Possible Insufficient Pump and New Pump Possibilities

[saxlylong]

Hello all. I have lurked around the site/forum for a couple of seasons now and have run into a problem that needs to be addressed.

I purchased my house with the pool early last year, so I have had a full season and the start of this season to try and learn what I needed to to make the pool work as best as possible. The amount of knowledge on this site/forum is staggering, and I have learned much.

My pool:

1. 25,000 gallons, oval shaped, 3 ft. shallow end - 8 ft. deep end. The pool was installed in the mid 80's.
2. 1 skimmer and 1 main drain
3. 3/4hp Super pump
4. S244T sand filter, I replaced the sand last spring, filter pressure 22 psi (verified with 2 different gauges)
5. CL200 chlorinator
6. Main drain is 40 ft/ from the pad, skimmer is 42 ft, (straight measurements). The pad is at water height.
7. All of the piping is 1.5". The main drain and skimmer run the full length as separate pipes and "T" right at the pump. There is 1x 1.5" pipe for the returns, which runs to 4x eyeballs on each side of the pool.
8. I have no idea how the plumbing underground is routed.

There is not much flow to the return eyeballs, even after a backwash. I blew out the suction and return lines to be sure there was nothing blocking the pipes. I also check that the impeller wasn't blocked. It doesn't take much more than an hour for the flow to cause at least 1, sometimes 2 of the eyeballs to stop flowing. The pool is cloudy but not bad. The pressure remains steady. I can't see how the filter would be getting clogged that quickly. Trying to filter the dead algae was a nightmare.

After doing extensive reading on pipe head and pumps, I have come to the conclusion that my 3/4 hp super pump is inadequate for the amount of head the pool has. With most of the underground plumbing unknown, I only know the pressure side head: 2.31 x 22 psi = 50.82 ft of head. I would imagine with 2x full 1.5" suction pipes from the drain and skimmer that the suction head really wont add much more. Is there a way to guesstimate the suction head without a vacuum gauge?

That being said and looking at the head curve for my pump, it looks at though there is about 25gpm flow at best, certainly not enough to get a turnover every 8 hours. This would require about 50 gpm.

Getting to my question: I am looking at options for a more powerful/higher head pump. Each option get most expensive. I am trying to keep upfront costs down, but I am also mindful of the long term costs of electricity of single speed vs. 2 speed vs. variable speed.

1. I can replace the motor on the Super pump with a Super II motor to handle the higher head.
2. I can replace the motor with a viable speed to handle the higher head for cleaning and such, with the ability to dial it down for general clean filtering and saving of power.
3. I could replace the entire pump with something like an Intelliflo, which gets good ratings on this forum. However, is this option total overkill for my plumbing setup?

Thanks in advance for any help you may offer.

 

[cowboycasey]

Welcome to TFP

Have you done a deep clean on your filter? Deep Cleaning a Sand Filter

Many people use the 3/4 pumps with great success but you are right if the filter gets clogged you will not have the power from the pump to get the water through..

many people like the VS pumps just install a surge protector, the computers don't like lightning..

 

[saxlylong]

I actually found the deep cleaning how-to shortly after I first posted. I did it, and the sand wasn't too bad (i replaced the sand beginning of the season last year). The flow did seem to improve a bit, but it still seems weak.

As far as the pump: from my extensive reading, it sounds like slower flow is better for 1.5" piping, however, I am not sure the lower flow is sufficient to clear the algae bloom in the spring. My current 3/4hp Super Pump 1 runs about 25gpm @ 50 ft of head. The same spec'd Super pump 2 runs around 40gpm @ 50ft of head, because it is a higher head pump.

I guess what I really need is to figure out what my vacuum head is. There are a few members that seem to know how to estimate the amount of vacuum head with the pool specs I listed above. With the total head, I can see how much water my pump is truly moving, and where I need to go from there.

Thanks for your help.

 

[saxlylong]

I think mas985 is the go-to for something like this. Is it proper etiquette around here to simply message them or just wait for them to possibly chime in?

Also since I put up the original post: I found a shot motor in the corner of my shed that is the A.O. Smith replacement motor for the Super II SP3005X7AZ (1.13 uprated hp), which is the Super II equivalent of my motor, but the specs would be more in line to what my pool would need. I am starting to think the previous owner took the new motor replacement into their own hands and simply replaced a 3/4hp motor with another 3/4 hp motor, without realizing its a totally different motor. Just a thought.

 

[jblizzle]

You are welcome to send Mark a PM to request he check out your thread

 

[saxlylong]

I will do that, thanks!

 

[CJadamec]

Do you have any check valves after the pump or sand filter? Are they working properly.
Is the directional valve on top of your sand filter working correctly? ie spider gasket intact
When you changed the sand were any of the laterals damaged?

Changing the pump may be a waste if you have a plumbing issue. If your filter pressure is already at 22 when its clean you might not have a lot of luck pushing more water volume thru it.
Weak flow on the returns that slows down over time while you are getting verified good pressure out of your pump would make me check the pressure side plumbing before blaming the pump.

