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Thread: weak jets! what do i do?

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    weak jets! what do i do?

    If you have weak jets, how do you know the difference between lack of water flow vs. lack of air flow? I'm not quite sure if I need a booster pump of a blower. I'm using 9 waterways plastics poly storm gunite jets rated at about 12 gpm each.
    15,000 gallon gunite pool, grey plaster with 8' raised spa
    Jandy PlusHP Pump 2 HP Dual Speed
    Sta-Rite 450 Sq. ft. Cartridge Filter
    Cleva-Chlor RP40HD
    Raypak 400k btu heater
    Jandy Aqualink RS-8 One Touch
    Savi Melody 12v LED lights

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    mas985's Avatar
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    Re: weak jets! what do i do?

    A blower just adds more air but not more force. If you want stronger jets, you need to increase flow rate and/or pressure. Assuming that your plumbing can handle higher flow rates, a larger pump would make for stronger jets. But if most of the head loss is in the plumbing vs jets, this may not help. Otherwise, you can reduce the orifice of the venturi jets and that will make them feel stronger although reduce the flow rate per jet.

    Post some more details about your spa setup and maybe we can make some suggestions.

    Pump model/size

    Plumbing size and length of runs

    Also, is the jet pump going through the filter or is it separate from the circulation system?
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

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    Re: weak jets! what do i do?

    Jandy PHPM2.0-2.. It's a 2 speed pump. 2 hp 1.1 service factor up-rated pump. The spa suction is 3" and runs through the filter which is a System:3 Modular Media SM Series, 450 sq. ft. sta-rite cartridge S8M150. The plumbing is 60' on the suction and return. The return lines are 2-1/2". The air line is 2" and is also 60'. The plumbing at the top to the right of the heater is to the dual salt cells. The filter is located behind me, out of the cameras view. When the jets are on the filter pressure is around 12 psi. The 2" air line is completely open, no restriction or baffle. Is that ok?
    Attached Images Attached Images
    15,000 gallon gunite pool, grey plaster with 8' raised spa
    Jandy PlusHP Pump 2 HP Dual Speed
    Sta-Rite 450 Sq. ft. Cartridge Filter
    Cleva-Chlor RP40HD
    Raypak 400k btu heater
    Jandy Aqualink RS-8 One Touch
    Savi Melody 12v LED lights

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    Guest

    Re: weak jets! what do i do?

    Pipe looks pretty small, is that mostly 1 1/2? PVC??

    Oops, my mistake, didn't see comments above images.

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    Re: weak jets! what do i do?

    I don't see a check valve between the heater and salt cells.

    The heater may be your restriction. A by-pass valve would be a good idea to siphon some of the flow between the heater's ports.

    How many and what type of jets are in the spa?

    Scott
    Owner of - PoolGuyNJ LLC
    Expert Pool and Spa Repairs, Renovations, and Augmentation. Helping people decide what is the right gear for meeting their needs. Expectations Set, Expectations Met, No Surprises.

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    Re: weak jets! what do i do?

    The pad is all 2" because it was already plummed when I bought the equipment. So I just made sure to run the larger pipe up to the valves and left the above ground stuff the way it was. There is no check valve between the heater and salt cells but they are up high so it creates a hartford loop. So on the heater bypass valve, would you leave that wide open to balance the pressure or throttle it back to divert most of the flow through the heater? The jets are the waterway plastics poly-storm. I used one of each, 9 total. I believe they are 10-12 gpm each but I am trying to get confirmation on that.
    DIRECTIONAL 212-8050G
    ROTO 212-8010G
    TWIN ROTO 212-8120G
    MASSAGE 212-8030G
    GALAXY 212-8190G
    GALAXY MASSAGE 212-8530G
    POWER STORM II 212-8250G
    MULTI MASSAGE 212-8270G
    HAND HELD 210-3250G
    15,000 gallon gunite pool, grey plaster with 8' raised spa
    Jandy PlusHP Pump 2 HP Dual Speed
    Sta-Rite 450 Sq. ft. Cartridge Filter
    Cleva-Chlor RP40HD
    Raypak 400k btu heater
    Jandy Aqualink RS-8 One Touch
    Savi Melody 12v LED lights

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    mas985's Avatar
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    Re: weak jets! what do i do?

