McQuay CCH072 User Manual
Catalog 1112-2
Enfinity™ Large Horizontal Water Source Heat Pumps
with R-410A Refrigerant
Horizontal Models CCH Standard Range & CCW Geothermal Range
Unit Sizes 072 – 120 (6 to 10 Tons) • R-410A Refrigerant
Engineered for exibility and performance™
Table of Contents
Introduction
........................................................................3
Nomenclature.....................................................................3
Features & Options ............................................................4-5
Control Features
Control Features ............................................................6
.................................................................6-9
MicroTech III Controller ..................................................7
I/O Expansion Module ....................................................8
MicroTech III Controller with Communication Module ....9
Applications ....................................................................10-14
Unit Location ................................................................10
Ductwork & Attenuation ................................................11
Typical Cooling and Heating Refrigeration Cycles .......12
Systems ..................................................................13-14
I
SO Performance Data .....................................................15
Water Loop ...................................................................15
Ground Loop ................................................................15
Ground Source .............................................................15
Heating & Cooling Capacity Data
Large Horizontal Unit .................................................16-21
Cooling Size 072 @ 2400 SCFM .................................16
Heating Size 072 @ 2400 SCFM .................................17
Cooling Size 096 @ 3000 SCFM .................................18
Heating Size 096 @ 3000 SCFM .................................19
Cooling Size 120 @ 4000 SCFM .................................20
Heating Size 120 @ 4000 SCFM .................................21
Operating Limits
Correction Factors
..............................................................23
..........................................................24
Airow Correction Factors ............................................24
Anitfreeze Correction Factors ......................................24
Performance Data - Fan Curves .....................................25
Size 072, 096 & 120 .....................................................25
Dimensional Data .......................................................26-28
Size 072 .......................................................................26
Size 096 .......................................................................27
Size 120 .......................................................................28
Accessories ................................................................29-34
Hanger Brackets ..........................................................29
Supply and Return Hoses ............................................29
Condensate Hose Kit ...................................................29
Combination Balancing & Shutoff (Ball) Valves ...........30
Motorized Valve ............................................................30
Multiple Unit Control Panel (MUCP).............................30
Thermostats and Wall Sensors ...............................31-32
Control Connection Diagrams .................................33-34
Typical Wiring Diagrams
............................................35-37
MicroTech III Controller with I/O Expansion Module &
Communication Module – 208/230V, 460V, 575V-60-3
Unit Sizes 096-120 .......................................................35
MicroTech™ III Controller with I/O Expansion Module &
Communication Module 208/230V, 460V, 575V-60-3
1.5 HP Motor ................................................................36
Electrical & Physical Data...............................................22
“McQuay” is a registered trademark of McQuay International.
©McQuay International 2009. All rights reserved throughout the world.
The information in this manual supersedes and replaces previous catalogues with regards to McQuay Water Source Heat Pump products.
Illustrations cover the general appearance of McQuay International products at the time of publication and McQuay International reserves the
right to make changes in design and construction at anytime without notice.
™®The following are trademarks or registered trademarks of their respective companies: LonTalk from Echelon Corporation, BACnet from ASHRAE, Protocol
Selectability, and MicroTech II from McQuay International.
Engineering Guide Specications
............................37-39
Page 2 of 42 McQuay Large Horizontal Water Source Heat Pumps Catalog 1112-2
Introduction
Large Horizontal Water Source Heat
Pumps - Models CCH & CCW
Sizes 072-120 (6 to 10 Tons)
Model CCH (Standard Range: 55°F to 110°F)
Model CCW (Geothermal Range: 30°F to 110°F)
McQuay 6- to 10-ton horizontal units have a common
cabinet size and common water, condensate, and duct con-
nection locations for easier and more efcient installation.
The cabinet is constructed of unpainted, G-60 galva-
nized steel. Large panels provide access to the fan/motor
compartment and the compressor/control compartment.
The interiors of the top and side panels and the bottom of
the unit are covered with 1/2" thick, 1½ lb. dual-density
berglass insulation. The lter is supported by a factorymounted combination lter rack and return air duct collar,
eliminating the need for eld-mounted brackets.
The water and condensate connections protrude through
the outside of the cabinet. The water connections are FPT
type for easy connection to exible stainless steel hoses.
The large condensate connection provides effective conden-
sate removal.
