I want to add a Jet Pump for my spa...

[joeg2246]

I am thinking of adding an additional Intelliflo 4x160 to handle my spa jets. I am wondering a 3" suction line from the spa would be enough water for both Intelliflo pumps. The reason I am adding the pump is because I have two ways to return water to the spa. One is though the floor the other is through the jets. I would like to be able to continuously keep the water hot with one pump by returning the heated water up through the floor and use the jets to recirculate the already heated water. I just need to know if the 2 intelliflos would get enough water from the one spa suction that is 3" pipe.

Thanks,
Joe

 

[Guest]

Do you have a way to draw water separately and then return it to the floor and the jets independently as well? I'm thinking that if you have one pump now, your PB put in a valve so that you could run the water to one or the other (or maybe both, to a degree), but you do not have 2 sets of suction and 2 sets of return pipes to really do what you are thinking.

Bruce

 

[joeg2246]

You are correct. I am using the Aquastar main drains and have 2 3" lines plumbed to my pad. Right now I am using one for a return and one for suction. If the 3" line that I am using for suction would support 2 intelliflo pumps then all my problems will be solved. If it can't then I could use both 3" lines for suction to the pumps. However that would mean that the only way I could return water to the spa would be the jets.

Do you think the 3" suction line would support both pumps?

Joe

 

[lborne]

Assuming the pumps normally use a 2" inlet, then yes, a 3" pipe will supply enough for 2 pumps.

3" PVC has an area over 2x greater than 2" - about 7in^2 compared to 3.1in^2. The max flow rates (according to pipe charts) you want through a 2" is about 75 gpm and for a 3" is about 160 gpm. Just split the 3" into two 2" pipes and you will supply sufficient water to your pumps.

 

[mas985]

Having a second 4x160 seems to be a bit overkill to me. Do you really need the control that the 4x160 offers or could you get away with a single speed pump. BTW, why do you need the second pump for flow rate?

Also, when pumps are run in parallel, both pumps experience the same head loss caused by both flow rates. So this means that both pumps will be running under fairly high suction head but the return head would be approximately the same as if running alone. This can cause some problems if the suction head gets too high and may even cause cavitation.

You would be better off running each pump off it's own suction port and then recombining the returns right at the line that goes to the jets. Each pump would then be a bit more balanced for suction and return head. Return head will be high, which is ok and suction head would be much lower. This would prevent any possibility of the cavitation. This would also allow you to go with a much lower HP second pump since you will have both pumps delivering flow to the jets. It would also allow you to go with a single speed pump for the second pump but you would still have the control of the original Intelliflo so you could adjust the strength of the jets with the Intelliflo. However, because of the higher pressure of the parallel pumps, you would need to find a high head single speed pump to use that matches the Intelliflo.

 

[Guest]

You are correct. I am using the Aquastar main drains and have 2 3" lines plumbed to my pad. Right now I am using one for a return and one for suction. If the 3" line that I am using for suction would support 2 intelliflo pumps then all my problems will be solved. If it can't then I could use both 3" lines for suction to the pumps. However that would mean that the only way I could return water to the spa would be the jets.

Do you think the 3" suction line would support both pumps?

Joe

Are the 3 inch lines separate (in other words, are there 2 separate 3 inch lines running all the way back to the equipment pad) so that you can hook each pump to a dedicated suction line, or are the two three inch lines you are seeing actually a split main drain? If you have the split drain application and only one 3 inch line to draw from at the equipment, I wouldn't try and hook two pumps to that. There is most likely not enough pipe diameter to supply two pumps if you ramp them both up!

The ideal scenario would be to have the split drain covers in the spa with two 3 inch lines beneath each cover. That way you would be able to draw from one set for the circulation pump and one set for the jet pump. Getting the water back via the warm water returns would come off the circ pump and the jets would obviously feed off of the jet pump.

Sorry if I'm missing something here, but I think you're missing one set of pipes to do exactly what you would like to do!

Bruce

 

[joeg2246]

I did a test tonight and I think I have talked myself into just replumbing the jet around the heater and salt cell. I will heat the water using the 3" line attached to the main drain then will turn the heater off and route my pump to just re-circulate the already heated water in the spa. My test tonight was a temp/time test. I heated the water up to 103 degrees and then turned the heater off and turned the jests on. I measured the temp of the water in 15 minute intervals. I only had a 6 degree loss over a 2 hour time period. I think I will save the money on an additional pump and just modify the plumbing. I would imagine once the spa is heated up staying in it for 2 hours is pretty rare so the temp loss should really not be an issue.
Joe

 

[mas985]

Another option would be to bypass most of the flow but leave enough through the heater and SWG to keep them operational. This is usually around 40 GPM. You can then recombine the water streams and have the best of both worlds. Because of the bypass, the total water flow should go up by some but because you are keeping the water flow lower through the heater and SWG, head loss in that part is kept to a minimum.

Also, you might consider a full bypass route around the filter as well to get the maximum effect but again have about 40 GPM going through the filter, heater and SWG. This should be fairly close to having a stand alone spa pump.