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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 repair or final unit disposal.
Wear safety glasses and gloves when handling
refrigerants. Keep torches and other ignition sources
away from refrigerants and oils.
CAUTION
PERSONAL INJURY HAZARD
Failure
to
follow
this
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 R-410A
Refrigerant
Replacement/retrofit installations require change-out of out-
door 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 is intended to be re-used,
check with the coil manufacturer to verify the coil construc-
tion is suitable for operation with the higher pressures of
R-410A refrigerant. Also determine if the existing TXV valve
is compatible with R-410A; replace if necessary. The mini-
mum factory test pressure rating must be 250 psig
(1725 kPa). Existing coil will need to be purged with Nitro-
gen 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 com-
pressor electrical failure, assume acid is in system. If sys-
tem is being replaced for any other reason, use an ap-
proved acid test kit to determine acid level. If even low lev-
els 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 operation.
Recommendation: Install a ball valve in the liquid line at the
filter drier location when installing a suction filter in the suc-
tion 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 dam-
age, corrosion or poor brazing. Flush the interconnecting
piping system with dry Nitrogen to eliminate as much trace
of mineral oil as possible.
Same tube sizes are capable of handling higher flow rates
(expressed as tons of cooling capacity) with R-410A refrig-
erant compared to R-22 at constant pressure drops. For ex-
ample, a 1/2-inch OD liquid line is rated at 33% higher tons
with R-410A than with R-22 (at 5°F pressure drop). A
1-1/8 inch OD suction line is rated at 53% higher tons with
2
caution
may
result
in
Specifications subject to change without notice.
R-410A than with R-22 (at 2°F pressure drop). Refrigeration
lines selected for R-22 use are typically oversized for
R-410A 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 sizing data in Tables 8 and 9 or; 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 tub-
ing and evaporator if they were not replaced. Remov-
ing oil from evaporator coil may require purging of
the tubing with dry nitrogen.
3. Unless indoor unit is equipped with a R-410A
approved metering device, change the metering
device to a thermal expansion valve (TXV) designed
for R-410A refrigerant.
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
metering 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
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 required 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 evacuate when replacing filter
driers. Continue to monitor the pressure drop across
suction-line filter drier. Repeat filter changes if neces-
sary. Never leave suction-line filter drier in system
longer than 72 hr (actual time).
GENERAL
See Fig. 1 for CAS model number nomenclature. For unit
dimensions see Fig. 2. For corner weights see Table 4. For
physical data see Tables 5 and 6.
Rated Indoor Airflow (cfm)
Tables 1 and 2 list the rated indoor airflow used for the AHRI
efficiency rating for the units covered in this document.
Table 1 — CAS (Single Circuit) with F*S/H or F*X
MODEL NUMBERS
CAS072 — F*X072
CAS091 — F*X091
CAS121 — F*X120
CAS151 — F*S/H150
FULL LOAD AIRFLOW (CFM)
2400
3000
4000
4400
CAS-072-153-01SI Rev. A
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