The electrical components are located in the compressor
section of the unit. Holes are provided on the cabinet to facilitate main power and low voltage control wiring through
separate holes. All wiring connections are made internal to
the cabinet for maximum safety. Each unit is rated to accept
time delay fuses for branch circuit and is protected by a
resettable circuit breaker.
The standard control for all large capacity units is the
MicroTech™ III unit controller. The unit controller receives
its power from the 75VA control transformer.
A LonWorks® or BACnet® communication module is
available as an option.
Nomenclature
W CCH 1 120 B L Y S Y Y F
Product Category
W = WSHP
Product Identier
CCH = Large Horizontal - Standard Range
CCW = Large Horizontal - Geothermal
Design Series
1 = A Design 4 = D Design
2 = B Design 5 = E Design
3 = C Design
Nominal Capacity
072 = 72,000 BTU/h
096 = 96,000 BTU/h
120 = 120,000 BTU/h
Controls
B = MicroTech III
A = DDC Less Board
Network Module Option
L = LonWorks® Module
B = BACnet® Module
Y = None
Note: For illustration purposes only. Not all options available with all models.
Please consult McQuay Sales Representative for specic availability.
Voltage
D = 208-60-3
F = 208/230-60-3
H = 230-60-3
K = 460-60-3
L = 575-60-3
N = 380-50-3
Reserved
Y = None
Reserved
Y = None
Condensate Overow
S = Standard Overow
Sensor
Current Sensing
Y = None
Catalog 1112-2 McQuay Large Horizontal Water Source Heat Pumps Page 3 of 42
CCH & CCW Features and Options
MicroTech® III Controller
Schrader Connections
L
onWorks®
Communication
Module
I/O Expansion Module
BACnet®
Communication
Module
Enfinity Large Horizontal Water
Source Heat Pumps
Sizes 072 - 120 (6 to 10 Tons)
Model CCH (Standard Range: 55°F to 110°F)
Model CCW (Geothermal Range: 30°F to 110°F)
1. Cabinet - Heavy gauge G-60 galvanized steel.
2. Fan Section - A forward curved, DWDI fan, solid steel shaft
mounted in ball bearings. Motor to be three phase,
Open- Drip Proof (ODP) type with variable pitch sheave
and adjustable base.
3. Insulation - All interior framework and panels are lined with
1/2" thick, 1½ lb. dual-density berglass insulation. Optional
(IAQ) closed-cell foam insulation.
4. Drain Pan - Heavy-gauge, insulated, galvanized steel or op-
tional stainless steel.
5. Filters - Standard 2" factory-installed lter rack with 2" throw-
away lters. Filter rack outtted with duct collar.
6. Refrigerant Circuit - All units have a dual refrigerant circuit
with scroll compressors, thermal expansion valve, plate to
plate heat exchanger, nned tube airside coil, reversing valve
and service valves.
LED Annunciators
7. Electrical - The control enclosure includes components neces-
sary for proper unit operation. These components include,
but not limited to: fan relay, compressor contactors, 24 VAC
control transformer and control circuit boards.
8. Schrader Connections - Four Schrader valves are located in-
side the end access panel – one on the low side and one on the
high side of the refrigeration circuit – for charging and servic-
ing. All valves
are 7/16" SAE ttings.
9. MicroTech® III Controllers – Designed for exibility, the control
board is used in standalone applications in conjunction with
the I/O expansion module for control of the second refrigerant
circuit. A separate L
onWorks® or BACnet® communication
module can be easily snapped onto the Microtech III board to
allow communication with a building automation system. The
control system accomodates the use of a two-stage heat/two-
stage cool 7-day programmable or non-programmable wall-
mounted thermostat, offered as a eld-installed option.
10. LED Annunciators – External LED status lights display fault
conditions to provide easy troubleshooting and diagnosis, vis-
ible without removing the access panel.
11. External Pipe Connections – Supply and return pipe connec-
tions located outside the cabinet make pipe connections easy
without removing access panels.
Safety Controls (Not Shown) - Low and high refrigerant pres-
sure switches and low refrigerant suction temperature
(freezestat) sensor.
Page 4 of 42 McQuay Large Horizontal Water Source Heat Pumps Catalog 1112-2
CCH & CCW Features and Options
Cabinet Construction
McQuay 6- to 10-ton horizontal units have a common
cabinet size and common water, condensate, and duct connec-
tion locations for easier and more efcient installation.
