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    ASHRAE 62-2010 and partial occupancy?

    Question from someone out of the industry for a while and don't have a copy of 62-2010 to refer to....what allowances does 62-2010 give for buildings with partial occupancy?

    I remember with 62-89...
  2. Small server room - precision or comfort cooling?

    Debate between me designer/contractor and younger designer about small server room - load less than 10 tons.

    I want to have a plain jane chilled water fan coil for daytime cooling and a plane jane...
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    Set limit on ductless tstat?

    My company leases over 200 apartment units around town and they are all cooled with ductless splits (we're in Asia). Some of the occupants are turning their tstats down 66F at all times. We pay the...
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    Any NFPA sources out there?

    Any message board similar to this one, but with commercial fire protection as its focus....or....any of you guys fire alarm system gurus who can answer a question for me?
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    I think I'll go with prog stat. For something as...

    I think I'll go with prog stat. For something as simple as retail, I don't want to complicate things. After we leave I can see the manager fiddling with stuff and messing it up. Thanks all!
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    Simplest chiller controls in the world?

    Office building with an old 200 ton Carrier water cooled chiller. CV AHU's throughout with RAT sensor turning off and on the AHU. No controls on anything other than that.

    Currently, if there's a...
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    Large retail - tstat or RAT sensor?

    Large retail - 20 ton unit - 2 stage Trane DX split. Currently using RAT sensors to control space temp. Another "HVAC guy" says we should change it to a programmable tstat in the space because it's...
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    ASHRAE 189 - what is a "green" bldg?

    Apologies right up front in that I'm "out" of the HVAC industry and in the facilities business, but I can't find an answer to this question.

    ASHRAE 189 is code-enforceable for green...
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    And can someone suggest a tstat that will turn...

    And can someone suggest a tstat that will turn the AHU fan off when the CHW valve is closed when space temp is met?????
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    And for what it's worth...each AHU has 3 way...

    And for what it's worth...each AHU has 3 way valves. All are cooling only.
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    Adding prog stats to old CHW system

    Building built in 1950
    2 - 60 ton water cooled Carrier chillers in 1975
    12 - 15 to 25 ton vertical CHW AHU's

    Each air handler is CV in a mechanical room.
    Each AHU has one manual thermostat in...
  12. But VVT still seems odd since the interior needs...

    But VVT still seems odd since the interior needs cooling when exterior needs heat. They could use CCN controls and someone else's FB. But I guess you're back to needing hot h20 which is going to...
  13. HVAC office Building Design in Upstate NY?

    Wanted to run something by you guys. I'm in NC and talking to a HVAC sub in NY - Albany specifically. We were talking about the way mid-size office buildings are designed up there vs NC. Using a...
  14. Heat txfer method in DX coil vs CHW coil?

    Is the return air blowing across a DX coil cooled because....

    1) As the refrigerant leaves the expansion valve, the refrigerant is evaporating due to the warm return air and subsequent change in...
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    Geothermal companies in South Texas?

    Anyone know of an HVAC sub in South Texas with experience doing commercial geo thermal jobs?
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    Chemical treatment for condenser water?

    My background is commercial and I know a condenser water loop going to a closed loop tower has anti-scaling chemicals installed and the water/tower is checked regularly.

    Do you have to add...
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    Pro/Cons for victaulic pipe

    Running chilled water and gas. 3" up to 6". What are the pro/copns of victaulic versus just welding it?
  18. What about just the need to have an disconnect of...

    What about just the need to have an disconnect of any type(fused or not)? I know I've seen that someplace - I just don't know where.
  19. Code reference for the need for elect. disc on units?

    Is the need for a fused disconnet only in the electrical code or is there a note in the mech code about it? If you could site where the reference is in either code I'd appreciate it.
  20. So pressurize stairwell, but my understanding is...

    So pressurize stairwell, but my understanding is elevator shafts should be negative? Right or wrong?
  21. High-rise elevator & stairwells pressure/smoke control?

    Can someone give me some guidelines - or point me to a website - that generally describes how stairwells and elevator shafts are to be designed relative to positive or negative pressure, necessity of...
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    Rules for air side economizer use?

    Having never designed outside of NC, I've always used what I was taught for when you need an economizer which was any unit 3,000 cfm and above.

    Then I went looking and found all sorts of different...
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    I found a couple of recent projects here in NC...

    I found a couple of recent projects here in NC still using '89 numbers and couldn't figure out why. But I guess if the local code people haven't caught on....

    Wow - ask a question about outside...
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    Is 62.1-2004 what everyone has to use?

    I haven't designed in some years now and wondered if ASHRAE 62.1-2004 is now the standard everyone uses for determining outside air calculation?
  25. Thread: R-421?

    by Grawburg
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    R-421?

