Installation Guidelines; Replacement/Retrofit; R-22 To Puron Refrigerant; Rated Indoor Airflow (Cfm) - Carrier Gemini 38AU 07 Series Installation, Start-Up And Service Instructions Manual

WARNING
PERSONAL INJURY AND ENVIRONMENTAL
HAZARD
Failure to follow this warning could cause personal injury or
death.
Relieve pressure and recover all refrigerant before system re-
pair or final unit disposal.
Wear safety glasses and gloves when handling refrigerants.
Keep torches and other ignition sources away from refriger-
ants and oils.
CAUTION
PERSONAL INJURY HAZARD
Failure to follow this caution may result in personal injury.
Sheet metal parts may have sharp edges or burrs. Use care and
wear appropriate protective clothing, safety glasses and gloves
when handling parts and servicing air conditioning equipment.

INSTALLATION GUIDELINES

Replacement/Retrofit —

R-22 to Puron Refrigerant

Replacement/retrofit installations require change-out of outdoor
unit, metering device, and filter driers. Change-out of indoor coil
(evaporator) and interconnecting tubing is recommended.
EXISTING EVAPORATOR COIL
If the existing evaporator coil may be re-used, check with the coil
manufacturer to verify the coil construction is suitable for opera-
tion with the higher pressures of Puron
Also determine if the existing TXV valve is compatible with
R-410A, replace if necessary. The minimum factory test pressure
rating must be 250 psig (1725 kPa). Existing coil will need to be
purged with Nitrogen to remove as much mineral oil as possible to
eliminate cross contamination of oils.
ACID TEST
If the existing system is being replaced because of a compressor
electrical failure, assume acid is in system. If system is being re-
placed for any other reason, use an approved acid test kit to deter-
mine acid level. If even low levels of acid are detected, install a
100 percent activated alumina suction-line filter drier in addition
to the replacement liquid-line filter drier. Remove the suction line
filter drier as soon as possible, with a maximum of 72 hr of opera-
tion. Recommendation: Install a ball valve in the liquid line at the
filter drier location when installing a suction filter in the suction
line.
EXISTING REFRIGERATION PIPING
Reuse of existing refrigerant piping involves three issues: quality
(strength) of existing tubing, cleanliness and tube size. Inspect all
tube segments and joints for signs of damage, corrosion or poor
brazing. Flush the interconnecting piping system with dry Nitro-
gen to eliminate as much trace of mineral oil as possible.
Same tube sizes are capable of handling higher flowrates (ex-
pressed as tons of cooling capacity) with Puron refrigerant com-
pared to R-22 at constant pressure drops. For example, a
OD liquid line is rated at 33% higher tons with Puron than with
R-22 (at 5°F pressure drop). A 1
at 53% higher tons with Puron than with R-22 (at 2°F pressure
drop). Refrigeration lines selected for R-22 use are typically over-
sized for Puron applications. Carefully check the existing suction
line size against the table for maximum size; replace vertical riser
segments if necessary. Check existing liquid line size against
refrigerant (R-410A).
®
/ -inch
1
2
/ -inch OD suction line is rated
1
8
sizing data in Table 8 , 9 or 10; replace with smaller lines when
feasible.
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 meter-
ing device, change the metering device to a thermal expan-
sion valve (TXV) designed for Puron refrigerant (R-410A).
4. Remove the existing outdoor unit. Install the new outdoor
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 metering
device.
6. If a suction line filter drier is also to be installed, install suc-
tion line drier downstream of suction line service valve at
condensing unit.
EQUIPMENT DAMAGE
Failure to follow this caution can result in equipment damage.
Do not install a suction-line filter drier in liquid line. A liquid-
line filter drier designed for use with R-410A refrigerant is re-
quired on every unit.
7. If required, install a 100% activated alumina suction line filter
drier at the outdoor unit.
8. Evacuate and charge the system according to the instructions
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 nitrogen and evacu-
ate when replacing filter driers. Continue to monitor the pres-
sure drop across suction-line filter drier. Repeat filter changes
if necessary. Never leave suction-line filter drier in system
longer than 72 hr (actual time).

Rated Indoor Airflow (cfm)

Tables 1 and 2 lists the rated indoor airflow used for the AHRI
efficiency rating for the units covered in this document.
Table 1 — 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 2 — 38AUD with 40RUA
MODEL NUMBERS
38AUD*12 — 40RUA*12
38AUD*14 — 40RUA*14
2
CAUTION
FULL LOAD AIRFLOW (CFM)
2400
2625
3000
4000
4375
FULL LOAD AIRFLOW (CFM)
4000
4400