Two pumps with check valve in between ok?

[mas985]

When two pumps are run in parallel, the pressure and head loss will increase because the flow rate is higher through the plumbing (2 vs 1 pump). But higher pressure just means higher head loss which in turn lowers efficiency. It doesn't mean that the pumps are in any danger. In fact, just the opposite. The operating points of both pumps will shift to left and the total pump power will be less than the sum of when each pump was run by itself.

The only situation that could cause problems when running both pumps is if the Intelliflo RPM is so low that the pump cannot produce the flow rate to open the check valve (i.e. dead head) because of the high pressure from the jet pump. In this case, the PB may be right. But if the RPM is high enough, it will open the check valve.

 

[jblizzle]

And the dead head will only occur if the valve has the pool returns turned off ... Which was claimed to never have the valve in that position.

Posted from my Droid with Tapatalk ... sorry if my response is short

 

[mas985]

What about heating the spa?

I can see a situation where the spa is isolated to run solar for heating the spa (faster) and OP forgets the valve is set that way and the filter pump ends up running on lower speeds. As long as the condition is possible, the OP needs to be careful.

 

[bhunjp]

To the last poster: Agreed - if the valve is in the wrong postion then the pool pump could dead head when the spa is turned on. To avoid this the 3way between the pool and spa will have a physical stop so there will always be some flow to the pool.

 

[bhunjp]

Ok I made some measurements today. The variables will be the two pumps on/off and the positions of the 3way between the pool/spa return.
The psi readings are at the filter.

Pool pump only with 3way 75%pool/25% spa (normal operating position): 15-17psi - varies as pop-ups (caretaker 99) cycle through zones
Pool pump only with 3way 100%pool/0% spa : 21-22psi
Pool & spa pump with 3way 75%pool/25% spa (normal operating position): ~21 psi
Spa pump only with 3way 75%pool/25% spa (normal operating position): 0 psi

Note the psi with the 3way all the way to pool and the 75/25 with the pool & spa pumnps on are the same.
I think this proves that the check valve is doing it's job.

 

[swimcmp]

The number two Intelliflo pump guy from Pentair told us to never put two pumps on the same line with a check valve. Especially when one is a variable speed or flow. There is a chance that the check could fail and create a situation for the variable to fail. Its your pump do as you please but the pool guy is correct to not install it that way.

 

[bhunjp]

Had the install last Friday!! The PB came up with a way that pleased him and allowed my air switch to control the spa pump and blower. It turned out that one of his major problems with my old setup was how ugly it was. There were too many valves and pipes cris-crossing and 1 1/5 in pipe and 2" pipe all mixed together. He determined that the valve after the pool pump could be eliminated. The only pool return if the one in the spa line. I will try to post some before and after shots.

Anyway the system looks so clean. My only objection was that he eliminated a short 2" line that went from the pool pump to the pop-ups and instead is using a 1 1/2 line that goes underground to the popups. It not a big deal though.

Anyway - so far I love the intelliflo and the clean & clear 150. They are so easy to use compared to my horrible, leaky Hayward setup. And the intelliflo is soo quiet. The pool pump is right outside the family room and master bedroom window so that's a big deal.

 

[bhunjp]

Here is an even more detailed view of my old set up and I will follow with how it changed:

                                   Pool
pool Main Drain -->3way---3way-----Pump---Filter --solar-->-|   
pool skimm  -------^        ^                              |
                            |                              |
spa drain------------------|                                |                       | ---> pool return popup(AA)
                                                            |        ---------------3way 
                                                              |      |               |----->-spa return (jets)
                                                            |        |
 pool return (pop ups) <--------------< 3waymanual --checkP>-------T
                                 |                                  |
                                 ^                                  |
                              ^check                              ^checkS
                                  ^                                 |
                            pool return(from spa area)(AA)           spa pump
                                                                       |
                                                                      spa drain

Note the pool return label AA. This is a 1 1/2" pipe that goes underground.

 

[bhunjp]

Here is the new set up. Note that pool return AA is now used. Another bonus with this setup is the spa does not drain to the pool level when the pumps turn off.

                                   Pool
pool Main Drain -->3way---3way-----Pump---Filter --solar-->---swg-------|   
pool skimm  -------^        ^                                           |       |---> pool return popup(AA)
                            |                                           |       |             (underground)
spa drain------------------|                                             -----3way 
                                                                                | 
                                                                                Vcheck 
                                                                                |                      
 pool return (pop ups) <--------|                                               | 
                                 |                                   |--------3way
                                 ^                                   |          |
                              ^check                              ^checks       |----->-spa return (jets)     
                                  ^                                 |
                            pool return(from spa area)(AA)         spa pump
                                                                    |
                                                                  spa drain

 

[UnderWaterVanya]

Here is the new set up. Note that pool return AA is now used. Another bonus with this setup is the spa does not drain to the pool level when the pumps turn off.

 pool return (pop ups) <--------|                         
                                 |                                   
                                 ^                                   
                              ^check                              
                                  ^                                           
                            pool return(from spa area)(AA)         
                                                                    |
                                                                  spa drain

How does this section get pressure? I don't follow where the pump is in this part of the diagram.

 

[JasonLion]

The two points labeled "pool return(from spa area)(AA)" are connected underground.

 

[UnderWaterVanya]

The two points labeled "pool return(from spa area)(AA)" are connected underground.

Doh!

Thanks.