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6.3 Simplified Approach Option for HVAC Systems
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The HVAC system must meet all of the following criteria:
- The system serves a single HVAC zone.
- The equipment must meet the variable flow requirements of Section 184.108.40.206.1.
- Cooling (if any) shall be provided by a unitary packaged or split-system air conditioner that is either air cooled or evaporatively cooled, with efficiency meeting the requirements shown in Table 6.8.1-1 (air conditioners), Table 6.8.1-2 (heat pumps), or Table 6.8.1-4 (packaged terminal and room air conditioners and heat pumps) for the applicable equipment category.
- The system shall have an air economizer meeting the requirements of Sections 6.5.1 and 220.127.116.11.
- Heating (if any) shall be provided by a unitary packaged or split-system heat pump that meets the applicable efficiency requirements shown in Table 6.8.1-2 (heat pumps) or Table 6.8.1-4 (packaged terminal and room air conditioners and heat pumps), a fuel-fired furnace that meets the applicable efficiency requirements shown in Table 6.8.1-5 (furnaces, duct furnaces, and unit heaters), an electric resistance heater, or a baseboard system connected to a boiler that meets the applicable efficiency requirements shown in Table 6.8.1-6 (boilers).
- The system shall meet the exhaust air energy recovery requirements of Section 18.104.22.168.
- The system shall be controlled by a manual changeover or dual set-point thermostat.
- If a heat pump equipped with auxiliary internal electric resistance heaters is installed, controls shall be provided that prevent supplemental heater operation when the heating load can be met by the heat pump alone during both steady-state operation and setback recovery. Supplemental heater operation is permitted during outdoor coil defrost cycles. The heat pump must be controlled by either (1) a digital or electronic thermostat designed for heat pump use that energizes auxiliary heat only when the heat pump has insufficient capacity to maintain set point or to warm up the space at a sufficient rate or (2) a multistage space thermostat and an outdoor air thermostat wired to energize auxiliary heat only on the last stage of the space thermostat and when outdoor air temperature is less than 40°F.
- The system controls shall not permit reheat or any other form of simultaneous heating and cooling for humidity control.
- Systems serving spaces other than hotel/motel guest rooms, and other than those requiring continuous operation, which have both a cooling or heating capacity greater than 15,000 Btu/h and a supply fan motor power greater than 0.75 hp, shall be provided with a time clock that (1) can start and stop the system under different schedules for seven different day types per week, (2) is capable of retaining programming and time setting during a loss of power for a period of at least ten hours, (3) includes an accessible manual override that allows temporary operation of the system for up to two hours, (4) is capable of and configured with temperature setback down to 55°F during off hours, and (5) is capable of capable of and configured with temperature setup to 90°F during off hours.
- Systems serving hotel/motel guest rooms shall comply with Section 22.214.171.124.5.
- Except for piping within manufacturers' units, HVAC piping shall be insulated in accordance with Tables 6.8.3-1 and 6.8.3-2. Insulation exposed to weather shall be suitable for outdoor service, e.g., protected by aluminum, sheet metal, painted canvas, or plastic cover. Cellular foam insulation shall be protected as above or painted with a coating that is water retardant and provides shielding from solar radiation.
- Ductwork and plenums shall be insulated in accordance with Table 6.8.2 and shall be sealed in accordance with Section 126.96.36.199.1.
- Construction documents shall require a ducted system to be air balanced in accordance with industry accepted procedures.
- Outdoor air intake and exhaust systems shall meet the requirements of Section 188.8.131.52.
- Where separate heating and cooling equipment serves the same temperature zone, thermostats shall be interlocked to prevent simultaneous heating and cooling.
- Systems with a design supply air capacity greater than 10,000 cfm shall have optimum start controls.
- The system shall comply with the demand control ventilation requirements in Section 184.108.40.206 and the ventilation design requirements in Section 220.127.116.11.
- The system complies with the door switch requirements in Section 6.5.10.