High filter PSI??

[stakeman]

We just opened our brand new pool Thursday. I was out of town so the PB gave my wife the lowdown..As I arrived home last night she was showing me the bubblers, sprayers ect... When she turned them off the pump started making a strange sound. This was at 8:30pm, dark; so I got a light and checked the filter pressure and it was at 24 psi. We turned everything back on and the pressure dropped to about 18-20 psi. At no time did we turn off the returns. My PB is due out today, so we just left the bubblers going all night. I posted some concern of a 3 h.p. pump being too large a few weeks back, and this is confirming my doubts!! Am I missing anything obvious? It's a 16k IG gunite, 6 returns, 2 skimmers.

Thanks Dave

 

[duraleigh]

Yeah, that pressure is a little higher than most sytems. The average seems to be somewhere around 12-15psi with a clean filter.

I am not familiar with how they plumb for accessories but if all your pump volume goes thru the filter first, then it sounds like a larger filter or smaller pump may have been a better design. Mas985 knows this stuff like the back of his hand.....don't take my opinion worth much but he and some others much smarter than me will comment, I'm sure.

 

[JasonLion]

Aside from the strange noise that all sounds fairly normal. You have a large pump so the pressure is higher than it would be with a smaller pump, but still in the acceptable range. The more routes the water has to get to the pool the lower the pressure should be, so the pressure going up when you turn off the bubblers make sense.

What does the noise sound like?

 

[divnkd101]

Stakeman,

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.

 

[stakeman]

Thanks for all the input everyone. You can check out the pics on the other forum. I'm happy with the way everything turned out, just a little concerned about the PSI. After reading the max psi the filter can accept is 50 I feel better. Ijust don't want to put too much backflow pressure on the pump. BTW there is 7 returns..thanks again for the feed back!!

Stakeman :-D

 

[mas985]

Somehow this got posted in another thread so here it is again:


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.

 

[stakeman]

I'll post the particulars here soon. FWIW the filter shows a max psi of 50..Thanks mas985 it sounds like you know the deal on this type of thing. At this point I feel like pinning the PB down on this pump size. I can't see why a smaller pump would not accomplish enough movement for a 16k pool, 3 bubblers and 2 sprayers.

 

[stakeman]

We are going to a 2 h.p. pump now, as soon as he can get the electricans out! I'll post the results later.

 

[stakeman]

Ok, we just got back from a Wedding out of state and my PB swapped out my 3 hp pump for a 1.5 hp. We still get good wqater movement and the filter PSI is still close to 20psi when just running the returns, but drops to around 18psi with the bubblers and sprayers on. I'm happy with this and think my electric bill should come down as well.