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Thread: Massive Humidity, where is it coming from

  1. #1
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    Massive Humidity, where is it coming from

    Hi everyone, I have a fire station with humidity right now at 77% which is low. In the summer it increases into the 90's. We have had HVAC guys out who are baffled. We replaced a v coil because they thought it wasn't draining and that did nothing to fix the issue. Now I'm hearing they think we should have fresh air from the outside which seems strange to me to take 95 degree air in the summer and cool it. Seems wildly inefficient. There are three HVAC units, two have been shut off because they thought we also had overcooling of the building. I don't know what equipment we have, I suppose I could take pictures if necessary but just thought someone could give me some things to look into or if someone is in the area of Northern Chicago Suburbs, they could look at it. Any help is appreciated.

  2. #2
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    Find a different contractor.

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    We've had 2 in communication with the manufacturer. No one can figure it out.

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    Do they wash the trucks inside the building?

    There may be a water source you haven't found. I have several times found that the cause of high humidity was roof leaks saturating the structure.

    What is the BTU capacity of the AC units?

    When the units are operating - how much condensate water do they each produce per hour? A measurement quoted in pints would be the handiest.

    PHM
    --------


    Quote Originally Posted by firehouse2701 View Post
    Hi everyone, I have a fire station with humidity right now at 77% which is low. In the summer it increases into the 90's. We have had HVAC guys out who are baffled. We replaced a v coil because they thought it wasn't draining and that did nothing to fix the issue. Now I'm hearing they think we should have fresh air from the outside which seems strange to me to take 95 degree air in the summer and cool it. Seems wildly inefficient. There are three HVAC units, two have been shut off because they thought we also had overcooling of the building. I don't know what equipment we have, I suppose I could take pictures if necessary but just thought someone could give me some things to look into or if someone is in the area of Northern Chicago Suburbs, they could look at it. Any help is appreciated.
    PHM
    --------
    The conventional view serves to protect us from the painful job of Thinking

  5. #5
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    Quote Originally Posted by Poodle Head Mikey View Post
    Do they wash the trucks inside the building?

    There may be a water source you haven't found. I have several times found that the cause of high humidity was roof leaks saturating the structure.

    What is the BTU capacity of the AC units?

    When the units are operating - how much condensate water do they each produce per hour? A measurement quoted in pints would be the handiest.

    PHM
    --------
    They rarely wash them in this station, usually outside. The building is pretty new, it opened in 2011. I'll have to drive out there and get the other info but they did just replace the A/C coil with no change.

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    With 3 Systems one should be running nonstop controlling humidity.

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    Measure the condensate output and post the results back here in pints per hour per ton. Or just post the model numbers of the units and how much water they put out in an hour. If they are not running - don't start measuring the condensate volume until 15-20 minutes after startup. And make sure they keep running the whole time you are collecting water.

    PHM
    -------


    Quote Originally Posted by firehouse2701 View Post
    They rarely wash them in this station, usually outside. The building is pretty new, it opened in 2011. I'll have to drive out there and get the other info but they did just replace the A/C coil with no change.
    PHM
    --------
    The conventional view serves to protect us from the painful job of Thinking

  8. #8
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    What exhaust fans are running in the building? Kitchen, equipment floor, hallways, bathroom’s?

  9. #9
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    What part of God's green earth are located in?

    What are your temperatures/%RH you want in the space. What is the temperature/%RH supplied to the space? This will tell us about what the a/c is doing. How many occupants in the space? Fresh air ventilation? Outdoor temperature, %RH, Dew point?
    Then we can comment.

    Regards Teddy Bear
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

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    Can you describe the building and the different areas and uses? Are all areas having the same humidity issue? Does the issue change with the weather?

    Chasing down high humidity issues can get quite involved. Looking at just the equipment is a sure way to make the solution take even longer, because in most instances the problem isn't with only the equipment. If large amounts of moisture are getting into the conditioned space in one form or another and the original equipment and controls weren't designed to handle it you'll have problems.

    You need to find someone that deals specifically with large commercial buildings and the HVAC components that are usually found in them.
    Use the biggest hammer you like, pounding a square peg into a round hole does not equal a proper fit.

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    Quote Originally Posted by pecmsg View Post
    What exhaust fans are running in the building? Kitchen, equipment floor, hallways, bathroom’s?
    None, kitchen duct may run for short period when they cook

  12. #12
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    Quote Originally Posted by firecontrol View Post
    Can you describe the building and the different areas and uses? Are all areas having the same humidity issue? Does the issue change with the weather?

    Chasing down high humidity issues can get quite involved. Looking at just the equipment is a sure way to make the solution take even longer, because in most instances the problem isn't with only the equipment. If large amounts of moisture are getting into the conditioned space in one form or another and the original equipment and controls weren't designed to handle it you'll have problems.

