Trane GSSD User Manual

Water Source Heat Pump Residential Split Configuration HVAC System
Installation Operation &
WSHPC-IOM-2
72-9041-02
Maintenance
Library Service Literature
Product Section Unitary
Product Water Source Heat Pump
Literature Type Installation, Operation and Maintenance
Sequence 2
Date June 1999
File No. SL-UN-WSHP-GSSD-IOM-2-6-99
Supersedes WSHPC-IOM-2 / 72-9041-01 (Jan 98)
©An American Standard Company
Since American Standard Inc. has a policy of continuous product improvement, it reserves the right to change specifications and design without notice. The installation and servicing of the equipment referred in this booklet should be done by qualified, experienced technicians.
Table of Contents
Model Number
Descriptions.....................
General
Information......................
Receiving and
Handling..........................
Installation
Drawings.........................
Installation (Water
Connections)....................
Installation
(Electrical).................
Diagram.................... 14
3 Installation (Water Loop).. 15
4 Refrigeration Charge........ 16
6 Refrigeration System....... 17
7 Accessories................... 18
10
11
Notice
The Trane Company urges that all HVAC servicemen working on Trane equipment, or any manufacturer’s products, make every effort to eliminate, if possible, or vigorously reduce the emission of CFC, HCFC, and HFC refrigerants to the atmo­sphere resulting from installation, operation, routine maintenance, or major service on this equipment. Always act in a re­sponsible manner to conserve refrigerants for continued use even when acceptable alternatives are available.
Refrigerant used in any type of air-conditioning or refrigerating equipment should be covered for reuse, recovered and/or recycled for reuse, reprocessed (reclaimed), or properly destroyed, whenever it is removed from the equipment. Never re­lease to the atmosphere.
Take extra care to properly maintain all service equipment directly supporting refrigerant service work such as gauges, hos­es, vacuum pumps, and recycling equipment. Stay aware of unit enhancements, conversion refrigerants, compatible parts and manufacturer’s recommendations which will reduce refrigerant emissions and increase equipment operating efficien­cies. Follow specific manufacturer’s guidelines for conversion of existing systems.
2
Model Number Description
DIGITS 1 & 2 - PRODUCT TYPE
GS = Ground Source Heat Pump
DIGIT 3 - PRODUCT CONFIGU­RATION
S = Split System
DIGIT 4 - DEVELOPMENT SE­QUENCE D
DIGITS 5,6 & 7 - UNIT NOMINAL CAPACITY (MBH)
024 = 24.1
030 = 29.6
036 = 36.4
042 = 41.1
048 = 48.7
060 = 59.2
072 = 65.6
GS S D 036 1 0 C 0 0 1 2 0 T
5
DIGIT 14 - FREEZE PROTEC­TION
1 = 35 Degree Freezestat
2 = 20 Degree Freezestat
DIGIT 15 - OPEN
0 = Open
DIGIT 16 - BRAND
C = Command Aire
T = Trane
10
15
DIGIT 8 - VOLTAGE/HERTZ/ PHASE
1 = 208/230-60-1
DIGIT 9 - UNIT ARRANGEMENT
0 = Split Condensing Unit
DIGIT 10 - DESIGN SEQUENCE C
DIGIT 11 - OPEN DIGIT
0 = Open Digit
DIGIT 12 - OPEN DIGIT
0 = Open Digit
DIGIT 13 - DESUPERHEATER
0 = No Desuperheater
1 = With Desuperheater
3
General Information
The GSSD split unit has been ARI rat­ed with the Trane TWE air handlers with ICM 2 variable speed motors to create a complete split system for res­idential applications. The GSSD equipment is completely assembled, piped, internally wired and test operat­ed in the factory. The GSSD equip­ment is ETL and CSA listed.
A prewired terminal strip is provided for field control wiring.
The system water inlet and outlet con­nections are female 1-inch National Pipe Thread (NPT) swivel quick con­nectors with stainless steel stop ring to simplify field installation.
The GSSD units are shipped with a pressurized dry nitrogen holding charge to ensure clean components.