    The filter pressure seems unusally low for spa jets. Have the jets always been weak or just since you last opened the pool?

    Also, some of the polystorm jets require up to 25 GPM each. The catalog doesn't say for all of them though.
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

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    Melt In The Sun's Avatar
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    Re: weak jets! what do i do?

    Pool is brand new. We all watched him build it!
    11,200 gal, Pebble-Tec; Tristar 2-speed 1hp - Swimclear 325 ft2 cart - SWG - A & A in-floor cleaner - Heat pump. For the poolside cooking, a Yoder Wichita and a Big Steel Keg!
    TF Test Kits -- PoolMath -- Pool School
    Make each day your masterpiece. - John Wooden

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    mas985's Avatar
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    Re: weak jets! what do i do?

    Just found this reference so it looks like they all take about 10 GPM. So that pump should easily put out 90 GPM especially with the pipe size. Being that the pressure is only 12 PSI, I would guess that there may be a suction side restriction of some sort or even something in the impeller. Given it is a new pool, it would seem unlikely though. Based upon your setup, I would have expected the filter pressure to be at least 26 PSI.
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

  10. Back To Top    #10

    Re: weak jets! what do i do?

    Also, I just read the Raypak heater manual and it mentions that there is an internal automatic bypass that is good up to 125 gpm. And since my filter pressure is lower than you expect I would not expect the heater to be an issue, because restriction through the heater would raise the filter pressure if I am thinking correctly. Tonight, I am going to lower the spa level a few inches and then raise it back to see how much flow I'm actually getting. I will also verify the filter pressue when in spa mode. I know for certain that in pool filter mode the presure is 16 psi. If my memory serves me correctly, it drops when I put it in the spa mode.
    15,000 gallon gunite pool, grey plaster with 8' raised spa
    Jandy PlusHP Pump 2 HP Dual Speed
    Sta-Rite 450 Sq. ft. Cartridge Filter
    Cleva-Chlor RP40HD
    Raypak 400k btu heater
    Jandy Aqualink RS-8 One Touch
    Savi Melody 12v LED lights

  11. Back To Top    #11

    Re: weak jets! what do i do?

    I was way off. The pressure in spa mode is 24 psi. And sure enough, flow rate was 3" per minute which comes out to 94 gpm. Does this mean I'm not getting enough air or that these jets suck? Anything else I should check? Does it matter that the end of the air line is wide open? I had someone put their hand half over it to add restriction and it didn't seem to help.
    15,000 gallon gunite pool, grey plaster with 8' raised spa
    Jandy PlusHP Pump 2 HP Dual Speed
    Sta-Rite 450 Sq. ft. Cartridge Filter
    Cleva-Chlor RP40HD
    Raypak 400k btu heater
    Jandy Aqualink RS-8 One Touch
    Savi Melody 12v LED lights

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    mas985's Avatar
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    Re: weak jets! what do i do?

    The pressure is more inline with what I would expect although a little bit on the low side. Still, you should be getting enough flow out of the heads. What exactly is the problem with the jets? Are they spinning, assuming they should? Do you see lots of air coming out too? Are they just not strong enough for your liking?

    First, double check the return lines and make sure the valves are getting set properly. If the pool and spa returns are both open, then the flow to the spa will be reduced and would also account for the lower pressure.

    Next, it would be worth a check to see if there are any blockages in the suction line. Sometimes plaster or debris can get into the suction lines during construction. Check the pump basket and impeller as well. Any blockage in the suction will reduce flow rates and lower pressure.

    One more thing to check is to remove the jet heads and then run the pump and see what the filter pressure is. This will allow me to determine what flow rates to expect.
    Mark
    Hydraulics 101; Pump Ed 101; Pump/Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, MaxFlo SP2303VSP, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

  13. Back To Top    #13

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    Re: weak jets! what do i do?

