Is this normal??

[kasparsport]

Hi everyone, I have an above ground 15x24 oval pool, with a Hayward perflex filter DE, & a Hayward Power Flow LX 1.5 hp pump.
I recently installed a Sungrabber solar heater to the pump & the pressure went from between 8-10 psi to 19-20 psi. I cleaned the filter & added new DE, but I still have the same pressure. I was wondering if this is normal or is solar panels too much for my pump to handle? (I wouldnt think so with a 1.5 hp pump)
The solar panels are 2'x20' & I installed 2 of them because that is what the size of my pool called for.
Any advice or recommendations are greatly appreciated..Thanks

[CarlD]

Are they directly in-line so your water must flow through them to get back to the pool, or are they parallel, off a tee?

If the former, the answer is easy: Re-plumb as the latter.
If the latter, then something was done wrong.

[kasparsport]

They are in-line with one another, the water flows from the inlet to the outlet into pool. I placed them on my awning so they are elevated. The water going into pool is very warm its just the pressure is so high, I dont want to kill my pump.
Thanks for the quick reply.

[Poconos]

KS, Welcome to the forum.
You should ideally plumb them in parallel and in addition put a bypass valve to divert some water around them. For efficient enough heating you don't need all the water going through them. With a pump that size you can probably divert 75% of the total water around them. The way to tell is to set the bypass so the temperature of the output of the solar heaters is just a couple degrees warmer than the input. If the output is too warm then close the bypass valve a little to get more water through the panels. You'll probably find doing it this way will result in very little pressure change. If it too clumsy to plumb in parallel then leave them in series, add the bypass, and apply the same reasoning to set the flow. Watermon has two 2x20s in series and they work just fine....with the bypass valve. She only sees about a 1-2 psi pressure change between full bypass and the setting for good panel flow.
Al

[kasparsport]

Thanks a lot poconos..I looked on the sungrabber booklet for troubleshooting & it says I would need a bypass valve if my pump was 1hp. I really thought the 1.5 hp pump would have been strong enough. I will put a bypass valve on, but in the meantime am I hurting my pump..?

As you can tell I am not very pool savy...

[Searcher]

Thanks a lot poconos..I looked on the sungrabber booklet for troubleshooting & it says I would need a bypass valve if my pump was 1hp. I really thought the 1.5 hp pump would have been strong enough. I will put a bypass valve on, but in the meantime am I hurting my pump..?

As you can tell I am not very pool savy...

Your pump motor is over sized for your application; it is TOO STRONG. Plumb the panel, as recommended, so that some water passes through the panel and the majority returns to the pool; parallel and NOT in series. You are getting so much pressure for that simple reason, an oversized motor. A smaller motor would move just as much water with much less strain on your system PLUS it would save you money.

To look at it another way, if you would put a 2 HP motor in place of the 1.5, you would not move any more water but you would raise the pressure considerably more.

No matter what size motor, the panel must be piped as noted. Your documentation seems to not worth the paper it is printed on.

The only thing that should be oversized on a pool is the filter.

Are you hurting your motor? Yes if you consider that I am running a dual speed motor, pushing 25,000 gallons on low speed "1/6th HP" and showing 2 pounds of pressure through an S 200 sand filter that holds 200 pounds of sand.

[Poconos]

Searcher is right in that the pump is oversized IF you direct all the flow through the panels either way they're hooked up, series or parallel. As we said, the trick is to flow enough water through the panels to do the job but no more.

This statement "To look at it another way, if you would put a 2 HP motor in place of the 1.5, you would not move any more water but you would raise the pressure considerably more." is not totally true. At higher pressure you would move more water but in your situation you don't need to do this. Through any pipe or restriction, higher pressure = higher flow.

Does operating at a higher pressure hurt the pump? I'm not really sure but I tend to say slightly. I think the shaft seal is in a high pressure area and if that is the case then running at higher pressures would increase wear and decrease seal life. Motor bearings aren't affected. Running at higher pressure is a waste of electricity however.

I stand by my statement that either a series or parallel hookup will work but parallel is preferred. There is a slight thermodynamic advantage of parallel over series. A simple way to look at it is in series the first panel is preheating the water for the second panel. You get maximum heat transfer (or absorbtion) when you have the largest temperature differential which means you want the coldest water through both panels. Thus parallel wins. In a practical sense, hook them up whichever way is easier and cosmetically better.

Al

[kasparsport]

Thanks for the help guys...