    Saw an ad in an HVAC mag about R-421 being a direct replacement for R22 and it meets the non-ozone requirements coming up. Why don't I hear more about this? All I hear about is R-410a. Any...
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    Well, it's for a general contractor who wants to...

    Well, it's for a general contractor who wants to identify equipment he sees so he's not going to know what to do on Trane's website. I used to have this sheets that listed all of the nomenclature.
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    Interpreting model numbers

    I used to have a collection of sheets of info from the major manufactures for interpreting model numbers for RTU's, chillers, CU's, etc... But I've lost it and it wouldn't have some of the newer...
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    What's a CV box?

    Is this different from a VAV box/zone damper?
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    List of HVAC Tech Schools?

    Anyone know of a list of either HVAC specific schools or community colleges that offer commercial tech training? I get asked this a lot by people and I've never been able to find a list I can pass...
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    Ok, maybe the better question is why would you...

    Ok, maybe the better question is why would you use a drycooler instead of a cooling tower. If both options are for cooling indoor condensers, what's the advantage of one over the other?
  31. Efficiency of R22 vs R410 in mid-size RTU's?

    What kind of operating efficiencies are we talking about between the two refrigerants?
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    Umm, what the hell kind of comment was that? I...

    Umm, what the hell kind of comment was that? I never said I was changing MY HEPA filters based on a rule of thumb. It was a question I got asked and didn't know the answer to so I asked it here. ...
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    Condensing units vs dry coolers?

    What's the difference and why is one designed over the other?
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    How often should HEPA'S be replaced?

    As a rule of thumb in say - a laboratory or surgery room?
  35. Anybody know how HVAC Contracting/Design is done in the UK?

    It doesn't appear they have a mechanical code book nor does it seem like HVAC designers need to be licensed. Anyone got any experience how its done over there?
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    Is there a chiller type comparison chart?

    Something that explains the differences between scroll, screw, centrif, absorption and what types of buildings you would see them on and why you'd pick them?
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    Animated pics of HVAC equipment?

    Anyone know of a site that shows animates pics of HVAC equipment or systems that explain them?
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    Animated pics of HVAC equipment?

    I teach a class to non-HVAC folks about commercial HVAC systems and wondered if you all knew of any site that had animated pics of HVAC equipment or systems?
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    Delta T for heat wheel?

    What's a typical delta T on an ERV with a desicant wheel when the building is in the cooling mode and the outside air temp is 100F?
  40. It's not for my house - it's for multi-story...

    It's not for my house - it's for multi-story residential that the guy is building. San Antonio DOES have a heating season so it seems a waste to just use elec. I guess the couple of hundred bucks...
  41. San Antonio Texas - split a/c or split hp?

    For San Antonio, Texas I was told by a builder that they are using split a/c with elec heat instead of split heat pump for multi story residential.

    Anyone know why they would not use a heat...
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    Line set design / length question.

    I had always used the rule of thumb that running line sets over 75 feet was hard on the units - but I'm seeing more and more 100+feet lines in multi-story residential/condo types.

    So, for a less...
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    In Europe, they definitely make ductless splits...

    In Europe, they definitely make ductless splits bigger than 3 tons. See it all the time. Maybe they're not approved for the US, but I know they make them.
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    Dan, ASHRAE 62-99 is going to consider this...

    Dan, ASHRAE 62-99 is going to consider this office space and will require 15 cfm of outside air per person.

    How do you figure this is not required and where are you getting a 10% O/A figure?
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    hvacconsultant - no, I'm not nuts. But *I* did...

    hvacconsultant - no, I'm not nuts. But *I* did read the OP's post completely which you obviously did not. I was talking about the control room with 2 men in it.
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    Thermal comfort is standard 55, ventilation is...

    Thermal comfort is standard 55, ventilation is 62. Is occupancy in the Fundamentals book or would they give you those numbers in 62?
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    You could always plant a bush or put up a small...

    You could always plant a bush or put up a small fence to block the view of the CU. I guess you'll just have to check to see if other manufacturers offer an indoor CU.

    If you've got 2 guys in the...
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    If no one's in there you won't need any outside...

    If no one's in there you won't need any outside air.

    Is the room tight? If yes, then the sensible load from the equipment will be what's dictating the cooling needs. Yes, there is latent in...
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    I'm assuming that the ONLY thing on this gas line...

    I'm assuming that the ONLY thing on this gas line is the 1.7 million BTU load. If that's not the case then ignore the rest of this. If it IS the only thing on the pipe system, then you'll use...
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    All of your examples, OP, are sensible heat.

    All of your examples, OP, are sensible heat.
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