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  1. Your township inspector has probably been to a...

    Your township inspector has probably been to a seminar or read an article on Hydrogen.

    Not sure what code you are under there, but the 2009 IMC section 502.4 indicates the hydrogen limit must be...
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    What is driving the requirement for the 3 filter...

    What is driving the requirement for the 3 filter banks? Is it a code requirement or an engineering (or other) spec item? If it’s a spec from an engineer I’d ask what their intent is.

    Otherwise...
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    19Character is correct, you described a...

    19Character is correct, you described a displacement ventilation system. It’s a new way to try to improve comfort and reduce energy. Go to Price’s website (http://www.price-hvac.com/) and search...
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    Psiman is on the right track. The leakage from...

    Psiman is on the right track. The leakage from your room(s) is a function of the total area of all the cracks in the room. Unless you can measure these (the cracks around doors, windows, electrical...
  5. Desert Aire is a reputable manufacture. They...

    Desert Aire is a reputable manufacture. They have very good design procedures which will give a good selection. Make sure you and the owner are aware of the design temperature of the room and the...
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    TB - You make my fingers cramp up just reading...

    TB - You make my fingers cramp up just reading your response.

    Great answer - You have a way of converting engineering into everyday language. I hope you teach somewhere.
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    Excellent question, and the discussion shows just...

    Excellent question, and the discussion shows just how stupid government regulations can be sometimes.

    If you charge a system with canned air and then vent it, ethically you have done nothing...
  8. The requirement is pretty much standard for...

    The requirement is pretty much standard for hospitals and ORs in particular (ASHRAE std. 170 - Ventilation of Health Care Facilities), but it is a range: max of 60% and min of 30% with the...
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    York YK seal oil usage

    I am working with an owner who has a new York/JCI 850 Ton, Variable Speed centrifugal chiller (model YK). The compressor shaft seal is a “wet seal” and I understand that this requires some oil to...
  10. Ditto what DoE said. Very difficult to reach...

    Ditto what DoE said. Very difficult to reach those conditions with regular DX (or standard chilled water) equipment!
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    Put a piece of tissue at the gap under the door...

    Put a piece of tissue at the gap under the door and see which way it goes.
  12. It appears the fan is trying to do more than 1/3...

    It appears the fan is trying to do more than 1/3 hp worth of work.

    Are you sure the new motors are the same RPM as the original?

    Do you have more info on the fan? The 100R2B does not ring...
  13. Not that you need anything else to worry about,...

    Not that you need anything else to worry about, but with the make-up air off and the exhaust fans for restrooms, etc. running your building is negative so it’s pulling air from somewhere you can’t...
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    There are manufacturers that make chillers...

    There are manufacturers that make chillers designed specifically for medical equipemnt. Filtrene is be best IMO.
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    I used a psych calculator and came up with 53.3...

    I used a psych calculator and came up with 53.3 lb/hr

    Here are the engineering geek details if you are interested:
    Assuming sea level, air at 93/75 has a density of 14.26 Cu Ft ./lb and contains...
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    The systems which seem to work the best lately...

    The systems which seem to work the best lately introduce the make-up air through a perforated plenum right at the edge of the hood itself. I have heard of a design which uses a low wall plenum...
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    I do not know anything about Ohio's healthcare...

    I do not know anything about Ohio's healthcare code, but all the one's I am familiar with do not require an x-ray room to be exhausted. The only associated room that is required is a "film...
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    No, the x-rays can not contaminate particals. ...

    No, the x-rays can not contaminate particals. The x-rays are just about like light, once they are turned off they are gone.
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    Sorry, No I really do not know where you might...

    Sorry, No I really do not know where you might look for this type of equipment.

    I believe most x-ray generators use a type of vacuum tube and very high voltage to generate the x-rays, but I am...
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    I do not know how the equipment operates but the...

    I do not know how the equipment operates but the x-ray machine itself may contain some radioactive material which is somehow causing the hair loss, but I doubt it. I would think those machines would...
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    There are several codes which are similar, but...

    There are several codes which are similar, but slightly different. The particular state you are in will probably have a governing code. Some states have their own set of rules, other use AIA’s...
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    The “S” in SEER stands for seasonal which means...

    The “S” in SEER stands for seasonal which means the efficiency number is kind of an average of very hot weather and cooler weather (seasonal). The new unit may be much more efficient in cooler...
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    Looks like the consensus is Propylene is the way...

    Looks like the consensus is Propylene is the way to go. Thanks for all the great input!

    Chillerguy you obviously know how to deal with us engineering types – give us two properties that offset...
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    Propylene or ethylene glycol?

    I am looking for pros and cons of using propylene or ethylene glycol in small chilled water systems that may be exposed to freezing conditions during cold weather. My background is design so I am...
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    I would like to build on what genduct said. At...

    I would like to build on what genduct said.
    At the beginning of a project it is very easy for the structural guy to say “I can save $XX by going with taller steel” and the general contractor says...
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    The fan runs an extra minute or two to extract...