    While the heater is rated to 125 gpm, that is pushing it's internal by-pass and forcing the water velocity through the exchanger faster than you want, loosing heating efficiency, stressing the by-pass, and eroding the heat exchanger with rapid water movement. An external bypass can/will allow some water to skip past the heater all together. I typically open them with a pump that size about 1/2 way to bleed off about 20-30 GPM from going past the heater.

    The filter, being 2" is another potential restriction. Two inch pipe will only allow so much water to pass at a given feed pressure.

    Have you tried turning off a couple of unused jets to increase the available flow to the others? Most residential spas max out with 8 jets on a single pump and 2" restrictions and a 2 HP pump.

    Scott
    Owner of - PoolGuyNJ LLC
    Expert Pool and Spa Repairs, Renovations, and Augmentation. Helping people decide what is the right gear for meeting their needs. Expectations Set, Expectations Met, No Surprises.

  14. Back To Top    #14

    Re: weak jets! what do i do?

    I do see lots of air. Visually, they look fine. They do seem to spin with the exception of maybe one. They definately aren't strong to my liking. The valves are fully seated and there is no water flowing into the pool return lines. To check the suction lines, do you mean to pull the main drain covers off and look into the drain itself? I opened up the pump basket, it didn't look bad through the window but it was a little dirtier than I thought so cleaned it. I had one jet that refused to stay in so I wrapped some duct tape around it to make it a tighter fit into the wall fitting. That seems to be working. This pump has a defuser so I don't have visual access to the impeller without taking it apart. I'm hesitant to remove the jets for you because when I take them out, they dont like to stay in afterwards, hence the duct tape on the aforementioned jet. Kinda bad design if you ask me. However, like I said earlier, I did measure it filling at 94 gpm so I do believe I have the proper flow. With the above steps done, the pressure is now up to 26 psi. I also cut my air line at the spa just below the hartford loop moving. All of these seemed to make marginal improvment. It may just be the jets because even when I turn some of them down, the others dont seems to get any stronger. Does anyone know of any smaller orifice jets that will thread into the waterway venturi tee bodies? It's a 1" npt for the air, and the water is 2-1/2" pvc.
    15,000 gallon gunite pool, grey plaster with 8' raised spa
    Jandy PlusHP Pump 2 HP Dual Speed
    Sta-Rite 450 Sq. ft. Cartridge Filter
    Cleva-Chlor RP40HD
    Raypak 400k btu heater
    Jandy Aqualink RS-8 One Touch
    Savi Melody 12v LED lights

  15. Back To Top    #15

    Re: weak jets! what do i do?

    Scott, when I turn some of them down, the others dont seems to get any stronger. On the heater bypass, this isn't anything special is it? Just a normal Jandy valve, a couple tees, and some pvc right? I'd also like to add a filter and salt cell bypass with a JVA for just when the spa is on. Is this recommended?
    15,000 gallon gunite pool, grey plaster with 8' raised spa
    Jandy PlusHP Pump 2 HP Dual Speed
    Sta-Rite 450 Sq. ft. Cartridge Filter
    Cleva-Chlor RP40HD
    Raypak 400k btu heater
    Jandy Aqualink RS-8 One Touch
    Savi Melody 12v LED lights

  16. Back To Top    #16
    Guest

    Re: weak jets! what do i do?

    Hmmmm, seems to me I'm having a little deja vu See if any of this sounds familiar:


    "Okay, now on to that single pump for the pool and spa...... Here's what will happen: you will want to use the spa,and you may turn it on low speed to heat it up. It will heat up, but it will draw cold air through the air line and fight the heater. It will obviously be more apparent if you use the pump on high speed. Next, you are in the spa, and you start to get itchy from the jets, or you just want to enjoy the evening in quiet, but you can't turn the jets off and keep the spa heating and circulating! So, what is the solution? Keep the 2 speed pump (I know, I'm blowing your budget! You'll thank me for this one though, trust me!) and get another pump (1 1/2 HP for up to 8 jets) and use it just for the jets. That way you can circulate, heat and clean the water on low speed with the circ pump, and turn the jet pump on when you want the jets (and lower the water temp about 8 degrees!). In addition, with that waterfall pump you will be able to have that running all at the same time as the spa, in any configuration that you desire

    Keep all of your plumbing runs the same coming and going (why feed the pump with 3" line and then skinny it down to 2 1/2" going back? Slow moving water at volume cleans and circulates better). The length of your runs are not bad, but the cost to go to 2 1/2" pipe from 2" isn't that much, so I'd run it all in 2 1/2". It will just make for a much more efficient pool".

