Larger Pumps - The Good and The Bad

[mas985]

With a 3 HP pump, I would be much more concerned that you may be exceceding the filter's flow rate than the PSI rating. It is difficult to exceed the pressure ratings on filters but it is much easier to exceed the flow rate of the filter with a high HP pump.

Also, with a 3 HP pump, high pressure will be the norm unless you have extremly large pipes. Again, it is likely that you have very high flow rates which are causing the high PSI rise.

24 PSI is 55 feet of return head and adding 10 feet for the suction gives you about 65 feet of head. Not sure of the brand of pump but a high efficiency 3 HP Northstar pump at 65 feet of head will give you as much as 165 GPM. I would check on the flow rate maximum of your filter to see if it exceeds that value. Depending on the filter type, that could be a problem.

 

[divnkd101]

I wrote:

Let me put your mind at ease. I also have a 3hp pump on my pool. My filter PSI runs at 24 psi constantly when I have my bubblers turned off (which is most of the time). When the bubblers are on, it normally drops to 20-22 psi. I demanded a lot of movement (agitation) of water in my spa (2.1/2" plumbed x 8 jets). I got exactly what I wanted. I was quite nervous at first as well for I was used to seeing pressure in the 15 psi range. As you can tell, I have grown accustom.

Mas, I am plumbed for 2" pipe throughout my pool except for the spa as I mentioned before. I am running a Hayward 5025 cart. filter rated at 150 GPM design flow rate. My nearest return is approx. 35-40 feet. I am in my first year of operation and have not had any issues with the pump/filter. However, should I have concerns for "down-the-line" use?

 

[mas985]

With a cartridge filter, I believe the only issue is with the media tearing so it may shorten the life a bit depending on how high your flow rate actually is. The 3 HP full rated Northstar is a beast and has one of the highest flow rates for a given head loss. A great pump if you need to move water.

About the only thing you can do is to keep an eye on the filters when you clean them. I suspect manufactures have a bit of head room in the flow rate specs of the filters so you may be able to exceed the spec by 10-20% without significant damage.

 

[divnkd101]

We just cleaned the carts last week and still look in tip top shape. I will keep an eye on them and advise my finidngs. Thanks for the input.