Arkansas HVACR NewsMagazine March 2020

S tate, National, Chapter News State national Chapter News

Programmable Thermostat Required This section probably does not change much as virtually all new construction is already using some version of a programmable thermostat. IECC Code Provision R403.1.1 Programmable thermostat. The thermostat controlling the primary heating or cooling system of the dwelling unit shall be capable of controlling the heating and cooling system on a daily schedule to maintain different temperature setpoints at different times of the day.

R-8 Duct Insulation The 2018 IECC would require R-8 duct insulation on all duct >=3” in diameter and located in the attic. This was a defining issue in 2015 but due to condensation problems, many have already moved toward R-8. insulated to an R -value of not less than R-8 for ducts 3 inches (76 mm) in diameter and larger and not less than R-6 for ducts smaller than 3 inches (76 mm) in diameter. Supply and return ducts in other portions of the building shall be insulated to not less than R-6 for ducts 3 inches (76 mm) in diameter and not less than R-4.2 for ducts smaller than 3 inches (76 mm) in diameter. Sealed Air Handler Every installer knows how much air leaks through the air handler. The IECC will reduce the allowable amount to 2% of the total design airflow rate. A 3 ton unit @ 400 cfm/ton could then leak 24cfm or about the same amount as a 3.4” round pipe at a friction of 0.1. As you ca n see, this isn’t an egregious requirement for the manufacturers. In fact, one could say, “Where is the improvement?” R403.3.1 Insulation (Prescriptive). Supply and return ducts in attics shall be IECC Code Provision R403.3.2.1 Sealed air handler. Air handlers shall have a manufacturer’s designation for an air leakage of not greater than 2 percent of the design airflow rate when tested in accordance with ASHRAE 193.

HP Supplementary Heat Control This was a big issue in 2014. Now most HP thermostats have it built in.

IECC Code Provision R403.1.2 Heat pump supplementary heat (Mandatory).

Duct Sealing 20 18 IECC references the International Mechanical Code which the HVACR Program is presently preparing to update. Interested persons should contact the Arkansas Department of Labor and Licensing at 501-682-9188. Heat pumps having supplementary electric-resistance heat shall have controls that, except during defrost, prevent supplemental heat operation when the heat pump compressor can meet the heating load. R403.3.2 Sealing (Mandatory). Ducts, air handlers and filter boxes shall be sealed. Joints and seams shall comply with either the International Mechanical Code or International Residential Code , as applicable.