Carrier SINGLE PACKAGE ROOFTOP UNITS ELECTRIC COOLING/GAS HEATING 48EJ Installation And Service Instructions Manual

Also see for 48EJ: Installation, Start-Up and Service Instructions User manual

Contents

IMPORTANT: When connecting the CCN communi-cation bus to a system element, use a color coding sys-tem for the entire network to simplify installation andcheckout. See Table 6.Table 6 — Color Code RecommendationsSIGNALTYPE CCN BUS CONDUCTORINSULATION COLOR CCN PLUGPIN NO.Positive (+) RED 1Ground WHITE 2Negative (−) BLACK 3NOTE: If a cable with a different color scheme is selected,a similar color code should be adopted for the entirenetwork.At each system element, the shields of the communica-tion bus cables must be tied together. If the communicationbus is entirely within one building, the resulting continuousshield must be connected to a ground at one point only. Ifthe communication bus cable exits from one building andenters another, the shields must be connected to grounds atthe lightning suppressor in each building where the cableenters or exits the building (one point per building only).To connect the unit to the network:1. Turn off power to the control box.2. Cut the CCN wire and strip the ends of the red (+), white(ground), and black (−) conductors. (If a different net-work color scheme is used, substitute appropriatecolors.)3. Remove the 3-pin male plug from the base module in themain control box, and connect the wires as follows:a. Insert and secure the red (+) wire to terminal 1 of the3-pin plug.b. Insert and secure the white (ground) wire toterminal 2 of the 3-pin plug.c. Insert and secure the black (−) wire to terminal 3 ofthe 3-pin plug.4. Insert the plug into the existing 3-pin mating connectoron the base module in the main control box.Step 9 — Make Outdoor-Air Inlet AdjustmentsECONOMIZERNOTE: If accessory power exhaust or barometric relief pack-ages are being added to the unit, install power exhaust orbarometric relief before installing economizer hoods.Economizer Hood Assembly — The economizer hood isshipped in a package secured to the outside of the unit andmust be field-assembled. There are 2 hoods on every unit.The 48EW/EY units are side supply and side return. The re-turn duct limits access to economizer filters from below.Filter tracks (mounting angle without tabs) must be installedcorrectly to allow access to economizer filters from each side.Perform the following procedure to assemble the econo-mizer hood:NOTE: Before assembly of the economizer hood, check alongthe outer edges of the economizer assembly for any seal stripprotruding past the flanges. Trim the excess seal strip so thatit is flush with the economizer assembly flanges.1. Apply black seal strip (provided in package) to outsidetop-edge of hood sides. Wrap seal strip over edge to covertop flange (4 hood sides). Make sure seal strip coversscrew holes. Allow strip to overhang 1 ⁄8 -in. past the endopposite the mounting flange. See Fig. 23.2. Assemble hood sides, top, and cross member with gas-keted screws provided. See Fig. 24.3. Attach 10 green speed clips (provided) to hood top.4. Apply black seal strip (provided) to mounting flanges ofhood sides being sure to cover mounting holes. SeeFig. 25.NOTE: Each hood assembly has a slotted side that shouldbe adjacent to the other hood when mounted to the unit.5. Apply black seal strip (provided) to hood top mountingflange. Seal strip of hood top mounting flange must presstightly against seal strip of hood side mounting flanges.See Fig. 26.6. Add gray foam strip (provided in package) to cross mem-bers on bottom tray. See Fig. 27.7. Place gray foam strip (provided) on inside of slotted hoodside between filter and cross member opposite the mount-ing end. See Fig. 28.8. Attach gray foam strip (provided) to block-off baffle onouter face of flange. See Fig. 29.9. Remove the screws on each end and along top of damperassembly of unit. Remove top 2 screws on each side offilter panel under damper assembly. Set hood assemblyin place and attach to unit using these screws.10. Attach accessory enthalpy bracket on hood side furthestfrom control box end. Locate bracket on inside upperright-hand corner of economizer hood using hood mount-ing holes. Mount outdoor-air thermistor to enthalpy bracket(if purchased). Attach and wire enthalpy assembly. Placequick connects on enthalpy wires.11. Remove screws along bottom of damper assembly. Lo-cate and mount blockoff baffle using these screws.12. Assemble 2 filter tracks side-by-side with the as-sembled ends together.13. Attach mounting angle (without tabs) to the assembledend of the filter track. See Fig. 30.14. Attach 6 green speed clips (provided) to mounting angles.Engagement section of clip faces inside of rack.15. Attach remaining mounting angle (with tabs) to otherend of the filter track with no. 10 screws provided. SeeFig. 31.16. Place filter track assembly in bottom of hood by placingtabbed end into slotted side (with tab on bottom) andattaching opposite end to hood with speed clips and gas-keted screws provided. Tabs can be hand bent after theyhave been inserted into the side.NOTE: The filter track assembly end with screws shouldface away from the other hood when mounted on theunit.NOTE: Tabs from both filter tracks will be in the samespace. After one filter track has been inserted into hoodside, bend the tabs so they will not interfere with in-stallation of the second hood.17. Attach black seal strip (provided) to filter cover. Sealstrip should be applied to the center of the large flangemaking sure to cover holes. See Fig. 32.18. Slide two 20 x 25-in. filters into cross members of hoodassembly. Attach filter cover over filters with screws andspeed clips provided.Minimum Damper Position Setting — Setting of the out-door air damper position is performed in conjunction with ashortened version of the field run test. This is performed byfirst opening DIP (Dual In-line Package) switch no. 4 thenno. 6. See Fig. 18 and 19 and Direct Digital Controls DIPSwitch Configuration section on page 33.24