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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
®
refrigerant (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 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 flow rates (ex-
pressed as tons of cooling capacity) with Puron refrigerant com-
pared to R-22 at constant pressure drops. For example, a 1/2-inch
OD liquid line is rated at 33% higher tons with Puron than with
R-22 (at 5°F pressure drop). A 1-1/8 inch OD suction line is
rated at 53% higher tons with Puron than with R-22 (at 2°F
pressure drop). Refrigeration lines selected for R-22 use are
typically oversized for Puron applications. Carefully check the
existing suction line size against the table for maximum size;
replace vertical riser segments if necessary. Check existing liq-
uid line size against sizing data in Tables 7 and 8 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 tubing 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.
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 (21 kPa), 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.
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 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.
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.
Table 1 — 38AUZ with 40RUA
MODEL NUMBERS FULL LOAD AIRFLOW (cfm)
38AUZ16 — 40RUA16 6000
38AUZ25 — 40RUA25 8300
Table 2 — 38AUD with 40RUA
MODEL NUMBERS FULL LOAD AIRFLOW (cfm)
38AUD16 — 40RU16 5625
38AUD25 — 40RU25 8000
38AUD28 — 40RU28 9375
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