All equipment has easy to read decals and labels to aid in service of unit, identifying port locations and indicat­ing caution areas.
Safety
The GSSD was designed with protec­tion of unit components in mind. High and low pressure cutouts are included to prolong the life of the compressor. A 35 degrees F freezestat for non-anti­freeze applications or 20 degrees F freezestat for closed loop with anti­freeze is included to protect against fluid freezing in the unit’s water heat exchanger. All safety devices with ex­ception of compressor internal over­load are connected to a lockout relay to turn off the compressor, the loop pumps and the desuperheater pump if a problem is incurred.
Note:
The lockout relay may be reset by cycling power to the unit at the dis­connect or thermostat system switch.
Brass Loop Water Connections
Two 1-inch brass swivel connectors on the units help eliminate the need for a backup wrench when tightening the loop water connections.
Gaskets for the brass connections can be found inside a cloth bag located in the electrical compartment.
Cabinet
The cabinet is constructed of galva­nized heavy gauge steel. The finish is applied by an electrostatic powder spray system in the color of crushed
ice.
The top, front half of the diagonal cab­inet is removable for access to all of the internal components by removing only two screws. All panels are insu­lated with 1/2-inch thick, neoprene backed, acoustical fiberglass insula­tion
Desuperheater
(Optional)
The double wall vented desuperheater uses heat off of the discharge line of the compressor to preheat a home’s domestic hot water. Hot water is pro­vided at virtually no cost to the user during the cooling operation and effi­ciently during the heating operation by reducing the amount of time the hot water heater runs.
The desuperheater’s stainless steel, voluted, circulator pump is built into the unit. The connections are 1/2-inch NPT female water inlet and outlet con­nections. The desuperheater has two temperature control sensors that mon­itor the temperature of the discharge line of the compressor and the temper-
ature-out of the hot water heater. The desuperheater is disable until the com­pressor discharge line reaches 145 de­grees F. The desuperheater pump will automatically shut off if the tempera­ture of the incoming water exceeds 125 degrees F to prevent excessive water temperatures and pump damage.
Trane provides a twist lock fuse for the desuperheater. The fuse is shipped loose to ensure pump integrity. The pump is water cooled and should be connected to the water heater prior to its running.
The fuse is located in a cloth bag in the electric box. (See Page 12, Figure 6
for fuse location).
Thermostats
The following wall mounted thermo­stats may be used in conjuction with these units:
! Single-stage manual changeover
with Heat-Off-Cool system switch and On-Off fan switch. This thermostat is suitable if there is no electric backup heater used with a water-to-air heat pump.
! A single stage cool/two stage heat
manual changeover with Heat­Off-Cool system switch, Auto/On fan switch, and a Normal­Auxiliary-Emergency Heat switch. The Normal-Auxiliary-Emergency Heat switch thermostat is suitable when an electric backup heater is used in conjunction with a water­to-air heat pump.
4
General Information
Warranty
The unit is warranted by the manufac­turer against any defects in material and factory workmanship for one year after installation (labor and parts).
The refrigerant circuit, including the compressor, expansion device, revers­ing valve (less solenoid coil), and all heat exchangers in contact with refrig­erants are warranted for an additional four years (parts only).
Optional extended warranties are available through the local distributor.
Note:
If any safety device is bypassed or removed, the warranty is voided.
5
Receiving and Handling
The GSSD is packaged in clear stretch wrap to allow immediate visual in­spection. A careful inspection should be made for shipping damage. All or-
ders are free on board (FOB) facto­ry, therefore claims must be made with the delivering carrier.
Carefully remove the stretch wrap and the top cardboard corner pieces. Also
remove the (4) four shipping brackets from the lower corners of the unit along with the shipping skid.
Note:
Before installing the unit:
! Verify nameplate and model
number are correct.
! Inspect the overall quality and
appearance of the unit
.
