GCGD
R-410A
INSTALLATION MANUAL
®
OUTDOOR SPLIT-SYSTEM
AIR CONDITIONING
MODELS: 13 & 14.5 SEER TCG(D,F)/GCGD/TCJ(D,F)/YCJ(D,F) SERIES
1.5 TO 6.3 TONS – 1 & 3 PHASE
LIST OF SECTIONS
GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
SAFETY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
UNIT INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
ORIFICE INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
TXV INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
EVACUATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
LIST OF FIGURES
Typical Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Installation of Vapor Line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Underground Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Heat Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Orifice Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Outdoor Unit Control Box (Single Phase) . . . . . . . . . . . . . . . . . . . . . .7
Outdoor Unit Control Box (Three Phase) . . . . . . . . . . . . . . . . . . . . . . .7
Typical Field Wiring (Air Handler / Electrical Heat) (Single-Phase) . . .8
Typical Field Wiring (Air Handler / Electrical Heat) (Three-Phase) . . .8
LIST OF TABLES
Application Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 R-410A Saturation Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
SYSTEM CHARGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
ELECTRICAL CONNECTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
INSTRUCTING THE OWNER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
WIRING DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
START UP SHEET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Thermostat Chart - Single Stage AC with PSC Air Handler . . . . . . . . 9
Thermostat Chart - Single Stage AC with PSC Air Handler . . . . . . . 10
Thermostat Chart - Single Stage AC with PSC Furnace . . . . . . . . . 11
Thermostat Chart - Single Stage AC with PSC Furnace . . . . . . . . . 12
Wiring Diagram - Single Phase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Wiring Diagram - Three Phase 2.5-5 Tons . . . . . . . . . . . . . . . . . . . . 15
Wiring Diagram - Three Phase 6.3 Ton . . . . . . . . . . . . . . . . . . . . . . 16
24 VAC Connection Wiring for 2-pipe A/C, 6.3 Ton
Condensing Unit with 7.5 Ton Air Handler . . . . . . . . . . . . . . . . . . . . 16
SECTION I: GENERAL
The outdoor units are designed to be connected to a matching indoor
coil with sweat connect lines. Sweat connect units are factory charged
with refrigerant for a matching indoor coil plus 15 feet of field-supplied
lines.
The refrigerant charge may need to be changed for some indoor-outdoor unit combinations, elevation differences or total line lengths. Refer
to Application Data covering “General Piping Recommendations and
Refrigerant Line Length” (Part Number 247077).
SECTION II: SAFETY
This is a safety alert symbol. When you see this symbol on
labels or in manuals, be alert to the potential for personal
injury.
Understand and pay particular attention to the signal words DANGER,
WARNING, or CAUTION.
DANGER indicates an imminently hazardous situation, which, if not
avoided, will result in death or serious injury
WARNING indicates a potentially hazardous situation, which, if not
avoided, could result in death or serious injury
CAUTION indicates a potentially hazardous situation, which, if not
avoided may result in minor or moderate injury
alert against unsafe practices and hazards involving only property damage.
This product must be installed in strict compliance with the
enclosed installation instructions and any applicable local, state,
and national codes including, but not limited to building, electrical,
and mechanical codes.
Johnson Controls Unitary Products 872678-UIM-C-0213
.
.
. It is also used to
R-410A systems operate at higher pressures than R-22 systems.
Do not use R-22 service equipment or components on R-410A
equipment. Service equipment
Improper installation may create a condition where the operation of
the product could cause personal injury or property damage.
Improper installation, adjustment, alteration, service or maintenance can cause injury or property damage. Refer to this manual
for assistance or for additional information, consult a qualified contractor, installer or service agency.
INSPECTION
As soon as a unit is received, it should be inspected for possib le damage during transit. If damage is evident, the extent of the damage
should be noted on the carrier’s delivery receipt. A separate request for
inspection by the carrier’s agent should be made in writing. See Local
Distributor for more information.
Requirements For Installing/Servicing R-410A Equipment
• Gauge sets, hoses, refrigerant containers, and recovery system
must be designed to handle the POE type oils, and the higher
pressures of R-410A.
• Manifold sets should be high side and low side with low side
retard.
• All hoses must have a 700 psig service pressure rating.
• Leak detectors should be designed to detect HFC refrigerant.
• Recovery equipment (including refrigerant recovery containers)
must be specifically designed to handle R-410A.
