what should my filter pressure be?

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flyweed

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Aug 3, 2009
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SW Wisconsin
I know this is kind of a vague question..but I just want to get an Idea of where I should be sitting on the reading of my pressure gauge.

Pool pump and filter are about 22 feet away from the pool. Same level..plumbed with 1 1/2" PVC pipe. I just started my pump and filter system up yesterday and the pressure gauge is reading 14 PSI. Is this about right, should it be more or less??????

Any insight would be wonderful

Dan
 
It's within reason, but every pool/pump/filter combination has a different "normal" pressure. There are no hard rules for what you should have.
 
Read your gauge after the filter(s) have been cleaned, pump and skimmer baskets cleaned, with system running under normal circumstances. This reading will be "normal" for your pool when everything is clean. As the pressure increases, filter(s) are becoming dirty. Usually a 10 psi increase indicates time to clean.
 
Well I just opened the pool from winterization...so skimmer basket was clean..pump basket was clean and sand filter was backwashed last fall a the close of the pool

So I should assume that the 14 PSI is my normal "clean" pressure, and then I should clean/backwash when I hit about 24 psi??

Dan
 
Just to keep things in perspective, a 10 PSI rise is 23 feet of additional head loss. I would never wait that long. I know some manufactures recommend that but I would backwash much sooner than that, +4 PSI, unless I had to do it more than once a week.

As for your typical pressure, it depends upon your exact setup.

Do you have multiple suction lines pool to equipment?

Multiple Return lines?

Is everything 1.5" plumbing?

How many return eyeballs and what size?

Does the gauge go to zero when the pump is off?
 
mas985 said:
Just to keep things in perspective, a 10 PSI rise is 23 feet of additional head loss. I would never wait that long. I know some manufactures recommend that but I would backwash much sooner than that, +4 PSI, unless I had to do it more than once a week.
Click to expand...

I agree with Mark. My flow is way down at 3 or 4psi increase from my normal 17psi. Looking at performance curves tells you that a 23 ft head loss moves the performance of a 2.5HP pump down to that of a 1HP pump in a typical pool setup.
 
some more specifics.
1 intake (wide mouth skimmer port)
1 return 1 1/2" return with built in light

line to pump is 22 feet of 1 1/2" pvc
line to pool return is 22ft of 1 1/2" pvc
from sand filter to heater, 2 inch pvc.....from heater to SWG 2 inch pvc...out of SWG cell back to pool 1 1/2" pvc

Nothing else is on return or suction line. I have a pool robot, so no vacuum on any of the lines or anything.

My pressure gauge is new and goes to 0 (zero) when the pump is off.
 
Thought I would re-start this thread instead of a new one, but my question is similar in a way.

I installed a new pump last month, previous one was a twice re-build 1HP Hayward (I bought this house after all re-builds). The previous "normal" PSI was around 12. Now with the newly installed pump (1HP Max-Flo), the average PSI after a clean etc is around 18. I would assume this is a good thing since that means greater flow/turnover, correct?

Second question from reading previous posts, a decrease in pressure means it's time to clean/backwash etc. but what about an increase? Would there be a natural situation that would move the PSI up?

Lastly, I have solar heat (Enersol system) and there's a bypass that I was told to turn half-way when I have my solar up and return opened - but that moves the pressure up around 21....when I ease the bypass to less than half it returns back to 18.....I think lower pressure is better for solar given it has longer time to sit on the coils....

I'm confused, thanks for any help in advance !

p.s. 1.5 inch plumbing
 
I would assume this is a good thing since that means greater flow/turnover, correct?
Click to expand...
Actually the opposite. Higher flow rates cost $$ in energy.

Second question from reading previous posts, a decrease in pressure means it's time to clean/backwash etc. but what about an increase? Would there be a natural situation that would move the PSI up?
Click to expand...
An increase in pressure (filter pressure gauge) means it is time to clean. Lower than normal pressure means that there might be clog in the suction side of the plumbing.


Lastly, I have solar heat (Enersol system) and there's a bypass that I was told to turn half-way when I have my solar up and return opened - but that moves the pressure up around 21....when I ease the bypass to less than half it returns back to 18.....I think lower pressure is better for solar given it has longer time to sit on the coils....
Click to expand...
Sorry, strike three. Solar is more efficient with higher flow rates but there are diminishing returns. Allowing the water to "heat up" just means that hotter water will loose more heat before it gets to the pool. Heat transfer is about moving BTUs efficiently but that also means keeping the water temperature difference between input and output as low as possible.
 

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Thanks Mark - good to know....maybe the question I was trying to get at was: "new" pump, same HP, producing a higher flow - does that seem normal given the motor is just better than the old one? Previous answers are all dependant on the set-up....nothing's changed for me except the pump. Does a 5 PSI increase seem abnormal or anything to be concerned about?
 
You have hit on one of this issues with pump labels. The simple answer is that even though two pumps can have motors with the same label HP, it really doesn't mean anything. There is only a very very loose correlation between motor HP and pump flow rates. I can show you a 1/2 HP pump (Whisperflo) with more flow rate than a 2 HP pump (OptiFlo).

As for the difference, what was the model # of your first pump?
 
Older motor was a Century 1081. Serial BB1 which is 1984. I pulled the back off it one day and couldn't believe it actually ran. It sounded like a lawn mower too.....brutally loud. When it was last rebuilt, end of last summer, they put a new front end (basket etc) of a Hayward max flo 2807X10A. That's the same model of my new one. I tried to keep it the same - just a newer motor. Got the whole pump for $270. The rebuild cost me $300 last summer and it came back louder and less powerful.
 
If the wet end is the same, then the pressure and flow rates should all be the same. An old motor does not reduce flow rate or pressure, it just fails. So something else might have changed (e.g. plumbing).
 
Well, new wiring. Same gauge as the old one. New rubber coupler from the front of the wet end (off the 90 PVC) onto the inflow pipe. I'm not sure what else it could be, but I'm happy with the performance so far, just curious on the jump in PSI. The new motor definately has more jump when it turns on. Literally shakes the sand filter for half a second.
 
Sounds like the old impeller was smaller, worn, or clogged. Or the suction side now has better flow or used to have a suction leak, or the return side now has more restriction, or the gauge broke between pump changes.

At any rate, the probability of a problem at this point is pretty low, so grab a drink and enjoy the pool!
 
They get a few things right in that article but are still using the old and out dated rule of thumb of a static pressure rise for cleaning a filter which is a mistake. A 10 PSI rise over a 10 PSI clean filter pressure is a doubling in return head loss which can dead head a pump. This is why one should use a relative rise (percentage) for determining when to clean a filter. On this forum, we have established a rise of 25% as reasonable filter rise for determining when to clean a filter.

Also, there claim about dirty filters causing more energy use is very misleading. In fact, a dirty filter reduces the amount of energy a pump uses. They are assuming that the pool owner increases run time to compensate which most pool owners do not do.
 
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