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Thread: Cleaning Chilled Water Coils - No water on roof,

  1. #1
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    Cleaning Chilled Water Coils - No water on roof,

    I am part of a team taking care of a building with 3/4 million sq/ft. We have multiple Huntair AHU's (26) both indoor and outdoor with Fanwall technology. The outdoor units are quite large 5000+ CFM. Each outdoor unit has at least 12 (24 x 24 x 2) pre-filters. A second set of the same number of pre-filters on the return side and the same number of primary Merv-14 filters. I included a picture of the system. Sorry for the large size, it is late and this is a new posting system for me and I don't have time to determine how to make it smaller. Prior to my arrival they received only minimal cleaning care. The cooling coils have never been cleaned with water because of significant access issues to a water bib.

    A few years ago, we experienced a major forest fire even in the area that filled the entire valley in which I live. We actually had to change filters as many as three times in a week on some of the AHU's

    Huntair suggests coil cleaning as a normal PM procedure, and I really want to clean these properly. I am unable to fully determine how clogged they might be. I do know that when I use an electric blower, I move a fair amount of dust out of the coils. I can say the coils are located in fairly atmospherically clean residential area, so I do not suspect grease or other sticky reside on the coils.

    A few main questions.

    In the big picture how, much does dust residue on cooling coils affect thermal transfer?

    I have a Supco ZPB140 Porta-A-Blaster coil cleaning machine. I have used this on one my our much smaller indoor units with reasonable sucess. Just quite slow. I probably used about 15 gallons water on that two-coil system. The outdoor units have a minimum of 9 banks cooling coils each.

    Here is the deal all water must be brough to the roof by hand in 5-gallon buckets walking as many as 200 feet plus. Or other by a different method, less walking but up a flight of stairs.

    An old thread dated 2008 mentioned some people have used 110 volt water pumps and long hoses. Might work, but even more water usage. And I not sure if that would be a demand pump.

    I could say more but I should stop before I get this post too long.

    Suggestions?

    Thanks
    Montana
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  2. #2
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    A building that large with large expensive equipment like that and no one can figure out how to get a hose bib piped to the roof for you????

    I call that ridiculous. Talk to whoever is in charge at that place and explain to them why they need to have a proper hose bin I stalled for you.

    Sent from my SM-G965W using Tapatalk

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  4. #3
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    Quote Originally Posted by BALloyd View Post
    A building that large with large expensive equipment like that and no one can figure out how to get a hose bib piped to the roof for you????

    I call that ridiculous. Talk to whoever is in charge at that place and explain to them why they need to have a proper hose bin I stalled for you.

    Sent from my SM-G965W using Tapatalk
    A BIG AZZZZZZZZZZZZZZZZ X2.

    Washing those units should be done EVERY YEAR. There should be several hose bibs up on the roof along w/ HUNDREDS of feet of garden hose. OP you will be using HUNDRES & HUNDREDS of gallons of water not a measly 15 gallons,lol.

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  6. #4
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    As others have said, it would be worth it to tap into the domestic water in the building then locate a place to make a roof penetration.
    If you can't fix it with JB Weld, Duct Tape, and Ty Wire it has to be replaced.
    No good deed goes unpunished.
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  7. #5
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    A temporary fix would be to rent a water wagon
    Officially, Down for the count

    YOU HAVE TO GET OFF YOUR ASS TO GET ON YOUR FEET

    I know enough to know, I don't know enough
    Why is it that those who complain the most contribute the least?
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  8. #6
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    I have on a 5 story building put the city water connection free flowing into a 5 gallon bucket because the volume and pressure is just not good enough to clean a 3" thick condenser coil. Then I use an irrigation style pump from Lowes to suck out of the bucket and into my much shorter hose to the unit. With this setup I get good consistent pressure at the nozzle. Yes it does waste water overflowing the 5 gallon bucket but I don't pay for the water bill.

    I have to agree with others though. At that large of a facility why isn't there a connection on the roof?

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  10. #7
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    Quote Originally Posted by Troubleshooting View Post
    I have on a 5 story building put the city water connection free flowing into a 5 gallon bucket because the volume and pressure is just not good enough to clean a 3" thick condenser coil. Then I use an irrigation style pump from Lowes to suck out of the bucket and into my much shorter hose to the unit. With this setup I get good consistent pressure at the nozzle. Yes it does waste water overflowing the 5 gallon bucket but I don't pay for the water bill.

    I have to agree with others though. At that large of a facility why isn't there a connection on the roof?
    This would work perfect in your situation.
    https://www.supco.com/web/supco_live...ts/ZPB140.html
    Officially, Down for the count

    YOU HAVE TO GET OFF YOUR ASS TO GET ON YOUR FEET

    I know enough to know, I don't know enough
    Why is it that those who complain the most contribute the least?
    MONEY CAN'T BUY HAPPINESS. POVERTY CAN'T BUY ANYTHING

  11. #8
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    Thread Starter
    The Supco system is exactly what I have. My primary issue is determining just to what extent it can clean the coils. That is to say, will there be enough water flow to get the task done.

    Optimum answer would be the irrigation pump you use. Is it a diaphragm or a centrifugal pump? Is it necessary that the nozzle be open at all times? Will it work with a standard garden spray shutoff nozzle? Would prime loss or cavitation be an issue?

    If this works, the trick would be to find a right sized pump that can clean the coils without using an excessive GPM. I would be supplying the water via a tank 32 gallon that would be filled with water in 5-gallon buckets carried to the site.

    As for why no water, budget cuts. My understanding was that building was getting expensive and the project manager thought that little detail as not priority.

  12. #9
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    Doesn't sound like my setup would work for you then. The centrifugal pump I use is a utilitech 0434281 and it looks like it's been replace with a model 148008. Uses about 4 gpm and about 60psi. You can shut the hose off with the pump still running and it's fine. It has 1" female connections on it which can be converted to hose connections (I just use boiler drains) and then it's standard garden hose in and out. On the inlet you can use a short washing machine hose. If you want this to work you have to get a flow of water to the roof through a separate hose. Is there really no hose connection anywhere on sight. A mop sink inside or a faucet outside? The hose to fill the tank can be long as you don't need pressure on the end. Even if the long hose can't give you 4gpm it's still way faster than buckets. Hope this helps

  13. #10
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    If there too cheap to find a way to supply water, make it worth your while.

    Safety 1st

    Take your time

    Take plenty of breaks!

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