Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 9 of 9

Thread: ORP Probe Failing; Current in the Water; Bonding Issue?

  1. Back To Top    #1

    In the Industry

    Join Date
    Aug 2015
    Location
    Norfolk, VA
    Posts
    9

    ORP Probe Failing; Current in the Water; Bonding Issue?

    Commercial Pool Keeps blowing ORP Probes!

    Suspect: Current in the water

    History: Commercial pool in Norfolk, VA. Apartment Complex, built 11/20014, Concrete. Pool on second floor equipment on first floor. Equipped with HCC200 system, (2) Aquarite salt generators w/ T-15 cells, Triton II Commercial Sand Filter, Whisperflo Pump, (1) Universal Color Logic (White), 17,500 Gallons, (3) Deck jets, (6) hand rails (S/S)
    Management has never been able to maintain proper chlorine level w/ automation ORP levels vary hour to hour, day to day.
    The pool has first been replaced with new probes, they read in the 350 mV range with 3.5 ppm Cl with DPD test
    Replaced the HCC2000 system still has the same problem
    Replaced probes again, same problem
    Hayward has authorized and provided these products
    I have been disconnected from this issue until today, and installed a CAT4000 to replace system
    Same problem low ORP and good Cl levels, but system locks out and stops producing chlorine
    Removed ORP probe and installed new probe but instead of installing in sample well, placed in bucket of pool water.
    Removed from the circulation system, probe is reading more accurate mV at 600
    pH probe is accurate both in bucket test and in sample well

    Hypothesis: This is not developed by myself, but by speaking with Pat with CAT controllers who is the developer of the system. The only possible issue is there is an electrical current in the circulation system that is damaging the probes. The problem is almost instantaneous and the ORP probe is destroyed

    What I am asking: I need an electrician that understands the equipotential bonding grid and can explain why and how to find the break in ground with the best resolve to the problem. I have considered running a bonding wire #8 from the panel ground to the pool equipment in the equipment room but dont want to keep damaging ORP Probes, they are not cheap. There is nothing within 5' or 10' of pool that could contribute to this problem I am at a loss.

    Very open to ideas and thoughts. I need to readdress issue by 8/17/15. Thanks in Advance
    Service Manager for Gracia & Vigil. Specialize in concrete pools, commercial and residential, but if the pool is in the ground I can fix it!

  2. Back To Top    #2

    Join Date
    Mar 2007
    Location
    San Rafael, CA USA
    Posts
    12,082

    Re: ORP Probe Failing; Current in the Water; Bonding Issue?

    See ORP Control. The problem is related to your use of saltwater chlorine generators. What is the location of your ORP system? If your generator, which outputs hydrogen gas bubbles, goes out a return too close to a skimmer or gutter returning water back to your equipment pad where your ORP is located, then you may be getting hydrogen gas bubbles that will mess up your ORP readings.

    Why don't you try your ORP system with the SWG turned off for an extended period of time. Say you only run it during the day -- then try the ORP system in the morning where the pump is running but you have the SWG system turned off. Does it work? If so then it is related to the SWG system. Could be the hydrogen gas bubbles if the ORP system doesn't fail the instant that the SWG is turned on.

    You say that this may be an electrical bonding problem and that the ORP is destroyed, but are you sure about that? With the ORP system measuring low in the pool, take it out and measure a bucket of chlorinated water with reasonably high FC level, say 5 or 10 ppm with no CYA. What happens then? If it measures OK, then the ORP is not actually destroyed, but rather temporarily disabled.

    By the way, this is one of several reasons why we do not recommend ORP controllers, at least not for residential pools. For commercial/public pools they are OK using a setpoint, but ultimately relying on the separately measured FC and CYA levels. Then again, it seems like there's an issue with SWG systems and ORP controllers that needs to be figured out.
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

  3. Back To Top    #3

    In the Industry
    lembi's Avatar
    Join Date
    Jul 2015
    Location
    Augsburg, Germany
    Posts
    9

    Re: ORP Probe Failing; Current in the Water; Bonding Issue?

    I agree with chem geek that this is not a problem with the probe, and i also think that it's not a problem with the electrical bonding or an external current in the water. The measurement amplifiers are galvanically isolated, so that a current in the water shouldn't have any effect on the probe and the reading.
    You can check the probe - like chem geek said - with a bucket of fresh water and a FC level of 3..5 ppm (no CYA). This should result in an ORP Level above 800mV.

    It's more a problem with the water itself or better with the SWG, generating something else than chlorine only. We are discovering same problems in several pools (not in all). And in no case the probe or the system itself is the reason for the low ORP reading.

    Maybe you can switch off the SWG for several days and try dosing CH or liquid chlorine for this time. I think that this will result in normal ORP readings -> so it should be the running SWG causing the problems (but not due to the fact that it is bringing a voltage into the water).