Top Cover
Corners
Figure 1: Shipment Packaging
Wooden Skid
Shipping Brackets
6
Installation-Location Considerations
Unit Size 024
Unit Size
024 163
23-5/16”
23”
LOW VOLTAGE
TOP VIEW
WATER REG (SCHRADER PORT)
24-5/16”
LOW PSI SCHRADER
DESUPER OUT 1/2” NPT
DESUPER IN 1/2” NPT
1-1/8” DIA.
PUMP CONTROL 1-1/8” DIA.
SUCTION/DISCH 3/4” O.D.
10-7/16”
7-3/16”
Unit Weight
(lbs.)
6-7/16”
5-1/2”
HI PSI SCHRADER
3-15/16” 1-7/16”
HI VOLTAGE 1-1/8” DIA.
LIQUID LINE 1/2” O.D.
WATER OUT 1” NPTI
13”
14-3/4”
13-15/16”
24-13/16”
8-7/16”
13-1/4”
WATER IN-1” NPTI
FRONT VIEW SIDE VIEW
7
2-1/16”
Installation-Location Considerations
Unit Size 030-042
23”
TOP VIEW
23-5/16”
WATER REG (SCHRADER PORT)
24-5/16”
LO PSI SCHRADER
Unit Size
DESUPER OUT 1/2” NPT
DESUPER IN 1/2” NPT
10-7/16”
Unit Weight
030 169
036 183
042 203
LOW VOLTAGE 1-1/8” DIA.
PUMP CONTROL 1-1/8” DIA.
SUCTION/DISCH 3/4” O.D.
7-3/16”
(lbs.)
6-7/16”
5-1/2”
HI PSI SCHRADER
3-15/16” 1-7/16”
HI VOLTAGE 1-1/8” DIA.
LIQUID LINE 1/2” O.D.
WATER OUT 1” NPTI
13”
14-3/4”
13-15/16”
24-13/16”
8-7/16”
11-1/2”
WATER IN-1” NPTI
FRONT VIEW SIDE VIEW
8
2-1/16”
Installation-Location Considerations
Unit Size 048-072
23”
TOP VIEW
23-5/16”
WATER REG (SCHRADER PORT)
Unit Size
DESUPER OUT
1/2” NPT
Unit Weight
(lbs.)
048 214
060 244
072 277
LOW VOLTAGE 1-1/8” DIA.
PUMP CONTROL 1-1/8” DIA.
SUCTION/DISCH 3/4” O.D.
6-7/16”
5-1/2”
3-15/16” 1-7/16”
HI VOLTAGE 1-1/8” DIA. LIQUID LINE 1/2” O.D.
WATER OUT
1” NPTI
24-13/16”
FRONT VIEW
24-5/16”
DESUPER IN 1/2” NPT
LO PSI SCHRADER
10-7/16”
9
7-3/16”
8-7/16”
11-1/2”
WATER IN-1” NPTI
SIDE VIEW
HI PSI SCHRADER
19-1/16”
14-3/4”
13-15/16”
2-1/16”
Location Consideration
! Unit should be placed on a level
surface in a indoor protected area. Units should not be installed or stored in an exterior environment.
Installation-Water Connections
! There should be approximately 2
to 3 feet of clearance available for accessing the unit for service.
Accessiblity into unit is made by re­moving (2) two screws at the base of the system. (See Figure 2). The top half of the cube then lifts off.
Water Connections
The loop water connections brought to the unit should be 1-inch male national pipe threads.
The desuperheater (optional) connec­tions should be 1/2-inch male national pipe threads.
(See Figure 3 for water hook-up loca­tions).
Remove these two screws for internal unit maintenance.
Desuperheater Water-in 1/2” Female NPT
Desuperheater Wat er -o ut 1/2” Female NPT
Figure 2: Unit access.
Wate r- ou t 1” Female NPT
Water-in 1” Female NPT
Refrigeration Connections
The refrigeration piping connections are copper stub-outs. All refrigeration connections are to be soldered into the unit. It may be necessary to provide an adapter to connect to the chosen air handler.
sizes).
Note:
All refrigeration piping between the air handler and the heat pump should be ade­quately insulated. Water piping should also be insulated to reduce heat transfer and the forming of condensation.
(See Figure 4 for location and
Unit Size
024
030-072
10
Suction
Line (O.D.)
