Describes common problems with HVAC systems, based on the author\’s experience over the past 20+ years.

5. 4. Deferred Maintenance: HVAC Hygiene is Sacrificed

11. 4. Deferred Maintenance: Debris in the Fan?!?

13. 10. OA Distribution in Heat Pump Systems

14. 10. OA Distribution in Heat Pump Systems

16. 11. Control of Outdoor Air in VAV Systems 980-RP: Techniques for Measuring and Controlling Minimum Outdoor Air Intake Rates in VAV Systems September 1997 - January 1999 The Regents of the University of Colorado Principal Investigator, Moncef Krarti TC 1.4 Control Theory and Application “ The objective of this research project is to . . . compare various techniques for measuring and controlling minimum outdoor air intake rates in VAV systems. Based on the results of these analyses, a set of guidelines will be provided to assess . . . each technique.” ASHRAE Research Project

17. 11. Control of Outdoor Air in VAV Systems (Transactions #4369: 2000 Summer Meeting in Mpls.) “ Experimental Analysis of Measurement and Control Techniques of Outside Air Intake Rates in VAV Systems” Abstract: “…control strategies using the direct measurement of the outside airflow from an averaging pitot-tube array or an electronic thermal anemometer provided the best ventilation control.” Discussion: “In cases where there is not sufficient unobstructed OA duct length to ensure uniformity of airflow profiles, … a dedicated minimum OA duct is recommended.” ASHRAE 980-RP

18. 12. Inadequate Filtration

19. 12. Inadequate Filtration

21. 12. Inadequate Filtration

22. 12. Inadequate Filtration: Should I use Antimicrobial Filters? ( ASHRAE Journal , December 2000) “ Efficacy of Antimicrobial Filter Treatments” Three treatments were studied: “…an amine neutralized phosphoric ester, a quaternary ammonium compound, and an iodine compound.” Results: “Little or no difference existed in the numbers of xerophilic fungi eluted from the…treated and untreated filters…” And: “…new filters generally are a hostile environment for microbial growth whether treated with antimicrobial agent or not.” Conclusions: “…two of the three antimicrobials inhibited the growth of the test organisms on new filters at all ERHs tested; the third did not [Table 2].” And: “…all of the filters, except for one, did permit the growth of fungi after dust loading [Table 3].” ASHRAE 909-RP

23. 12. Inadequate Filtration: Should I use Antimicrobial Filters? ( Indoor Environment Connections , November 1999) “ ASHRAE Study Shows Mixed Results for Antimicrobial Filters” Products identified: “Antimicrobial 1 is Sporax …Antimicrobial 2 is Intersept …Antimicrobial 3 is Aegis Microbe Shield …” Per Al Veeck, Chairman of the ASHRAE Project Monitoring Committee: “When you find filters with biological growth, it’s always due to a problem upstream in the system. If that problem were fixed, there would be no need for an antimicrobial filter . ” And: “… in hot, humid climates the use of an antimicrobial filter may prove beneficial as part of a holistic approach to IAQ.” ASHRAE 909-RP

24. 13. Combinations Yield Negative Synergies Deferred Maintenance + Inadequate Filtration +++

27. 13. Combinations Yield Negative Synergies Deferred Maintenance + Inadequate Filtration

28. 13. Combinations Yield Negative Synergies Deferred Maintenance + Inadequate Filtration

29. 13. Combinations Yield Negative Synergies Deferred Maintenance + Inadequate Filtration

30. IAQ and Ventilating Systems Problems Found with All System Types 1. Previous building codes 2. Energy conservation measures 3. Provision for exhaust/relief overlooked

44. IAQ and Ventilating Systems 2. Energy Conservation Measures

49. Good Design in Packaged Units?

50. Good Design or Symmetry?

51. Are Building Codes Sufficiently Protective?