Trane GEH 009, GEH 036, GEH 012, GEH 024, GEH 030 User Manual

High Efficiency
Horizontal and Vertical
Water-Source Comfort System

Axiom
1/2 - 5 Tons — 60 HZ
12 1/2 - 25 Tons — 60 HZ

TM

WSHP-PRC001-EN

Introduction

Imagine a full range of comfort utiliz­ing efficiency, sound attenuation, in­tegrated controls, and superior
maintenance accessibility... Trane
imagined it, then brought it to life.

Introducing models GEH and GEV
water source comfort solutions.

Model GEH (pictured below) is a ceil­ing hung product that provides a
sleak, innovative shape, along with
convertibility of the supply-air and the
return-air arrangement; serviceability
to maintenance components; indoor
air quality standards; sound attenua­tion; and best of all, higher efficien­cies with certified ARI-ISO 13256-1
performance and ASHRAE 90.1
standards.

Trane’s new design incorporates
system advantages such as:

Maximum return-air and

1

supply-air flexibility
Superior maintenance

2

accessibility

3

Dual-sloped, plastic drain pan

4

Multi-speed motor

Quiet unit design

5
6

Integrated controls

7

Orifice ring motor mounting
device as standard for ease of

motor service

8

High and low pressure
safeties as standard

9

Internal air-to-refrigerant coil
(horizontal design)

©American Standard Inc. 2002 WSHP-PRC001-EN

Table of Contents

Introduction 2
Features and Benefits 4

Options
Controls

16

Application Considerations 26
Selection Procedures 40

How to Select by Computer
Manual Selection Procedure
Model Number Description

40
41
44

General Data 46
Performance Data 49

Cool and Heat Performance
Correction Factors
Electrical Performance
Fan Performance
Waterside Economizer Performance
Sound Performance
Anti-Freeze Correction Factors

49
84
85

89
101
102
106

4

Controls 107

Wiring

Dimensional Data 111
Accessories 132

Thermostats
Options

Mechanical Specifications 140

WSHP-PRC001-EN 3

107

132
138

Figure 1: Horizontal service access

Features and
Benefits

Design Advantages

The horizontal configuration model
GEH product offers a range of
capacities from 1/2 to 5 ton.

This innovative design offers superior
field flexibility at the jobsite along with
service accessibility.

Cabinet

The cabinet design includes a modular
platform that utilizes similar parts and
assemblies throughout the product
line. It is constructed of heavy gauge
(non-painted) galvanized metal for
maximum durability and corrosive re­sistive exterior.

The cabinet front allows service ac­cess for the controls and refrigeration
circuitry. Water-in/out connection and
high/low voltage hook-up is accom­plished at the 45-degree corners on
the front-side of the equipment.

The new horizontal design offers six
product variations of return-air and
supply-air combinations which may
be order-specific or job-site modi­fied.(See Figure 1 for service access
and Figure 2 for component platform
location).

Figure 2: Component platform location

4 WSHP-PRC001-EN

Features and
Benefits

Cabinet

The cabinet design includes a modular
platform that utilizes similar parts and
assemblies throughout the product
line. It is constructed of heavy gauge
(non-painted) galvanized metal for
maximum durability and corrosive
resistive exterior.

The cabinet front allows service access
for the controls and refrigeration
circuitry. Water-in/out connection,
drain connection, and high/low
voltage hook-up is accomplished at
the 45-degree chamfered corners on
the front-side of the equipment.

The vertical design offers four product
variations of return-air and supply-air
combinations.

Figure 4: Component platform location

Design Advantages

Like it’s horizontal (GEH) counterpart,
the GEV offers a range of capacities
from 1/2- to 5-ton, and 12 1/2 through
25-ton. Only, with the vertical design,
Trane includes a 3 1/3-ton
configuration physically sized for
condominium installations.

The GEV configuration incorporates
the unique modular component
platform design of the horizontal
configuration to provide a repetitious
look and feel to installation and
maintenance personnel.

The 1/2 through 5-ton supply-air ar­rangement may be field convertible
with service kit to aid in stocking of a
single unit variation. (See Figure 3 for
service access of the unit. See
Figure 4 for component platform
location.)

This orchestrated family share fea­tures and benefits with only a few vari­ances.

WSHP-PRC001-EN 5

Figure 3: Service access of
small tonnage vertical

Field Convertible

The bullet listing below shows the
available return-air/supply-air combi­nations on the GEH model whether
specified by order or modified on-site
to meet your unique installation re­quirement. The six combinations in­clude:

Left return-air with left supply-air

1

combination
Left return-air with rear supply-air

2

combination
Left return-air with right sup-

3

ply-air combination
Right return-air with left sup-

4

ply-air combination
Right return-air with rear

5

supply-air combination
Right return-air with right

6

supply-air combination

See Figure 5 for the six convertible
combinations.

Features and
Benefits

1

UNIT

FRONT

4

UNIT

FRONT

Figure 5: Six convertible combinations (GEH 1/2 through 5-ton)

2

5

FRONT

UNIT

FRONT

UNIT

3

FRONT

6

FRONT

UNIT

UNIT

More Flexibility

The GEV model is also capable of
on-site modifications. With the vertical
configuration, the supply-air is easily

1

UNIT

FRONT

3

UNIT

FRONT

Figure 6: Four combinations (GEV 1/2 through 5-ton)

6 WSHP-PRC001-EN

2

UNIT

FRONT

4

UNIT

FRONT

converted from a top supply-air to a
back supply-air with a service retrofit
kit. The return-air option is order spe­cific. The four combinations include:

Right return-air with top sup-

1

ply-air combination
Right return-air with back sup-

2

ply-air combination
Left return-air with top supply

3

-air combination
Left return-air with back sup-

4

ply-air combination

See Figure 6 for the four supply-air/
return-air combinations.

Features and
Benefits

Vertical Advantages

The vertical (model GEV) configuration offers a range of
capacities from 12 1/2-ton through 25-ton.

The sleek, narrow cabinet is designed to fit through a
standard doorway for installation during new construc­tion, or retrofit purposes. The units sturdy cabinet is de­signed for durability, and corrosive resistance. The
upper panels feature an key hole hanging design for
ease of maintenance of the unit, allowing the panel to be
hooked into place when attaching the panel to the unit.
The panels are also sealed with a rubber gasket at all four
edges to help eliminate air from escaping around the
panel’s edge.

1

2

Supply/Return Combinations

The 12 1/2 through 25-ton GEV models are available in four sup­ply-air/return-air combinations. These combinations are order
specific via the unit model number. The four combinations in­clude:

3

4

Figure 6: Supply-air/return-air combinations

WSHP-PRC001-EN 7

Front return-air with back supply-air combination

1

Front return-air with top supply-air combination

2

Back return-air with front supply-air combination

3

Back return-air with top supply-air combination

4

The 12 1/2 to 25 ton verticals are most prevalently installed in
small equipment rooms or above the space on a mezzanine. They
are typically used to feed atriums, or core areas of a building
where a large heating or cooling load is required. See Figure 6
for the flexibility of the vertical unit offering of four supply-air/re­turn-air combinations.

