Rated Indoor Airflow (Cfm); Identify Factory Options; Matching 38Au Model To Evaporator Coil; General - Carrier Gemini 38AU07 Series Installation Instructions Manual

Air-cooled condensing units with puron (r-410a) refrigerant
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Table 2 — Equivalent Lengths for Common Fittings
NOMINAL
TUBE OD
90° Std
90° Lrad 90° Street
3
/
1.3
0.8
8
/
1.4
0.9
1
2
/
1.6
1.0
5
8
3
/
1.8
1.2
4
7
/
2.0
1.4
8
1
1
/
2.6
1.7
8
1
3
/
3.3
2.3
8
1
/
4.0
2.6
5
8
2
/
5.0
3.3
1
8
NOMINAL
Branch
TUBE OD
Flow
No Reduct Reduce 25% Reduce 50%
/
2.6
3
8
1
/
2.7
2
5
/
3.0
8
3
/
3.5
4
7
/
4.0
8
1
1
/
5.0
8
1
/
7.0
3
8
1
5
/
8.0
8
2
1
/
10.0
8
NOTE: Equivalent line lengths will vary based on tube diameter.
Calculate equivalent line length for each pipe by adding equiva-
lent length adjustments to linear lengths for each pipe.
Enter the appropriate table to select the recommended line
sizes.
INSTALLATION
1.
Remove the existing evaporator coil or fan coil and
install the replacement coil when appropriate.
2.
Drain oil from low points and traps in suction line tubing
(and hot gas bypass tubing if appropriate) and evaporator
if they were not replaced. Removing oil from evaporator
coil may require purging of the tubing with dry nitrogen.
3.
Unless indoor unit is equipped with a Puron approved
metering device, change the metering device to a thermal
expansion valve (TXV) designed for Puron refrigerant
(R-410A).
4.
Remove the existing outdoor unit. Install the new out-
door unit according to these installation instructions.
5.
Install a new field-supplied liquid-line filter drier at the
indoor coil just upstream of the TXV or fix orifice meter-
ing device.
6.
If a suction line filter drier is also to be installed, install
suction line drier downstream of suction line service
valve at condensing unit.
CAUTION
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment dam-
age or improper operation. Never install suction-line filter
drier in the liquid line of a Puron system.
7.
If required, install a 100% activated alumina suction line
filter drier at the outdoor unit.
(ft)
ELBOWS
90° Std
90° Street
2.2
0.6
1.0
2.3
0.7
1.1
2.5
0.8
1.3
2.9
0.9
1.5
3.2
0.9
1.6
4.1
1.3
2.1
5.6
1.7
3.0
6.3
2.1
3.4
8.2
2.6
4.5
TEES
Straight-Thru
0.8
1.1
1.3
0.9
1.2
1.4
1.0
1.4
1.6
1.2
1.7
1.8
1.4
1.9
2.0
1.7
2.3
2.6
2.3
3.1
3.3
2.6
3.7
4.0
3.3
4.7
5.0
8.
Evacuate and charge the system according to the instruc-
tions in this installation manual.
9.
Operate the system for 10 hr. Monitor the pressure drop
across the suction line filter drier. If pressure drop
exceeds 3 psig (21kPa), replace suction-line and liquid-
line filter driers. Be sure to purge system with dry nitro-
gen and evacuate when replacing filter driers. Continue
to monitor the pressure drop across suction-line filter
drier. Repeat filter changes if necessary. Never leave suc-
tion-line filter drier in system longer than 72 hr (actual
time).

Rated Indoor Airflow (cfm)

Tables 3 and 4 lists the rated indoor airflow used for the
AHRI efficiency rating for the units covered in this document.
Table 3 — 38AUZ with 40RUA
MODEL NUMBERS
38AUZA/B07 — 40RUA*07
38AUZD/E07 — 40RUA*07
38AUZ*08 — 40RUA*08
38AUZ*12 — 40RUA*12
38AUZ*14 — 40RUA*14
Table 4 — 38AUD with 40RUA
MODEL NUMBERS
38AUD*12 — 40RUA*12
38AUD*14 — 40RUA*14

Identify Factory Options

Factory options will affect 38AU unit pipe sizing selections.
Coil type impacts liquid lift limits; Hot Gas Bypass impacts
the selection of suction tube size in vertical riser segments.
Check this unit's Model Number against the Model Number No-
menclature, Fig. 1. Determine the significance of this unit's val-
ues in Position 11 (Coil type) and Position 6 (Hot Gas Bypass,
38AUDC12 only). Copy the unit's Model Number from the
unit's dataplate into the open line in the header above Fig. 1 to
facilitate this step. For date of unit manufacture see Serial Num-
ber Nomenclature, see Fig. 2.

Matching 38AU Model to Evaporator Coil

The Model 38AUZ is a single-circuit unit design, requiring
one set of refrigeration piping. This model can be connected to
an evaporator coil with one circuit or with two circuits (by mani-
folding the evaporator connections into a single piping system).
The Model 38AUD is a dual-circuit unit design that requires
two sets of refrigeration piping between the outdoor unit and the
evaporator coil (or coils). This model can only be connected to
an evaporator coil that has two refrigeration circuits (or to two
separate evaporator coils). The Model 38AUD CANNOT be
connected to a single-circuit evaporator coil. The Model 38AUD
CANNOT be field-converted to a single-circuit design.
Before unpacking this new 38AU model, compare the evapo-
rator coil design to the 38AU model.

General

For unit dimensions see Fig. 3. For corner weights see Ta-
ble 5. For physical data see Table 6.
MODEL/POSITION
#6
38AUZ
38AUD
3
FULL LOAD AIRFLOW (CFM)
2400
2625
3000
4000
4375
FULL LOAD AIRFLOW (CFM)
4000
4400
QUANTITY OF LINE
TABLE
SETS
7
1
8
2

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