Is it worth it for me to bypass filter for spa jets in pool

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T

toofast

0
May 9, 2013
993
North East Ohio
Ok, so I have a "shallow" end of the pool that has 3 spa jets on each side of the seats

Like this, so six in total.[attachment=0:25mcqdfl]jets.jpg[/attachment:25mcqdfl]

There is also a "air blower" going to the jets and they have spa style rotating returns.

The plan is to allow for all 6 to be on and then shut off one side for more action, etc.

I have a single two speed pump that on HIGH puts out a bit more than 100 GPM. I have all 2" rigid PVC with relatively short runs.
The filter has a max flow of 93 GPM (not sure if this is before or after sand, it is a Waterco S750 Fiberglass.

So is it really worth to install yet another manifold to divert the flow pass the filter when using the jets ? Seems like I am getting very little gain...other than I am not sure if that flow in filter is input or output?

Any comments or thoughts or questions, let me have it!
 

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Re: Is it worth it for me to bypass filter for spa jets in p

How do you know the pump puts out 100 GPM? Do you have a flow meter installed? 100 GPM would be very high for a 1 HP pump.

Sand filters are pretty robust so if the pump truly is putting out 100 GPM, which I seriously doubt, then it should be ok even though it is over the rating. Also, the rating is both input and output since the flow rate is the same.

Also, a 1 HP is likely to be under powered for 6 spa jets. Can you described the spa plumbing in a bit more detail. Pipe sizes and lengths.
 
Re: Is it worth it for me to bypass filter for spa jets in p

Below are the pump specs...on high speed 100 gpm. I also noted the pump itself said 1.15HP so did some reading and looks like a few mfg have a higher rated vs. spec, etc.

As for description of jets...I have all 2" rigid running to the jets. I have two main feeds per each set of 3 jets, the spa jets themselves downsize to 1 1/2" input for water, and same for air.

The run length of the plumping is about 30' then perhaps 50' for the other side. I can turn one site off from the other, etc. They spa jets themselves are the spinner type adjustable jets.

[attachment=0:36crgwev]pump specs.jpg[/attachment:36crgwev]
 

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Re: Is it worth it for me to bypass filter for spa jets in p

A pump never achieves max flow rate, especially on a spa. That is called the run out point and the point at which a pump cavitates. The head curve shows the flow rate as a function of head loss. A 6 jet spa will have at least 50' of head and probably more so the flow rate will be closer to 50 GPM.

I hate to tell you this but it really sounds like a very poor spa design and the performance of the jets is probably going to be very disappointing. The PB put an up rated 1 HP on a 6 jet spa which will never deliver the performance you want. Also, a spa should have at least 2.5" plumbing.

There is a section on spa design in the Hydraulics 101 sticky that you should read and probably your PB should read too. I can help but I would need some more information on the spa jets. Specifically, the recommended flow rate per jet.
 
Re: Is it worth it for me to bypass filter for spa jets in p

Dang....well I think it is too late for much change...other than maybe adding a second dedicated spa pump. All the lines are run and buried....

I wish I would have found this forum sooner! DANG IT.

Would a second dedicated pump be the best option at this point ?
 
Re: Is it worth it for me to bypass filter for spa jets in p

If the plumbing doesn't support the flow rates, then a second pump may not help. However, you mentioned two sets of 2" lines. Is that going from the pump all the way to the spa jets? Also, are there two 2" lines on the suction side as well. Four total pipe to/from the spa?
 
Re: Is it worth it for me to bypass filter for spa jets in p

Ok, there may be some hope. But do you know the recommended flow rate for the jets? What is the part #.
 
Re: Is it worth it for me to bypass filter for spa jets in p

This is what I have...my PB says the JETS have a max flow of 10 GPM of water. Could not find a way to validate though.

Also I am not sure if I mentioned but the 2" feeds reduce to the 1 1/2 fittings below.

[attachment=0:10j8a83p]fitting and jet.jpg[/attachment:10j8a83p]
 

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Re: Is it worth it for me to bypass filter for spa jets in p

Given those are low flow heads you may be ok but at 10 GPM each, the total flow rate needs to be 60 GPM which means the total head loss cannot be more than about 45' of head. And that would be fairly low head loss for a spa so each jet may end up with less than 10 GPM. If plan on just using 3 most of the time, it might not be an issue but a bypass may help give you a little more margin because you have both a heater and a filter and could bypass both. Of course, you could go with a 1.5 HP pump and have plenty of flow rate for all the jets even with the filter and heater in the loop.
 

