Orange County NC Website
Browse       Search
DocuSign Envelope ID: 9826C043- 4C32- 49CD- A4CC- DC28ABAB7CE7 <br />SECTION 239500 - MULTI - INDOOR VRV SYSTEM <br />i) Changeover evaluated by room temperature and setpoints of the indi- <br />vidual indoor unit group in the changeover group <br />ii) Changeover affects individual indoor unit group in the changeover <br />group <br />4) Average method <br />i) Changeover evaluated by the average of all indoor unit group's room <br />temperatures and setpoints operating in Cool, Heat, or Auto mode in <br />the changeover group list <br />ii) If none of the indoor units in the group meet the above requirements <br />the Fixed method of changeover will be applied <br />iii) A weighted demand (0 — 3) can be configured for each indoor unit in <br />the changeover group. <br />iv) Changeover affects all indoor unit groups in the changeover group. <br />5) Vote Method <br />i) In each indoor unit, the cooling demand is calculated based upon the <br />difference between the room temperature and cooling setpoint. If the <br />room temperature falls below the primary cool changeover point (cool <br />setpoint plus the primary changeover deadband) the cooling demand <br />is considered as 0 (zero). Then the total cooling demand is calculated <br />as the sum of each indoor unit's cooling demand <br />ii) The opposite is true for the total heating demand <br />iii) A weight (0 -3) can be added to each indoor unit's demand in the <br />changeover group. The default setting is 1 <br />iv) The weight 0 (zero) means the indoor unit's demand is not added in <br />the total demand, so the indoor unit's demand is considered to be 0 <br />(zero) <br />v) The weight 2 or 3 means the indoor unit's demand is added 2 or 3 <br />times in the total demand, respectively <br />vi) Changeover to cooling mode shall occur when the total cooling de- <br />mand is greater than the total heating demand. <br />vii) The opposite is true for changeover to heating <br />viii) Vote supports a Heating Override option, which prioritizes switching <br />to the heating mode if at least one room temperature falls below the <br />secondary heat changeover point (heat setpoint minus the secondary <br />changeover deadband) even if the total cooling demand is greater <br />than the total heating demand. <br />ix) Changeover affects all indoor unit groups in the changeover group. <br />6) Changeover shall change the operation mode of the indoor unit that is <br />set as the Changeover Master. The Changeover Master indoor unit <br />shall then change the operation mode of all indoor unit groups daisy <br />chained to the same outdoor unit in the Heat Pump system or branch se- <br />lector box in the Heat Recovery system. <br />7) Guard timer <br />i) Upon changeover, guard timer will prevent another changeover during <br />the guard timer activation period (15, 30, 60 (default) min). <br />Reece, Noland & McElrath, Inc. 239500-74 Orange County Board of Elections <br />Orange Co., NC 05/04/18 <br />