Features and
Benefits

Hanging Device

The hanging bracket resides in the
chamfered corner of the horizontal
unit. This partially-concealed bracket
design eliminates added height,
width, or length to the product. The
brackets are factory mounted to short­en job installation requirements.

The structural integrity of the design
helps assure no bracket deflection or
unit bowing from the unit’s weight.

Field return-air hook-up and filter
maintenance are more simplistic be­cause of this innovative design. Isola­tion for the hanging bracket is
provided with a neoprene rubber
grommet design. This isolation device
helps prevent sound vibration from
reaching the structural support mem­bers of the building during compres­sor start and stop. (See Figure 7 for
isolation device).

Drain Pan

The unit drain pan is composed of
plastic, corrosive resistive material.
The pan is positively sloped to comply
with ASHRAE 62 for (IAQ) indoor air
quality conformity.

Access to the drain pan is provided
through two access panels for clean­ing purposes for all models. (See Fig-
ure 8 for plastic drain pan).

Refrigeration Piping

The unit’s copper tubing is created
from a 99% pure copper formation that
conforms to the American Society of
Testing (ASTM) B743 for seamless,
light-annealed processing.

The unit’s copper refrigeration system
is designed to be free from contami­nants and conditions such as drilling
fragments, dirt, or oil. This excludes
the possibility of these contaminants
from damaging the compressor mo­tor.

Compressor

The unit’s design includes a wide vari­ety of compressor motors to accom­modate dedicated voltages and
tonnage sizes. The 1/2 ton through
1 1/2 ton products will embody a rota­ry compressor design, where as unit
sizes ranging from 2 ton through 4 ton
include a reciprocating compressor
style, while the 5 ton unit contains a
scroll compressor. These different de­signs allow Trane to provide the volt­age variations along with noise
reduction. (See Figure 9 for recipro­cating compressor).

The larger tonnage (GEV model)
12 1/2 through 25 ton units include a
dual circuit system which incorporate
scroll compressors.

Figure 7: Hanging bracket design

Figure 8: Plastic drain pan

Important!

Although the drain pan is sloped, the
horizontal unit should be hung at a
dual angle (per local code) to provide
proper drainage of the condensate
system.

Cabinet Insulation

The cabinet insulation design meets
UL 181 requirements. The air stream
surface of the insulation is fabricated
of a non-biodegradable source.

8 WSHP-PRC001-EN

Schrader Connections

The connections for the low and high
side of the refrigeration system are lo­cated directly beside the control box at
the front (service access) panel. (See
Figure 10 for schrader connection lo­cations).

Figure 9: Reciprocating compressor

Figure 10: Schrader connections

Features and
Benefits

Co-axial Water-to-Refrigerant Coil

The unit’s internal heat exchanging
water coil is engineered for maximum
heat transfer.

The copper or cupro-nickel seamless
tubing is a tube within a tube design.
The inner-water tube contains a deep
fluted curve to enhance heat transfer
and minimize fouling and scaling. It is
available in either copper or cu­pro-nickel (selectable option) coil.The

Figure 11: Coaxial water coil

Figure 12: Water connection device

Figure 13: 12 1/2-ton + water hook-up

Figure 14: Thermal expansion valve

WSHP-PRC001-EN 9

outer refrigerant gas tube is made
from steel material. The coil is leak
tested to assure there is no cross leak­age between the water tube and the
refrigerant gas (steel tube) coil. Co-ax-

ial heat exchangers are more tolerant
to freeze rupture. (See Figure 11 for

co-axial water coil).

Compressor and Co-axial Coil
Isolation

For the 1/2-ton through 5-ton units, vi­bration isolation of the compressor
and co-axial water coil is accom­plished by increasing the rigidity and
stiffness at the base. This platform in­cludes double isolation to the com­pressor and single isolation to the
co-axial water coil. The combination in
the double isolation provide additional
attenuation during compressor start
and stop.

Water Connections
(1/2 thru 5-ton)

The water-in/water-out connections to
the co-axial water coil are located on
the right-hand chamfered corner of
the unit. The fittings are mounted flush
to the chamfered wall to help limit
shipping damage.

The water connection devices are con­structed of copper or bronze material
and include a National Female Pipe
Thread (NFPT) junction. The connec­tions are attached to the unit’s cham­fer corner to alleviate the need for a
back-up wrench during installation.
(See Figure 12 for water connection
device).

Water Connections
(12 1/2 thru 25-ton)

Water hookups for the larger tonnage
units are located internal to the unit to
help alleviate damage to the water
copper during shipment or job storage
of units prior to installation. Each unit
(although dual circuited) contains a
single supply and return water con­nection. (See Figure 13 for large ton­nage water hook-up). Fittings for the
supply and return are internally
threaded.

Table 1 defines water connection siz­ing for 1/2 ton through 25 ton configu­rations

Table 1: Water connection sizes

Unit Size

(MBH)

006 thru 015 1/2 FTP
018 thru 042 3/4 FTP
048 thru 060 1 FPT
150 thru 180 1 5/8 FPT
240 thru 300 2 1/8 FPT

Expansion Valve

All Trane water-source systems in­clude an expansion valve flow meter­ing device.

This thermal expansion valve (TXV) al­lows the unit to operate with an enter­ing fluid temperature from 25 F to 110
F, and entering air temperatures from
40 F to 90 F. The valve is designed to
meter refrigerant flow through the cir­cuitry to achieve desired heating or
cooling.

Unlike cap-tube assemblies, the ex­pansion valve device allows the exact
amount of refrigerant required to meet
the coil load demands. This precise
metering by the TXV increases the ef­ficiency of the unit. (See Figure 14 for
thermal expansion valve).

Fitting Size

(in)

FPT

Features and
Benefits

Reversing Valve

A system reversing valve (4-way
valve) is included with all heating/
cooling units. This valve is piped to be
energized in the cooling mode to al­low the system to provide heat if valve
failure were to occur. Once the valve is
energized for cooling, it will remain
energized until the control system is
turned to the OFF position, or a heat­ing cycle is initiated.

Units with the cooling only option will
not receive a reversing valve. (See
Figure 15 for reversing valve).

Blower Motor

The 1/2 through 5-ton supply-air
(blower) motor is a multi-speed motor
with internal thermal overload protec­tion. The motor bearings are perma­nently lubricated and sealed. Standard
motors are rated from .20 ESP. Option-
al high static motors are rated from .40
to 1.40 ESP. All motors are factory
wired to the option selected. A high,
medium, and low speed tap is provid­ed for field customization on all volt­ages. The speed tap modification can
be made in the control box of the unit.
(See Figure 16 for blower motor).

Note: The 380, 415, 460 and 575
volt designs are provided in a dual
or three-speed version only. See

fan performance section for factory
ratings (Page 91).