    The fan runs an extra minute or two to extract all of the heat out of the coil and into your house. The air temperature drops to near room temperature and since the air is moving is feels cool but...
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    ASHRAE 170 is becoming the standard for...

    ASHRAE 170 is becoming the standard for healthcare ventilation; however different states have different requirements. Unfortunately you have to buy a copy of the ASHRAE standard, but here is an...
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    "My question is, if it's a cleanroom , is there...

    "My question is, if it's a cleanroom , is there any other ways to design HVAC for it? I'm confused which one is correct, 16.5 (with 1.5 pre cooling) or 6.5 Ton!! Because, one with 16.5 is saying for...
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    I've been in some buildings with enough duct...

    I've been in some buildings with enough duct leaks that this might work!
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    That's the new 2-stage window shaker!

    That's the new 2-stage window shaker!
  31. Interesting question, I don’t know that I’ve ever...

    Interesting question, I don’t know that I’ve ever calculated it. We usually size condensate drain based on nominal tonnage:

    <2 tons = ¾” 5 tons = 1” 30 tons = 1 ¼” 50 tons = 1 ½” 175...
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    All outside air should be conditioned...

    All outside air should be conditioned (dehumidified) before introducing into the building.
  33. Replies
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    Agree 100% with Gunny. Here are some other...

    Agree 100% with Gunny. Here are some other things to look at.

    I have found that sweating ductwork is usually caused by outside air infiltrating into the ceiling plenum unless the insulation is...
  34. What temperature is the space where the RH is...

    What temperature is the space where the RH is 59-61? If they are trying to drive the temperature too low (less than 68 or so) then that RH is about right for typical chilled water application.
    ...
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    2 Bad Defrost Boards in Cooling Mode?

    New (8 months old) Payne 2 ton HP. Started going into “defrost” during cooling operation. (Condenser fan stops, compressor keeps running until it trips.) Contractor came out diagnosed as bad...
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    Are the chilled water valves 2-position or...

    Are the chilled water valves 2-position or modulating? Modulating valves will keep chilled water flowing and do some dehumidifing.

    Probably the best thing to do is dedicate a coulple of FCUs...
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    If they are only looking for a digital readout...

    If they are only looking for a digital readout why go with a programmable at all? Why not one of the non programmable ones.

    Most of the SR Living facilities I have worked on they wanted the old...
  38. I don't mean to muddy the water and I think...

    I don't mean to muddy the water and I think understand your logic, but if your "HAND" position still has to depend on a damper position contact to make before starting, then it's really kind of still...
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    You have the numbers you need. Since your water...

    You have the numbers you need. Since your water is entering at 44, but leaving at only 50 it does not sound like a water flow issue to me.

    Either too high air flow or poor heat transfer and...
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    Pool environments are more complex than standard...

    Pool environments are more complex than standard heating and air conditioning because the air needs to also be dehumidified all the time. There are manufacturers who specialize in this type of...
  41. When you say rigid duct, I assume you mean sheet...

    When you say rigid duct, I assume you mean sheet metal.

    You have come to the right place to get good advice. You already seem to be aware of many of the main items related to the duct system -...
  42. The film on the inside pane causes too much heat...

    The film on the inside pane causes too much heat to build up within the window itself and can cause it to crack or loose it's seal and fog up. At least on some older windows.
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    Gevans, It takes a REAL MAN to admit something...

    Gevans,
    It takes a REAL MAN to admit something like that especially on this web site.....I bet you'll never do it again.
  44. Thanks guys for the responses. Skippedover,...

    Thanks guys for the responses.

    Skippedover, when you say the compressor may go into by-pass mode, do you mean internally relieving the pressure?

    Would this also be a potential problem in...
  45. 13 seer HP condenser with old 10 seer AHU

    I have a friend with a beach house on the NC coast with 2 heat pumps, one upstairs and one down. The air handling units are in good shape, but the condensing units outside were falling apart due to...
  46. I have seen and lived in similar situations. What...

    I have seen and lived in similar situations. What you are really battling is the natural buoyancy of warm air and it can be quite difficult to remedy with existing system. In the summer the warm air...
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    Natural gas is essentially Methane. Bottled gas...

    Natural gas is essentially Methane. Bottled gas is LP (liquefied petroleum) is mostly propane and butane.

    Neither will technically explode (like dynamite), but they do burn VERY rapidly and if...
  48. Those small fans are notorious for coming up...

    Those small fans are notorious for coming up short on static. The main reason is that the manufacturer (and all do it, not just cook) list their fans under basically ideal conditions with very long...
  49. sjones is correct. Mini split system is the way...

    sjones is correct. Mini split system is the way to go.

    There are several manufacturers, including Mitsubishi and they are available in very high effeciency versions.
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    :oops: Thanks chillerguy the model number...

    :oops:

    Thanks chillerguy the model number didn’t mean much to me. Should have been a clue.

    I guess this is one case when the old saying “it is better to be silent and thought an idiot than to...
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