3/4” 7/8”
Figure 3: Water hook-up locations.
Liquid Line 1/2” O.D.
Figure 4: Liquid and suction lines.
Installation- Electrical
Field Wiring Connections
Power wiring to the unit should be in­stalled per local electric codes by a professional electrician. The wires can be run to the unit through the available knockouts and to the control box in the top half of the unit. Control wiring to the unit is 24 volt. The termination point identifications for the terminal strip is identified per Figure 5.
5
Compressor Reversing valve (energized
6
in cooling)
1
Common
T-Stat
(X13510588020)
Manual changeover:
-two-stage heat
-one-stage cool
TWE
(Sizes 031-065)
GSSD
(Sizes 024-072)
GSSD 24V Field Wiring
RF
RG YO B
34561
Figure 5: Field wire connections.
Y
OC
2
1K1 to
Water Pump and L1 / L2
W
W
W
1
1
2
W
2
Low Voltage
Pump Control
Hi Voltage
Terminal Strip for Low Voltage to TWE
Ground
11
Installation- Electrical
Electrical System
The factory tested and installed control box contains all of the necessary de­vices to control unit operation in both the heating and cooling mode. A re­mote wall thermostat is necessary for the control of the unit operation. See
General Information for thermostat in­formation.
The nameplate provides information for the application of either time delay fuses or HACR circuit breakers for branch circuit protection from the pri­mary source of power. See Figure 6 for
component specifications.
.
Table 1: Electrical Data
Unit Model: GSSD 024 030 036 042 048 060 072
Volts-60HZ/1Phase 208-230 208-230 208-230 208-230 208-230 208-230 208-230
Compressor RLA 11.4 13.6 15 18.4 20.4 28 32.1
Compressor LRA 56 67 73 95 109 169 169
Electrical
Blower Motor RLA 3 5 5.6 5.6 5.6 7.4 7.4
Min. Circuit Amp. 14.7 17.4 19.2 23.4 25.9 35.4 40.5
Max Fuse Size 25 30 30 40 45 60 70
Desuperhtr Pump RLA 0.40 0.40 0.40 0.40 0.40 0.40 0.40
LOCKOUT RELAY; 24VAC
FUSE; 2 AMP 480V
IF DESUPERHEATER IS USED, THE FUSE IS SHIPPED IN A CLOTH BAG
10 POLE TERMINAL STRIP; 20A-250V
Figure 6: Electric component location.
24VAC ENERGY LIMITING CLASS II 75VA BREAKER TYPE TRANSFORMER
COMPRESSOR RUN CAPACITOR
370V
COMPRESSOR CONTACTOR
3 POLE-24VAC
ALUMINUM GROUND TERMINAL
Note: 208/230 volt equipment is designed to operate between 197 and 253 volts. Operation outside of these ranges is likely to adversely affect the service life of the equipment.
12
Pressure Switch
E
A high pressure switch is provided to protect the compressor against exces­sive refrigeration pressure. The low pressure switch should be wired in ac­cordance with the type of freezestat that is used. Trane factory supplies two low pressure switches in the re­frigerant circuit. The electrical con­nection is dependant upon which freezestat (35 or 20 degree) is selected The pressure switch is used to protect the compressor against operation un-
HEAT EXCHANGER
7 PSIG LOW PRESSURE SWITCH USED FOR 20 DEGREE FREEZESTAT
DESUPERHEATER
COMPRESSOR
Installation- Electrical
der low charge or catastrophic loss of charge situations.
The low water temperature switch is provided to protect the water-to-re­frigerant heat exchanger from freez­ing. This device triggers the lock out relay when leaving water temperatures fall below the preset freezestat setting. This device may be reset by cycling power, but the system should be re­viewed for operational error.
Important Notice
The low pressure switch should be wired to activate at refrigerant pressures of 35 psig when a 35 degree F freezestat is used; 7 psig when a 20 degree F freezestat is used. The installer should verify that the correct freezestat and low pressure switch are used in your application. Misapplication can produce a failure to the unit and cause the warranty to be voided.
