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Looking for a Slime Killer

urinal hokey pucks however Brad made me do it *~/:)

My buddy Fred wants to make a cookie cutter type deal so he can chomp down on one with the cookie cutter and make them look like someone took a bite out of one and threw it in the urinal... :)


  • Constantin
    Constantin Member Posts: 3,782
    It's Saturday night and I feel alright...

    ... OK, maybe not. I just found the basement storeroom full of condensate thanks to a condensate drain that was full of slime and a condensate pan without a float switch. A full (!!!) wet vac later, the secondary drain pan was empty and the floor just damp.

    Blowing out the P-trap in the drain using a puff of air worked. I followed that with Clorox. However, I fear it's just a question of time before it happens again. Besides asking my AC installer to put in two float switches in series (to prevent the AC from running if the secondary drain pan OR the condensate pan in the AC are full), what can I do to prevent the brown slime from blocking my drain again?

    I have heard of bare copper wire and clorox-like tablets being used for this application. Whatever the best solution is, it has to be compatible with the little condensate pump that lifts the condensate to the drain. Your thoughts are appreciated!
  • Empire_2
    Empire_2 Member Posts: 2,343

    I have tried this due to the same problem. It has occurred every year till, (get ready for this) I added a salt tablet to the farthest point from the drain. This has to be a hard tablet even if it's off a horse lick(like a chip off the block) no pun intended. It's cheap and since I haven't been called back in 2 years now for that problem, I would say it works. Bacteria and fungi cannot grow in the presence of salt. I'm not sure why.....I have tried other condensate tabs, but they dissolve too quickly. On this job I needed a longer term solution and so far so good.

    Mike T.
  • don_182
    don_182 Member Posts: 69
    Why not

    start with something to prevent growth of fungi and bacterial organisms to began with.

    Like a good filtration system.For the record I never had a drain problem what so ever on a system that had a good filtration system on it.

    Also I would properly stay away from the clorox as well, the
    only thing that will do is cause formicary corrosion.

    It appears to me you have not been on top of your filters and if you have then its properly a poor filtration system from the get go.

    Hope this helps.
  • Techman
    Techman Member Posts: 2,144

    Hi Constantin! I have NEVER had ANY kind of drain related problem's with ANY of my "prevenative maintenance"customer's.By washing out the evap coil ,drain pan ,drain line, and condensate pump once a year,my condensate problems get flushed down the drain.! Enjoy!
  • Eugene Silberstein
    Eugene Silberstein Member Posts: 1,380
    Absolutely Don

    This in one thing that I have stressed to customers who have had the same (relatively) problem.

    If you keep the nasties out of the drain pan and condensate line in the first place, the severity of the problem with the slime will be greatly reduced.

    To keep the slime out of my house, on the other hand, I have a high fence.
  • Constantin
    Constantin Member Posts: 3,782
    Thanks for the reply!

    That's an interesting possibility. I thought an Aprilaire 5000 was a pretty good filtration unit and we changed the filter this year, as per mfgr specs. Luckily, I have a few more on hand, so I'll go change it again.

    When I looked at the coil in the air handler, it was pristine on both sides... no dust, no dirt, no pet hair, just clean wavy aluminum fins. Now that I have sealed up the air handler better (in my previous quest to quiet the organ-pipe sounds the duct system was making), there is no chance for room air to leak into the distribution system and bypass the filter anymore.

    Presently, I think it has more to do with a drain pan that does not drain 100% all the time and hence has a small layer of water to promote growth in but I'll change the filter and report back. Some brown nastiness can still be seen in the P-trap as I peer down into it, so despite pouring clorox into the drain trap and flushing it a few times, I fear that the foundation for future growth remains in place...

    I have also heard of folk using larger drain lines than the 1" or 3/4" stuff the OEM sends to good effect. Your thoughts?
  • rucomfy
    rucomfy Member Posts: 43
    Proative suggestionj

    If you are referring to evaporator coil drains, there are pads that are available that lay in the drain pan. Calgon makes them and are available here (NJ) locally at various PiercePhelps or United Ref. I usually place them as far possible away from the drain outlet. You might also want to try a product like Bio-Fresh applied to the coil itself to disinfect the coil. I used it with success numerous times, not sure if it will accelerate formicary corrision. Will need to check with mfg. or oem.
  • Techman
    Techman Member Posts: 2,144

    Can you use the "UV" type of air purification system? That crazy light kills !Enjoy! Hay,rucomfy! What kind of corrision? thanks!
  • Empire_2
    Empire_2 Member Posts: 2,343

    can you please stop saying ENJOY? ;-) What am I supposed to enjoy?.;-)

    Mike T. Just kidding..........
  • Weezbo
    Weezbo Member Posts: 6,232
    for some reason...

    i kind of like the reply Eugene:)

    it has a certain perfect balance

    it may only seem like this Just happened Constantin buh i have to think it is slowly building over time....might go for slightly more periodic maint cleaning...

