840 N BROADWAY 2017-08-21 - Laserfiche WebLink

C403.4.1 Multiple-zone system fan control.Controls and be provided with controls that allow heating and shall be provided for fans in accordance with Sections cooling supply temperatures at the changeover point C403.4.1.1 through C403.4.1.2. to be no more than 30°F(16.7°C)apart. ■ C403.4.1.1 Static pressure sensor location.Static C403.4.2.3 Hydronic(water loop)heat pump pressure sensors used to control VAV fans shall be systems.Hydronic heat pump systems shall comply located such that the controller setpoint is no greater with Sections C403.4.2.3.1 through C403.4.2.3.3. than 1.2 inches w.c.(2099 Pa).Where this results in C403.4.2.3.1 Temperature dead band.Hydronic one or more sensors being located downstream of heat pumps connected to a common heat pump major duct splits,not less than one sensor shall be water loop with central devices for heat rejection located on each major branch to ensure that static and heat addition shall have controls that are pressure can be maintained in each branch. configured to provide a heat pump water supply Exception: Systems complying with Section temperature dead band of at least 20°F(11.1°C) C403.4.1.2. between initiation of heat rejection and heat 0403.4.1.2 Set points for direct digital control.For addition by the central devices. systems with direct digital control of individual zones Exception:Where a system loop temperature reporting to the central control panel,the static optimization controller is installed and can pressure setpoint shall be reset based on the zone determine the most efficient operating requiring the most pressure.In such cases,the set temperature based on real time conditions of point is reset lower until one zone damper is nearly demand and capacity,dead bands of less than wide open.The direct digital controls shall be capable 20°F(11°C)shall be permitted. of monitoring zone damper positions or shall have an C403.4.2.3.2 Heat rejection.Heat rejection alternative method of indicating the need for static equipment shall comply with Sections pressure that is configured to provide all of the C403.4.2.3.2.1 and C403.4.2.3.2.2. following: Exception:Where it can be demonstrated that a 1. Automatically detecting any zone that heat pump system will be required to reject heat excessively drives the reset logic. throughout the year. 2. Generating an alarm to the system operational location. 0403.4.2.3.2.1 Climate Zone 4.For Climate 3. Allowing an operator to readily remove one or Zone 4: more zones from the reset algorithm. 1. If a closed-circuit cooling tower is used directly in the heat pump loop,either an 0403.4.2 Hydronic systems controls.The heating of automatic valve shall be installed to fluids that have been previously mechanically cooled bypass all but a minimal flow of water and the cooling of fluids that have been previously around the tower,or lower leakage mechanically heated shall be limited in accordance with positive closure dampers shall be Sections C403.4.2.1 through C403.4.2.3.Hydronic provided. heating systems comprised of multiple-packaged boilers and designed to deliver conditioned water or 2. If an open-circuit tower is used directly in steam into a common distribution system shall include the heat pump loop, automatic valve automatic controls configured to sequence operation of shall be installed to bypass all heat pump water flow around the tower. the boilers.Hydronic heating systems comprised of a single boiler and greater than 500,000 Btu/h(146,550 3. If an open-or closed-circuit cooling tower W)input design capacity shall include either a is used in conjunction with a separate heat multi-staged or modulating burner. exchanger to isolate the cooling tower C403.4.2.1 Three-pipe system.Hydronic systems from the heat pump loop,then heat loss that use a common return system for both hot water shall be controlled by shutting down the circulation pump on the cooling tower and chilled water are prohibited. loop. C403.4.2.2 Two-pipe changeover system.Systems C403.4.2.3.2.2 Climate Zone 5.For Climate that use a common distribution system to supply both Zone 5,if an open-or closed-circuit cooling heated and chilled water shall be designed to allow a tower is used,then a separate heat exchanger dead band between changeover from one mode to the shall be provided to isolate the cooling tower other of at least 15°F(8.3°C)outside air from the heat pump loop,and heat loss shall be temperatures;be designed to and provided with controlled by shutting down the circulation controls that will allow operation in one mode for at pump on the cooling tower loop and providing an least 4 hours before changing over to the other mode; automatic valve to stop the flow of fluid. 2015 Washington State Energy Code CE-63