Not enough circulation suction

[4PoolJoe]

Hi, I have a 20x40 in ground pool. The pool has always had enough suction to operate a 1.5" skimmer suction hose that attaches to the end of a pole- but just barely. Last year, i replaced the 1.25 HP pump with a new 1.5 HP pump. I also replaced the 1.5" 3 way diverter valve as the old one was damaged when a toy lodged in it (found when I had the lines snaked bc I couldnt get enough water to prime the pump. Afterwards, the system would circulate, but it will not get near enough suction to operate the skipper hose which I use to suck leaves out of the bottom. Also notice that the clear section of the pump above the basket does not fully fill with water- nearly, but not fully. Any thoughts as to what would cause the pressure reduction and how I can boost it back up?

I have a Hayward pool heater (not running due to low pressure switch) and sand filter. The purchased pump is this one:

Amazon.com

Thanks!

 

[mas985]

Just because a pump has a higher label HP does not mean it is a stronger pump.

Do you know the make/model# of each pump?

What was the clean filter pressure with the old vs new pump?

 

[4PoolJoe]

Just because a pump has a higher label HP does not mean it is a stronger pump.

Do you know the make/model# of each pump?

What was the clean filter pressure with the old vs new pump?

Thank you for your reply.

The old pump was an AOSmith/Century B853 / 0-177215-04 1.0 HP Motor and ran about 16 lb of pressure with a clean filter, although it was tough to prime.. The new pump is an Aquastrong PSP150T 1.5 HP motor/pump, supposedly rated at 135 GPM but operates 13ish lb of pressure with a clean filter? To be honest, that is going off memory as the pool gage is needing to be replaced after winter.

 

[PoolStored]

That's the motor, what what the pump brand/model?

 

[mas985]

Thank you for your reply.

The old pump was an AOSmith/Century B853 / 0-177215-04 1.0 HP Motor and ran about 16 lb of pressure with a clean filter, although it was tough to prime.. The new pump is an Aquastrong PSP150T 1.5 HP motor/pump, supposedly rated at 135 GPM but operates 13ish lb of pressure with a clean filter? To be honest, that is going off memory as the pool gage is needing to be replaced after winter.

That means to me that the newer pump has a lower head curve than the old pump so it will produce less flow rate and less suction. When replacing pumps, it is always a good idea to compare head curves so you know what you are getting.

 

[4PoolJoe]

That means to me that the newer pump has a lower head curve than the old pump so it will produce less flow rate and less suction. When replacing pumps, it is always a good idea to compare head curves so you know what you are getting.

Thanks again.

So I am not familiar with head curves- what do I need to do to properly size a pump for my unit? The unit I purchased and installed is a pump/motor combo- the old one had a square flange motor with a pump but that unit is long gone now.

How likely is it a matter of the wrong pump vs something/anything else? I understand you cannot know for certain, but I'm not sure what else might be affecting it.

 

[4PoolJoe]

That's the motor, what what the pump brand/model?

It's a motor/pump combination on there now. Previously, I do not know the pump brand.

Here is a link to the new one : Pool Motor/Pump

 

[PoolStored]

Previously, I do not know the pump brand.

Can't compare the head curve without the old pump model.

 

[4PoolJoe]

Can't compare the head curve without the old pump model.

Thanks. Any suggestions as to how to resolve the problem?

 

[duraleigh]

Also notice that the clear section of the pump above the basket does not fully fill with water- nearly, but not fully

If the pump basket is gurgling, splashing, etc it is indicative of a suction side leak. This article may help Suction Side Air Leaks

 

[mas985]

Thanks again.

So I am not familiar with head curves- what do I need to do to properly size a pump for my unit? The unit I purchased and installed is a pump/motor combo- the old one had a square flange motor with a pump but that unit is long gone now.

You need a pump with a higher head curve. Here is the new pump head curve:

How likely is it a matter of the wrong pump vs something/anything else? I understand you cannot know for certain, but I'm not sure what else might be affecting it.

As I said previously, you replaced a stronger pump with a weaker one so one should expect poorer performance.

If you want the same performance as your old pump, you need to match the head curve. However, I don't think you have identified the pump model #, only the motor which is not enough.

Do you still have the old pump and can you post a picture of it?

One option is to simply replace the motor on the old pump.