35-DEGREE F
OR
20-DEGREE F FREEZESTAT
FILTER DRIER
EXPANSION VALVE
DESUPERHEATER PUMP
LIQUID LINE
WATER-OUT
SUCTION-DISCH
LINE 35 PSIG LOW PRESSUR SWITCH USED FOR 35 DEGREE FREEZESTAT
WATER-IN
DESUPERHEATER-OUT
DESUPERHEATER-IN
REVERSING VALVE
13
Typical Wiring Diagram
L2
L1
230V 6A MAX
TO WATERSOURCE PUMP
1TB3-1
16
1TB3-5
18
1TB3-6
25
5F3
1K1
L3
T3
1K1
L1
T1
6A,C,D,E
A,C
5F2
5F1
4
2A
6E
7C
C
1C1
7A
4S5
6F
A
A
5C
4S6
2B1
6H
6B1
5C
DESUPER­HEATER PUMP
6G
R
S
C
G
F,G
1K3
C2
C1
A
1K3
19A
4S3
20A
4S4
21A
5
4S1
C
A
1TB3-7
23
1TB3-8
1TB3-2
23
A
D,F
16
1K1
1K3-24
D
1K1-12,14
A
4S4
F
DEVICE
1K1 1K3
1TB3
1C1 2B1
4L1 4S1 4S3 4S4 4S5 4S6
5F1,2,3
6B1
LEGEND
DESCRIPTION
COMPRESSOR CONTACTOR LOCKOUT RELAY
TERMINAL STRIP COMPRESSOR RUN CAPACITOR COMPRESSOR
REVERSING VALVE FREEZE PROTECTION SW 1 HIGH PRESSURE SW LOW PRESSURE SW DISCHARGE LINE T’STAT ENTERING WATER T’STAT
FUSE DESUPERHEATER PUMP
NOTES:
1.
2.
4
14
UNLESS OTHERWISE NOTED. ALL SWITCHES ARE SHOWN AT 77 DEGREES F AT ATMOSPHERIC PRESSURE. AT 50% RELATIVE HUMIDITY, WITH ALL UTILITIES TURNED OFF, AND AFTER A NORMAL SHUTDOWN HAS OCCURRED.
DASHED LINES INDICATE RECOMMENDED FIELD WIRING BY OTHERS. DASHED LINE ENCLOSURES AND/OR DASHED DEVICE OUTLINES INDICATE COMPONENTS PROVIDED BY THE FIELD. DOT LINE ENCLOSURES INDICATE ALTERNATE CIRCUITRY OR AVAILABLE SALES OPTIONS. SOLID LINES INDICATE FACTORY WIRING.
BEFORE INSTALLING FUSE IN DESUPERHEATER CIRCUIT, BE CERTAIN PUMP PIPING IS CONNECTED AND FILLED WITH WATER
Loop Water Applications
It should be noted that there is no me­chanical difference between geother­mal (closed loop) and ground water (open loop) GSSD units. Generally in a closed loop application, there is a percentage of antifreeze in the water. In these applications, the 20 degree F freezestat, along with the 7 psig safety pressure switch may be used. All other applications require the 35 degree F freezestat, along with the 35 psig safe­ty pressure switch.
Ground Water Applications (Open Loop)
Where an existing or proposed well can provide an ample supply of suit­able quality water, open ground water systems may be very efficient. How­ever, there are several potential con­siderations that should be addressed prior to installation of an open loop system:
! A 60 mesh straining device must
be placed in the incoming water line. The sand filter/separator helps ensure clean water by removing any particles in the water. Note: A filter/separator
should be available from your local dealer.
! Even if plenty of water is
available, there needs to be an acceptable way to discharge it after it has passed through the heat pump. A three-ton heat pump is
Installation - Water Loop
apt to use one million gallons of water per year. It may be necessary to install a recharge well to return the water to the aquifer. In some soils, this may be difficult to do.
! Water quality must also be
acceptable to maintain the integrity and life of the unit. The loop fluid must have minimal suspended solids, and must be non-corrosive to copper or brass. See Table 2 for specifications.