  • Christian Egli_2
    Christian Egli_2 Member Posts: 812
    Shitake mushrooms? Mmmmm

    This is more of a follow up question.

    Leave non city sanitized water in an open container for some time and stuff happens. The usual is the formation of a slippery goo on the walls of the container. It's intriguing.

    I have an outdoor tank that fills with rain water for the flowers. This tank is made of fiberglass and resin and its walls don't build up a coat of goo. That's good enough for me.

    Now, playing in this tank like the small kids we all are, if I put all my toys in it, I notice something interesting. Metal items don't grow slime on them. Plastics do, but not all the same way.

    Nor polyethylene (PE, PEX, HDPE, LDPE) nor polypropylene (PP, the stuff of sink traps) do build any really noticeable slime coat. Acrylic and ABS seem more prone to the build up. On the other hand, PVC provides the big time effect, soft PVC garden hoses build a nasty slime very quickly and very soft vinyl coatings (some grips on hand tools and tubing) immediately get slimy.

    What's up with that? Has anyone noticed the same?

    Is slime more of a characteristic of the substrate than of something in the air or in the water? Surely Constantin's plastic pan is made of PVC, would it be better to have a metal one?

    Or am I enjoying too much fun playing with water? :)
  • Techman
    Techman Member Posts: 2,144
    Mike T

    Lucky You!!!You asked!Life ,Family,Friends-Then there is "work" "a profession" "a job""the ole'saltmine",then there are those of us who "enjoy"what we do for the 8-14 hrs a day and "enjoy"being a wallie.And "ENJOY"fixing the harder problems. So, to you Mike T.,,,,,Enjoy!
  • Empire_2
    Empire_2 Member Posts: 2,343
    :-) :-)

  • Constantin
    Constantin Member Posts: 3,782
    Interesting point...

    ... I haven't had a PM done her yet, as this is the first year that we have a AC system in the house. It has been running for about 2 months now.

    On the other hand, the air handlers, etc. were installed over a year ago, so any slime that likes to live in filled P-traps presumably had a long time to gestate. I will buy Calgon drain pan killer at the local supply house to kill the P-trap denizens.

    As for the Aprilaire filter I pulled out today, it was quite clean. Some construction dust was caught in it (wood shavings, wood dust) and very minute amounts of regular dust, but no hair.
  • Constantin
    Constantin Member Posts: 3,782
    Some thoughts...

    Well, you're absolutely right, there is a reason we never see anything growing on some metals like copper. A copper drain pan would be very unlikely to build up slime because the slow leaching of the copper is sure to kill most bugs.

    Copper bottoms have been used for over three hundred years as a means of keeping slime, barnacles, and other stuff off boats. I could try coating the inside of the p-trap/coil pan with an ablative copper paint like Petit-50... :-P
  • Techman
    Techman Member Posts: 2,144

    How soon does the slime grow back after a washing out of the drain parts?Yeast and airated spores cause slime to grow in AC 's and Ice Machihes, like from the empty beer bottle storage room of bars/restaurants.Enjoy!
  • Constantin
    Constantin Member Posts: 3,782
    I don't know yet...

    ... as I've pointed out above, the system has only been running this year (though the air handlers were installed in late 2004), so I cannot yet gauge how quickly the slime grows.

    What I do know though is that there aren't any beer bottles anywhere near that air handler, unless the installers left even more souvenirs beside the candy-wrappers, empty soda cups, etc.

    What bugged me about the install though is the lack of a float switch in either pan. That Air Handler should have been "off", not flooding the basement.

  • Tom_80
    Tom_80 Member Posts: 22
    Condensate gook

    Make sure the drain pan is not back pitched away from the drain opening even slightly. This can cause a small amount of standing water to remain when the compressor cycles off. Check air handler for level and the pan. There is usually enough play to shim air handler or pan to insure pitch to drain. A small amount of standing water will cause problems over time.
  • Brad White_9
    Brad White_9 Member Posts: 2,440
    Got Slime?

    Perhaps skewed off topic but if the condensate overflows and you are worried about pumping it away, you might consider a Water-Bug or other water switch to shut off the AC process when it sees Dihydrogen Monoxide...

