Carrier 50HC Series, Installation Instructions Manual, Page: 47 / 52

47
Fig. 65 — EconoMi$er IV Wiring
Step 12 — Adjust Factory-Installed Options
SMOKE DETECTORS
Smoke detector(s) will be connected at the Controls Connections
Board, at terminals marked “Smoke Shutdown.” Cut jumper
JMP 3 when ready to energize unit.
ECONOMI$ER IV OCCUPANCY SWITCH
See Fig. 65 for general EconoMi$er IV wiring. External occupan-
cy control is managed through a connection on the Controls Con-
nections Board.
If external occupancy control is desired, connect a time clock or
remotely controlled switch (closed for Occupied, open for Unoc-
cupied sequence) at terminals marked OCCUPANCY. Cut jumper
JMP 2 to complete the installation.
Step 13 — Install Accessories
Available accessories include:
• Roof curb
• Thru-base connection kit (must be installed before unit is
set on curb)
• Electric heaters and single-point connection kits
• Manual outside air damper
• Two-position motorized outside air damper
• EconoMi$er
® IV (with control)
• EconoMi$er2 (without control/for external signal)
• Power Exhaust
• Differential dry-bulb sensor (EconoMi$er IV)
• Outdoor enthalpy sensor
• Differential enthalpy sensor
• CO
2
sensor
• DDC interface (PremierLink™)
• Louvered hail guard
• Motormaster
® head pressure controls
• Phase monitor control
• EnergyX
® Recovery Ventilation (ERV)
Refer to separate installation instructions for information on in-
stalling these accessories.
Step 14 — Check Belt Tension
Measure the belt span length as shown in Fig. 66. Calculate the re-
quired deflection by multiplying the belt span length by 1 /
64
. For
example, if the belt span length is 32 inches:
32 x 1 /
64
= 1 /
2
-in. deflection.
BELT FORCE — DEFLECTION METHOD
Check the belt tension with a spring-force belt force deflection
gage (available from drive belt manufacturer).
1. Place a straightedge along the belt between the two pul-
leys. Measure the distance between the motor shaft and the
blower shaft.
2. Set the tension gage to the desired tension (see Table 1 in
Fig. 66). Place the large O-ring at that point.
3. Press the tension checker downward on the belt until the
large O-ring is at the bottom of the straightedge.
4. Adjust the belt tension as needed.
Adjust belt tension by loosing the motor mounting plate front bolts
and rear bolt (see Fig. 67) and slide the plate towards the fan (to
reduce tension) or away from the fan (to increase tension). Ensure
the blower shaft and motor shaft are parallel to each other (pulleys
aligned). Tighten all bolts securely when finished.