• Do not use an R-22 TXV.
• A liquid-line filter drier is required on every unit.
Must Be Rated for R-410A.
872678-UIM-C-0213
NOTICE
60” OVERHEAD
CLEARANCE
MINIMUM 18” SERVICE
ACCESS CLEARANCE
ON ONE SIDE
WEATHERPROOF
DISCONNECT
SWITCH
THERMOSTAT
10” CLEARANCE
AROUND PERIMETER
CONTROL
ACCESS
PANEL
TO INDOOR COIL
NEC CLASS 1 WIRING
NEC CLASS 2 WIRING
TO FURNACE OR
AIR HANDLER
TERMINAL BLOCK
SEAL OPENING(S) WITH
PERMAGUM OR EQUIVALENT
NOTES:
ALL OUTDOOR WIRING MUST BE WEATHERPROOF.
MINIMUM 24” UNIT TO UNIT CLEARANCE.
LIMITATIONS
The unit should be installed in accordance with all National, State and
Local Safety Codes and the limitations listed below:
1. Limitations for the indoor unit, coil, and appropriate accessories
must also be observed.
2. The outdoor unit must not be installed with any duct work in the air
stream. The outdoor fan is the propeller type and is not designed
to operate against any additional external static pressure.
3. The maximum and minimum conditions for operation must be
observed to ensure a system that will give maximum performance
with minimum service.
TABLE 1:
Application Limitations
Ambient Air Temperature
on Outdoor Coil
Air Temperature on
Indoor Coil
Min. DB Max. DB Min. WB Max. WB
50°F 115°F 57°F 72°F
4. The unit should not be operated at outdoor temperatures below
50°F without an approved low ambient operation accessory kit
installed.
5. The maximum allowable line length for this product is 75 feet.
SECTION III: UNIT INSTALLATION
LOCATION
Before starting the installation, select and check the suitability of the
location for both the indoor and outdoor unit. Observe all limitations and
clearance requirements.
The outdoor unit must have sufficient clearance for air entrance to the
condenser coil, air discharge, and service access. See Figure 1.
For multiple unit installations, units must be spaced a minimum of
18” (46 cm) apart (coil face to coil face).
If the unit is to be installed on a hot sun exposed roof or a black-topped
ground area, the unit should be raised sufficiently above the roof or
ground to avoid taking the accumulated layer of hot air into the outdoor
unit.
Provide an adequate structural support.
ADD-ON REPLACEMENT/RETROFIT
When this unit is being used as a replacement for an R-410A unit, it is
required that the outdoor unit, indoor coil, and metering device all be
replaced. The following steps should be performed in order to insure
proper system operation and performance. Line-set change out is also
recommended.
1. Change-out of the indoor coil to an approved R-410A coil/ condensing unit combination with the appropriate metering device.
2. Change-out of the line-set when replacing an R-22 unit with an
R410-A unit is highly recommended to reduce cross-contamination of oils and refrigerants.
3. If change-out of the line set is not practical, then the following precautions should be taken.
• Inspect the line set for kinks, sharp bends, or other restrictions,
and for corrosion.
• Determine if there are any low spots which might be serving as oil
traps.
• Flush the line set with a commercially available flush kit to
remove as much of the existing oil and contaminants as possible.
• Install a suction line filter-drier to trap any remaining contaminants, and remove after 50 hours of operation.
4. If the outdoor unit is being replaced due to a compressor burnout,
then installation of a 100% activated alumina suction-line filter
drier in the suction-line is required, in addition to the factory
installed liquid-line drier. Operate the system for 10 hours. Monitor
the suction drier pressure drop. If the pressure drop exceeds 3
psig, replace both the suction-line and liquid-line driers. After a
total of 10 hours run time where the suction-line pressure drop has
not exceeded 3 psig, replace the liquid line drier, and remove the
suction-line drier. Never leave a suction-line drier in the system
longer than 50 hours of run time.
FIGURE 1: Typical Installation
2 Johnson Controls Unitary Products
GROUND INSTALLATION
NOTICE
NOTICE
Liquid
Line
Incorrect
Tape
Sheet Metal Hanger
TO INDOOR COIL
Liquid Line
PVC
Conduit
Insulated
Vapor Line
TO OUTDOOR UNIT
Cap
The unit should be installed on a solid base that is 2” (5.1 cm) above
grade and will not shift or settle, causing strain on the refrigerant lines
and possible leaks. Maintain the clearances shown in Figure 1 and
install the unit in a level position. The base pad should not come in contact with the foundation or side of the structure because sound may be
transmitted to the residence.