The 12 1/2 through 25 ton GEV models
incorporate a belt driven motor selec­tion into the design. The 12 1/2 and 15
ton units include a single fan assem­bly, while the 20 and 25-ton units in­clude dual fan assemblies. Because
the motor sheave and the motor base
are adjustable in the field, a greater
variation in external static pressures
are available. The large tonnage units
are capable of providing 0 ESP to 3.0
ESP allowing a higher static ductwork
to be applied on the mechanical sys­tem when the application requires

extensive ductwork design. This is a
low cost alternative to purchasing, in­stalling, and maintaining multiple
smaller tonnage units to meet the re­quired air flow demand for the space.

Serviceability to the motor is made
through either of the two air-side ac­cess doors for the horizontal configu­ration, and through one air-side
access door for the 1/2 through 5-ton
vertical configuration. The motor and
blower wheel are removable by an or-
ifice ring mounted to the fan hous­ing.

Access to the 12 1/2 through 25 ton
units is made through the back of unit
by way of two panels, and/or through
a side access panel if adjustment to
the motor belt or motor base are need­ed. (See Figure 17 for motor
accessibility).

Blower Housing

The blower housing is constructed of
non-corrosive galvanized steel. A fac­tory-mounted orifice ring is provided
for ease of motor serviceability on the
1/2 through 5-ton direct drive units.

All air-side panels are interchangeable
with one another for ease of field con­vertibility of the supply-air on the GEH
model.

Air-Side Filter

The air-side filter incorporates a 1-inch
thick (nominal) or 2-inch thick (nomi­nal) disposable fiberglass option.
These filters include an average syn­thetic dust weight arrestance of ap­proximately 75%. This dust holding
capability includes a colorless, odor­less adhesive to retain dirt particles
within the filter media after fiber con­tact. (See Figure 18 for filter media)

Figure 15: Reversing valve

Figure 16: Blower motor (direct drive)

Figure 17: Motor accessibility

Figure 18: Filter media

10 WSHP-PRC001-EN

Features and
Benefits

Air-to-Refrigerant Coil

The air-to-refrigerant heat exchanger is constructed of staggered

copper tubes with die-formed corrugated lanced aluminum fins.

The fins are then mechanically bonded to the tubes through ex-

pansion.

The coil is placed internal of the unit design for model

GEH to assure no fin surface damage during shipment,

jobsite storage, or installation.
The internal placement of the coil on the horizontal con-

figuration provides an option of a dual filtration applica­tion. With dual filtration to the GEH unit, maintenance to
the filter is significantly less than with a single filtration
system.

The maximum working pressure for both the GEH and
GEV coils is 450 psig. It is designed for maximum capac­ity with an additional benefit of physical unit size reduc-

tion.

Coil specifications for both GEH and GEV may be found on

in the General Data section on page 48 of this catalog. See

Figure 19 for internal air to refrigerant coil placement.

Figure 19: Internal air-to-refrigerant coil placement (GEH)

The sound package for the horizontal unit includes:

Table 2: Sound Package (1/2 through 5-ton units ONLY)

Enhanced Sound Attenuation

Package

18-gauge compressor enclosure 16-gauge compressor enclosure
18-gauge single wall front panel 16-gauge single wall front panel
lined compressor enclosure with

1/2-inch cabinet insulation
compressor discharge muffler compressor discharge muffler
12-gauge compressor/water-to-refrig-

erant heat exchanger pan with second
stage of vibration isolation

compressor vibration isolation compressor vibration isolation
water-to-refrigerant heat exchanger

vibration isolation
lengthwise unit base stiffeners lengthwise unit base stiffeners

Deluxe Sound Attenuation

Package

lined compressor enclosure with
1/2-inch cabinet insulation

12-gauge compressor/water-to-refrig­erant heat exchanger pan with second
stage of vibration isolation

water-to-refrigerant heat exchanger
vibration isolation

3/32-inch foam gasket sealant placed
around the compressor and end panel
perimeter

Sound Attenuation Package

Testing of conventional units has iden­tified that the sound radiated by the
casing of the unit is an important com­ponent of the sound that reaches occu­pants, especially when the unit is
located directly over the occupied
space.

This sound reduction package reduces
radiated noise from the cabinet. Trane
double-isolates the compressor and
single-isolates the co-axial coil in the
unit. This design absorbs the vibration
that contributes to radiated sound

For sound critical spaces, an
enhanced sound package as de­scribed in Table 2 provides additional
attenuation.

Complete sound data taken in accor­dance with ARI 260 is available for all
1/2 through 5-ton units. The test data
reflects multi-speed fan motor along a
single system curve. (See sound per­formance data on Page 107.)

WSHP-PRC001-EN 11

Boilerless Control/Electric Heat

(option)

In cooling dominant regions where
heat may be used 15 to 30 days out of
the winter season, eliminating the
boiler may be an economical advan­tage to the building owner. Eliminat­ing a boiler from the system reduces
costs associated with the mechanical
system installation, as well as the
maintenance and service of the boiler.

How can heat be provided for the few
days of the year when heat is neces­sary? Through the water-source heat

pump of course. The advantage of the
water-source heat pump is it’s ability
to provide heat recovery within the
closed water-loop. While some
WSHPs may be extracting heat from
the closed water loop, other WSHPs
may be adding heat to the closed
water loop. This creates a perfect sys­tem balance for heat sharing or move­ment from one space to another.

But when water temperatures fall in a
boilerless system, and no further heat
recovery may be made via the closed
loop, heat may be added to the space
through a boilerless control electric
heat option. See Figure 20 for the
boilerless control, electric heat system
diagram.

With the boilerless electric heat
option, the heat pump encompasses
an internal nichrome open wire heat-

Features and
Benefits

Figure 20: Boilerless control, electric heat system

ing element (factory mounted and
wired in the 1/2 through 5-ton models)
It is comprised of a single stage of
electric heat designed to invoice an
electric heater in place of the com­pressor in the event entering water
temperature falls below 55 F or a field
adjusted temperature setting between
25 F to 60 F.

The 12 1/2 through 25-ton GEV model
will contain the boilerless controls

ONLY to interface for a field provided
supplemental electric heat selection.
The heater for this model shall be
placed external to the equipment by
the contractor for ease of installation.
All power connections for the electric
heater will be completely separate
from the unit for field supplied electric
heat.

12 WSHP-PRC001-EN

Boilerless Control/Electric Heat

Heating/Cooling Mode

In heating mode, when the water tem­perature falls below 55 F (factory set­ting), the electric heater
is energized, locking
out the compressor.
The systems electric
heat source will continue to be
utilized for primary
heating until
the loop
tempera­ture rises
above 60 F.
Once the
entering water tempera­ture rises above 60 F, the boiler­less controller returns the unit to
normal compressor heating opera­tion and locks out the electric heater.
This maximizes efficiency from the
unit during the few days requiring
heat from the mechanical system. See
Figure 21 for the factory mounted
and wired boilerless control electric
heat water-source heat pump. Avail-

able on the 1/2 through 5-ton equip­ment ONLY as a single point power
connection.