The cabinet is constructed of heavy-gauge G-60 galva-
nized steel. Large panels provide access to the fan/motor
compartment and the compressor/control compartment. The
interiors of the top and side panels and the bottom of the unit
are covered with 1/2" thick, 1½ lb. dual-density berglass
insulation. Closed-cell foam (IAQ) insulation is available as
a selectable option, suitable for berglass-free applications.
The lter is supported by a factory-mounted combination lter
rack and return air duct collar, eliminating the need for eldmounted brackets.
The water and condensate connections protrude through
the outside of the cabinet. The water connections are FPT type
for easy connection to exible hoses. The large condensate
connection provides effective condensate removal.
The electrical components are located in the compres-
sor section of the unit. Holes are provided on the cabinet to
facilitate main power and low voltage control wiring through
separate holes. All wiring connections are made internal to the
cabinet for maximum safety. Each unit is rated to accept time
delay fuses for branch circuit and is protected by a resettable
circuit breaker.
Figure 1: Controls and Compressor Compartment
Extended range units include coil and piping insulation to
protect against condensation in low temperature geothermal
applications.
Safety controls include low suction temperature (freez-
stat) and high pressure switches to lock out compressor
operation at extreme conditions. The safety controls can
only be reset from the main disconnect switch - not from
the wall thermostat.
For additional safety, each unit has a 7 psi (48 kPa) low
pressure switch to protect the compressor from low refrig-
erant charge. The low setting prevents nuisance trips while
providing adequate protection.
Figure 2: Piping Compartment
Thermal Expansion Valve
Units include a Thermal Expansion Valve (TXV) for
refrigerant metering. The TXV allows the unit to operate at
optimum efciency with uid temperatures ranging from
25ºF to 110ºF (geothermal capable units only) and entering
air temperatures ranging from 40ºF to 90ºF. The TXV pre-
cisely meters the exact amount of refrigerant ow through
the system to meet the load and deliver rated heating and
cooling capacity.
Fan Section
The fan section includes the fan housing, fan wheel, fan
motor, adjustable sheave, high strength V-belt, and drain
pan. The standard drain pan is made of G-60 galvanized
Refrigeration System
Units have a dual circuit design and the two circuits
operate independently to enable load shedding when condi-
tions allow. Each circuit employs a random start feature to
prevent both compressors from energizing simultaneously
after an “unoccupied” cycle.
Units contain two of each refrigerant system compo-
nent, including high efciency compressors, plate-to-plate
heat exchangers, reversing valves, expansion valves,
high/low side refrigerant service valves, and required safety
controls. Large access panels are provided for easy service
access to any of these components.
The reversing valves are energized in the heating mode
and will “fail-safe” to the cooling mode, which is the pre-
dominant mode of operation.
The air-to-refrigerant coil is a dual circuit coil on one
slab. It is split equally along the horizontal axis for maxi-
mum efciency. The ns are lanced and the tubes have
nned edges on the inside to enhance heat transfer capabilities.
Catalog 1112-2 McQuay Large Horizontal Water Source Heat Pumps Page 5 of 42
steel and is insulated from the cabinet. A stainless steel
drain pan is available as an option. The pan has ample
height to allow self-priming of the condensate trap. The
fan motor is a single speed, high efciency PSC type with
an adjustable sheave for eld adjustment. The motor is iso-
lated from the fan housing to minimize vibration transmis-
sion to the cabinet. The fan housing protrudes through the
cabinet to provide adequate material to connect to a eldprovided exible duct collar. The fan discharge can exit
from the end or the side of the unit and must be congured
at the factory.
Optional Factory Installed Features
Geothermal range units are available for applications
requiring heating operation at reduced entering condi-
tions. The geothermal range unit will operate at 25ºF (5ºC)
minimum entering water temperature, 40ºF (5ºC) minimum
entering air temperature.
Control Options – Control Choices And Added Functionality
The control enclosure houses the major operating electri-
cal controls including the MicroTech® III controller and I/O
expansion module, control transformer, compressor relays
and fan relay. Each component is easily accessed for service
or replacement.