    Sometimes they listen, and some times they don't

  17. Back To Top    #17

    Re: weak jets! what do i do?

    Bruce, I appreciate all of your help, it has been very valuable throughout the build. But....it's not a heat issue, it actually heats very fast even with the cold air being introduced. And I don't think a 1 1/2 hp pump on its own would do any better than my 2 hp pump going through the filter, since the filter is enormous and really not a choking point. I think I simply chose weak jets as I have the proper flow.
    15,000 gallon gunite pool, grey plaster with 8' raised spa
    Jandy PlusHP Pump 2 HP Dual Speed
    Sta-Rite 450 Sq. ft. Cartridge Filter
    Cleva-Chlor RP40HD
    Raypak 400k btu heater
    Jandy Aqualink RS-8 One Touch
    Savi Melody 12v LED lights

  18. Back To Top    #18
    Guest

    Re: weak jets! what do i do?

    Quote Originally Posted by n8scstm
    Bruce, I appreciate all of your help, it has been very valuable throughout the build. But....it's not a heat issue, it actually heats very fast even with the cold air being introduced. And I don't think a 1 1/2 hp pump on its own would do any better than my 2 hp pump going through the filter, since the filter is enormous and really not a choking point. I think I simply chose weak jets as I have the proper flow.
    I am happy to have helped, I just have strong feelings about single pump pool/spa set-ups. A dedicated jet pump always works better than asking a single pump to do double duty. A pump that runs through a filter and heater will always have "issues" when asked to do the work of a jet pump that has no restrictions.

    You'll get it working fine, I'm sure. I just had to bust your chops a little bit It really does look great

  19. Back To Top    #19

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    Re: weak jets! what do i do?

    WRT to the heater bypass, Two Tees and a a 2 way valve. For the cells, most controllers turn the power down to 2% to prevent super chlorination. If your controller doesn't talk to the cell's controller, then a JVA activated in spa mode might be the way to go but I would keep some bleach handy as spas tend to make people perspire and that can build up. I don't think, give the filter's size, making a bypass there will of much help.

    Air coming out of the jets should be expected as the water flow will draw some from the air line via the venturi action. If the spa was sitting for a while, the air line may fill with water, If the spa doesn't draw air after it's been sitting for a while and suddenly does after a short period, this is what is happening. I assume there is a soft, spring loaded check valve below the blower so water can't come up the pipe and hit the blower's exhaust port.

    How many jets did you turn off and was there any pressure increase in the tank?

    It may just be these jets and your expectations that aren't in line. The jet strength won't be like those found in a portable hot tub.

    Scott
    Owner of - PoolGuyNJ LLC
    Expert Pool and Spa Repairs, Renovations, and Augmentation. Helping people decide what is the right gear for meeting their needs. Expectations Set, Expectations Met, No Surprises.

  20. Back To Top    #20

    Re: weak jets! what do i do?

    Got in it last night and it is much better. I'm not sure why. I don't think the 2 psi that I gained in the filter would make a huge difference. I'm guessing the biggest gain came from cutting into the air line near the spa rather than forcing it to suck air all the way from the pad. And since it's behind that back wall, just below the concrete, it's not noisy at all. Unfortunately, my controller doesn't talk to the salt cells so I wired the cells to the low speed of the pump so that it turns off when in spa mode. I'm not sure if I will have enough flow for that to work properly and wont know for a few more weeks when I add the salt and give it a try.
    15,000 gallon gunite pool, grey plaster with 8' raised spa
    Jandy PlusHP Pump 2 HP Dual Speed
    Sta-Rite 450 Sq. ft. Cartridge Filter
    Cleva-Chlor RP40HD
    Raypak 400k btu heater
    Jandy Aqualink RS-8 One Touch
    Savi Melody 12v LED lights

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