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 and checkout. See Table 6.
Table 6 Ð Color Code Recommendations
SIGNAL | CCN BUS CONDUCTOR | CCN PLUG |
TYPE | INSULATION COLOR | PIN NO. |
Positive (+) | RED | 1 |
Ground | WHITE | 2 |
Negative (−) | BLACK | 3 |
NOTE: If a cable with a different color scheme is selected, a similar color code should be adopted for the entire network.
At each system element, the shields of the communica- tion bus cables must be tied together. If the communication bus is entirely within one building, the resulting continuous shield must be connected to a ground at one point only. If the communication bus cable exits from one building and enters another, the shields must be connected to grounds at the lightning suppressor in each building where the cable enters 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 appropriate colors.)
3.Remove the 3-pin male plug from the base module in the main control box, and connect the wires as follows:
a.Insert and secure the red (+) wire to terminal 1 of the 3-pin plug.
b.Insert and secure the white (ground) wire to terminal 2 of the 3-pin plug.
c.Insert and secure the black (−) wire to terminal 3 of the 3-pin plug.
4.Insert the plug into the existing 3-pin mating connector on the base module in the main control box.
Step 9 Ð Make Outdoor-Air Inlet Adjustments
ECONOMIZER
NOTE: If accessory power exhaust or barometric relief pack- ages are being added to the unit, install power exhaust or barometric relief before installing economizer hoods.
Economizer Hood Assembly Ð The economizer hood is shipped in a package secured to the outside of the unit and must be ®eld-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 ®lters from below. Filter tracks (mounting angle without tabs) must be installed correctly to allow access to economizer ®lters from each side. Perform the following procedure to assemble the econo- mizer hood:
NOTE: Before assembly of the economizer hood, check along the outer edges of the economizer assembly for any seal strip protruding past the ¯anges. Trim the excess seal strip so that it is ¯ush with the economizer assembly ¯anges.
1.Apply black seal strip (provided in package) to outside top-edge of hood sides. Wrap seal strip over edge to cover top ¯ange (4 hood sides). Make sure seal strip covers screw holes. Allow strip to overhang 1¤8-in. past the end opposite the mounting ¯ange. 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 ¯anges of hood sides being sure to cover mounting holes. See Fig. 25.
NOTE: Each hood assembly has a slotted side that should be adjacent to the other hood when mounted to the unit.
5.Apply black seal strip (provided) to hood top mounting ¯ange. Seal strip of hood top mounting ¯ange must press tightly against seal strip of hood side mounting ¯anges. 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 hood side between ®lter and cross member opposite the mount- ing end. See Fig. 28.
8.Attach gray foam strip (provided) to block-off baffle on outer face of ¯ange. See Fig. 29.
9.Remove the screws on each end and along top of damper assembly of unit. Remove top 2 screws on each side of ®lter panel under damper assembly. Set hood assembly in place and attach to unit using these screws.
10.Attach accessory enthalpy bracket on hood side furthest from control box end. Locate bracket on inside upper right-hand corner of economizer hood using hood mount- ing holes. Mount outdoor-air thermistor to enthalpy bracket (if purchased). Attach and wire enthalpy assembly. Place quick connects on enthalpy wires.
11.Remove screws along bottom of damper assembly. Lo- cate and mount blockoff baffle using these screws.
12.Assemble 2 ®lter tracks side-by-side with the as- sembled ends together.
13.Attach mounting angle (without tabs) to the assembled end of the ®lter 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 other end of the ®lter track with no. 10 screws provided. See Fig. 31.
16.Place ®lter track assembly in bottom of hood by placing tabbed end into slotted side (with tab on bottom) and attaching opposite end to hood with speed clips and gas- keted screws provided. Tabs can be hand bent after they have been inserted into the side.
NOTE: The ®lter track assembly end with screws should face away from the other hood when mounted on the unit.
NOTE: Tabs from both ®lter tracks will be in the same space. After one ®lter track has been inserted into hood side, bend the tabs so they will not interfere with in- stallation of the second hood.
17.Attach black seal strip (provided) to ®lter cover. Seal strip should be applied to the center of the large ¯ange making sure to cover holes. See Fig. 32.
18.Slide two 20 x 25-in. ®lters into cross members of hood assembly. Attach ®lter cover over ®lters with screws and speed clips provided.
Minimum Damper Position Setting Ð Setting of the out- door air damper position is performed in conjunction with a shortened version of the ®eld run test. This is performed by ®rst opening DIP (Dual In-line Package) switch no. 4 then no. 6. See Fig. 18 and 19 and Direct Digital Controls DIP Switch Con®guration section on page 33.