Three unique control choices are offered with the Micro-
Tech III control system:
■ Standalone operation using a MicroTech III controller and
I/O expansion module
■ MicroTech III controller and I/O expansion module with a
LonWorks® communication module
■ MicroTech III controller and I/O expansion module with a
BACnet® communication module
Each option features direct quick-connect wiring to all
unit-controlled components for “clean” wiring inside the
control box. Each control circuit board receives power from
a 75 VA transformer.
Table 1: Control Options
Control Description Application Protocol
MicroTech III
(Standalone)
The MicroTech III controller is a standalone microprocessor-based control
board conveniently located in the unit
control enclosure for easy accessibility.
The board is designed to provide thermostat control of a Water Source Heat
Pump using a two-stage wall thermostat. The unit controller provides unitwide control of the WSHP and control
of the rst refrigerant circuit.
Each unit controller is factory programmed, wired,
and tested for complete control of single zone, standalone operation of your McQuay Water Source Heat
Pump.
Unit Controller
with
I/O Expansion
Module
The I/O Expansion Module is an extension of the Microtech III controller and
provides control of the second refriger-
ant circuit. External LED status lights
display fault conditions to provide easy
troubleshooting and diagnosis of the
second circuit.
Allows for:
• Control of second refrigeration circuit.
Uni t-mounted
or wall-mounted
thermostat
Wal l-mount ed
the rmostat or
sensor
LonWorks
Communication
Module
BACnet
Communication
Module
Page 6 of 42 McQuay Large Horizontal Water Source Heat Pumps Catalog 1112-2
The MicroTech III control system
accepts a plug-in LonWorks commu-
nication module to provide network
communications and added functional-
ity to easily integrate with an existing
BAS. The communication module can
be factory- or field-installed and is
tested with all logic required to monitor
and control the unit.
The MicroTech III controller accepts
a plug-in BACnet communication
module to provide network commu-
nications and added functionality to
easily integrate with an existing BAS.
The communication module can be
factory- or eld-installed and is tested
with all logic required to monitor and
control the unit.
Designed to be linked with a centralized building
automation system (BAS) through a L
munications network for centralized scheduling and
management of multiple heat pumps.
Designed to be linked with a centralized building
automation system (BAS) through a BACnet communications network for centralized scheduling and
management of multiple heat pumps.
onWorks com-
L o nMa rk 3 .4
certied
BACnet
MS/TP
Control Features – MicroTech® III Unit Controller
The MicroTech III Controller is a microprocessor-based
control board conveniently located in the unit control box for
easy access through a removable access panel. The standalone
unit controller is a hard wired interface and provides all the
necessary eld connections. The board can be wired for 24volt AC output to the wall thermostat by using terminals R
& C. An LED annunciator is located on the front of the unit
chassis to allow quick check of the unit operating status.
MicroTech III Operating Features
Assumes cycle fan operation-not continuous fan operation:
■ Start-up – The unit will not operate until all the inputs
and safety controls are checked for normal conditions.
■ Cooling mode – On a call for cooling from the wall ther-
mostat, the controller will energize the fan relay and stage
compressors to satisfy the space temperature setpoint.
When the load is satised, the controller will disable the
compressor and fan.
■ Heating Mode – On a call for heating from the wall
thermostat, the controller will enable the fan, energize
circuit one reversing valve and circuit 1 compressor to
satisfy the space heating setpoint. If the space temperature
setpoint is not satiseld, circuit two reversing valve and
circuit 2 compressor will be energized and run until the
heating setpoint at the thermostat is satised.
■ Random Start Power-up Delay Timer – In the event of
a building power outage, this feature prevents multiple
units from starting simultaneously upon building power
restoration.
■ Unoccupied Mode – A simple “grounded” signal between
terminals U and C (no power source required), puts the
unit into the unoccupied mode for night setback operation.
■ Interstaging Timer – A default value of 5 minutes be-
tween staging of compressors, this feature minimizes short
cycling of compressors and improves comfort.
■ Override Mode – A switch on the deluxe automatic
changeover thermostat can be activated during the unoc-
cupied mode to put the unit back into the occupied mode
for two hours for after-hours heating or cooling.
■ Motorized Valve/Pump Restart – The IV/PR (H8) ter-
minals on the The MicroTech III unit controller are used
to energize (open) a motorized valve or start a water pump
to get water circulating prior to starting the compressor on
call for heating or cooling. The IV/PR (H8) terminal may
be “daisy chained” between a maximum of 200 units.
