Carrier 38AU - Manual (Page 2)

2
INSTALLATION GUIDELINE
Replacement /Retrofit – R22 to Puron ®
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 operation with the higher pressures
of Puron ® (R-410A). Also determine if the existing TXV valve
is compatible with R-410A, replace if necessary. The minimum
factory test pressure rating must be 1725 kPa (250 psig).
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 replaced for any other reason, use an approved
acid test kit to determine 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 operation. Recommendation:
Install a ball valve in the liquid line at the filter drier location
when installing a suction filter in the suction line (to facilitate
evacuation of the system’s low side when suction filter-drier is
removed).
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® (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 fil.ter-drier is also to be installed, install
the suction line filter-drier immediately upstream of the
suction line service valve at the outdoor unit. Note the
recommendation above regarding use of ball valve in the
liquid line.
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 21kPa (3 psig), 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 is necessary. Never leave
suction-line filter drier in system longer than 72 hr.
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could cause personal injury
or death.
Before performing service or maintenance operations on
unit, always turn off main power switch to unit and install
lockout tag. Unit may have more than one power switch.
UNIT OPERATION AND SAFETY HAZARD
Failure to follow this warning could cause personal injury,
death and/or equipment damage.
Puron® (R-410A) refrigerant systems operate at higher
pressures than standard R-22 systems. Do not use R-22
service equipment or components on Puron refrigerant
equipment.
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.
CUT 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 38AU units.
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment
damage or improper operation.
Never install suction-line filter drier in the liquid-line of a
Puron ® system.