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Re: Is it worth it for me to bypass filter for spa jets in p

Yeah, I think I am in trouble...filter is already mounted and PB is not wanted to swap. I guess down the road I could always upgrade. I will have the main returns manifolded (is that a word) off as well, so I can divert all pump to either just 3 jets or all 6 and the main returns off of course.

Thanks for the guidance and the help!
 
Re: Is it worth it for me to bypass filter for spa jets in p

Fast forward....

So...as an updated and new question.

As it turns out, with all 6 jets on the flow is a bit slow, the jets rotate, but slowly and not a ton of action. PB said that when the BLOWER was installed it will improve.

But with just 3 of the jet's on - the action is fairly good...almost like a real SPA. So I was really looking forward to the BLOWER adding to the action.

Yesterday, the blower is installed...with all 6 jets on and the blower on - I get lots of air, but the jets now don't even rotate. So I was gonna close 3 of the jets and just work off the blower and the 3 jets. PB "yelled" at me and told me I could never do that, as the back pressure would be great and the WATER would work itself into the blower and destroy it.

So I am left with a non-functioning expensive attempt to have a mini-spa.

I am confused though on WHY this would be a problem...and maybe it would not - but before I try something, I wanted to run this by the experts.

If I need to give any more info just let me know of course.

Thanks in advance for the feedback!
 
Re: Is it worth it for me to bypass filter for spa jets in p

Seems like you could add a valve on the blower line to reduce the amount of air or close it off so that you can run just 3 of the jets.

That is my only thought.
 
Re: Is it worth it for me to bypass filter for spa jets in p

Ok...understand the option.

As a follow up though, the jets are strong with just 3 of them running (aka I have a valve that allows me to run 3 or 6 jets) I want to TRY the Blower and just 3 Jets - but I am afraid to as the PB said it will cause water to backup in the blower motor? Does that make any sense ?
 
Re: Is it worth it for me to bypass filter for spa jets in p

Well, can you just lift the blower motor off and run the 3 jets with the blower pipe open? If the water comes out, then it may be a valid concern, if the water never comes up and out of the blower pipe, then it should not be anything to worry about.

And if the water DOES come out the blower pipe, wonder if you could just add a check valve in the blower pipe.
 
Re: Is it worth it for me to bypass filter for spa jets in p

Blowers do not add power, only bubbles. A blower only helps to clear the air pipe of water so that the venturi jets can work properly. But again, a properly designed spa should not need a blower. A blower is simply a crutch for the PB because they do not understand hydraulics very well.

But as I understand the set up, you have two separate water loops but only a single air loop? But if you did not have any water back up with 3 jets and without the blower, then there should be no water with the blower. The water will only backup into the air line if one of the jets is clogged not if the line is shut off. Again, I don't think your PB understands hydraulics very well.
 
Re: Is it worth it for me to bypass filter for spa jets in p

Yeah, I am guessing that while my PB did a great job on nearly everything...this was sort of a "mistake"...but I think his intentions were about trying to do the right thing.

Anyways...I do indeed have 2 air loops and 2 water loops...so I could leave the air on all six jets and just the water on three. The water does not back up to the blower with 3 jets, because my PB tells me to keep the VALVES for the air closed if I only am running three jets.

Do we think that my problem is TOO MUCH air ? And that is why my jets drop spinning when the air comes on ?
 
Re: Is it worth it for me to bypass filter for spa jets in p

Air has less momentum that water so it will impart less energy to spin the jets. However, if there was enough flow through the jets, that is not normally an issue.

An up rated 1 HP pump is really too small for 6 jets. In fact, there are only a couple 1 HP full rated pumps that are big enough to handle 6 jets. In most cases, a 1.5 HP is the minimum size for 6 jets and that is without pad plumbing. So if you had a larger pump, it would produce higher flow rates which would make the spinners spin faster and the venturi's to pull air better so it is quite possible that you would not even need the blower.
 
Re: Is it worth it for me to bypass filter for spa jets in p

Gotcha....now I get why the air stops the jets...makes sense.

At this point what if my best option...other than replace the pump ? Assume bleeding off air would help the most ? Heck I don't even have a way to introduce air, without the blower on....or if I open the blower VALVES but don't turn the blower on will that allow air to bypass the blower and enter the 2" PVC ? Sorry for all the "silly" questions.
 

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