If the unit employs a cooling only unit
design, the electric heat contactor is
wired directly to the thermostat for
primary heating, and the compressor
contactor for cooling.

Note: For geothermal applications,
the boilerless controller has an adjust­able setting of 25, 35, 45, 55 and 60
degrees.

Features and
Benefits

Figure 21: Boilerless control, electric heat water-source heat pump

What is NOT available with the boilerless electric heat option?

Hot gas reheat

1
2

Basic 24 volt controls
TracerTM ZN510 controls

3

115 and 575 volt ratings

4

Supplemental or emergency heat applications

5
6

And, a factory installed heater (applies to unit sizes 12 1/2 through 25-ton
ONLY)

WSHP-PRC001-EN 13

Features and
Benefits

Figure 22: Model GEH with waterside economizer package

Note: Condensate overflow is not available with

the waterside economizer option.

Figure 23: Waterside economizer system

Waterside Economizer (option)

The beauty of the waterside economiz­er is it’s ability to take advantage of
any loop condition that results in cool
water temperatures. A prime example
would be during fall, winter and spring
when cooling towers have more ca­pacity than required and could be con­trolled to lower temperatures for
economizer support.

Another more common inexpensive
means of free comfort cooling in­cludes buildings systems where pe­rimeter heating and core cooling are
needed. In this system, the perimeter
units extract heat from the building
loop while in the heating mode, forc­ing the building loop temperature to
drop. Where as, the core are of a build­ing may require cooling in summer or
in winter based upon lighting, people
and equipment.

If the water-source system design con­tained an economizing coil option, the
moderate temperature loop water cir­culated through a core water-source
system can provide an inexpensive
means to satisfy room comfort with­out operating the water-source heat
pump’s compressor.

During economizer mode, fluid enters
the unit, and passes by a water tem­perature sensing bulb. This tempera­ture sensing bulb determines whether
the two position, three-way valve will
direct the water through the waterside
economizing coil, and to the heat
pump condenser, or through the con­denser only. If the water temperature
is 55 F or less, fluid will flow into the
economizing coil, while simultaneous­ly halting mechanical operation of the
compressor. Mechanical cooling will
continue on a call for second stage
from the thermostat.

The factory built waterside economiz­er is available on all GEH models, and
all 12 1/2 to 25 GEV models. The 1/2
through 5-ton GEV may be ordered to
accept a field provided waterside
economizing package.

14 WSHP-PRC001-EN

Features and
Benefits

Hot Gas Reheat (option)

For space conditioning and climate
control, Trane provides an accurate
and cost effective dehumidification
control through a hot gas reheat op­tion. This option is designed to accom­modate unit sizes 012, 036, 060, 180
and 240.

With this reheat option, the return air
from the space is conditioned by the
air-to-refrigerant coil, then reheated
by the reheat coil to control not only
the space temperature, but to also re­duce the relative humidity of the
space. The moisture removal capabili­ty of a specific heat pump is deter­mined by the units latent capacity
rating.

When operating in the reheat mode
(meaning the sensible temperature
has been met in the space), the humi­distat signals the reheat relay coil to
energize, allowing the high pressure
refrigerant gas to flow from the (1)
compressor, through the (2) reheat
valve, into the (3) reversing valve, or
through the (4) reheat coil for dehu­midification. A switching relay has
been provided for the reheat applica­tion to adjust the blower motor from
normal operation to low speed when
hot gas reheat is energized.

Note: Trane places an air separation
space between the air-to-refrigerant
coil, and the reheat coil to allow for
maximum moisture removal.

Common Reheat Applications

The hot gas reheat option is designed
to support building applications re­quiring fresh-air ventilation units de­livering unconditioned-air directly to
the space. It also provides dehumidifi-

cation to large latent load spaces such
as auditoriums, theaters and class­rooms, or anywhere humidity control
is a problem.

Do’s and Don’ts in Design

The factory installed hot gas reheat
option is only available with Deluxe or
ZN524 controls packages.

A high static blower motor option will
be required to support the hot gas re­heat option.

Water regulating valves should not be
used with the hot gas reheat option.
Trane places a thermal expansion
valve on all water-source heat pumps,
as well as ground-source heat pumps,
to regulate refrigerant flow vs. water
flow, making the heat pump more effi­cient to run.

The water-source heat pumps with hot
gas reheat should not be used as a
make-up air unit.

Figure 24: Hot gas reheat heat pump

WSHP-PRC001-EN 15

Features and Benefits
Controls

Controls by Trane

Whether involved in a retrofit or new construction application, Trane has the control design to fit your system requirement.
Our control options provide a broad range of packages from the most cost efficient 24 volt standalone to a complete build­ing automation solution, Trane is the right choice in comfort gratification. The following chart provides a brief overview in
the different control combinations.

Graphic Description Application ICS Protocol Where to find

Basic 24V

Available on 1/2

through 5 ton

equipment ONLY.

Deluxe 24V

Standard offering

for the 6 through

25 ton equipment.

Tracer ZN510

TM

Used in

single circuit

WSHP design.

Tracer ZN524

TM

Used in

multi-circuit

WSHP design. Or,

for single circuited

WSHPs with HGR,

WSE, or BEH.

TracerTM Loop

Controller

Tracer Summit®

Compressor lockout
relay, low and high
pressure switches.

24 volt electro­mechanical board
designed to provide
control of the entire
unit, as well as mul­tiple relay offerings
to maximize system
performance.

Direct Digital Con­trol board designed
to provide control
of the entire unit as
well as outputs for
unit status and fault
detection.

Direct Digital Con­trol board designed
to provide control
of the entire unit as
well as outputs for
unit status and fault
detection.

Microproces­sor-based controller
that coordinates the
water side (boiler,
pumps, cooling
tower, etc.) of a
water-source heat
pump system.

Microprocessor
based controller
that coordinates full
building automa­tion from HVAC to
lighting.

Retrofit market where sin­gle and multiple unit
replacement occurs.

New building design where
field provided controls are
specified.

Retrofit market where sin­gle and multiple unit
replacement occurs.

Multi-unit installation
where units may be daisy­chained directly to the

Trane TracerTM Loop Con­troller.

Retrofit market where over­all system upgrade is speci­fied.

Multi-unit (100+) installa­tion where units are linked
by a common twisted pair
of wire for a communica­tion link.

Retrofit market where over­all system upgrade is speci­fied.

Multi-unit (100+) installa­tion where units are linked
by a common twisted pair
of wire for a communica­tion link.

Wherever the Tracer ZN510
controls or 24 volt elec­tro-mechanical
controls are specified for
complete control of the
water loop and pumps.

Where any controller is
specified.