■ Brownout Protection – The MicroTech III unit controller
measures the input voltage and will suspend compres-
sor and fan operation if the voltage falls below 80% of
the unit nameplate rated value. A unique LED status is
generated.
■ Unit Shutdown – A simple grounded signal puts the unit
into the shutdown mode. Compressor and fan operations
are suspended. A unique LED status is generated.
■ Condensate Overow Protection – The MicroTech III
controller incorporates a liquid sensor at the top of the
drain pan. Upon sensing water ow, cooling operation is
suspended. A unique LED status is generated.
■ Remote Reset of Automatic Lockouts – The Remote
Reset feature provides the means to remotely reset auto-
matic lockouts generated by high-pressure and/or lowtemperature faults. When the MicroTech III controller is
in automatic lockout due to one of these faults, and the
cause of the fault condition has been alleviated, energizing the O-terminal for 10 seconds or more will force the
control board to clear the lockout. A unit power cycle can
also be used to clear an automatic lockout if the conditions
causing the fault have been alleviated.
■ Intelligent Reset – The Fault Retry feature helps to
minimize nuisance trips of automatic lockouts caused by
high-pressure and/or low-temperature faults. This feature
clears faults the rst two times they occur within a 24-hour
period and triggers an automatic lockout on the 3rd fault.
The retry count is reset to zero every 24 hours.
■ Equipment Protection Control – The MicroTech III
controller receives separate input signals from the refrigerant high-pressure switch and the low suction line tem-
perature sensor. In a high-pressure situation, compressor
operation is suspended. In a low temperature situation,
the unit goes into a defrost cycle where the unit is put
into cooling operation for 60 seconds until the coaxial
heat exchanger is free of ice. Each switch generates its
own unique LED status.
Note: Most unit fault conditions are the result of operating
the equipment outside the unit specications.
Table 2: MicroTech III Controller LED & Fault Outputs
Mode / Fault
Occupied, Bypass,
Standby, or Tenant Off On Off Energized
Override
Unoccupied On On Off Energized
Condensate Overow On Off Off De-energized
High Pressure 1 Fault Off Off Flash De-energized
Low Pressure 1 Fault Off Off On De-energized
Low Temperature 1 Fault Flash Off Off De-energized
Brownout
Emergency Shutdown Off Flash Off De-energized
Room/Return Air or Low
Temp Sensor 1 Failure
Service Test Mode
Enabled
Serial EEPROM
Corrupted
Network “Ofine”
Received
1
Compressor relay/compressor terminal is labeled COMP, switched line of
the same electric input as any of the L1 terminals.
Status LED’s
1
Yellow Green Red Output-Terminal “A”
Off Flash Off De-energized
Flash Flash On De-energized
Flash Flash Flash De-energized
On On On De-energized
Off Off Off De-energized
Thermostat Alarm Light
Catalog 1112-2 McQuay Large Horizontal Water Source Heat Pumps Page 7 of 42
Control Features – MicroTech III with I/O Expansion Module
I/O Expansion Module
The I/O Expansion Module is factory-installed for control
of the second refrigeration circuit.
The I/O Expansion Module has an independent LED an-
nunciator to identify operational fault conditions for the
second refrigeration circuit.
Table 3: I/O Expansion Module LED & Fault
Outputs
Terminal “A”
Invalid Conguration
Jumper Setting
Base Board
Communication Fail
High Pressure #2 Fault Off Off Flash De-energized
Low Pressure #2 Fault Off Off On De-energized
Unoccupied Mode On On Off Energized
Occupied, Bypass,
Standby, or Tenant
Override Modes
Note: Mode / Faults are listed in order of priority.
1
2
Mode / Fault
Low Suction Temp #2 Fault Flash Off Off De-energized
Sensor Failures Low Suction
Low Suction Temp #2, Flash Flash On De-energized
1
EWT (w/ Boilerless EH only)
2
Service Test Mode Enabled Flash Flash Flash De-energized
Normal Operation Off On Off De-energized
Boilerless electric heat only
Alarm/fault LED indications take precedence over service test mode LED
indication. The controller shall use service test mode if the service test
mode jumper is installed, even if the LED’s indicate an alarm/fault.