Table 2: Water Supply Requirements
Scaling
Calcium and magnesium salts (total hardness)
Corrosion
pH 7.5-9.5
Hydrogen Sulfide Less than 1 ppm
Sulfates Less than 25 ppm
Carbon dioxide Less than 75 ppm
Chloride Less than 125 ppm
Total dissolved solids (TDS)
Biological Growth
Iron bacteria Low
Erosion
Suspended Solids Low
Less than 350 ppm
Less than 1000 ppm
Ground Water Applications (Closed Loop)
Loop sizing should be done by a qual­ified installer to insure maximized unit performance.
In areas where the ground water tem­perature is 66 degrees F or less, the earth coupling fluid requires at least a 15 percent by volume antifreeze solu­tion. Using Table 3, calculate the ap­proximate water volume of the system. Add one gallon to your total as an allowance for water in each heat pump and connection hoses. Check the earth coupling design for the anti­freeze percentage required. MORE IS NOT BETTER-Do no exceed the amount indicated in the design specifi­cations.
Table 3: Water Volume
Volume in Gallons/100 Ft.
Pipe Size 3/4” 1”
Vo l um e SDR-11
Vo l um e SCH 40
3.02 4.73 7.52 9.85 15.4
2.77 4.49 7.77 10.6 17.4
Use only FULL STRENGTH INHIB­ITED PROPYLENE GLYCOL OR METHANOL, not solutions which have already been diluted.
Note:
The water quality of the fluid loop should meet the same specifications as in Table 2.
1 1/4” 1 1/2”
2”
15
Refrigerant Charge
GSSD Units Coupled with TWE Air Handlers
The GSSD IS coupled with the TWE­E series. Table 4 may be used to deter­mine the amount of charge necessary for the split unit system without any refrigerant line connecting the two. Table 5 can be used to determine the amount of refrigerant needed for lines. By adding the two weights together, the approximate total system charge can be obtained. For fine tuning the charge, see Units Coupled with Non-
TWE Air Handlers and Fine Tuning
in next section.
Table 4: R22 Requirements
GSSD Model
Number
GSSD024 TWE031E 5.0
GSSD030 TWE031E 5.0
GSSD036 TWE040E 8.25
GSSD042 TWE040E 9.25
GSSD048 TWE065E 9.25
GSSD060 TWE065E 10.125
GSSD072 TWE065E 10.75‘
TWE
Model
Number
Lbs of R22
for both
GSSD & TWE
Table 5: R22 requirement per foot of line
O.D. Tube
Size
1/4-inch 0.352 N/A
3/8-inch 0.928 N/A
1/2-inch 1.152 0.032
5/8-inch 1.840 0.048
3/4-inch 4.272 0.064
7/8-inch N/A 0.080
1 1/8-inch N/A 0.144
Liquid Line
(oz.)
Suction
Line (oz.)
Note:
If piping runs exceed 50 feet, the next highest pipe size should be used.
GSSD Units Coupled with Non-TWE Air Handlers and Fine Tuning
1. Place the GSSD system in the
cooling mode.
2. Throttle down the water flow with a ball valve until the leaving fluid temperature is 95 degrees F.
3. Charge the system unit until a level of 10 degrees superheat is achieved. To determine super­heat, an accurate suction line temperature needs to be taken along with the suction pressure.
4. The sub-cooling will be approxi­mately 8 degrees to 5 degrees F.
5. Allow system to run 20 minutes for conditions to stabilize before measuring the super­heat.
6. Return water flow to 3 gpm per
nominal ton of capacity.
16
Refrigeration System
! Compressor: The unit includes a
high efficiency scroll compressor with and internal vibration isolator that absorbs starting and stopping energy. It also contains an internal overload protection. External vibration isolation is provided by rubber mounting devices located underneath the mounting base of the compressor.
! Water-to-Refrigerant Heat
Exchanger: The water-to­refrigerant heat exchanger is a high quality stainless steel braze plate heat exchanger. This stainless material offers exceptional corrosion resistance. The heat exchanger has a working pressure rating of 450 psig on both the refrigerant and water sides. To help ensure clean water for the water-to-refrigerant heat exchanger, Trane recommends a sand filter/separator for open loop systems.
