Carrier CRECOMZR077A00 Installation Instructions Manual

Also see for CRECOMZR077A00: Installation instructions

Contents

15Installing Differential Return Air SensorThe CRDIFRASN01A00 differential return air sensor kit mustbe field mounted in the system’s return duct work. The kit in-cludes a wiring harness that connects the EconoMi$er X har-ness in the return chamber of the unit to the providedHH57AC081 sensor. Wire per Fig. 33.In addition to using the HH57AC081 (Honeywell C7400S) sen-sor (see Fig. 32) for a single enthalpy sensor, it can also be usedas a differential return enthalpy or dry bulb sensor. Figure 31shows the dual enthalpy boundaries in the W7220 Jade control-ler. With dual enthalpy, the HIGH LIMIT boundary is ES1 whenthere are no stages of mechanical cooling energized and HL(high limit) when a compressor stage is energized. Table 7shows the High Limit Curves for each setting.NOTE: To use the HH57AC081 sensor for differential return air,the dipswitches on the sensor must be set to ON-OFF-OFF. SeeTable 8.When using the CRDIFRASN01A00 differential return enthal-py or dry bulb temperature option, see Table 9 for CaliforniaTitle 24 setting requirements by region.Fig. 33 — Wiring Differential Return Air SensorCalifornia’s Title 24 High Temperature LimitSettingsCalifornia’s Title 24 code requires a high temperature limit set-ting for all dry bulb outside air economizer change over. Thetemperatures vary by region within California. See Table 9 forhigh limit settings.* Only the high limit control devices listed are allowed to be used andat the set points listed. Others such as Dew Point, Fixed Enthalpy,Electronic Enthalpy, and Differential Enthalpy Controls, may not beused in any climate zone for compliance with Section 140.4(e)1unless approval for use is provided by the Energy CommissionExecutive Director.† At altitudes substantially different than sea level, the FixedEnthalpy limit value shall be set to the enthalpy value at 75°F and50% relative humidity. As an example, at approximately 6,000 footelevation, the fixed enthalpy limit is approximately 30.7 Btu/lb.Demand Controlled Ventilation (DCV)Refer to EconoMi$er X wiring diagram (Fig. 25 and 30) andDCV instructions if demand controlled ventilation (CO 2 sen-sor) is used. CO2 sensor will wire into the blue and black con-nections at the Jade controller as shown in Fig. 25, 30, and 34.If a field-installed CO2 sensor is connected to theEconoMi$er X controller, a demand controlled ventilationstrategy will operate automatically. As the CO 2 level in thespace increases above the set point (on the EconoMi$er X con-troller), the minimum position of the dampers will be increasedproportionally, until the Maximum Ventilation setting isreached. As the space CO2 level decreases because of the in-crease in fresh air, the outdoor damper will follow the higherdemand condition from the DCV mode or from the free cool-ing mode.Fig. 34 — CO2 Wiring Connections to Jade Controller12-PIN FEMALEPLUG FROM ECONOMIZERBLUBLKGRA GRA GRAGRA GRAGRAGRAPNKVIO 672310115112948REDORGPL6PLUG 12-PIN MALEPLUG IN UNITBRNYEL*HH57AC081DIFFERENTIAL RETURNSENSOR. FIELD MOUNTEDIN RETURN DUCTWIRINGHARNESS**PROVIDED INCRDIFRASN01A00 KitTable 9 — California Title 24 Regional High Limit DryBulb Temperature SettingsTABLE 140.4-B AIR ECONOMIZER HIGH LIMIT SHUT OFFCONTROL REQUIREMENTSDEVICE TYPE* CLIMATEZONESREQUIRED HIGH LIMIT(ECONOMIZEROFF WHEN):DESCRIPTIONFixed Dry Bulb1, 3, 5, 11-16 OAT exceeds 75°F2, 4, 10 OAT exceeds 73°F6, 8, 9 OAT exceeds 71°F7 OAT exceeds 69°FDifferential Dry Bulb1, 3, 5, 11-16 OAT exceedsRA temperature2, 4, 10 OAT exceeds return airtemperature minus 2°F6, 8, 9 OAT exceeds return airtemperature minus 4°F7 OAT exceeds return airtemperature minus 6°FFixed Enthalpy†+ Fixed Dry Bulb AllOAT exceeds 28 Btu/lb of dry air †orOAT exceeds 75°FBLACK WIREIAQ 2-10 VDCBLUE WIREIAQ COM