Yellow Green Red
Status LED's
Flash Flash Off De-energized
Off Flash Flash N/A
Off On Off Energized
Thermostat Alarm
Light Output
Figure 3: I/O Expansion Module Conguration
Jumper Terminals
Jumper Terminals
JP1 shorted in units with
2 compressors
JP1 through JP8 not
used with 2 circuit units.
Page 8 of 42 McQuay Large Horizontal Water Source Heat Pumps Catalog 1112-2
Control Features – MicroTech III with Communication Module
MicroTech® III Controller with LonWorks® or
BACnet Communication Module
Each Ennity Large Vertical and Horizontal Water
Source Heat Pump can be equipped with a LonWorks or
BACnet communication module. The LonWorks module is
LonMark 3.4 certied and designed to communicate over a
LonWorks communications network to a Building Auto-
mation System (BAS). The BACnet module is designed to
communicate over a BACnet MS/TP communications net-
work to a building automation system. Both controllers are
microprocessor-based and can be factory or eld-installed.
The control modules are programmed and tested with all
the logic required to monitor and control the unit. Optional
wall sensors may be used with the communication modules
to provide limited local control of the Horizontal Water
Source Heat Pump. The MicroTech III controller monitors
water and air temperatures and passes information to the
communication module. The module communicates with
the BAS, to provide network control of the Water Source
Heat Pump.
MicroTech III LonWorks Communication Module
The LonWorks communication module is designed for
units that are integrated into a LonWorks communication
network for centralized scheduling and management of
multiple heat pumps.
MicroTech III Controller with Communication Modules
Features
The MicroTech III Controller with LonWorks or BACnet
Communication Module orchestrates the following unit
operations:
Enable heating and cooling to maintain space
temperature setpoint based on a room sensor setting
Enable fan and compressor operation
Monitors all equipment protection controls
Monitors room and discharge air temperatures
Monitors leaving water temperature
Relays status of all vital unit functions
An amber, on-board status LED indicates the status of the
MicroTech III LonWorks or BACnet module.
The MicroTech III Controller Includes:
A unit-mounted return air sensor
A unit-mounted discharge air sensor
A leaving water temperature sensor
The communication modules provide network access to
setpoints for operational control
Available Wall Sensors Include:
Room sensor
MicroTech III BACnet Communication Module
Designed to be linked with a centralized building auto-
mation system (BAS) through a BACnet communications
network for centralized scheduling and management of
multiple heat pumps.
Room sensor with LED status and tenant override
button
Temperature sensor with LED status, timed-override
button, and ±3°F setpoint adjustment
Room sensor with LED status, timed-override
button, 55° to 90°F setpoint adjustment
Catalog 1112-2 McQuay Large Horizontal Water Source Heat Pumps Page 9 of 42
Applications
Typical Horizontal Unit Installation
Unit Location
It is important to leave enough space for service person-
nel to perform maintenance or repair. Locate the horizon-
tal unit to allow for easy removal of the lter and access
panels. Allow a minimum of 18" (46 cm) clearance on each
side of the unit for service and maintenance access and
do not install the unit above any piping. Always be sure
to leave at least one side of the lter rack unobstructed so
that the service personnel will be able to slide the lter out.
Each unit is suspended from the ceiling by four 3/8" thread-
ed rods fastened to the unit by a hanger bracket and rubber
isolator. The design should place the unit directly below the
structural members so that it is securely anchored.
Avoid installing units directly above spaces where
building occupants will reside (e.g. above ofce desks or
classrooms) to reduce the requirement for noise attenuation.
Do not place units above high trafc areas because service
access may be limited during occupied hours. For example,
units are typically installed above the hallway drop ceiling
in Schools and the supply and return air is routed directly
into classrooms. Local code may require re dampers to be
used with this application.
Piping
The WSHP unit is typically connected to the supply/return piping using a “reverse return” piping system which
includes a ow control device so that ow requirements are
met for each zone. A short, high pressure “exible hose” is
used to connect the unit to the building’s hard piping and
Figure 4: Typical Ceiling Installation
acts as a sound attenuator for both the unit operating noise
and hydraulic pumping noise. One end of the hose has a
swivel tting to facilitate removal of the unit for replace-
ment or service. Include supply and return shutoff valves
in the design to allow removal of a unit without the need to
shut down the entire heat pump system. The return valve
may be used for balancing and will typically have a “memory stop” so that it can be reopened to the proper position
for the ow required. Fixed ow devices are commercially
available and can be installed to eliminate the need for
memory stop shut off valves. Include Pressure / Temperature ports to allow the service technician to measure water
ow and unit operation.
