Is my pump too big/lines too small? Hayward thinks so..

[rcy]

I just got off the phone with Hayward, and the tech guy I was talking to thinks my pump is too big for my system and my lines too small. He was a bit surprised that it has been working since 2007 without failing (working too hard to push the water through the 1.5 inch lines???)

Here is what the pool store did back in 2007. Hayward Tri-Star 1HP pump SP3210EC Single Speed, 2" line from the skimmer then it all goes to 1.5 inch including back the returns (if I had known back then (i.e. if I had been a troublefreepool member) I would have demanded 2" for everything). The sand filter is 3.14 sq ft with a design flow rate of 63gpm. When running, the pressure gauge shows 22psi and it bumps up to 26 when the solar is on.

Would it help for me to change all the lines in the pump house to 2"? The lines going to the returns will still be 1.5" and so will the suction cleaner line. The other thing I've been considering is a cartridge filter, and the guy at Hayward said not a bad idea as they can handle more flow than a sand filter. I was actually looking at the Jandy CL460.

The last picture is the performance data for the Tri Star line. The 3210EE just a newer model number for my 3210EC. If I'm reading the chart right, even at the max 70 feet of head, the pump is putting out almost the maximum my filter is designed for???

 

[rcy]

Well...I actually took a measuring tape out with me and the line from the skimmer is 3" across and everything else is 2" across. Is that the proper measurement I want when someone asks if I have 2" lines?

If that's the case, is my pump still too big for the filter?

 

[mas985]

While not the most efficient design, it doesn't make the pump "work harder". In fact, pumps draw less current on higher head loss plumbing. The filter is a bit small for that pump but the good news is that sand filters are pretty resilient and I doubt the filter will get damaged if the design flow rates are exceeded. However, the filter would probably work a little better if the flow rate was lower.

Is there any particular issue that you are experiencing other than high pressure?

If you want to lower the flow rate, then the easiest thing to do would be to swap out the impeller with a smaller one.

 

[rcy]

No..no issues at all. I was considering a two speed pump or variable for energy savings which is how I ended up on the phone with Hayward. I was also considering replacing the sand filter with a cartridge filter. One thing I do notice is that when I backwash, I always see sand in the sight glass when I'm done and some on the driveway where the backwash hose empties. Is this maybe because of too much flow from the pump?

 

[mas985]

Is this maybe because of too much flow from the pump?

Could be.

A two speed or VS would help with energy costs but the upgrade cost would be high and it might take a while to pay for itself. Also, since you have solar, the pump would need to be on a high(er) speed anyway.

My advise would be to downsize the impeller. It is a cheap and easy fix. BTW, how high are your solar panels? If a two story or lower (< 30'), even the 1/2 HP impeller would be big enough.

When the motor fails, then you can think about a two speed motor. Also, what do you pay for electricity.

 

[Isaac-1]

One other thing, pumps generally like to have a section of straight pipe feeding into the suction side, having that valve T'd in so close will make it see even more resistance to flow. The exact length needed depends on the pump, amount of flow, and pipe diameter, but as little as 6-10 inches is enough for many pool pumps.

 

[mas985]

I know a lot of manufactures recommend that but I believe that is a hold over for pumps without pump baskets. A pump with a pump basket won't benefit much from a straight piece of pipe since the turbulence in the basket dominates. Although it is still a good idea for future plumbing mods or pump change outs.

 

[rcy]

Is this maybe because of too much flow from the pump?

Could be.

A two speed or VS would help with energy costs but the upgrade cost would be high and it might take a while to pay for itself. Also, since you have solar, the pump would need to be on a high(er) speed anyway.

My advise would be to downsize the impeller. It is a cheap and easy fix. BTW, how high are your solar panels? If a two story or lower (< 30'), even the 1/2 HP impeller would be big enough.

When the motor fails, then you can think about a two speed motor. Also, what do you pay for electricity.

The panels are on the roof of a two story house - the lines up to the roof are about 8 feet from the pump.

Electricity here in Ontario has switched to a time of use system (and of course, for solar heat I need the pump to run during the most expensive time..lol). Weekdays - 7am to 11am and 5pm to 7pm - mid peak, 10.4 cents kw/h; 11am to 5pm - on peak, 12.4 cent kw/h; 7pm to 7am - off peak, 6.7 cents kw/h. Weekends are considered off peak all the time. In the winter mid peak and on peak switch times. Before time of use, I think I was paying 5 or 6ish cents kw/h all the time.

Thanks for the tips - I think I'll just wait for the pump to need replacement, though that might be a while - it's in a shed protected from the elements so I would expect a long life (hopefully).