    Copper oxide is indeed a good biocide, used for years with standing pan steam immersion humidifiers in hospitals, such were the days... makes good gutters too for that reason.

    If bleach does not kill it, it was not meant to die. But be wary of Ms. Vitola and her sensibilities should she be nearby. Sealed combustion is a good thing but cannot be too careful especially if they share a drain.

    Something about urinal style hockey pucks that makes me want to...

    gotta go!

  • Constantin
    Constantin Member Posts: 3,782
    Oh, the switches are coming...

    ... two of them, in series. One for the drain pan in the air handler, the second for the overflow pan. If either switch detects water, the system shuts down... the way it ought to be.

    I don't worry much about Ms. Vitola, she's in the next room over and when I am done with sealing the adjacent walls, she'll be quite segragated from the rest of the house. No sealed combustion for Ms. Vitola, BTW, Viessmann only offers it on the Vitoflame 300, which AFAIK, is not available on this side of the pond.

    The most aggressive cleaner I use around her is the one-two punch combination of the OEM cleaning brush and the vaccuum cleaner.
  • Constantin
    Constantin Member Posts: 3,782

    ... that might be a business opportunity... the "cookies" might be too brittle though for a blade to do the job consistently... I would cast about for friends with waterjet cutters at work, they're made for stuff like that.

    Or.. convince the OEM to cast them as hockey-pucks with teeth marks instead of as boring disks.
  • Constantin
    Constantin Member Posts: 3,782
    That is my thinking also...

    ... the small film of water that remains in our drain pan looks like an ideal bacterial breeding ground. I will have to investigate just how level our current setup is, something that is not aided by the fact that the wood blocks that the AC is standing on are saturated with water from the secondary drain pan at the moment.
  • Brad White_9
    Brad White_9 Member Posts: 2,440
    Now, Weezbo....

    THAT was funny! And Constantin has obviously seen past the humor towards making such a thing a reality!

    On the off topic: When standing in front of said appliance in a public facility, my inner child occassionally has me "tap" the porcelain with my knuckle several times to denote completion. My neighbors may look a tad bemused as I whistfully smile... What can I say?
  • Eugene Silberstein
    Eugene Silberstein Member Posts: 1,380
    Vacuum cleaner?

    That sucks!
  • Constantin
    Constantin Member Posts: 3,782
    Oh ...

    ... it's not so bad. I simply wait until the vac bag is almost full. They're the HEPA type and trap dust to 0.5 microns. These days there is so little to vacuum and it's small layer of brown soot that is a byproduct of air-rich combustion. I need to get a specialist in for oil-fired systems, then the Vitola will be even less "sooty"

    In the meantime, the lack of sulfur in the ultra low-sulfur B5 fuel I switched to makes the whole cleaning process much more pleasant than when I had to deal with black soot, sulfur, etc. with the regular #2 or Diesel.
  • Constantin
    Constantin Member Posts: 3,782
    Slime Update...

    ... today I tooled around the badlands of Charlestown and Somerville in search of evap coil cleaner and some handy-dandy coil case biocide tablets. I eventually arrived at an outpost of United Refrigeration, which was kind enough to part with both wanted items for a nominal sum of money.

    I returned home to do battle with the basement evaporator. On closer inspection, I found the source of the brown slime, in the form of very fine wood dust. I presume it got sucked into the evap cabinet "downstream" from the Aprilaire 5000 cleaner, as the 30" x1/4" gap between the air handler and the ductwork had been open for a long time (before I closed it with pookie).

    Wielding the can of green coil cleaner, I sprayed all HX surfaces I could reach. Then, I started pouring water into the coil from above using a paper cup, to flush it. Areas resistant to cleaning were zapped over and over with green death until the brown stuff started to flow.

    The slime continued to emerge from the coil for over an hour as I poured and poured. Once the water entering the drain pan became clear, I started to gain hope that I was starting to get the upper hand. At present, very little muck flows anymore, and I hope that the biocide tablets I used in addition to the coil cleaner will kill whatever remains.

    In short, the dirty coil camp was right, the coil WAS dirty. It didn't look that way, it hadn't been used, it had a great filter in front of it, but the effluent coming out of the coil taught me otherwise.

    Moral of the story: During construction, protect those air handlers with filters, upstream and downstream... you never know what direction the dust may be coming from. Our installer thought the Aprilaire 5000 would be sufficient, evidently it was not. Presumably, air tight duct work would have helped also.
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