No Non Applicable Page 17

No Non Applicable Page 19

Yes

Yes SCC LonTalk

Yes LonTalk

Yes BACnet

SCC LonTalk®

open protocol

(Comm5)

open protocol

(Comm5)

compatible

(Comm5)

(Comm 2,3,4,5)

Page 22

Page 22

WSHP-MG-3

EMTW-SVN01B-EN
EMTW-SVP01B-EN
EMTW-SVU01B-EN

HGR = Hot Gas Reheat
WSE = Waterside Economizer
BEH = Boilerless Electric Heat

16 WSHP-PRC001-EN

Features and Benefits
Basic Controls

Basic 24 Volt Controls

The basic 24 V electro-mechanical unit
control provides component protec­tion devices for maximum system reli­ability. Each device is factory
mounted, wired and tested.

Figure 25: Basic 24 volt control box

WSHP-PRC001-EN 17

The Basic 24 volt control package is
only available for the 1/2 through 5-ton
unit sizes. See Figure 25 for basic 24
volt control box (model GEH shown).

Figure 26: Safety devices

Safety Devices

System safety devices are provided to
prevent compressor damage through
the use of low and high pressure
switches in the refrigeration circuit.

The low pressure switch or suction
line temperature sensor to prevent
compressor operation during low tem­perature operation. The switch and
sensor are set to activate at refrigerant
pressures of 20 psig to fit most appli­cations.

In cases where a low charge, or exces­sive loss of charge occurs, each com­pressor comes equipped with an
external overload device to halt the
compressor operation.

The high pressure switch prevents
compressor operation during high or
excessive discharge pressures that ex­ceed 395 psig.

A lockout relay provides the me­chanical communication of the low
and high pressure switches to prevent
compressor operation if the unit is un­der low or high refrigerant circuit pres­sure, or during a condensate overflow
condition. The lockout relay may be re­set at the thermostat, or by cycling
power to the unit.

General alarm is accomplished
through the lockout relay and is used
in driving light emitting diodes. This
feature will drive dry contacts only,
and cannot be used to drive field in­stalled control inputs.

See Figure 26 for safety devices on
the basic 24V control unit.

Features and Benefits
Basic Controls

Stand-alone System

The 24 volt electro-mechanical design may be applied as a stand-alone control
system. The stand-alone design provides accurate temperature control directly
through a wall-mounted mercury bulb or electronic thermostat. This system
set-up may be utilized in a replacement design where a single unit retrofit is
needed. It may be easily interfaced with a field provided control system by way
of the factory installed 18-pole terminal strip.

This stand-alone control is frequently utilized on lower volume jobs where a
building controller may not be necessary, or where field installed direct digital
controls are specified. This type of control design does require a constant flow of
water to the water source heat pump. With a positive way to sense flow to the
unit, the units safety devices will trigger the unit off.

The stand-alone system design provides a low cost option of installation while
still allowing room control for each unit. See Figure 27 for 24 volt stand-alone

system controls.

Figure 27: 24 volt stand-alone system

18 WSHP-PRC001-EN

Features and Benefits
Deluxe Controls

Deluxe 24V Electronic Controls

The deluxe 24V electronic unit control provides component protection devices
similar to the basic design, but contains upgraded features to maximize system
performance to extend the system life. Each device, is factory mounted, wired,
and tested in the unit.

Note: On dual circuited systems, Each circuit contains a deluxe micro-processing

control board.

Figure 28: Deluxe 24 volt control box

The deluxe 24 volt control package is
available for all unit sizes. See
Figure 28 for deluxe 24 volt control
box (model GEH shown).

WSHP-PRC001-EN 19

Features and Benefits
Deluxe Controls

Microprocessor Design

The 24 volt deluxe design is a
microprocessor-based control board
conveniently located in the control
box. The board is unique to Trane
water-source products and is
designed to control the unit as well as
provide outputs for unit status and
fault detection.
The Trane microprocessor board is
factory wired to a terminal strip to
provide all necessary terminals for
field connections. See Figure 29 for
the deluxe 24V control board.

Figure 29: Deluxe 24V control board

Deluxe 24V features include:
Random Start

The random start relay provides a time
delay start-up of the compressor when
cycling in the occupied mode. A new
start delay time between 3 and 10
seconds is applied each time power is
enabled to the unit.

Anti-short Cycle Timer

The anti-short cycle timer provides a
three minute time delay between
compressor stop and compressor
restart.

Brown-out Protection

The brown-out protection function
measures the input voltage to the
controller and halts the compressor
operation. Once a brown-out situation
has occurred, the anti-short cycle
timer will become energized. The
general fault contact will not be

affected by this condition. The voltage
will continue to be monitored until the
voltage increases. The compressors
will be enabled at this time if all
start-up time delays have expired, and
all safeties have been satisfied.

Compressor Disable

The compressor disable relay pro­vides a temporary disable in compres­sor operation. The signal would be
provided from a water loop controller
in the system. It would disable the
compressor because of low water
flow, peak limiting or if the unit goes
into an unoccupied state. Once the
compressor has been disabled, the an­ti-short cycle time period will begin.
Once the compressor disable signal is
no longer present, and all safeties are
satisfied, the control will allow the
compressor to restart.

Generic Relay

The generic relay is provided for field
use. Night setback or pump restart are
two options that may be wired to the
available relay. (Note: Night setback is
available as factory wired). An exter­nal Class II 24VAC signal will energize
the relay coil on terminals R1 and R2.
Terminals C (common), NO (normally
open), and NC (normally closed) will
be provided for the relay contacts.

Safety Control

The deluxe microprocessor receives
separate input signals from the refrig­erant high pressure switch, low suc­tion pressure switch and condensate
overflow.

In a high pressure situation, the
compressor contactor is de-energized,
which suspends compressor opera­tion. The control will go into soft lock-
out mode initializing a three minute
time delay and a random start of 3 to
10 second time delays. Once these de­lays have expired, the unit will be al­lowed to run. If a high pressure
situation occurs within one hour of the
first situation, the control will be
placed into a manual lockout mode,

halting compressor operation, and ini­tiating the general alarm.

In a low temperature situation, the
low pressure switch will transition
open after the compressor starts. If the
switch is open for 45 seconds during
compressor start, the unit will go into
soft lockout mode initializing a three
minute time delay and a random start
of 3 to 10 second time delays. Once
these delays have expired, the unit will
be allowed to run. If the low pressure
situation occurs again within 30 min­utes, and the device is open for more
than 45 seconds, the control will be
placed into a manual lockout mode,
halting compressor operation, and ini­tiating the general alarm.

In a condensate overflow
situation, the control will go into

manual lockout mode, halting com­pressor operation, and initiating the
general alarm.

The general alarm is initiated when
the control goes into a manual lockout
mode for either high pressure, low
pressure or condensate overflow con­ditions.

Diagnostics

Component device connections to the
microprocessor board are referenced
in Figure 29. Three LEDs (light emitting
diodes) are provided for indicating the
operating mode of the controller. See
the unit IOM for diagnostics or trouble­shooting through the use of the LEDs.

20 WSHP-PRC001-EN

Features and Benefits
Deluxe Controls

Small Building Control

The deluxe 24V electro-mechanical design may be applied as a stand-alone
control system or as a multi-unit installation system. With a stand-alone design,
units run independently of one another with a mercury bulb or electronic digital
thermostat.