    Independently of that... it can be also just a problem with a too low production rate and a too high bather load (even if you reach "normal" FC Levels). We have here, for example, no problems with pools using an "oversized" SWG, where the runtime of the SWG is usually rather short (i.e. SWG for 30-40.000 gallon-pool used for a 6.500 gallon pool). But if you have a high CYA level the runtime will always be longer to raise ORP back to the desired level (I'm from Germany, we normally don't use any CYA here - No CYA results in a faster reaction of the ORP on chlorine dosing)

    Have you checked the salinity of the water? How long is the daily runtime of the SWG? 24/7 because of low ORP reading?

    >>Pool on second floor
    So it's indoor? Or is it outside on the roof?


    Alex
    26.600 gallon outdoor, in-ground, PP spillway pool. 2x 600mm Astral Cantabric sandfilters, 2x Speck Bettar 14, 45 square meter EDPM solar absorber, 440.000 BTU/hr oil heater

  4. Back To Top    #4

    In the Industry

    Join Date
    Aug 2015
    Location
    Norfolk, VA
    Posts
    9

    Re: ORP Probe Failing; Current in the Water; Bonding Issue?

    Pool is outdoor in a courtyard above the parking garage. Pool equipment in the parking garage. Apartments built up aboave and around the pool. Salinity is 3200, and the salt systems work just fine if I take the flow switches off the automation sytem. Automation locks out because ORP is too low. Our company has 35 years experience building pools and all modern pools are equipped with salt. Never had an issue like this.
    Service Manager for Gracia & Vigil. Specialize in concrete pools, commercial and residential, but if the pool is in the ground I can fix it!

  5. Back To Top    #5

    In the Industry

    Join Date
    Aug 2015
    Location
    Norfolk, VA
    Posts
    9

    Re: ORP Probe Failing; Current in the Water; Bonding Issue?

    Pool is only 17,500 Gallons with (2) T-15 Cells. The SWG's are not the problem because the problem starts before they are introduced to the system. Immediately after installing a brand new system or probes the ORP reads approx 320-350 (in the testing wells). I have put brand new PRO-25-Au probes into a cup of the same pool water and they read 625-635 mV. Will hold as long as I dont put them into the circulated water. Once they are introduced to circulated water they fail and never read right again.
    Service Manager for Gracia & Vigil. Specialize in concrete pools, commercial and residential, but if the pool is in the ground I can fix it!

  6. Back To Top    #6
    JoyfulNoise's Avatar
    Join Date
    May 2015
    Location
    Tucson, AZ
    Posts
    11,588

    Re: ORP Probe Failing; Current in the Water; Bonding Issue?

    Two questions -

    1. Possible chemical contaminant in the water? Have you and your company had control of the pool chemistry? Do your water test parameters all look normal?

    2. Can you hire an electrician that specializes in detecting stray voltages? You said the pool is built on top of a parking structure. Any apartment I ever lived in with a dedicated parking garage always had all of their electrical/mechanical rooms in the garage. I wonder if something in that garage is causing a problem.


    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

  7. Back To Top    #7
    Mod Squad Bama Rambler's Avatar
    Join Date
    Jun 2009
    Location
    SouthWest Alabama
    Posts
    22,345

    Re: ORP Probe Failing; Current in the Water; Bonding Issue?

    I'd like to know if the probes are actually damaged or if they're just reading wrong when in in the pool.

    If they are being damaged then I agree that you need someone well versed in stray voltages and also a full chem panel ran.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

  8. Back To Top    #8
    JoyfulNoise's Avatar
    Join Date
    May 2015
    Location
    Tucson, AZ
    Posts
    11,588

    Re: ORP Probe Failing; Current in the Water; Bonding Issue?

    Quote Originally Posted by Bama Rambler View Post
    I'd like to know if the probes are actually damaged or if they're just reading wrong when in in the pool.

    If they are being damaged then I agree that you need someone well versed in stray voltages and also a full chem panel ran.
    I think the OP answered that - if they go into the pool water they are irreversibly changed.

    Quote Originally Posted by VAPoolboy788 View Post
    Immediately after installing a brand new system or probes the ORP reads approx 320-350 (in the testing wells). I have put brand new PRO-25-Au probes into a cup of the same pool water and they read 625-635 mV. Will hold as long as I dont put them into the circulated water. Once they are introduced to circulated water they fail and never read right again.



    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

  9. Back To Top    #9

    In the Industry
    lembi's Avatar
    Join Date
    Jul 2015
    Location
    Augsburg, Germany
    Posts
    9

    Re: ORP Probe Failing; Current in the Water; Bonding Issue?

    So if you remove the probes from the testing wells an put them back into the bucket they still only read 325mV?
    Have you tried to clean them? ... Put them in a glass of water with at least 10% chlorine for about 30 minutes and then try to measure the bucket again.

    What kind of metal components are used in the pool and in the piping? ... Feeders, Adapters... anything made of brass (for example)? in lower quality then 316L stainless steel? Or different types of metals? Are these parts electrically connected to the ground?
    26.600 gallon outdoor, in-ground, PP spillway pool. 2x 600mm Astral Cantabric sandfilters, 2x Speck Bettar 14, 45 square meter EDPM solar absorber, 440.000 BTU/hr oil heater

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •