7
S
Recovery cylinder service pressure rating must be 400
psig, DOT (Department of Transportation) 4BA400 or
DOT BW400.
S
Puron systems should be charged with liquid refrigerant.
Use a commercial type metering device in the manifold
hose when charging into suction line with compressor op-
erating.
S
Manifold sets should be 700 psig high side and 180 psig
low side with 550 psig low--side retard.
S
Use hoses with 700 psig service pressure rating.
S
Puron refrigerant, as with other HFCs, is only compatible
with POE oils.
S
Vacuum pumps will not remove moisture from oil.
S
Polyol Ester oils absorb moisture rapidly. Do not expose oil
to atmosphere.
S
Polyol Ester oils may cause damage to certain plastics and
roofing materials.
S
Wrap all filter driers and service valves with wet cloth when
brazing.
S
factory approved, liquid--line filter drier is required on ev-
ery unit.
S
Do not use a TXV (thermostatic expansion valve) designed
for use with R--22 refrigerant. Refer to separate indoor unit
installation instructions for more details.
S
If using a suction line drier, do not leave in place for more
than 72 hours.
Heating Check Chart Procedure -- Heating Mode
To check system operation during heating cycle, refer to the
Heating check Chart on outdoor unit. This chart indicates whether
a correct relationship exists between system operating pressure and
air temperature entering indoor and outdoor units. If pressure and
temperature do not match on chart, system refrigerant charge may
not be correct. Do not use chart to adjust refrigerant charge.
NOTE
: When charging is necessary during heating season, charge
must be weighed in accordance with unit rating plate
±
0.6 oz./ft. of
3/8--in. liquid line above or below 25 ft. (7.6 m) respectively.
To calculate additional charge required for a 35--ft. (11 m) line set:
35 ft. (10.6 m) -- 25 ft. (7.6 m) = 10 ft. X 0.6 oz./ft. = 6 oz. of
additional charge.
CHECK CHARGE -- UNITS WITH TXV COOLING
METERING DEVICE
Factory charge amount and desired subcooling are shown on unit
rating plate. Charging method is shown on information plate inside
unit. To properly check or adjust charge, conditions must be
favorable for subcooling charging. Favorable conditions exist
when the outdoor temperature is between 70
_
F and 100
_
F (21
_
C
and 38
_
C), and the indoor temperature is between 70
_
F and 80
_
F
(21
_
C and 27
_
C). Follow the procedure below:
Unit is factory charged for 15 ft (4.6 m) of line--set. Adjust charge
by adding or removing 0.6 oz/ft of 3/8 liquid line above or below
15 ft (4.6 m) respectively.
For standard refrigerant line lengths (80 ft/24 m or less), allow
system to operate in cooling mode at least 15 minutes. If conditions
are favorable, check system charge by subcooling method. If any
adjustment is necessary, adjust charge slowly and allow system to
operate for 15 minutes to stabilize before declaring a properly
charged system.
If the indoor temperature is above 80
_
F (27
_
C), and the outdoor
temperature is in the favorable range, adjust system charge by
weight based on line length and allow the indoor temperature to
drop to 80
_
F (27
_
C) before attempting to check system charge by
subcooling method as described above.
If the indoor temperature is below 70
_
F (21
_
C), or the outdoor
temperature is not in the favorable range, adjust charge for line set
length above or below 15 ft (4.6 m) only. Charge level should then
be appropriate for the system to achieve rated capacity. The charge
level could then be checked at another time when the both indoor
and outdoor temperatures are in a more favorable range.
NOTE
: If line length is beyond 80 ft (24.4 m) or greater than 20 ft
(6 m) vertical separation, See Long Line Guideline for special
charging requirements.
Units with Indoor Pistons
Units installed with indoor pistons require charging by the
superheat method. The following procedure is valid when indoor
airflow is within
±
21% of its rated CFM.
1. Operate unit a minimum of 10 minutes before checking
charge.
2. Measure suction pressure by attaching an accurate gauge to
suction valve service port.
3. Measure suction temperature by attaching an accurate
thermistor type or electronic thermometer to suction line at
service valve.
4. Measure
outdoor
air
dry--bulb
temperature
with
thermometer.
5. Measure indoor air (entering indoor coil) wet--bulb
temperature with a sling psychrometer.
6. Refer to Table 1. Find outdoor temperature and evaporator
entering air wet--bulb temperature. At this intersection, note
superheat.
7. Refer to Table 2. Find superheat temperature located in item
6 and suction pressure. At this intersection, note suction line
temperature.
8. If unit has a higher suction line temperature than charted
temperature, add refrigerant until charted temperature is
reached.
9. If unit has a lower suction line temperature than charted
temperature, reclaim refrigerant until charted temperature is
reached.
10. When adding refrigerant, charge in liquid form into suction
service port using a flow--restricting device.
11. If outdoor air temperature or pressure at suction valve
changes, charge to new suction line temperature indicated
on chart.
MAINTENANCE
!
WARNING
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal
injury or death.
Before installing, modifying, or servicing system, main
electrical disconnect switch must be in the OFF
position. There may be more than 1 disconnect switch.
Lock out and tag switch with a suitable warning label.
LUBRICATION
Compressor
Compressor contains factory oil charge; replace oil when lost. Use
Mobile 3MA--POE oil.
CLEANING COILS
Coil should be washed out with water or blown out with
compressor air. Note that the blow--thru design causes dirt and
debris to build up on the inside of the coils. Clean coil annually or
as required by location and outdoor air conditions. Inspect coil
monthly and clean as required. Fins are not continuous through
538B
