter would be somewhat helpful, but also probably not necessary. You should be able to tell from skimmer action, return flow and cleaner performance.

What flow rate are you trying to achieve?

 

[fyton2v]

Ok. I've been pondering this. Still having a tough time getting my pool vac to operate well without those tiny bubbles appearing in the pump. Also, you can see some of them coming out there the pool inlets. They are a little like sparkling water bubbles. The problem I believe i'm having is that my return configuration isn't supplying enough back pressure when the pool drains/skimmers are throttled back enough to give the vac enough suction. Or to put it another way... I need to partially close down the 2 suction valves supporting my 2 drains/skimmers so enough suction is redirected towards the vac line. When this happens my water flow decreases on the suction side (this is a theory, but seems to make sense) and minor cavitation starts. But I have done much testing at RPMs below 2500 yet... about 2800 seems to be a sweet spot right now.

I'm thinking that increasing the pipe size on the suction side will increase the flow and provide for a larger adjustment range on the vac line.... more flow and more suction. On the return side of the pump it wouldn't be hard to increase the pipe there... BUT...

My Jandy LXi heater and Aquapure 1400 SWG seem to want 2" pipe according to the manual. Perhaps I need to put in a bypass for both of these connections? My cartridge filter can handle high flow rates, but these 2 don't seem to be suited. At the end of the day 80GPM would be fine. Before I rip everything out I'm going to add a valve on the return side of my pool. At this moment I don't have the ability to control flow (from filter pump) between my pool and spa. I could reduce the amount of water going to my 4 pool returns and probably improve filter pump performance. Anyway... I have a lot to learn here and I'm going to experiment slowly.

Thanks for the advice so far.

 

[JamesW]

What are the make and model of the pool vac?

A vacuum gauge and a flowmeter would be helpful.

By using the vacuum and pressure gauges, and the flowmeter, you could figure out the system curve by varying the flow rate and recording the pressures.