! Freezestat and Lock-out Relay: A
freezestat is included to protect the unit from unusually cold loop fluid temperatures or no fluid flow conditions. A 35 degree F freezestat is necessary in open
Refrigeration System
loop applications and closed loop applications without adequate antifreeze. A 20 degree F freezestat may be used with closed loop applications with antifreeze solution only. A lockout relay circuit consisting of three safety devices (low pressure, high pressure, and Freezestat) will trigger the lockout relay to shut off the compressor, the loop pumps and the desuperheater pump (optional) when a safety is tripped. A triggered lock-out relay is a key indication that there is a problem in the system and service may be necessary. The safety that caused the lockout relay to energize will reset itself after approximately five minutes. If the lockout relay is manually reset by power interruption prior to this five minute period, the unit will be unable to run. To manually reset the lockout relay, the disconnect or system switch at the thermostat must be toggled.
! Reversing Valve: The reversing
valve is a pilot operated sliding piston type with replaceable encapsulated magnetic coil. The reversing valve is energized when
the unit is in the cooling mode and de-energizes in the heating mode.
! Refrigerant Tubing: All refrigerant
tubing is constructed of copper. The low temperature refrigerant lines are factory insulated with a 3/ 8-inch thick elastomeric insulation (UL 94V-5 rated), with a flame spread rating of less than 25 and smoke density rating of less than
50. It has been tested in accordance with ASTM-85.
! Refrigerant Metering: The
refrigeration circuit is provided with a bi-directional thermal expansion valve to allow operation with entering water temperatures from 25 degrees F to 120 degrees F.
! Liquid Line Filter: The unit
contains a bi-directional liquid line filter drier to remove any contaminants within the refrigeration circuit.
! Servicing Pressure Ports: The
equipment is provided with both high and low pressure schraeder ports. The ports are located outside the unit case for convenient access.
17
Miscellaneous Equipment
Accessory Items
Note:
The following equipment may be pur­chased through the nearest Trane dis­tributor.
! Water Regulating Valve Assembly:
The water regulating valve assembly consists of a direct acting valve and a reverse acting valve. The direct acting valve opens in response to an increase in discharge pressure during the cooling cycle. The reverse acting valve opens in response to a decrease in suction pressure during the heating cycle. Water regulating valves should be used where low flow, and low or high fluid temperature conditions could occur.This option is beneficial with open loop systems, but not necessary.
! Motorized Water Valve for open
loop systems: The motorized water valve is installed on the return line of the system between the loop
and the loop pump module. This isolation device is a much less expensive and very effective alternative. When the compressor begins running, the valve will open, allowing water to flow through the unit. As the compressor shuts down, the valve slowly closes off. The main purpose of the automatic device is to prevent water hammer, by keeping the pressure raised in the loop system during off cycles.
! Electric Strip Heaters: If the ETL
listed strip heaters are used, they can be installed directly inside the TWE air handler. These heaters are rated at 230 volts and provide electric heat for both supplemental and emergency heat requirements. There are a number of heater capacities available.
! Pump Module: The pump module
and the hose kit make a complete self-contained pumping package for the earth-coupled heat pump system. These kits contain all the
necessary components for the installation, operation and maintenance of the water circuit of a closed loop geothermal application. Standard pump module features include insulated Grundfos pumps, insulated cabinet, optional cast iron or bronze pumps, 3-way brass valves and the choice of a one or two pump module.
! Hose Kits: The hose kits include
two brass, 1-inch male pipe thread (MPT) by barb-fittings, two brass 90 degree 1-inch, MPT by barb­elbows with pressure/temperature ports and 10 feet of rubber hose with 4 hose clamps.
! Sand Filter/Separator: A sand
filter/separator helps ensure clean water for the water-to-refrigerant heat exchanger. The recommended strainer is 60 mesh or greater. The strainer keeps particles and debris from entering the system.
18
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