With a multiple unit installation, the units may be
daisy-chained directly to the Trane Tracer loop controller
(TLC), pump(s), boiler, and tower for a complete networked
water-source system. The TLC provides a night setback
output, and a pump request input for system

optimization.See
Figure 30 for
24 volt deluxe
control system.

Figure 30: 24 volt deluxe control system

WSHP-PRC001-EN 21

Features and Benefits
ZN510 & ZN524 Controls

Tracer ZN510 & ZN524 Controls

The Tracer ZN510 and ZN524 are direct digital control (DDC) systems specifically
designed for single and dual circuited water-source equipment to provide control
of the entire unit, as well as outputs for unit status and fault detection. Each de­vice is factory installed, commissioned, and tested to ensure the highest level of
quality in unit design.

Each of the controller’s features and options were selected to coordinate with the
unit hardware to provide greater energy efficiency and equipment safety to pro­long the equipment life.

In addition to being factory configured for control of the unit fan, compressor and
reversing valve, the ZN510 and ZN524 controllers are designed to coordinate the
waterside of the water-source system through the Tracer Loop Controller (TLC).
If applied in a peer-to-peer communication environment, data between similar
controllers may be exchanged without requiring a building automation system.

By teaming the ZN510 and ZN524 with the TLC, a low first-cost for the mechanical
equipment, water loop, and water pump optimization is provided to the owner.

For owners who require a full building integrated "open protocol" system, The
ZN510/ZN524/TLC application is upgradable to support complete building con­trol through Tracer Summit. Because the ZN510 and ZN524 is LonTalk certified,
it is capable of working with, and talking to other LonTalk certified controllers
providing the building owner more choices, and the design engineers more flex­ibility to meet the challenges of building automation. See Figure 31 for ZN510
control box.

Figure 31: ZN510 control box

22 WSHP-PRC001-EN

Features and Benefits
ZN510 & ZN524 Controls

Direct Digital Controls

When the ZN510 or ZN524 controller is
linked directly to the Tracer Summit,
each Tracer Summit building
automation system can connect a
maximum of 120 Tracer ZN510 or
ZN524 controllers. See Figure 32 for
the Tracer ZN524 board.

Figure 32: Tracer ZN524 controller

Tracer ZN510 and ZN524
functions include:

Compressor Operation

The compressor is cycled on and off to
meet heating or cooling zone de­mands. Single and dual compressor
units use the unit capacity and pulse
width modulation (PWM) logic along
with minimum on/off timers to deter­mine the compressor’s operation. The
compressor is controlled ON for long­er periods as capacity increases and
shorter periods as capacity decreases.

Random Start

To prevent all of the units in a building
from energizing major loads at the
same time, the controller observes a
random start from 0 to 25 seconds.
This timer halts the controller until the
random start time expires.

Reversing Valve Operation

For cooling, the reversing valve output
is energized simultaneously with the
compressor. It will remain energized
until the controller turns on the
compressor for heating. At this time,
the reversing valve moves to a
de-energized state. In the event of a
power failure or controller OFF
situation, the reversing valve output

will default to the heating
(de-energized) state.

Fan Operation

The supply air fan operates at the fac­tory wired speed in the occupied or oc­cupied standby mode. When switch is
set to AUTO, the fan is configured for
cycling ON with heating or cooling. In
heat mode, the fan will run for 30 sec­onds beyond compressor shutdown in
both occupied and unoccupied mode.

Fan Run Timer

The controller’s filter status is based
on the unit fan’s cumulative run hours.
The controller compares the fan run
time against an adjustable fan run
hours limit and recommends unit
maintenance as required.

Data Sharing

The Tracer ZN510/ZN524 controller is
capable of sending or receiving data
(setpoints, fan request, or space tem­perature) to and from other controllers
on the communication link. This al­lows multiple units to share a common
space temperature sensor in both
stand-alone and building automation
applications.

Night Setback

The four operations of the Tracer
ZN510/ZN524 controller include occu­pied, occupied standby, occupied by­pass and unoccupied.

In an occupied situation, the con­troller uses occupied heating and cool­ing setpoints to provide heating and
cooling to the building. This occupied
operation is normally used during the
daytime hours when the building is at
the highest occupancy level.

In an occupied standby situation,
the controllers heating and cooling
setpoints are usually wider than the
occupied setpoints. This occupied
standby operation is used during day­time hours when people are not
present in the space (such as lunch­time or recess). To determine the
space occupancy, an occupancy sen­sor is applied.

In an unoccupied situation, the
controller assumes the building is va­cant, which normally falls in evening
hours when a space may be empty. In
the unoccupied mode, the controller
uses the default unoccupied heating
and cooling setpoints stored in the
controller. When the building is in un­occupied mode, individual units may
be manually placed into timed over­ride of the unoccupied mode at the
units wall sensor. During timed over­ride, the controller interprets the re­quest and initiates the occupied
setpoint operation, then reports the ef­fective occupancy mode as occupied

bypass.
In the occupied bypass mode, the

controller applies the occupied heat­ing and cooling setpoint for a 120
minute time limit.

High and Low Pressure
Safety Controls

The Tracer ZN510/ZN524 controller
detects the state of the high pressure
or low pressure switches. When a
fault is sensed by one of these switch­es, the corresponding message is sent
to the controller to be logged into the
fault log. When the circuit returns to
normal, the high pressure control and
low pressure control automatically re­set. If a second fault is detected within
a thirty-minute time span, the unit
must be manually reset.

Condensate Overflow

When condensate reaches the trip
point, a condensate overflow signal
generates a diagnostic which disables
the fan, unit water valves (if present),
and compressor. The unit will remain
in a halted state until the condensation
returns to a normal level. At this time,
the switch in the drain pan will auto­matically reset. However, the control­ler’s condensate overflow diagnostic
must be manually reset to clear the di­agnostic and restart the unit.

WSHP-PRC001-EN 23

Features and Benefits
ZN510 & ZN524 Controls

Additional Functions of the
ZN524 Controller

When the building owners choice is
Trane Tracer controls, the ZN524 con­troller is required when any of the fol­lowing applications are selected on a
single and dual circuited equipment.

Waterside Economizer

Hot Gas Reheat

(for Dehumidification)

Boilerless Control for Electric Heat

Water Isolation Valve Control

(for Variable Speed Pumping)

Entering Water Temperature
Sampling

The ZN524 controller will sample the
entering water temperature to deter­mine proper control action for units
equipped with boilerless electric heat
or waterside economizer.

Waterside Economizer: Entering
water temperature (EWT) sampling
will automatically occur at power up
when the unit is equipped with a wa­terside economizer (WSE). The EWT is
used to determine if economizing is
feasible. When the conditions are met,
the isolation valve(s) are driven open
for three minutes and the EWT reading
is taken. The determination as to
whether or not the economizer can be
enabled will be made and the control­ler will take appropriate action. The
isolation valve will remain open re­gardless if the WSE or the DX cooling
is enabled.

