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Thread: New Pressure gauge, reading incorrectly??

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    Join Date
    May 2009
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    Azle, Texas
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    New Pressure gauge, reading incorrectly??

    We seem to never be able to keep a pressure gauge for very long, they seem to all sit at 0 and we get a new one and they work for awhile then go to 0.

    I went to the pool store today, got a replacement. On low my pressure reads 5, on high it reads 15. Should it read the same at both high and low speeds?

    I backwashed and the gauge is still sitting at 15. We have had the pool for 3 years now and this is how the gauges have always read. We backwash and the pressure never goes down.

    I turn the dial to backwash
    Once clean I let it continue for a few minutes
    Turn to rinse
    Leave it there for a few more minutes
    Return to Filter

    What is going on?

    We have a 2 speed sand filter.

    Thanks for your help!!!
    27 ft round AG, vinyl, 17,100 gallons, 2 HP pump, sand filter

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    Re: New Pressure gauge, reading incorrectly??

    I forgot one more questions. When my pump is on low, it is on LLLOOOOOWWWW. Is this normal? It has been like this since it was new.
    27 ft round AG, vinyl, 17,100 gallons, 2 HP pump, sand filter

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    launboy's Avatar
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    Re: New Pressure gauge, reading incorrectly??

    All sounds pretty normal to me. I only have a 1 HP pump, but probably a smaller filter to, and my gauge reads 13 without solar and 14-15 with it. By the time the gauge rises 1 psi, my flow will have diminished greatly. So I just backwash based on flow from the return.

    Oh yeah, the pressure gauges usually don't last very long(for most people) because of the quick changes in pressure when you turn the pump on, etc.

    Adam
    18' x 42" Intex Easyset Pool, with 16' x 52" deep end in the middle. Approx. 5500 Gal.
    Hayward Power-Flo LX 1 HP, 100# Jacuzzi Brand Sand Filter(Piped underground so it looks nice) 8)
    3 - 2' x 20' Solar Pool Heater Panels(roof mounted)
    Goin' on 9 summers...NOBODY thought it would last this long.
    Buried Portable Spa sharing pumps and water with pool (Almost complete project)

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    Re: New Pressure gauge, reading incorrectly??

    Should it read the same at both high and low speeds?
    No. Your readings are typical.

    1. You can purchase better guages for $20-25, I think. They may last longer.

    2. In your detailed backwash procedure, you do not mention turning off the pump before switching functions.....do you?

    3. Why do you backwash with no indication from the guage? (no pressure rise) Unless your guage goes 6-8 lbs above normal ("normal" seems like 15psi in your case) there should be no need to backwash.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: New Pressure gauge, reading incorrectly??

    2. In your detailed backwash procedure, you do not mention turning off the pump before switching functions.....do you?

    Yes I do, I forgot to mention that.

    3. Why do you backwash with no indication from the guage? (no pressure rise) Unless your guage goes 6-8 lbs above normal ("normal" seems like 15psi in your case) there should be no need to backwash.

    "The Pool Store" told us when we bought the pool that when the guage shows 15 you need to backwash..... Once we backwash the pressure will go down.

    Is it normal that my pump runs very slow (in my opinion) on low?

    I have been studying pool school alot. I think I have a small knowledge of my chemcials. Now I have got to read alot on pumping stations.

    Thanks for taking the time to post.
    27 ft round AG, vinyl, 17,100 gallons, 2 HP pump, sand filter

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    Re: New Pressure gauge, reading incorrectly??

    Is it normal that my pump runs very slow (in my opinion) on low?
    Yes. they run slowly enough that many folks have difficulty hearing them.
    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: New Pressure gauge, reading incorrectly??

    On low speed, the pressure should read about 1/4 of high speed +-. You are within the range of error so I would say it is working properly. Also, low speed is about 1/2 the flow rate of high speed so it may seem like it is very low beause both pressure and flow rate decreases substantially.

    As to why you gauges keep failing, when you remove the gauges, do you check the small hole at the end of the gauge to see if anything is getting stuck in the gauge? Gauges are plumbed before the water is filtered so they can get clogged at times. Other than that, I cannot think of anything else other than a harsh winter which might cause failures.
    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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