 

[saxlylong]

No check valves. The multi-valve works correctly as far as I know. When I pulled off the top to do the "deep cleaning", the gasket seemed OK. The outer circumference of the gasket was not glued down, but the inner "spider legs" seemed to stay put. If the whole thing should be glued down, then I can order a replacement. Also, bypassing the filter on recirculate doesn't really change the amount of perceived flow. I have attached a pic of my plumbing setup (not sure why it is rotated. It looks fine in photoshop).

 

[CJadamec]

Is There any kinda of blockage in the clorinator? Possible you have a chunk of puck lodged in the return line somewhere.

The small line tee'd off of the return line is that waste to drain? Make sure that valve isn't leaking. Also check and see if opening that valve drops your filter pressure.

 

[mas985]

The filter pressure is way too high for that pump and plumbing setup so there is clearly something wrong with the plumbing and changing out the pump probably won't help much. But you do have a lot of unions which might make it easier to narrow down the issue. Although this will be a little messy, I would remove the union at the output of the filter and run the pump for a few seconds and take a reading of the filter pressure. If the pressure drops by a lot (>10 PSI), then issue is post filter. If the pressure drops by only a few PSI, then the issue is the filter itself.

 

[saxlylong]

The small "tee'd" line goes to the water slide, which I forgot to mention.

There is a union right before the chlorinator that you can't see in the picture. The PSI dropped to 8, which Mark mentioned would be post filter. What exactly in the chlorinator should I be looking for as a possible problem? There is only the union on the input side, so I can't easily remove the chlorinator from the plumbing to take it apart. If not the chlorinator, should I try blowing out the lines again with a compressor?

After some preliminary reading, it sounds like the in-line chlorinators restrict the entire flow by default, and there are many additional problems with the Hayward specifically. From a pure plumbing perspective, would it be worthwhile to replace the unit with an off-line unit?

 

[CJadamec]

You could leave it in place and plumb a bypass around it. As for the internals I'm not familiar with how that unit goes together. You could also just take it out all together.

 

[saxlylong]

Actually there is a union that attaches the valve for the return. Taking off the chlorinator and looking in the pipe, it tapers to about 3/4 of an inch where the chlorine feeds. I would imagine this is the choke point and the source of the high pressure, since this is the only return. Should I try to get a couple unions and insert a straight pipe to see if that is the issue?

 

[mas985]

It looks like the valve after the chlorinator has a union of some type. Does that allow you to take apart the valve? If so, you could run through the chlorinator but not the return line and see if the PSI jumps back up.

 

[saxlylong]

I'll put just the chlorinator on and report back the filter psi here in a little while.

 

[saxlylong]

Ok, the suction side through the filter only is 8 psi. Adding only the chlorinator brings it up to 12 psi. Adding the rest of the return brings it up to the full 22 psi. Is the chlorinator the problem or is there something later on in the return line that is the issue?

 

[mas985]

While the chlorinator head loss is quite high and you might be wise to remove it, the return line should not have that much head loss either. Are there eyeballs installed in the pool where the return lines come out? Can you remove all the eyeballs and see if the pressure changes at all.

 

[saxlylong]

I will remove the chlorinator and replace that area with straight pipe and look into an off-line chlorinator. I will also check the pressure without the eyeballs. Its about to storm real bad here in STL, so it may not be until tomorrow.

 

[saxlylong]

Ok, so I replaced the chlorinator with straight pipe. No change in PSI. Nothing. Eyeballs or not, it stays at 22 psi. I used 2 different gauges and the psi reads the same. However, the perceived flow is definitely higher after removing the chlorinator. This does not explain the lack of change to the pressure. I am at a loss as to what is going on, so I defer to the more knowledgeable minds here. I can only come up with 2 things:

1. The 2 gauges I have are both BAD and bad in the exact same way. They are both pretty old (hayward branded) and have been left outside in a deck box during off season (I recently read this was bad for them). I had considered getting a nice oil filled pressure gauge. Is this worthwhile to get an accurate reading? If so, is there a recommended brand and reading scale (up to 30 psi, 60, etc)?

2. The return plumbing is so badly designed that would explain the high head loss. I am having a hard time with 2 of the 4 returns and getting them to put out enough flow. As far as I can tell, the single 1.5" return pipe goes from the pad to the pool and splits off in a Y, and each leg of the Y feeds 2 ports. The farthest of each leg is the one I am having a hard time with the flow, which makes sense because of fluid dynamics. I am using a 1/2" eyeball on the closer 2 ports to help flow go to the 2 farther ports, which I am using 3/4" eyeballs. With this configuration, all 4 of the eyeballs put out comparable flow.

Any ideas as to the high pressure?

On another note: Are there any chlorinators specifically recommended here on the forum? It seems like the pentair rainbow units are about the best. I don't really have a problem with CYA and the tablets because St. Louis rains enough to replace about 1/4-1/3 of the water over a season. I want something temporarily because in a year or two I may spring for a liquid unit.

 

[mas985]

1. 30 PSI gauge is best because it is rare to be over 30 PSI and you get better resolution. But the old gauges, do they go to zero when the pump shuts off?

2. Do you know if they used flex pipe underground? It could have collapsed.

I believe the issue is with the underground piping. But it is difficult to know for sure what the issue might be. It could just be very small pipes.

As for chlorination, the only thing we generally do not recommend is tri-chlor puck chlorination because it adds CYA. SWGs, manual dosing, peristaltic pump and the liquidator are all acceptable.