The unit’s waterside economizer will
contain a 2-position water valve wired
to the ZN524. The economizing water
coil will be optimized to provide 100%
of the unit capacity at 80.6 F/66.2 F re­turn air temperature with 45 F entering
water. The flow rate is established at
86 F entering water temperature and
96 F leaving water temperature.

Low leaving air protection will be fur­nished to protect the unit against de­livering air that is cold enough to
sweat discharge air grilles. Coil icing
protection will also be provided.

Waterside economizer cooling will be
active during occupied, unoccupied
and standby cooling modes.

Boilerless Control Electric Heat
and Supplemental Electric Heat:

The ZN524 supports a single stage of
boilerless electric heat operation or
concurrent heating.

When the unit is configured for boiler­less control, the EWT will be used to
determine whether DX heating should
be disabled and the electric heater en­abled. When these conditions are met,
the isolation valve(s) are driven open
for three minutes and the entering wa­ter temperature reading is taken. The
determination as to whether or not to
utilize electric heat will be made and
the controller will take appropriate ac­tion. If boilerless electric heat is en­abled, then the isolation valve will be
closed, shutting down the water flow
to the unit.

When the unit is configured for con­current operation of DX heating (com­pressor in heat pump mode) and
electric heat, the electric heat will act
as a second stage of heat for single
compressor units, and a third stage of
heat for dual compressor units. Note:

With concurrent (or supplemental)
electric heat, the electric heater is field
provided.

Water Isolation Valves

Variable speed pumping systems are
supported by the ZN524 controller
when water isolation valves are
present. Up to two isolation valves are
supported by the controller (one for
each compressor circuit).

The valves are normally closed unless
DX heating, DX cooling, waterside
economizer or dehumidification is re­quested. When the isolation valves are
driven open for operation, the outputs
will be driven for 20 seconds to ensure

adequate water flow before the com­pressor outputs are energized. Once
an isolation valve has been opened, it
will remain open for a 10 minute mini­mum to reduce excessive cycling of
the valve.

Dehumidification

Dehumidification for the single and
dual circuited water-source heat pump
is applicable with the ZN524 control­ler. The controller is capable of direct­ing one stage of DX cooling in
conjunction with one stage of reheat
(hot gas reheat).

Dehumidification can only occur when
the controller is in the cooling mode. A
humidity transmitter is used to mea­sure the zone’s relative humidity (RH),
then compares the zone relative hu­midity to the relative humidity enable/
disable setpoint parameters. The de­fault values for dehumidification en­able is 60% RH with the disable point
at 52% RH. These values are config­urable.

24 WSHP-PRC001-EN

Features and Benefits
ZN510 & ZN524 Controls

Building Control Advantages

The Tracer ZN510/ZN524 controller has the ability to share information with one
or several units on the same communication link. This sharing of information is
made possibe via a twisted pair of wire and a building automation system or
through Trane’s Rover

An advantage of installing a ZN510/ZN524 is its capability to work with other
LonTalk certified controllers. This provides greater flexibility to the building own­er, as well as greater flexibility in design.

Integrating the ZN510/ZN524 on water-source equipment, and tying it to a Tracer
Summit system provides a complete building management system. Each Tracer
Summit can connect to a maximum of 120 controllers. With the ICS system, the
Tracer can initiate an alarm on a loss of performance on equipment malfunctions;
allowing problems to be handled in a timely manner before compromising com­fort.

This type of application would most commonly be used for a large space(s) that

TM

service tool .

may require more than one unit. In

addition to this application

design, the Tracer

ZN510/ZN524
controller provides a
way for units located
within the same
space to share the
same zone sensor to
prevent units from

simultaneously
heating and cooling in
the same space.See

Figure 33 for Tracer
ZN510/ZN524
controller system.

Figure 33: Tracer ZN510/ZN524 controller system

WSHP-PRC001-EN 25

Application
Considerations

How it Works?
Cooling Mode (Figure 34) If cooling is called for, the thermostat activates the

centrifugal blower and sets the reversing valve into the cooling position. If all
safeties are met, high temperature refrigerant vapor is pumped from the
compressor throught the reversing valve to the
refrigerant-to-water heat exchanger. The refrigerant
vapor condenses to a liquid as it passes through the heat
exchanger, giving up its heat to the circulating water
loop. High pressure liquid refrigerant then passes
through the expansion device into the

refrigerant-to-air fin
tube coil heat

exchanger. As the low
pressure refrigerant
passes through the coil,
it evaporates to become
a low temperature
vapor, absorbing heat
from the air, which is
drawn over the coil by the blower. The refrigerant
then flows as a low pressure gas through the reversing
valve back to the suction side of the compressor where
the cycle begins again.

Heating Mode (Figure 35) If heating is called for, the thermostat activates the
centrifugal blower and sets the reversing valve into the heating position. If

all safeties are met, high temperature refrigerant vapor is
pumped from the compressor through the reversing
valve to the refrigerant-to-air fin tube coil heat
exchanger. The high pressure refrigerant vapor
condenses to a liquid as it passes through the coil,
giving up its heat to the air which is drawn over the
coil by the blower. Liquid refrigerant then
passes through the
expansion devise into
the
refrigerant-to-water
heat exchanger. As the
low pressure
refrigerant passes
through the heat
exchanger, it evaporates
to become a low temperature vapor,
absorbing heat from the circulating water. The
refrigerant then flows as a low pressure gas through the

reversing valve back to the suction side of the
compressor where the cycle begins again.

Figure 34: Cooling mode

The energy generated from the com­pressor motor operation will also be
rejected to the air-to-refrigerant heat
exchanger (heating) or water-to-refrig­erant heat exchanger (cooling).

Figure 35: Heating mode

26 WSHP-PRC001-EN

Application
Considerations

Flexibility

The high efficiency vertical and hori­zontal water-source heat pump sys­tem is versatile for installation in
boiler/cooling tower applications, as
well as ground-source (geothermal)
applications. The system design may
employ either a central pumping de­sign, or a distributed pumping design.

A central pumping design involves a
single pump design, usually located
within a basement or mechanical
room to fulfill pumping requirements
for the entire building system. An aux­iliary pump is typically applied to less­en the likelihood of system downtime
if the main pump malfunctions.

A distributed pumping system con­tains a single pump module connected
directly to the units supply and return.
This module is field installed and
piped to the unit. This design requires
individual pump modules specifically
sized for each water-source heat
pump.

Advantages of Geothermal

The advantages of a geothermal heat
pump system could literally cut a busi­ness’ heating and cooling costs by 30
to 40-percent. The units are durable,
and typically last longer than conven­tional systems because they are pro­tected from harsh outdoor weather
conditions, and because the unit is in­stalled indoors and the loop under­ground. (According to ASHRAE, the
estimated service life for a commercial
water-to-air heat pump is 19-years.)
Geothermal heat pumps have fewer
mechanical components, making
them more reliable and less prone to
failure. Manufacturers of the loop ma­terials guarantee their products for up
to 25-years, with no maintenance re­quired.

Geothermal heat pumps work toward
the preservation of the
environment by reducing the environ­mental impacts of electric power gen­eration.