    You need to find someone that deals specifically with large commercial buildings and the HVAC components that are usually found in them.
    Large three bay apparatus bays for the vehicles sealed off from living area with bunk room, large kitchen/living room, locker room with two separate shower rooms, watch office, Lieutenant Office, a couple bathrooms. It is on Well and septic . It also has three units, one is not used at all and one was shut down by HVAC contractors saying we had too much cooling in the building. It also had an energy recovery system that has now been bypassed thinking that may have been the issue. We are in Northern Chicago Suburbs with 41%RH today and the building right now is 77% inside. In the summer it gets significantly worse.

  13. #13
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    The building was opened in 2012

  14. #14
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    I'll see if I can find pictures

  15. #15
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    Wont let me post photos

  16. #16
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    Here is an article with the building
    https://patch.com/illinois/grayslake...d-to-les-stang

    The one side picture shows the vents on the roof, that is where the HVAC system is. You can see the vent on the side where the energy recovery system took in outside air but again it has been bypassed at this point. The three vents near the edge of the roof right side are pretty much where the three HVAC units are.

  17. #17
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    Quote Originally Posted by firehouse2701 View Post
    Large three bay apparatus bays for the vehicles sealed off from living area with bunk room, large kitchen/living room, locker room with two separate shower rooms, watch office, Lieutenant Office, a couple bathrooms. It is on Well and septic . It also has three units, one is not used at all and one was shut down by HVAC contractors saying we had too much cooling in the building. It also had an energy recovery system that has now been bypassed thinking that may have been the issue. We are in Northern Chicago Suburbs with 41%RH today and the building right now is 77% inside. In the summer it gets significantly worse.
    A well setup a/c can remove 3 lbs. of moisture per hour per ton. The starting point is to adjust the air flow through the a/c coil to the 3 lbs. of dehumidification per ton. Measure the a/c supply temperature /%RH verses the temperature/%RH in the conditioned space. No fresh air venilation???? Ventilation will increase the problem when the outdoor dew point is +55^F.

    I have fixed several buildings like your in FL. The air flow through the a/c coils to a significant reduction in dew point. Add a large whole space dehumidifier. We need to know more about the siize of the space, the number of occupants, and the size of the a/cs.

    Willing to talk to the a/c techs.

    Keep us posted.
    Regards Teddy Bear
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

  18. #18
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    Quote Originally Posted by teddy bear View Post
    A well setup a/c can remove 3 lbs. of moisture per hour per ton. The starting point is to adjust the air flow through the a/c coil to the 3 lbs. of dehumidification per ton. Measure the a/c supply temperature /%RH verses the temperature/%RH in the conditioned space. No fresh air venilation???? Ventilation will increase the problem when the outdoor dew point is +55^F.

    I have fixed several buildings like your in FL. The air flow through the a/c coils to a significant reduction in dew point. Add a large whole space dehumidifier. We need to know more about the siize of the space, the number of occupants, and the size of the a/cs.

    Willing to talk to the a/c techs.

    Keep us posted.
    Regards Teddy Bear
    Carrier Model 59TP5A080E211120 is the main one running

    3 personnel in the fire station most times

    Large Dayroom/Kitchen combo with 5 recliners and regular sized kitchen. Bunk room for 5, locker room with two bathrooms, two offices and a watch office which is about 1.5x the size of the regular sized office. I don't have square footage. It's not too big in the living space.

    Here is the HVAC Room

    https://ibb.co/0Kw8gMv


    Here is the model Number of the main unit

    https://ibb.co/ctGQZRD

  19. #19
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    Quote Originally Posted by firehouse2701 View Post
    Large three bay apparatus bays for the vehicles sealed off from living area with bunk room, large kitchen/living room, locker room with two separate shower rooms, watch office, Lieutenant Office, a couple bathrooms. It is on Well and septic . It also has three units, one is not used at all and one was shut down by HVAC contractors saying we had too much cooling in the building. It also had an energy recovery system that has now been bypassed thinking that may have been the issue. We are in Northern Chicago Suburbs with 41%RH today and the building right now is 77% inside. In the summer it gets significantly worse.
    These areas require Outside air to keep the rooms positive pressure to the equipment floor.

    The bathroom / showers should have an exhaust fan running 24/7. At the least tied into motion / RH sensors.

    Why was the ERV disconnected? Why was one unit discontinued. Possibly that was conditioned make up air?

    That's a relatively new building, get the original mechanical drawings and find out what changed.

  20. #20
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    Quote Originally Posted by pecmsg View Post
    These areas require Outside air to keep the rooms positive pressure to the equipment floor.

    The bathroom / showers should have an exhaust fan running 24/7. At the least tied into motion / RH sensors.

    Why was the ERV disconnected? Why was one unit discontinued. Possibly that was conditioned make up air?

    That's a relatively new building, get the original mechanical drawings and find out what changed.
    Bathroom fans run when lights turned on, currently broken and we are getting repaired

    ERV was disconnected by HVAC techs thinking the humidity was coming from outside the building

    Crews are now telling me they see water on the floor coming from underneath the tiles. I thought this may be a shower leak since its on the other side of the wall but this area they are finding water is in the middle of the hall. Could there be a water break under the concrete floor coming up?

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