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  1. #1

    Cooling tower questions ?

    I am new to the world of cooling towers. I work in maintenance at a 150 bed Assisted Living/Skilled Nursing facility. We currently utilize a hydronic heat pump system for the 150 individual apartments. Each separate living unit has one 10,000
    BTU heat pump for one bedroom units or two 7,500 BTU heat pump for two bedroom units.

    My Question concerns water treatment for our closed loop system. We have a chemical treatment pot where our chemical
    salesman adds chemicals. (The salesman reputation is questionable) So is it standard procedure to add chemicals & then
    circulate the chemicals for 20 minutes in the closed loop system ? After 20 minutes the chemical pot is isolated until next
    months treatment.
    Or would it be more beneficial to continuously circulate water through the treatment pot ?

    Thank You for your input. John

  2. #2
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    You dont need chemicals in a closed loop system unless the water is pretty bad, now in the open side (tower) there is a need for biocides to kill the living stuff and phosphates to keep the solids suspended.
    Once the chemicals are fed into the tower water there is no need to circulate the water through the treatment pot.

  3. #3
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    Quote Originally Posted by valdelocc View Post
    You dont need chemicals in a closed loop system unless the water is pretty bad, now in the open side (tower) there is a need for biocides to kill the living stuff and phosphates to keep the solids suspended.
    I disagree that closed loop systems don't need chemical treatment. Once treated the loop needs to be tested periodically to make sure the concentrations are correct. If the concentrations drop dramatically it could point to a leak in the system. I agree that the open side of a cooling tower needs more vigilant care.

  4. #4
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    Quote Originally Posted by KnewYork View Post
    I disagree that closed loop systems don't need chemical treatment. Once treated the loop needs to be tested periodically to make sure the concentrations are correct. If the concentrations drop dramatically it could point to a leak in the system. I agree that the open side of a cooling tower needs more vigilant care.

    Agreed. We have a site that we have checked once a year. The loop has a percentage of glycol mixed in with the water. to add chemical every month I don't think is needed unless there is a leak as Knew York has stated. If there is a leak, need to find and repair.
    no signature blast'em man blast'em
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  5. #5
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    Quote Originally Posted by John120/240 View Post
    I am new to the world of cooling towers. I work in maintenance at a 150 bed Assisted Living/Skilled Nursing facility. We currently utilize a hydronic heat pump system for the 150 individual apartments. Each separate living unit has one 10,000
    BTU heat pump for one bedroom units or two 7,500 BTU heat pump for two bedroom units.
    Nice attention to detail, but.... We would have to assume some stuff and want more information.

    Do you have a cooling tower with a remote heat exchanger or a fluid cooler?, the reason I ask is why would they just stop by and add chemicals all willy nilly? If you have a remote heat exchanger you could have a bad plate or two and your chemicals could be leaking out into the tower, could still happen with a fluid cooler, but much less likely.

    Also agree with the above mentioning the open side of the system, the open loop is just as, if not more important than the closed side.

    Quote Originally Posted by John120/240 View Post
    My Question concerns water treatment for our closed loop system. We have a chemical treatment pot where our chemical
    salesman adds chemicals. (The salesman reputation is questionable) So is it standard procedure to add chemicals & then
    circulate the chemicals for 20 minutes in the closed loop system ?
    He should be using a test kit to verify and document the loop chemical amounts. We typically use a sodium nitrite kit and maintain a level of sodium nitrite of between 500 and 800 PPM for a closed condenser loop.

    Just adding chemicals every month without this information would be grounds for kicking the dude to the curb...

    Does the system leak? where are the chemicals going? do you have a bacteria eating up the chemicals? what is he using to treat the system? Do you have a water meter on the make up?

    These are all very important questions that pertain to proper system treatment.

    Quote Originally Posted by John120/240 View Post
    After 20 minutes the chemical pot is isolated until next
    months treatment.
    This is pretty typical, the pot could be left in the loop all the time, but not really necessary and can eliminate a lot of accidental water leaks, we normally isolate ours as well, personal preference really.

    Quote Originally Posted by John120/240 View Post
    Or would it be more beneficial to continuously circulate water through the treatment pot ?
    The pots are just a "fat spot in the pipe" so to speak, there is no hocus pocus in them, once the chemicals are in the loop, it has done it's job.

    Quote Originally Posted by John120/240 View Post
    Thank You for your input. John
    No problemo...
    If a day goes by and you have learned nothing, I hope you got a lot of sleep.

  6. #6
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    you do need water treatment both closed and open loops spent time rebuilding and maint. in phx az .now years ago we used nitrite but found out that it could form bacteria so we switched to mulibdate. this was for closed loop systems' open loops are treated differant .sudjest you consult a few water treatment co . we circulted the potfeeder for corosion resons .wighert pot feeders have a o ring that sometimes leak .be carefull .

  7. #7
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    I agree that you do need to treat both closed and open loops. also, it is my understanding that if you have a concentration of 30%+ glycol you do not have to add chemicals to kill bacteria.

  8. #8
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    Quote Originally Posted by demidos89 View Post
    I agree that you do need to treat both closed and open loops. also, it is my understanding that if you have a concentration of 30%+ glycol you do not have to add chemicals to kill bacteria.
    Does the glycol have a inhibitor in it. If not u need to add inhibitor glycol can become corrosive in a system.

  9. #9
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    Quote Originally Posted by GT Jets View Post
    Nice attention to detail, but.... We would have to assume some stuff and want more information.

    Do you have a cooling tower with a remote heat exchanger or a fluid cooler?, the reason I ask is why would they just stop by and add chemicals all willy nilly? If you have a remote heat exchanger you could have a bad plate or two and your chemicals could be leaking out into the tower, could still happen with a fluid cooler, but much less likely.

    Also agree with the above mentioning the open side of the system, the open loop is just as, if not more important than the closed side.



    He should be using a test kit to verify and document the loop chemical amounts. We typically use a sodium nitrite kit and maintain a level of sodium nitrite of between 500 and 800 PPM for a closed condenser loop.

    Just adding chemicals every month without this information would be grounds for kicking the dude to the curb...

    Does the system leak? where are the chemicals going? do you have a bacteria eating up the chemicals? what is he using to treat the system? Do you have a water meter on the make up?

    These are all very important questions that pertain to proper system treatment.



    This is pretty typical, the pot could be left in the loop all the time, but not really necessary and can eliminate a lot of accidental water leaks, we normally isolate ours as well, personal preference really.



    The pots are just a "fat spot in the pipe" so to speak, there is no hocus pocus in them, once the chemicals are in the loop, it has done it's job.



    No problemo...


    perfect advice, closed loops don't need much attention, but if you don't test it and check it, and keep an eye on your makeup water. The problems you can create could be major problems..the one other thing i would check is, is the loop piping all the same type of material...If you have copper, iron mix you need to know this and so does your chem company.

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