The length of the refrigerant tubing between the outdoor unit and indoor
coil should be as short as possible to avoid capacity and efficiency
losses. Excessive spacing of the outdoor unit from the home can result
in the refrigerant lines being restricted by trampling or being punctured
by lawn mowers. Locate the outdoor unit away from bedroom windows
or other rooms where sound might be objectionable.
Adverse effects of snow or sleet accumulating on the outdoor coil can
be eliminated by placing the outdoor unit where the prevailing wind
does not blow across the unit. Trees, shrubs, corners of buildings, and
fences standing off from the coil can reduce capacity loss due to wind
chill effect.
Provide ample clearance from shrubs to allow adequate air to pass
across the outdoor coil without leaves or branches being pulled into the
coil.
ROOF INSTALLATION
When installing units on a roof, the structure must be capable of supporting the total weight of the unit, including a pad, lintels, rails, etc.,
which should be used to minimize the transmission of sound or vibration into the conditioned space.
LIQUID LINE FILTER-DRIER
The air conditioning unit’s filter/dryer is located on the liquid line.
Replacements for the liquid line drier must be exactly the same as
marked on the original factory drier. See Source1 for O.E.M.
replacement driers.
Failure to do so or using a substitute drier or a granular type may
result in damage to the equipment.
Filter-Drier
Source 1 Part No.
S1-02922195000 All
Apply with Models
872678-UIM-C-0213
This system uses R-410A refrigerant which operates at higher pressures than R-22. No other refrigerant may be used in this system.
Gauge sets, hoses, refrigerant containers, and recovery system
must be designed to handle R-410A. If you are unsure, consult the
equipment manufacturer.
Never install a suction-line filter drier in the liquid line of an R-410A
system. Failure to follow this warning can cause a fire, injury or
death.
PRECAUTIONS DURING LINE INSTALLATION
1. Install the lines with as few bends as possible. Care must be taken
not to damage the couplings or kink the tubing. Use clean hard
drawn copper tubing where no appreciable amount of bending
around obstruction is necessary. If soft copper must be used, care
must be taken to avoid sharp bends which may cause a restriction.
2. The lines should be installed so that they will not obstruct service
access to the coil, air handling system, or filter.
3. Care must also be taken to isolate the refrigerant lines to minimize
noise transmission from the equipment to the structure.
4. The vapor line must be insulated with a minimum of 1/2" foam rub-
ber insulation (Armaflex or equivalent). Liquid lines that will be
exposed to direct sunlight, high temperatures, or excessive humidity must also be insulated.
5. Tape and suspend the refrigerant lines as shown. DO NOT allow
tube metal-to-metal contact. See Figure 2.
6. Use PVC piping as a conduit for all underground installations as
shown in Figure 3. Buried lines should be kept as short as possible
to minimize the build up of liquid refrigerant in the vapor line during
long periods of shutdown.
7. Pack fiberglass insulation and a sealing material such as perma-
gum around refrigerant lines where they penetrate a wall to reduce
vibration and to retain some flexibility.
8. For systems with total line length exceeding 70 feet (21.3 m), see
APPLICATION DATA and worksheet "General Piping Recommendations and Refrigerant Line Length" for vapor and liquid line sizing, calibration of liquid line pressure loss or gain, determination of
vapor line velocity, elevation limitations, orifice connections, system charging, traps, etc.
PIPING CONNECTIONS
The outdoor condensing unit must be connected to the indoor evaporator coil using field supplied refrigerant grade (ACR) copper tubing that is
internally clean and dry. Units should be installed only with the tubing
sizes for approved system combinations as specified in tabular data
sheet. The charge given is applicable for total tubing lengths up to 15
feet (4.6 m). See Application Data Part Number 247077 for installing
tubing of longer lengths and elevation differences.
Using a larger than specified line size could result in oil return problems. Using too small a line will result in loss of capacity and other
problems caused by insufficient refrigerant flow. Slope horizontal
vapor lines at least 1" (2.5 cm) every 20 feet (6.1 m) toward the outdoor unit to facilitate proper oil return.
