Do Salt Water Generators Reduce Flow?

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Cant see the rear connection from that POV.

If there is nothing between the pump and filter other than pipe, there should not be that much head loss. So either one of the pressure gauges is off or there maybe something stuck in that pipe.
 
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Here another view of the plumbing. I tried opening the hose bib on top of the pipe going to the filter. When opened all the way, both the gauge on the pump and the filter go down exactly 2 2PSI.
 

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tonygret said:
Mas985,

Isn't the filter gauge after the filter medium? Would that explain the drop?
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As @proavia points out, it is before the filter media so the head loss in the media is included in both gauge measurements. A 7 PSI loss in 4' of pipe and 3 90s would required the flow rate to be around 240 GPM which is not possible. So as I said before, either there is something wrong with one of the two gauges OR there is something wrong with that pipe and/or the filter.

What is the pump model#?

BTW, did you add the heat pump when you added the SWG?
 
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mas985 said:
What is the pump model#? BTW, did you add the heat pump when you added the SWG?
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The pump model is Jandy HP Flopro FHPM1.5-2. I have also added a photo of the specs sticker on the pump. The Heat pump was installed in November 2021 and the SWG was about 30 days ago.
 

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Tony,

I just noticed that you have a two-speed pump..

Are you running on low speed or high speed?

Is it possible that you are confusing the pressures you saw when in High speed vs. Low speed?

Thanks,

Jim R.
 
Jimrahbe said:
Tony,
Is it possible that you are confusing the pressures you saw when in High speed vs. Low speed?
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No, I am giving you the pressure from both gauges when on high speed. The difference in pressure between low and high is enormous, with about an 80% difference on both gauges. I think the only thing I can do is run an inspection camera down the pipe from the filter to the pump. I will do that when I clean the filter in a few days and report back. Knowing there is only a 2PSI drop when opening the hose bib, the blockage would have to be after that and before the filter, if there is one.

I am starting to think the correct answer here is that one of the gauges is inaccurate. But that doesn't explain the noticeably lower flow rate out of the returns since adding the SGW. Stay tuned . . .
 
Also, do both gauges go to zero when the pump shuts off?

With that pump and the measurements you made with the gauges at the pump, the flow rate is predicted at 37 GPM which is very low.

If I assume the filter pressure is correct, then the flow rate is 72 GPM which is not nearly as bad. So my guess is that there may be an issue with the filter pressure gauge, assuming there is no issue with the plumbing. An easy test is to swap the gauges and remeasure.
 
28 psi on the pressure side is 64.6 feet of head.

3” Hg on the vacuum side is 3.4 feet of head.

The total is 68 feet of head, which looks like about 30 GPM.

If we model the suction as about 100 feet of 2” PVC, we get about 45 GPM at 3.4 feet of head.


The low head loss on the suction points to an obstruction on the pressure side.

Since you have unions everywhere, I would take it all apart and look for some sort of obstruction.

Make sure that the filter and Heater “In” and “Out” are correct.

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mas985 said:
With that pump and the measurements you made with the gauges at the pump, the flow rate is predicted at 37 GPM which is very low.
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These estimates are from manufacture measurements in the Energy Star database so they can be different than the published head curves.
 
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With unions everywhere, it should be relatively easy to take everything apart and look for an obstruction.

Also open the filter and check valve to look for obstructions.

Make sure that the flapper in the check valve is not backwards.
 
JamesW said:
Since you have unions everywhere, I would take it all apart and look for some sort of obstruction. Make sure that the filter and Heater “In” and “Out” are correct.
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I just opened the filter assembly and noticed there is a diffuser at the outlet of the pipe inside the filter, as shown. I removed the pipe from the pump to the filter, which is 100% clear of any obstructions. Could this diffuser be responsible for the PSI dropping so precipitously?
 

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The next step is to switch the pressure gauges. However, assuming they are both OK and the pressure drops from the pump to the dirty side of the filter (which we know is clear save for the diffuser), anything on the other side of the filter membrane would not affect that drop. Perhaps the pump gauge is taken the pressure inside the impeller cavity, which you would think would be much higher than the pressure inside any of the pipes.

On the other hand, the water is dumped from a 2" pipe into a cavernous filter assembly with much less resistance. Wouldn't that account for the drop?
 
tonygret said:
I have a new SWG and it seems to me the flow from the returns is notably reduced.
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Did the eyeballs get removed or changed?

How are you judging the flow, by feel or sight?
tonygret said:
The only things I can see different is that the suction side is higher than before by about half and the pressure side is about 5 lbs higher also.
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Do all gauges go to zero when the pump is off?
 
JamesW said:
Did the eyeballs get removed or changed?

How are you judging the flow, by feel or sight?

Do all gauges go to zero when the pump is off?
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  1. I recently got new glasses from Sam's that I am still getting used to, but my depth perception is almost back to normal, and I no longer feel nauseous. I swim without my glasses, but I try to avoid the walls.
  2. All this came up because I use the jets on my bum back (really, I do), and the pressure is way down. It's very obvious.
  3. All gauges go to zero when the pump is off.
 

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