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  1. NegativeZero

    Fire trip

    What should the proper reset strategy be in your opinion? its a pain but all fans should be reset manually. However, I have seen fans on a BMS have delay starts staggered, so all fans don't come on at once.
  2. NegativeZero

    Using evaporative (swamp) coolers to provide outdoor air to reverse cycle ducted units

    How big are we talking or how many units will this supply? Cons....PM nightmare..
  3. NegativeZero

    Ground Source Heat Pump Loop (geothermal) anti-freeze

    why would use glycol in the ground loop? but Propylene glycol is food grade
  4. NegativeZero

    need some ideas on how a 18" cooling water underground pipe leak

    if your pipe continues to have leaks than you may have water issues or overall coating issues. But this looks like a isolated hole. Someone hit it with a shovel or bad back fill exposed the raw pipe....and you got corrosion.
  5. NegativeZero

    Water spray atomization humidification

    preheat return air> filters> coils> spray..
  6. NegativeZero

    Building Science

    great vid, I thought I was the only one who felt that way about LEED projects.. thanks for sharing
  7. NegativeZero

    Dehumidification with DX Split

    5 ton split, will run until it makes temp or cuts out on low pressure. I will assume the fan runs during occupancy? while compressor is off, OA is coming in. If you have a high humid day your in for a fun day. Reheats will be popping on and off. Because you need to have them cut in on a supply...
  8. NegativeZero

    Dehumidification with DX Split

    I would not use a standard 5 ton split with electric heat to control humidity. the electric heat in a split is not designed to be a reheat unless you rewire it to do so. but now your inventing. need to figure what your sensible cooling load and latent cooling load will be. And size the unit...
  9. NegativeZero

    cooling a high heat load space

    all you need to do is keep the room from getting to hot above design of what the condensors are rated for. So I wouldn't worry about bringing the temp down to much. if you kept the room at 80* you will be fine. So the worst case scenario is all machines running when its 95* outside. if your...
  10. NegativeZero

    Exhaust/Ventilation requirements for Evidence Storage

    If this is a Police station I would ask the contracting officer overseeing the work for some guidance. I completed a GSA job with an evidence storage room and they had particular requirements we had to meet with exhaust, temp and security requirements. Depending on the room they may ask for 24/7...
  11. NegativeZero

    Fire Damper / Smoke Damper / Fire + Smoke Damper

    All the smoke dampers I used were in rooms using FM200 systems. Smoke dampers need to be hooked up to a smoke head or a relay from the fire panel. fire dampers are rated, smoke dampers alone may not be fire rated for fire walls unless specified and have low or no leakage. Fire and Smoke...
  12. NegativeZero

    New to pump systems, need advice.

    http://legacy.shurflo.com/pages/home.html small pumps with a lot power.
  13. NegativeZero

    Pump mechanical seal starts leaking with water temperature drop

    the rubber used in this seal is well within the temperature ranges. If you have glycol in the water that could mess with Fluorocarbon type of o-ring. Do you have glycol? Also if they ran the seal dry that will could damage the seal. (It don't take much time minute or less) or the seal came...
  14. NegativeZero

    HW Reheat Coil

    that is for a small residential ac unit with reheat. I think its insane.
  15. NegativeZero

    Pump mechanical seal starts leaking with water temperature drop

    Spec sheet that's all it says. Their other seals will give a min/max.. I think you need to call Crane http://www.johncrane.com/~/media/J/Johncrane_com/Files/Products/Specification%20Sheets/S-3710.ashx ■ Temperature: Up to 121°C/250°F ■ Pressure: Vacuum to 13.7 bar g/200 psig ■ Speed: 3600 rpm up...
  16. NegativeZero

    Email Management û An Overwhelming Amount of Emails.

    I just archive them by month. Inbox and sent get separated by month. At the end of each month I move them and start with a clean Outlook. depending on how much I have, I will move the oldest to a back up hard drive. I tried everything but this works the best. If I need to find something I use...
  17. NegativeZero

    Pump mechanical seal starts leaking with water temperature drop

    can you show me where you get those temp specs for the 3710 split? because I cant find those spreads you posted. Unless I'm looking at the wrong Crane type 3710 split mechanical seal.
  18. NegativeZero

    HVAC Duct Design for Value Engineering

    ^^^^that's called contractor design build....flip a coin and hope for the best.
  19. NegativeZero

    Pump mechanical seal starts leaking with water temperature drop

    How long has this been doing this? and has anyone tried to make adjustments? IMO they have to rebuild the seal. if that much water is coming out, the seal is shot. Any dirt in the water most likely compromised the seal at this point. If they cant tighten it anymore they most likely tighten to...
  20. NegativeZero

    2 Pipe Chilled Water/Hot Water Changeover Fan Coil System

    where will this system be used in. will this system be the only set up to maintain temps? I can see a two pipe working when OSA temps fall and you can have a setback controller, controlling water temp based on OSA temps. The FCU would need to have a danfoss valve or something sensing room temp...
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