A ground source (geothermal)
system consist of a:

• A ground water heat pump

• A closed loop ground heat ex­changer made of high density
polyethylene pipe (guaranteed
25- years or more by many man­ufacturers); and

• A low wattage circulating pump(s)

The fluctuating temperatures of fluid
from the earth are more stable than
air, allowing the equipment to operate
at a lower discharge pressure and use
fewer kilowatts. The constant earth
temperature will heat or cool the fluid
running through buried high density
polyethylene pipe to provide heating
and cooling to a building.

Figure 36: Geothermal energy recovery loop

A geothermal loop can be installed ei­ther horizontally or vertically. Vertical
loops require less overall land area to
reject (i.e., sink) the excess heat from
the building. Horizontal loops require
trenches in the ground spanning a
larger overall land area.

Although external piping is the re­sponsibility of the installer and/or pip­ing manufacturer, many electric
utilities and rural electric cooperatives
are offering monetary incentives to in­stall geothermal systems. Utility com­panies offer the incentives because of
reduced peak loads that flatten out
their demand curve over time, and
save them money. These savings are
ultimately transferred to the consum­er. See Figure 36 for geothermal en­ergy recovery loop.

WSHP-PRC001-EN 27

Application
Considerations

Boiler/Cooling Tower Application

In a boiler/cooling tower application (Figure 37), the closed water-loop, along
with multiple water-source heat pumps are utilized in a more conventional
manner.

Typically, a boiler is used to maintain closed-loop temperatures
above 60 F, and a cooling tower is used to maintain
closed-loop temperature below 90 F. All the units
function independently, either by adding heat,
or rejecting heat, or moving heat from the
closed water-loop. Because the heat
from a building is being rejected
through a cooling tower, the system
is more efficient than air cooled sys­tems.

The boiler/cooling tower system pro­vides a low installation cost to the
owner when compared to other sys­tems, and is the most common applica­tion. It also allows the owner to add units to
the condenser water loop as needed.

Ground Coupled Application

Systems that utilize the ground-coupled (geothermal) design are also applied to
a closed water-loop, along with the multiple ground-source heat pumps.
With the ground-coupled (geothermal) system, heat is exchanged with the earth
by either moving heat into the earth, or absorbing heat from the earth. Water
temperature ranges vary from 25 F to 105 F depending on climate, and season.
Because the ground-coupled system does not use the fluctuating outside-air
temperature, the geothermal heat pumps are capable of using less energy.

The choices in earth-loop coupling consists of a vertical (Figure 38), hor­izontal, or a pond-loop design. Each of these options offer different
system design characteristics. The vertical and horizontal loop
systems can be designed to provide the same fluid temper­atures under a given set of conditions.

Operating and maintenance cost are lower
because an auxiliary electric/fossil fuel
boiler and cooling tower are not re­quired to maintain the loop tempera­ture in a properly designed system.

Because the ground loop is made of
chemically inert, non-polluting, high
density polyethylene pipe, the loop
is environmentally responsible. The
heat pumps use HCFC-22 refrigerant,
which has a low ozone depletion poten­tial. Because the closed-loop system does
not require a heat adder, there are no C02 emis­sions. Less power is consumed by the system, thereby
reducing secondary emissions from the power plant. Therefore, the
ground-coupled system offers advantages not seen by other HVAC system types.

Figure 37: Boiler/cooling tower

application

Figure 38: Vertical bore ground loop

application

28 WSHP-PRC001-EN

Figure 39: Pond loop system

Application
Considerations

Open-Loop Design

Ground water from a well can be used to exchange heat

in an open-loop system Figure 39. The ground
water is pumped from the well into the geothermal
heat pump, where heat is extracted or rejected and
then returned to an aquifer. The only change to the
ground water is a slight temperature difference. The

rejected water is dumped into a surface well,

lake, or stream, continually removing

water from the aquifer. Alternatively,

a recharge well may be installed to

return the water into the ground.

Open-loop systems use a large
amount of water, and can only
be economically justified where
wells and disposal systems are
easy to install.

Operation and benefits are

similar to those for closed-loop

systems. There are, however, several

considerations that should be addressed

prior to installation.

1 Water quality must be acceptable, with minimal suspended solids
and proper pH. To help ensure clean water, a straining device may be
required.

2 An acceptable way to discharge the significant volume of used water from

the heat pump should be defined. It may be necessary to install a recharge

well to return the water to the aquifer.

Slinky Loop

With the slinky-loop system application Figure 40,
groups of water-coupling, pipe coils are submerged
several feet below the low water level or within a

horizontal ground trench. This system has all of the

advantages of a vertical bore, or horizontal trench

application, and can be very cost effective

when applied in the proper land region.

With the slinky-loop system design,

some special considerations should be

taken for the installation if a pond
application is used.

1 The body of water should be close

to the structure. If the distance

from the water to the building must

accommodate a horizontal field, the

submerged loop would offer no

advantage over a horizontal water-loop

design.

Figure 40: Slinky loop system

be used.

WSHP-PRC001-EN 29

3 The loop should not be placed within a moving body of water that is subject

to flooding.

2 Anti-freeze fluid of at least 20-percent by volume must

Application
Considerations

Central Pumping System

Units that employ a central pumping
system contain single or dual pumps
to fulfill pumping requirements for the
entire building system.

The central system’s supply and re­turn lines should be sized to handle
the required flow with a minimum
pressure drop.

The water-source heat pump (in this
case a high efficiency GEH) may in­clude add-on accessories to help aid in
system balancing, acoustics and safe­ty requirements. Some of these items
may be ordered from the factory, then
field installed. Many are provided by
the contractor.

1

Hose kits are used to connect the

water supply and return line to the
water inlets and outlets. Trane of­fers various hose kit combina­tions to better facilitate
system flow balancing.
These flexible hoses also aid
in the reduction of vibration
between the unit and the rig­id central piping system.

A two position isolation valve is
often applied to systems which in­corporate variable frequency
pumping. This valve is capable of
stopping/starting water flow to the
unit, which in-turn reduces
the pumping requirements
for the entire system.

The central system supply and

5

return lines should be sized to

handle the required flow with a
minimum pressure drop.

Note: Pipe will sweat if low tem­perature water is below the dew
point of the surrounding space.
Trane recommends that these
lines be insulated to prevent dam­age from condensation when con­denser loop is designed to be
below 60 F.

For acoustically sensitive areas, a

6

six-inch deep fiberglass insula­tion is recommended to be field

installed below the horizontal unit.
This field supplied insulation
should be approximately twice the
footprint size of the unit. It pro­vides sound damping of the unit
while in operation.

2

The unit’s (item 2) 3/4-inch high

voltage and (item 3) 1/2-inch low

3

voltage connections are located

on the left chamfered corner
of the unit. They are de­signed to accept con­duit.

A field supplied line voltage dis-

4

connect should be installed for

branch circuit protection. Check
local codes for requirements.

30 WSHP-PRC001-EN