Step 8 - Install Outdoor-Air Hood; Step 9 - Install All Accessories; Motormaster I Control Installation - Carrier 50TJ016 Installation, Start-Up And Service Instructions Manual

Step 8 — Install Outdoor-Air Hood —
type of factory-installed hood is used on units with 25% air
ventilation and units with an economizer.
NOTE: The hood top panel, upper and lower filter retain-
ers, hood drain pan, baffle (028), and filter support bracket
are secured opposite the condenser end of the unit. The screens,
hood side panels, remaining section of filter support bracket,
seal strip, and all other hardware are in a package located
inside the return-air filter access panel (Fig. 17).
1. Attach seal strip to upper filter retainer. See Fig. 18.
2. Assemble hood top panel and side panels, upper filter re-
tainer, and hood drain pan (Fig. 19).
3. Secure lower filter retainer and long section of filter sup-
port bracket to unit. See Fig. 19. Leave screws loose on
028 units.
4. Slide baffle (size 028 unit) behind lower filter retainer and
tighten screws.
5. Loosen sheet metal screws for base unit top panel located
above outdoor-air inlet opening, and remove screws for
hood side panels located on the sides of the outdoor-air
inlet opening.
6. Match notches in hood top panel to unit top panel screws.
Insert hood flange between unit top panel flange and unit.
Tighten screws.
7. Hold hood side panel flanges flat against unit, and install
screws removed in Step 5.
8. Insert outdoor-air inlet screens and spacer in channel cre-
ated by lower filter retainer and filter support bracket.
9. Attach remaining short section of filter support bracket.
ENTHALPY CONTROL INSTALLATION
NOTE: The accessory outdoor-air enthalpy sensor must be
installed BEFORE the economizer hoods are installed on the
unit or hoods will have to be removed.
1. Remove and discard the factory-installed jumper assem-
bly containing the 800-ohm resistor on the economizer
control module (between terminals S
Fig. 15.
2. Remove black wire assembly containing the 620-ohm re-
sistor from between economizer control module terminal
S and the outdoor-air thermostat (OAT). Place this wire
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assembly (containing the 620-ohm resistor) between econo-
mizer control module terminals S
jumper removed in Step 1. See Fig. 15.
3. Disconnect the blue wire from the OAT.
4. Remove OAT from the outside of the economizer (see
Fig. 13).
5. Mount the enthalpy sensor (Fig. 20) to the economizer on
the outside of the unit (in the same location from which
the OAT was removed) using the 2 screws provided. See
Fig. 13.
6. Reconnect the blue wire removed in Step 3 to the en-
thalpy sensor terminal +.
7. Cut the violet wire provided to desired length and ter-
minate with quick-connect terminal provided. Route the
violet wire from the enthalpy sensor terminal S, through
the snap bushing, and to the economizer control module
terminal S . See Fig. 15.
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8. Set changeover set point to the desired location.
See Fig. 21.
NOTE: For maximum benefit of outdoor air, set the en-
thalpy control to the ''A'' setting. At this setting, when
the relative humidity is 50% and the outdoor air is below
74 F, the relay contacts on the sensor will be closed.
9. Reinstall economizer hoods if removed.
The same
and +). See
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and +, replacing the
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IMPORTANT: Be sure all seal strips and RTV sealant
are intact. A watertight seal to inside of unit must be
maintained.
DIFFERENTIAL ENTHALPY CONTROL
NOTE: The accessory outdoor-air enthalpy sensor must be
installed BEFORE the economizer hoods are installed on the
unit or hoods will have to be removed.
1. Remove and discard the factory-installed jumper assem-
bly containing the 800-ohm resistor on the economizer
control module (between terminals S
Fig. 15.
2. Disconnect black wire from economizer control module
terminal S and blue wire from the OAT (outdoor-air
O
thermostat).
3. Remove OAT and black wire assembly containing the
620-ohm resistor from the outside of the economizer (see
Fig. 13).
4. Mount the outdoor-air enthalpy sensor (first sensor) to
the economizer on the outside of the unit (in the same
location from which the OAT was removed) using the 2
screws provided. See Fig. 13.
5. Reconnect the blue wire removed in Step 2 to the en-
thalpy sensor terminal +.
6. Cut the violet wire provided to desired length and ter-
minate with quick-connect terminal provided. Route the
violet wire from the enthalpy sensor terminal S, through
the snap bushing, and to the economizer control module
terminal S .
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7. Mount the second enthalpy sensor in the return-air duct
(return-air sensor).
8. Route the blue wire (provided) from terminal + on the
return-air enthalpy sensor to the economizer control mod-
ule terminal +.
9. Route the violet wire (provided) from terminal S on the
return-air enthalpy sensor to the economizer control mod-
ule terminal S .
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10. Turn changeover set point dial clockwise past the ''D''
setting, or the control will not operate on a differential.
See Fig. 15.
11. Reinstall economizer hood if removed.
IMPORTANT: Be sure all seal strips and RTV sealant
are intact. A watertight seal to inside of unit must be
maintained.
Step 9 — Install All Accessories —
factory-installed options have been adjusted, install all field-
installed accessories. Refer to the accessory installation in-
structions included with each accessory.
MOTORMASTER I CONTROL INSTALLATION (50TJ016
and 020 Only)
Install Field-Fabricated Wind Baffles — Wind baffles must
be field-fabricated for all units to ensure proper cooling cycle
operation at low ambient temperatures. See Fig. 22 for baffle
details. Use 20-gage, galvanized sheet metal, or similar
corrosion-resistant metal for baffles. Use field-supplied screws
to attach baffles to unit. Screws should be
and 5 ⁄ -in. long. Drill required screw holes for mounting baffles.
8
To avoid damage to the refrigerant coils and electrical
components, use recommended screw sizes only. Use
care when drilling holes.
and +. See
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After all the
1 ⁄ -in. diameter
4