Condensate Drain Piping
Condensate piping can be made of steel, copper or PVC
pipe. In most cases, PVC pipe eliminates the need to wrap
insulation around the pipe to prevent sweating. A threaded,
factory supplied condensate tting allows the connection of
PVC, exible vinyl hose or steel braided hose.
The condensate piping must be trapped at the unit and
pitched away from the unit not less than 1/4" per foot. A
vent is required after the trap so that the condensate will
drain away from the unit. The vent can also act as a clean
out if the trap becomes clogged. To avoid having waste
gases entering the building, the condensate drain should
not be directly piped to a drain/waste/vent stack. See local
codes for the correct application of condensate piping to
drains.
Figure 5: Typical Condensate Piping
Condensate
Drain (P Trap)
1 1/2"
(38mm)
Page 10 of 42 McQuay Large Horizontal Water Source Heat Pumps Catalog 1112-2
1 1/2"
(38mm)
Optional
Field Installed Vent
1/4" Per Foot
(21mm Per Meter)
Ductwork and Sound Attenuation Considerations
Applications
Ductwork is normally applied to ceiling-mounted heat
pumps on the discharge side of the unit. A discharge collar
is provided on all horizontal unit models for fastening the
ductwork. Use a exible connector between the discharge
collar and the duct transformation to help reduce vibration
straight length of duct, 5 to 10 times the duct width, before
the next tting to smooth out airow. Diffusers that are lo-
cated in the bottom of a trunk duct can also produce noise.
For this same reason, volume control dampers should be
located several duct widths upstream from an air outlet.
transmission from the cabinet and to simplify disconnection
of the unit from the ceiling ductwork. If return ductwork
is to be used, attach a exible connector to the lter rack
collar to help reduce vibration transmission and removal of
the unit. Return plenum ducting should be at least 12 inches
away from the coil so that the coil is evenly loaded with
return air.
For Hotel, Motel, Dormitory or Nursing Home applica-
tions that use a single duct discharge, a velocity of 500 to
600 fpm is suggested. These applications typically have
static pressures as low as 0.05 inches of water and duct
lengths approximately six feet in length. The discharge
duct must be fully lined and have a square elbow without
turning vanes. Return air for these applications should
As a general recommendation, duct interiors should
have an acoustic / thermal lining at least 1/2 inch thick
over the entire duct run. For better sound attenuation, line
the last ve diameters of duct before each register with a
one-inch thick sound blanket. Elbows, tees and dampers
can create turbulence or distortion in the airow. Place a
enter through a “low” sidewall lter grille and route up the
stud space to a ceiling plenum. For horizontal heat pumps
mounted from the ceiling, an insulated return plenum is
sometimes placed at the return air opening to further
attenuate line-of-sight sound transmission through return
openings.
Figure 6: Suggested Supply Ducting per ASHRAE and SMACNA Publications
Flexible Connector
Acoustic/Thermal Lining
3ft. (.9m) to 5ft. (1.5m)
Acoustic/Thermal
Lining
Diffuser
(Ductwork Sized Based on Airow)
Figure 7: Suggested Return Ducting per ASHRAE and SMACNA Publications
Two 90° Turns Prior to the Intake
(Ductwork Sized Based on Airow)
Ductwork Supported
Independent of Unit
Acoustic/Thermal
Lining
Flexible Connector
Ductwork Supported
Independent of Unit
Diffuser
Two 90° Turns
Acoustic/Thermal
Lining
Return Air Intake
Located
Away from the
Unit Blower
Catalog 1112-2 McQuay Large Horizontal Water Source Heat Pumps Page 11 of 42
Acoustic/Thermal
Lining 10ft. (3 meters)
Flexible Connector
Applications
Typical Cooling and Heating Refrigeration Cycles – Dual Compressors
Note: Typical temperature readings are at full load conditions at ISO-13256 for boiler-tower applications.
