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Thread: low pressure with navigator cleaner

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    low pressure with navigator cleaner

    Hi - I switched from a barracuda to a navigator because I find the navigator better at picking up the eucalyptus leaves. I have seen better suction pressure when I backwash the pump and I have checked for the common problems with suction. I do have a rather old 1.5 HP pump.

    The question I had is that I have 3 valves on my outflow line and they are the for the skimmer, the cleaner and then for the other end of the pool that has a trap basket but the inlet and outlet are both under the water line (I assume that is for circulation).

    What I do to increase power to the navigator is close the valve to the line running to the other end and partially close the skimmer. If I fully close the skimmer the pump works harder and starts sucking in air.

    Do you think getting a 2.0 HP pump would fix the problem? I am not sure because if I cannot close the skimmer valve without it sucking in air, I am not sure if motte HP's will help. I am not also sure what causes the air to be sucked in other than the pump is working harder than the skimmer return can provide. My suction line is left wide open.

    Ideallly I would like to have a system where I do not need to partially or fully close all valves to operate the suction cleaner. When I have them all open the navigator barely moves but with the closed and partially closed positions on the other valves, I get slow movement. It does not climb walls or go as fast as it did on the pool I had prior to moving to this home. Any suggestions on improving performance for the navigator?

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    duraleigh's Avatar
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    Re: low pressure with navigator cleaner

    Is there any air in the pump basket when you are running the cleaner and all valve (those are suction valves) are open?
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    mas985's Avatar
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    Re: low pressure with navigator cleaner

    Quote Originally Posted by tomsop
    Ideallly I would like to have a system where I do not need to partially or fully close all valves to operate the suction cleaner.
    That is probably not possible. Water takes the path of least resistance and a cleaner is very restrictive so it will usually require valve adjustments when you have multiple suction paths. However, with actuators, you could automate the process.
    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: low pressure with navigator cleaner

    ok, so if I stick with the valve placement - do I go to 2HP ?

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    mas985's Avatar
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    Re: low pressure with navigator cleaner

    Why would you? You will still need to adjust the valves and a larger pump will just cost more to run.
    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: low pressure with navigator cleaner

    I am not getting enough suction to power the navigator so I assumed 2HP would do the trick. I cannot close the 2nd valve because if I close it fully the pump starts straining and air is introduced into the pump - it is like the pump cannot pull in enough water through the suction line only fast enough so I lose pressure in the pump and see air being introduced as well.

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    mas985's Avatar
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    Re: low pressure with navigator cleaner

    I run my suction cleaner on a 1/2 HP pump so the size of pump is not the problem.

    If you are seeing air in the pump basket, there is probably an air leak on the suction side of the pump. Most likely the pump lid gasket or the pump drain plugs. You can try pool lube on both and see if that helps. Also, make sure the cleaner hose is free of debris and there are no clogs.
    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: low pressure with navigator cleaner

    Maybe I was not clear, I only see air when I close the other two valves. To maximize suction I close the first valve and the skimmer valve I close half way. My navigator moves but based on the flow gauge it comes with to measure ideal suction I am not getting enough. So the next logical step is to try to close the skimmer valve and once I do that then the motor seems works harder and I start to see air at the top of the pump and the filter pressure gauge starts to go down. It is like as if the water being pulled just from the cleaner can't keep up with the demands of the pump intake. Then the air pocket gets so big the pump loses its prime and then builds up and repeats the cycle.

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    mas985's Avatar
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    Re: low pressure with navigator cleaner

    When you close those two valves, it increases the flow rate through the cleaner but it also reduces the pressure (increases the suction) in the pump basket which in turn can create air leaks. This is not uncommon to happen under high suction conditions. This is also why the filter pressure decreases. If you can fix the air leak, it might solve all your problems.

    Again, there are two things that could be causing this. First, you need to make sure the pump basket lid is sealed properly and has no cracks so try some pool lube (drain plugs too). And second, the cleaner hose may have a obstruction so make sure that is clear.
    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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