Johnson Controls Unitary Products 3
FIGURE 2: Installation of Vapor Line
FIGURE 3: Underground Installation
872678-UIM-C-0213
NOTICE
PRECAUTION S DUR IN G BRAZING OF LINES
All outdoor unit and evaporator coil connections are copper-to-copper
and should be brazed with a phosphorous-copper alloy material such
as Silfos-5 or equivalent. DO NOT use soft solder. The outdoor units
have reusable service valves on both the liquid and vapor connections.
The total system refrigerant charge is retained within the outdoor unit
during shipping and installation. The reusable service valves are provided to evacuate and charge per this instruction.
Serious service problems can be avoided by taking adequate precautions to assure an internally clean and dry system.
Dry nitrogen should always be supplied through the tubing while it
is being brazed, because the temperature required is high enough
to cause oxidation of the copper unless an inert atmosphere is provided. The flow of dry nitrogen should continue until the joint has
cooled. Always use a pressure regulator and safety valve to insure
that only low pressure dry nitrogen is introduced into the tubing.
Only a small flow is necessary to displace air and prevent oxidation.
PRECAUTION S DUR IN G BRAZ I NG SERVICE VALVE
Precautions should be taken to prevent heat damage to service valve
by wrapping a wet rag around it as shown in Figure 4. Also, protect all
painted surfaces, insulation, and plastic base during brazing. After brazing, cool joint with wet rag.
Do not install any coil in a furnace which is to be operated during
the heating season without attaching the refrigerant lines to the coil.
The coil is under 30 to 35 psig inert gas pressure which must be
released to prevent excessive pressure build-up and possible coil
damage.
4. Braze the liquid line to the evaporator liquid connection. Nitrogen
should be flowing through the evaporator coil.
5. Slide the grommet away from the vapor connection at the indoor
coil. Braze the vapor line to the evaporator vapor connection. After
the connection has cooled, slide the grommet back into original
position.
6. Protect the vapor valve with a wet rag and braze the vapor line
connection to the outdoor unit. The nitrogen flow should be exiting
the system from the vapor service port connection. After this connection has cooled, remove the nitrogen source from the liquid fitting service port.
7. Replace the Schrader core in the liquid and vapor valves.
8. Go to SECTION IV or SECTION V for orifice or TXV installation
depending on application.
9. Leak test all refrigerant piping connections including the service
port flare caps to be sure they are leak tight. DO NOT OVERTIGHTEN (between 40 and 60 inch - lbs. maximum).
This is not a backseating valve. The service access port has a
valve core. Opening or closing valve does not close service access
port.
If the valve stem is backed out past the chamfered retaining wall,
the O-ring can be damaged causing leakage or system pressure
could force the valve stem out of the valve body possibly causing
personal injury.
Valve can be opened by removing the plunger cap and fully inserting a
hex wrench into the stem and backing out counter-clockwise until valve
stem just touches the chamfered retaining wall.
Connect the refrigerant lines using the following procedure:
1. Remove the cap and Schrader core from both the liquid and vapor
service valve service ports at the outdoor unit. Connect low pressure nitrogen to the liquid line service port.
2. Braze the liquid line to the liquid valve at the outdoor unit. Be sure
to wrap the valve body with a wet rag. Allow the nitrogen to continue flowing.
3. Carefully remove the plugs from the evaporator liquid and vapor
connections at the indoor coil.
Line set and indoor coil can be pressurized to 250 psig with dry
nitrogen and leak tested with a bubble type leak detector. Then
release the nitrogen charge.
Do not use the system refrigerant in the outdoor unit to purge or
leak test.
10. Evacuate the vapor line, evaporator, and liquid line to 500 microns
or less.
11. Replace cap on service ports. Do not remove the flare caps from
the service ports except when necessary for servicing the system.
Do not connect manifold gauges unless trouble is suspected.
Approximately 3/4 ounce of refrigerant will be lost each time a standard manifold gauge is connected.
12. Release the refrigerant charge into the system. Open both the liquid and vapor valves by removing the plunger cap and with an
allen wrench back out counter-clockwise until valve stem just
touches the chamfered retaining wall. If the service valve is a ball
valve, use a cresent wrench to turn valve stem one-quater turn
counterclockwise to open. Do not overturn or the valve stem may
break or become damaged. See “PRECAUTIONS DURING
BRAZING SERVICE VALVE”.
13. Replace plunger cap finger tight, then tighten an additional 1/12
turn (1/2 hex flat). Cap must be replaced to prevent leaks.
