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  1. #1

    Pneumatics Air Dryer Failure - Water at devices - need advice

    Refrigerated air dryer allowed water to enter my system. Compressor in basement and devices on 3rd floor have water at supply inlets. disconnecting supplies and attempting to purge water and dry devices. Any advice? Am I wasting my time? This is a 3 story commercial building with 100% pneumatic controls.

  2. #2
    Join Date
    Aug 2009
    Location
    Prattville, Alabama
    Posts
    2,065
    You are doing what I would be doing. Hopefully if there is more that can be done, someone will tell us. There used to be small filter/dryers available to be installed in the supply line to individual devices. The clear plastic housing would let you see the white element inside, which would turn red when it was exposed to high humidity. Such as when moisture was in the system, but not yet at the device. Seems like this would be a good time to install some. At the easily accessible devices at least, so you can monitor them. And you probably have already thought about monitoring your compressor and air dryer more closely.

  3. #3
    Luckily, I am able to get dry air from a secondary compressor. The air dryer actually showed no signs of failure and I just cleaned the coils on it last week and didn't notice anything unusual. Yesterday when i looked at it closer and disassembled the filters they were all caked with oil/water mix. Closer scrutiny of the elements may have saved me, but the indicators were all in the green.

    Hopefully someone will chime in, there are a lot of devices that would need to be checked and dried. Not even sure if drying is an option. Seems like water and oil in the diaphragms and small orifices would be impossible to clean without rebuilding each device. Might be time to push for DDC. Getting ready to hook the first T-Stat back up and see if it will work. Thanks for all of the help.

  4. #4
    Join Date
    Aug 2009
    Location
    Prattville, Alabama
    Posts
    2,065
    When I make my rounds in the equipment room, I like to feel the temp of the line leaving the dryer to check that it's operating. Our original dryers would normally have a cold line, but our new dryers actually have a warm line. I was concerned until I checked the manual - it's supposed to be warm. Also, our new ones don't have a condenser fan, and the condenser wraps around the unit and looks more like a cage than a condenser. I feel it to see that it's warm, too. Good luck.

  5. #5
    So far blowing the TStats out with compressed aior from a can, disconnecting the supply and letting it blow free until it stops dripping, back flushing the device line off the TStat with canned air followed by a quick re-calibration appears to be working, for the stats at least. Have not looked at any volume reset controllers yet, hopefully i find them dry. Water definately knocked the stats out of calibration.

  6. #6
    Join Date
    Jul 2001
    Location
    Canada
    Posts
    1,813
    Check this out for cleaning the mains and devices.http://www.nucalgon.com/products/spe..._pneuflush.htm

    Have used it on oil / water problems and works great.

  7. #7
    Thanks for the link. Hopefully I won't have to go that far with it. Still too early to tell the extent of the damage done. I pulled a supply off of a reset controller on a parallell box yesterday and it had water in it. Not a good situation right now. Just going to continue purging everything, drying, re-checking, re-drying, re-calibrating and tuning. I should be busy for a while as I'm the only one on staff that works with the controls.

  8. #8
    Join Date
    Jul 2001
    Location
    Canada
    Posts
    1,813
    Also hopefully you are aware of the AFTER EFFECTS when the water / moisture dries up and leaves the mineral deposits behind. This plays haovic on the internal parts of the thermostats , reciever controllers and sensors.

    Had jobs where it blocked the bleed ports / nozzles also can affect the diaphraghms in valve and damper actuators if oil mixed in with the water.

  9. #9
    Join Date
    Jul 2008
    Location
    Seattle, WA
    Posts
    49
    I'll second "Control Man" you're going to be changing out a lot of equipment in the next year... I've had a similar issue in a hospital a few years back. I got 95%~ of it back up within a couple days but after that I spent a significant amount of time replacing stats and reset controls, etc that ended up failing. Good luck! Looks like you'll have plenty of work for a while.

  10. #10
    Agreed, things are gonna fail and have to be replaced. Just trying to regain control of the comfort level first. So far, everything I dried yesterday has water back to it again today, so rinse and repeat. Luckily, there seems to be isolated areas that didn't get water (3 stats I checked on 2nd floor were dry).

    Thanks for everyones input, it's a PITA but has to be done. Wish I had someone on staff that knows pneumatics or was passionate enough to learn it. I'm the Facilities Manager and doing the HVAC work at the same time. It stinks in a way, but I also love to turn wrenches, so I should consider myself lucky. Paperwork falls behind though....

  11. #11
    Join Date
    Jul 2001
    Location
    Canada
    Posts
    1,813
    Where abouts are you located ? Are you into heating MODE yet

    What your doing is like trying to bail out the TITANIC with a dixie cup with the rinse and repeat method.

    1) Need to pull off as many stats as possible and let the main lines BLEED off , start as close to the compressor if possible and see how much you get.

    2) Same with the main lines going into the control cabinets.

  12. #12
    The Stats are JCI 4000 series. Would removing the test port from each be an acceptable way to bleed vs. pulling them off every time?

    I have to be careful as to what I bleed and when, the chilled water and hot water in the building is not confined to occupant comfort and can't be down for an extended period. All valves are pneumatic. Same with cooling towers and hot water reset and bypass valves.

    We are in heating mode. The system is a combination of VAV, Parallel boxes w/hot water coils, FCU's, etc. VAV's are hot water re-heat.

    I will open as many "non-critical" lines and bleed as I can. The critical lines I'll have to deal with one at a time in a controlled manner. The TStats I'm rinsing and repeating are in the office area of the building and is about 15 or so...

    Thanks again for the advice.

  13. #13
    Join Date
    Jul 2001
    Location
    Canada
    Posts
    1,813
    Pulling the air lines off the stat keeps the moisture from going through the INARDS of the tsat ( where you do not want moisture ) major bleed off of the airlines would have to be after hours.

    Just finished a 2 story medical building last week with same problems , custodian was looking after things since they cancelled service contract on the pneumatics 3 years ago.

    1 Doctor complained of water leak ( water running down the wall at thermostat ) and thats what alerted them to a Um SLIGHT problem. In this case the air drier was on BYPASS and auto drain on air tank was turned off for quite awhile.

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