New filter and redesigning plumbing: 2 Questions

[sjsoldo]

I am having problems with my current system and would appreciate some help from this resource. Currently I have the configuration below, I have labeled the different components. It is set up such that for an hour a day, the return to the pump switches from the skimmer to a suction pool cleaner, and the pump output increases as it is programmed to . Then it switches back to skimmer and lower pump output. My pump is a Pentair VF so I can adjust the flows and timing by programming the device.

Problems with this:

• There is always some air in the pump chamber. I think there is a suction leak, probably from that black Jandy valve. One of the screws that hold the lid on is stripped, and it temporarily t gets better after I lube the O-Ring.
• I want to get rid of that multiport valve, and the filter is about 18 years old. I clean the filter by opening it and hosing off the grids.
• So, in changing these items, I want to redesign the whole system

Here is what I want to accomplish:

• Eliminate any suction leak. Hopefully new plumbing will do that.
• New filter
• Maintain a system that permits use of a suction vacuum for maybe an hour a day, either with one pump or two (see below).
• Place diverter plumbing to bypass flow into the heater, done properly without possibility of choking the system

Here are my questions:

• For a 25,000 gallon pool I have been using the Pentair FNS 48, which I had planned on buying again. But would there be any benefit of getting the FNS 60 (i.e. 60 sq foot filter instead of the 48) ?
• Should I keep the same system, with the VF pump and an actuator switch? Or add a dedicated pump for the vacuum circuit with appropriate timing for the vacuum to go on, shutting the skimmer pump off (don't want returns from two sources at once). I have an old 1 hp Whisperflow that works fine.​

I appreciate how knowledgeable everyone is that contributes to this forum.

 

[Jimrahbe]

S,

The first thing I would suggest is that you move up from the 70's into this Century and buy a Dolphin Robot..

Something like this one..

If you want to get rid of the Multiport valve, and make your plumbing simple, you will need to go with a cartridge filter, the bigger the better.

At low speed/flow, you will always see some bubbles under the pump lid. As long as they don't get bigger and bigger it is not an issue.

By passing the filter will allow you to run your pump at a lower RPM.. On average I'd guess about 300 to 500 RPM less.

Thanks,

Jim R.

 

[ajw22]

A few comments...

On the stripped screw in the diverter - Sometimes this works, and sometimes it does not.

Take off the lid and set it aside. Then using two-part slow-setting epoxy, fill all the screws holes, and then before the epoxy sets up, dip the screw threads into Vaseline and screw them into the holes. Let dry overnight.

In theory, the screws should back right out. Clean up the lid area and make sure to replace the o-ring or seal.

Install the lid and make sure not to torque the screws to 100 foot lbs.

On replacing your filter - If the shell of your FNS DE filter is not cracked or leaking I see no reason to replace it. If you need to replace the grids then buy new grids. The new filter will not be any better then what you have.

On air in your pump chamber - what RPM are you running your pump? At low RPMs it is normal to have an air bubble form in the pump basket. Does it clear when you increase the RPMs?

On getting rid of the MPV - A DE filter requries an MPV for maintenance. I like having an MPV as the RECIRCULATE setting can be useful when you want to take the filter out of the circulation loop. Such as when you have a big algae problem clogging the filter and stopping the flow. The WASTE setting can also be useful at times.

Installing a heater bypass is easy to do - Heater Bypass - Further Reading

As Jim said, get a robot cleaner to fix your pool cleaner problems. You will have to clean your filter less often using a robot cleaner.

Why do you open your FNS DE filter and hose off the grids instead of using the MPV BACKWASH and RINSE settings to backwash the filter and then reload in some DE? It takes me less then 10 minutes to do a backwash of my DE filter.

 

[Dirk]

I run a suction-side vac with great success. I would not want a robot. I wouldn't try to talk you out of one, I understand they are superior for cleaning a pool. But there are a few deal-breakers I don't like. If you'd like to learn more about how to optimize your suction-side vac, I can help you with that, as I did the same to mine. You only need one pump for everything, so don't add a pump just for vacuuming.

Here's a method to find your suction side leak(s):

 

[sjsoldo]

In reply to the suggestions above:

• A robot would be difficult in that I would have to run a low voltage wire across my pool deck. I would rather not have to do that. A suction vacuum works fine.
• In terms of the diverter lid stripped screw hole, I actually did this trick about five years ago. Worked fine for a while.
• Air in the pump chamber gets WAY WORSE at higher RPM (esp. when the vacuum cycle is running, 25 gal/min) to the point that the pump stalls because being starved of water. I assume this is related to a vacuum leak.
• My preference when cleaning the filter is to take the grids out and hose off all of the dirty earth. I NEVER use the MPV.
• I watched that video and tried the technique to identify the source of the leak. Was not that helpful. I did replace the o-ring in the union and also the o-ring in the diverter, using lube. This helped some.

Thank you.

 

[Dirk]

• A robot would be difficult in that I would have to run a low voltage wire across my pool deck. I would rather not have to do that. A suction vacuum works fine.

That, having to haul a heavy robot out of the water (worse the older I get) and having to clean its dirt trap often are three of my main complaints about a robot. Even though my vac's collections go to my filter, I still only have to clean my filter once a year. That works for me!

• Air in the pump chamber gets WAY WORSE at higher RPM (esp. when the vacuum cycle is running, 25 gal/min) to the point that the pump stalls because being starved of water. I assume this is related to a vacuum leak.

Sure sounds like it. You wrote that slathering on lube helps for a while? Did you thoroughly inspect and clean both sides of the channel that the o-rings sits in?

• I watched that video and tried the technique to identify the source of the leak. Was not that helpful. I did replace the o-ring in the union and also the o-ring in the diverter, using lube. This helped some.

If you do in fact have a suction-side leak, then either you did the hose-test incorrectly, the leak is small enough to fool that test, or the leak is underground. Have you considered hiring a leak detection specialist? Or if you plan on re-plumbng everything, perhaps doing that before you hire someone might solve the mystery.

 

[Jimrahbe]

S,

I have a couple of rent houses with DE filters.. Just like you, I never backwash anymore, so when one of them had a frozen MPV valve, I just removed it. As long as you don't need to backwash or run recirculate, it will work fine. I did add a Jandy valve between the pump and the filter to prevent the filter from draining back into the pool when I remove the pump lid. I'm also going to add a Jandy valve between the filter and the SWCG to prevent old DE from going back to the pool when I open the drain plug on the filter.

When you increase the speed of the pump to vacuum, it makes any little leak much worse.. I like the garden hose method of leak detection, but another one is to use saranwrap around all the suction side pipes and connections to help isolate the problem. I'd removed the actuator, when trying to find the leak, and I would be testing in the VAC mode..

Thanks,

Jim R.

 

[sjsoldo]

Appreciate all of the above

 

[setsailsoon]

A robot would be difficult in that I would have to run a low voltage wire across my pool deck. I would rather not have to do that.

That's what I thought but I put the cord in an outdoor cord cover and it's never been an issue:


I've never had a problem with the cord and having the robot is so much better cleaner than my previous suction cleaner I'm really amazed.

Just my $.02.

Chris

 

[sjsoldo]

Yes, I see how you have the set up. Probably works for you.

However, if a kid tripped over this, I would never hear the end of it. And, I’m basically satisfied with the suction cleaner.

 

[setsailsoon]

Pools are all about what works for you!

 

[Dirk]

Pools are all about what works for you!

Typo? I think you meant to write: "Pools are all about getting someone else to do the work for you!"