FIGURE 4: Heat Protection
4 Johnson Controls Unitary Products
Never attempt to repair any brazed connections while the system is
under pressure. Personal injury could result.
See "System Charge” section for checking and recording system
charge.
Supplied with the outdoor unit is a Schrader Valve Core and Orifice for
highest sales volume indoor coil. The valve core must be installed in
equalizer fitting of the indoor coil.
SECTION IV: ORIFICE INSTALLATION
LIQUID LINE
SWIVEL COUPLING
(This fitting is a right-hand thread,
turn counter-clockwise to remove)
ORIFICE
DISTRIBUTOR
872678-UIM-C-0213
Only 1TVM900 series valves are to be used on this product.
Failure to install Schrader Valve Core on orifice applications could
result in total refrigerant loss of the system!
Install Schrader Valve Core and Orifice as follows:
1. Slide indoor coil out of cabinet far enough to gain access to equalizer fitting on the suction line.
2. After holding charge is completely discharged remove black plastic cap on equalizer fitting.
3. Install Schrader Valve Core supplied with the outdoor unit into
equalizer fitting using a valve core tool.
4. Loosen and remove the liquid line fitting from the orifice distributor
assembly. Note that the fitting has right hand threads
5. Install proper size orifice supplied with outdoor unit. Refer to supplied Tabular Data Sheet for specific orifice size and indoor coil
match up.
6. After orifice is installed reinstall the liquid line to the top of the orifice distributor assembly. Hand tighten and turn an additional 1/8
turn to seal. Do not over tighten fittings.
7. Leak test system.
8. Replace black plastic cap on equalizer fitting.
9. Slide indoor coil back into cabinet.
.
1. Relieve the holding charge by pulling off the rubber cap plug on
the suction manifold line of the coil.
2. After holding charge is completely discharged, loosen and remove
the Schrader cap seal.
3. Loosen and remove distributor cap seal.
4. Install the thermal expansion valve to the orifice distributor assembly with supplied fittings. Hand tighten and turn an additional 1/4
turn to seal. Do not overtighten fittings.
5. Install the liquid line to the top of the thermal expansion valve with
fitting supplied with the liquid line. Hand modify the liquid line to
align with casing opening. Hand tighten the liquid line and an additional 1/4 turn to seal.
6. Install the TXV equalizer line into the vapor line as follows:
a. Hand tighten the 1/4” SAE nut to the Schrader fitting and an
additional 1/3 turn to seal.
7. Install the TXV bulb to the vapor line near the equalizer line, using
the bulb clamp(s) furnished with the TXV assembly. Ensure the
bulb is making maximum contact.
a. Bulb should be installed on a horizontal run of the vapor line if
possible. The bulb should be installed on top of the line.
b. If bulb installation is made on a vertical run, the bulb should
be located at least 16” (40.6 cm) from any bend, and on the
tubing sides opposite the plane of the bend. The bulb should
be positioned with the bulb tail at the top, so that the bulb acts
as a reservoir.
c. Bulb should be insulated using thermal insulation pro vided to
protect it from the effect of the surrounding ambient temperature. Cover completely to insulate from air-stream.
FIGURE 5: Orifice Installation
SECTION V: TXV INSTALLATION
When using a TXV, 13 SEER models 12-48 require a hard start kit.
Models 12-48 with a “H” on the end of the model number have a
factory installed hard start.
The following are the basic steps for installation. For detailed instructions, refer to the Installation Instructions accompanying the TXV kit.
Install TXV kit as follows:
In all cases, mount the TXV bulb after vapor line is brazed and has
had sufficient time to cool.
Schrader valve core MUST NOT be installed with TXV installation.
Poor system performance or system failure could result.
SECTION VI: EVACUATION
It will be necessary to evacuate the system to 500 microns or less. If a
leak is suspected, leak test with dry nitrogen to locate the leak. Repair
the leak and test again.
To verify that the system has no leaks, simply close the valve to the vacuum pump suction to isolate the pump and hold the system under vacuum. Watch the micron gauge for a few minutes. If the micron gauge
indicates a steady and continuous rise, it’s an indication of a leak. If the
gauge shows a rise, then levels off after a few minutes and remains
fairly constant, it’s an indication that the system is leak free but still contains moisture and may require further evacuation if the reading is
above 500 microns.
