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  1. ChrisConley

    Changing careers - HVAC manufacturing to consulting?

    You are describing the actual route I took to consulting. I consider the time I spent on the manufacturing side of the world invaluable. I wouldn't go back... but I know many people who truly enjoy that style of work. The experience doesn't directly translate, and you do decide to make the...
  2. ChrisConley

    5 year warranty for HVAC equipment - reasonable?

    I usually check with suppliers on what the cost of the extended warranty is... and what it covers. I had the unpleasant task once of dealing with a manufacturer (rhymes with fork) that had a $17 elbow fail on a large air cooled chiller. They replaced the elbow, but the lost refrigerant was not...
  3. ChrisConley

    HVAC JOB

    Don't forget to apply for the jobs looking for a year or two of experience. I got my first job in consulting by misreading the job application. I had a few years in manufacturing (air handling equipment) and sales. I read the application, didn't notice they were looking for 7-15 years in...
  4. ChrisConley

    I would like to gain some insight..HVAC-Contractor currently..

    YES. Assuming you go down the path of a BSME and move into an HVAC firm your knowledge will be greatly appreciated. We've actually hired older HVAC installers to review drawings and perform contract admin. Knowing what a duct is will put you head and shoulders above most of the new grads I have...
  5. ChrisConley

    NuClimate Chilled Beams vs. VRF ( First Cost, Service & Efficiency)

    I agree with you cry22 that the psychometrics involved with chilled beams are tricky. Not just tricky, but resistant to rule of thumbs and oversizing. The main issue I found was that the 'industry standard' temperatures for chilled water and air temp have to be completely re-evaluated. Lower...
  6. ChrisConley

    Chilled water coil performance 10deg F delta-T versus 12 deg F

    My guess is that are trying to get more capacity out of the chillers which were designed on a 12 deg delta T originally, or there is a 'low-delta T' problem in the building. I'd consider a pressure-independent control valve on the chilled water coils to help maintain the 12 deg F. It is easy to...
  7. ChrisConley

    psychrometrics question

    You can (as a reasonable analogy) view the evaporation of water into air as water being 'dissolved' into the air. This is different from the phase change process of boiling.
  8. ChrisConley

    How tolerant is your company of wrong answers?

    We have an old plumber on staff who is invaluable for his bits of wisdom and experience. Once when sitting in a meeting and trying to explain to a client how a co-ordination item was missed in the original design he piped up: "If you wanted a perfect design you should have hired God, but you...
  9. ChrisConley

    Heat Gain from Electric Motor High?

    "kinetic energy that never truly settles out in the real world" = perpetual motion.
  10. ChrisConley

    Primary Secondary w bull headed tee

    Pressure drop in your decoupling link will cause a percentage of secondary flow to run through the primary loop. I can see this creating control problems but not really the issue relating to morning warm-up.
  11. ChrisConley

    Pumping in to an empty pipe

    PVC is probably not a bad choice if you see the pipe as sitting empty most of the time. Air and steel equals rust. Vents should be the same size, or larger, then the discharge pipe going into the tank.
  12. ChrisConley

    Radiant Heat across a distance

    I'd be more concerned that a ball would push the net into the radiant heater. I can't really imagine using a radiant heater in a gym, net or netless. I'm assuming gas-fired radiant, not hydronic radiant?
  13. ChrisConley

    HRV fresh air supply ok?

    Your defrost strategy is relevant as well, as you don't want untempered air dumping in the space. Exhaust only defrost is my preference for small HRV. Ventilation should be sized on people (cfm/person) and area (cfm/ft2). Also, you may be exhausting for industrial purposes? Washrooms? I'd...
  14. ChrisConley

    Ceiling Space conditions

    Same comment as previous then, but replace the word attic with ceiling space.
  15. ChrisConley

    how much clamping force is required?

    More of a general mechanical problem, but no amount of clamping force will eliminate deflection. The 'beam' in this case will deflect due to the exterior load on it relative to the dimensions of the beam. This isn't a beam, it's a plate, but beam calculations will still work (just a long flat...
  16. ChrisConley

    Closed hydronic system with standard expansion tank and auto vents

    I'd recommend against auto-air vents on any system. We use one auto-air vent, in the mechanical room, working with the air separator. We use manual vents all over the place. Auto-air vents spit. Depending on location, a spitting auto-air vent could cause a world of problems.
  17. ChrisConley

    Ceiling Space conditions

    Bah, who needs numbers. Yes. Conditions warrant duct insulation to prevent condensation on the duct. Unless you expect the dewpoint in the attic to never exceed the surface temperature of the duct. Even then, why waste energy 'cooling' the attic. Duct insulation will save energy and help...
  18. ChrisConley

    Rule of thumb for heating system selection based upon wall heat loss?

    We use ceiling mounted radiant panels adjacent the exterior wall with great success in our climate (Canada... cold). Not as effective with tall spaces, but very effective in standard height applications.
  19. ChrisConley

    ISPE GPG HVAC Book year 2009

    This should almost become a FAQ section. Buy the book.http://files.engineering.com/getfile.aspx?folder=27f250bd-e24e-45f8-915d-b565880b4c2c&file=Engineerings_Texts_-_General_Response.pdf
  20. ChrisConley

    Fans for chlorine bleach atmosphere

    FRP (fiberglass reinforced plastic) is likely the way to go. Greenheck and others.... MK plastics. Check with them about the suitability in your application.

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