Figure 8: Cooling Refrigeration Cycle
When the wall thermostat calls for COOLING, the revers-
ing valve (de-energized) directs the ow of the refrigerant,
a hot gas, from the compressor to the water-to-refrigerant
heat exchanger (coaxial heat exchanger). There, the heat is
removed by the water, and the hot gas condenses to become
a liquid. The liquid then ows through a thermal expansion
valve to the air-to-refrigerant heat exchanger coil (evapora-
tor). The liquid then evaporates and becomes a gas, at the
same time absorbing heat and cooling the air passing over the
surfaces of the coil. The refrigerant then ows as a low pres-
sure gas through the reversing valve and back to the suction
side of the compressor to complete the cycle.
Figure 9: Heating Refrigeration Cycle
When the wall thermostat calls for HEATING, the
reversing valve (energized) directs the ow of the refriger-
ant, a hot gas, from the compressor to the air-to-refrigerant
heat exchanger coil (condenser). There, the heat is removed
by the air passing over the surfaces of the coil and the hot
gas condenses and becomes a liquid. The liquid then ows
through a thermal expansion valve to the water-to-refrigerant
heat exchanger (evaporator). The liquid then evaporates and
becomes a gas, at the same time absorbing heat and cooling
the water. The refrigerant then ows as a low pressure gas
through the reversing valve and back to the suction side of
the compressor to complete the cycle.
Page 12 of 42 McQuay Large Horizontal Water Source Heat Pumps Catalog 1112-2
Applications – Systems
Water source heat pump systems are one of the most ef-
cient, environmentally friendly systems available for heating
and cooling buildings. High-efciency, self contained units
(sizes 7,000 btuh to 290,000 btuh) can be placed in virtually
any location within a building. Each unit responds only to
the heating or cooling load of the individual zone it serves.
This permits an excellent comfort level for occupants, better
control of energy use for building owners and lower seasonal
operating costs. The Air-Conditioning Refrigeration Institute
(ARI) and the International Standards Organization (ISO)
publish standards so that water source heat pumps are rated
for specic applications. The ARI/ISO loop options shown in
this catalog are typical water source heat pump loop choices
available in today’s market. These systems offer benets rang-
ing from low cost installation to the highest energy efciency
available in the market today.
Boiler / Tower Applications: ARI 320 / ISO
13256-1
A “Boiler/Tower” application uses a simple two-pipe
water circulating system that adds heat, removes heat or
transfers rejected heat to other units throughout the build-
ing. The water temperature for heating is generally main-
tained between 65ºF – 70ºF and is usually provided by a
natural gas or electric boiler located in a mechanical room.
The condensing water temperature, during cooling months,
is maintained between 85ºF and 95ºF and requires the use
of a cooling tower to dissipate waste heat. Cooling tow-
ers can be located on the roof, or inside or adjacent to the
building. This application can be the lowest cost of the loop
options available.
Note: ASHRAE 90.1 standards require that circulating
pumps over 10 HP will require use of “variable frequency
drive” equipment and pipe insulation to be used whenever
water temperatures are below 60 degrees and above 105
degrees. See ASHRAE 90.1 Standards for details.
Open Loop Well Water Applications: ARI
325 / ISO 13256-1
“Open Loop” well water systems use ground water
to remove or add heat to the interior water loop. The
key benet of an open loop system is the constant water
temperature, usually 50ºF to 60ºF, which provides efcient
operation at a low rst cost. Most commercial designers
incorporate a heat exchanger to isolate the building loop
from the well water. Using heat exchangers can reduce
maintenance issues while still allowing the transfer of heat
from unit to unit as with the “Boiler/Tower System”. A successful design provides an ample amount of groundwater
(approximately 2 GPM per ton) and adequate provisions
for discharging water back to the aquifer or surface. Open
Loop applications are commonly used in coastal areas
where soil characteristics allow reinjection wells to return
the water back to the aquifer. Note that some states have requirements on the depths of return water reinjection wells,
and such wells must be approved by the United States En-
vironmental Protection Agency. Also, bad water quality can
increase problems with heat exchanger scaling. Suspended
solids can erode the heat exchanger. Strainers can be used
to contain suspended solids.
Figure 11: Open Loop Well Application
Figure 10: Boiler/Tower Application
Catalog 1112-2 McQuay Large Horizontal Water Source Heat Pumps Page 13 of 42
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