Johnson Controls Unitary Products 5
872678-UIM-C-0213
SECTION VII: SYSTEM CHARGE
The factory charge in the outdoor unit includes enough charge for the
unit, a 15 ft. (4.6 m) line set, and the smallest indoor coil match-up.
Some indoor coil matches may require additional charge. See tabular
data sheet provided in unit literature packet for charge requirements.
Do not leave the system open to the atmosphere.
The “TOTAL SYSTEM CHARGE” must be permanently stamped on the
unit data plate.
Total system charge is determined as follows:
1. Determine outdoor unit charge from tabular data sheet.
2. Determine indoor coil adjustment from tabular data sheet.
3. Calculate the line charge using the tabular data sheet if line length
is greater than 15 feet (4.6 m).
4. Total system charge = item 1 + item 2 + item 3.
5. Permanently stamp the unit data plate with the total amount of
refrigerant in the system.
Use the following charging method whenever additional refrigerant is
required for the system charge.
DO NOT attempt to pump “Total System Charge” into outdoor unit
for maintenance, service, etc. This may cause damage to the compressor and/or other components. the outdoor unit only has enough
volume for the factory charge, not the “Total System Charge”.
Refrigerant charging should only be carried out by a qualified air
conditioning contractor.
Compressor damage will occur if system is improperly charged. On
new system installations, charge system per tabular data sheet for
the matched coil and follow guidelines in this instruction.
If a calibrated charging cylinder or accurate weighing device is available, add refrigerant accordingly. Otherwise, model-specific charging
charts are provided on the access panel of the unit.
SUPERHEAT CHARGING METHOD PISTON INDOOR
1. Set the system running in cooling mode by setting the thermostat
at least 6°F below the room temperature and operate system for at
least 10 – 15 minutes.
2. Refer to the technical guide for the recommended airflow and ver ify indoor airflow (it should be about 400 SCFM per ton).
3. Measure and record the outdoor ambient (DB) temperature and
the suction pressure at the suction service valve.
4. Using the charging chart located on the unit, find the intersection
of the outdoor ambient dry bulb and the suction pressure obtained
in step 3. This is the recommended suction tube temperature at
the service valve.
5. Measure and record the suction tube temperature at the service
valve and compare to the recommended temperature obtained in
step 4.
6. Add charge if the measured suction temperature in step 5 is above
the recommended value. Remove / recover refrigerant if the measured suction temperature is below the recommended value.
Example: The suction tube temperature listed on the table at the
intersection of the outdoor DB and the suction pressure is 63°F.
Temperature of the suction tube at the service valve is 68°F. It would
be necessary to add refrigerant to drop the suction tube temperature
to 63°F.
SUBCOOLING CHARGING METHOD - TXV INDOOR
For cooling operation, unless otherwise specified, the default subcooling is 10°F.
1. Set the system running in cooling mode by setting the thermostat
at least 6°F below the room temperature and operate system for at
least 10 – 15 minutes.
2. Refer to the technical guide for the recommended indoor airflow
and verify it is correct (it should be about 400 SCFM per ton).
3. Measure and record the indoor wet bulb (WB) and the outdoor
ambient dry bulb (DB) temperature.
4. Using the charging chart located on the unit, find the intersection
of the indoor wet bulb and the outdoor dry bulb. This is the recommended liquid pressure (and subcooling value).
5. Measure and record the pressure at the liquid valve pressure port
and compare to the value obtained in step 4.
6. Add charge if the measured liquid pressure is lower than the recommended value. Remove / recover charge if the measured liquid
pressure is above the recommended value.
Example: The liquid pressure listed at the intersection of the indoor
WB and the outdoor DB 320 psig. Pressure at the liquid valve is 305
psig. It would be necessary to add refrigerant to increase the liquid
pressure to 320 psig.
Condenser subcooling is obtained by calculating the difference of the
saturated refrigerant temperature of the pressure measured at the liquid
base valve and the liquid tube temperature as measured at the liquid
base valve.
Subcooling Temp. (TC) = Saturated Temp. (TS) – Liquid Temp. (T).
IT IS UNLAWFUL TO KNOWINGLY VENT, RELEASE OR DISCHARGE REFRIGERANT INTO THE OPEN AIR DURING
REPAIR, SERVICE, MAINTENANCE OR THE FINAL DISPOSAL
OF THIS UNIT.
6 Johnson Controls Unitary Products
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