Johnson Controls JMW Series Owner's manual

Water Source Heat Pumps
Installation, Operation, Maintenance Supersedes:14806-NOM1-1221 Form: 14806-NOM1-0223
97B0059N07
Issue Date: February 28, 2023
JMW-Series
Water Source Heat Pump
MODELS JMW
3-28 Tons

WATER-SOURCE HEAT PUMPS
JMW-Series
Rev.: February 28, 2023
Installation, Operation, Maintenance
2
Table of Contents
Model Nomenclature 3
General Information 4-5
Unit Physical Data 6
JMW036-120 – Unit Dimensional Data 7
JMW170 & 340 – Unit Dimensional Data 8
Unit Installation 9
Piping Installation 9-10
Load Plumbing Installation 10
Water-Loop Heat Pump Applications 11
Ground-Water Heat Pump Applications 12-13
Ground-Loop Heat Pump Applications 14-15
Water Quality Standards 16-19
Electrical – Line Voltage 20
Electrical – Accessories 21
Electrical – Line Voltage 22
Electrical – Low Voltage 23
Wiring Diagram Matrix 24
Controls - CXM2 and DMX2.5 25
Unit & System Checkout 26
Unit Start Up Procedure 27
Operating Pressures 28-29
Preventative Maintenance 30
Start-Up Log Sheet 31
Refrigeration Troubleshooting Form 32
Revision History 36

JMW-Series
Rev.: February 28, 2023
THE SMART SOLUTION FOR ENERGY EFFICIENCY
Installation, Operation, Maintenance 3
Model Nomenclature
J M W A0 3 6 CG 1 0 C 0 C S
1 2 3 4 5 6 7
8
9 10 11 12 13 14 15
JM = JOHNSON CONTROLS
Water to Water
MODELTYPE
W = WATER TO WATER HEAT PUMP
CONFIGURATION
UNIT SIZE
036 - E,F,G,H
REVISION LEVEL
A= CURRENT 036
B = CURRENT 060, 120, 170, 340
VOLTAGE
CONTROLS
CABINET INSULATION
1 = EXTENDED RANGE
HOT WATER GENERATOR OPTIONS
(JMW036-120 ONLY)
C = COPPER
SOURCE WATER COILOPTIONS
N = CUPRO-NICKEL
C = COPPER
LOAD WATER COILOPTIONS
N = CUPRO-NICKEL
S = STANDARD
0 = NONE
RESERVED-FOR FUTURE OPTIONS
0 = NONE
060 - F,G,H,N
120 - F,G,H,N
170 - F,H,N
340 - F,H,N
2 = EXTENDED RANGE w/Sound Attenuation Package
2 = HWG (COILONLY)
G = 208-230/60/1
E = 265/60/1
H = 208-230/60/3
F = 460/60/3
N = 575/60/3
AVAILABLE
VOLTAGES
{
Control
CXM2
DXM2.5
CXM2 w/ MPC
DXM2.5 w/ MPC
C
D
N
P
A
B
R
S
w/oDisconnect w/Disconnect

WATER-SOURCE HEAT PUMPS
JMW-Series
Rev.: February 28, 2023
Installation, Operation, Maintenance
4
General Information
WARNING! To avoid the release of refrigerant into the
atmosphere, the refrigerant circuit of this unit must be
serviced only by technicians who meet local, state, and
federal prociency requirements.
CAUTION! To avoid equipment damage, DO NOT use
these units as a source of heating or cooling during the
construction process. The mechanical components and lters
can quickly become clogged with construction dirt and debris,
which may cause system damage and void product warranty.
⚠ WARNING! ⚠
⚠ WARNING! ⚠
⚠ CAUTION! ⚠
Safety
Warnings, cautions, and notices appear throughout this
manual. Read these items carefully before attempting any
installation, service, or troubleshooting of the equipment.
DANGER: Indicates an immediate hazardous situation,
which if not avoided will result in death or serious injury.
DANGER labels on unit access panels must be observed.
WARNING: Indicates a potentially hazardous situation,
which if not avoided could result in death or serious injury.
CAUTION: Indicates a potentially hazardous situation or
an unsafe practice, which if not avoided could result in
minor or moderate injury or product or property damage.
NOTICE: Notication of installation, operation, or
maintenance information, which is important, but which is
not hazard-related.
WARNING! All refrigerant discharged from this unit must
be recovered WITHOUT EXCEPTION. Technicians must
follow industry accepted guidelines and all local, state, and
federal statutes for the recovery and disposal of refrigerants.
If a compressor is removed from this unit, refrigerant circuit
oil will remain in the compressor. To avoid leakage of
compressor oil, refrigerant lines of the compressor must be
sealed after it is removed.
⚠ WARNING! ⚠
WARNING! The installation of water-source heat pumps and
all associated components, parts, and accessories which
make up the installation shall be in accordance with the
regulations of ALL authorities having jurisdiction and MUST
conform to all applicable codes. It is the responsibility of
the installing contractor to determine and comply with ALL
applicable codes and regulations.
WARNING! This product can expose you to chemicals
including formaldehyde, which is known to the state of
California to cause cancer. For more information, go to
www.P65Warnings.ca.gov.
⚠ WARNING! ⚠

JMW-Series
Rev.: February 28, 2023
THE SMART SOLUTION FOR ENERGY EFFICIENCY
Installation, Operation, Maintenance 5
General Information, Cont’d.
Inspection - Upon receipt of the equipment, carefully
check the shipment against the bill of lading. Make sure
all units have been received. Inspect the carton or crating
of each unit, and inspect each unit for damage. Assure
the carrier makes proper notation of any shortages or
damage on all copies of the freight bill and completes a
common carrier inspection report. Concealed damage
not discovered during unloading must be reported to
the carrier within 15 days of receipt of shipment. If not
led within 15 days, the freight company can deny the
claim without recourse. Note: It is the responsibility of
the purchaser to le all necessary claims with the carrier.
Notify the Johnson Controls Customer Service of all
damage within fteen (15) days of shipment.
Storage - Equipment should be stored in its original
packaging in a clean, dry area. Store units in an upright
position at all times. Do not stack JMW170 or 340. The
stack limit for JMW036, 060 and 120 is three.
Unit Protection - Cover units on the job site with
either shipping packaging, vinyl lm, or an equivalent
protective covering. Cap the open ends of pipes stored
on the job site. In areas where painting, plastering, and/
or spraying has not been completed, all due precautions
must be taken to avoid physical damage to the units and
contamination by foreign material. Physical damage and
contamination may prevent proper start-up and may
result in costly equipment clean-up.
Examine all pipes, ttings, and valves before installing
any of the system components. Remove any dirt or trash
found in or on these components.
Pre-Installation - Installation, Operation, and
Maintenance instructions are provided with each unit..
The installation site chosen should include adequate
service clearance around the unit. Before unit start-up,
read all manuals and become familiar with the unit and its
operation. Thoroughly check the system before operation.
Prepare units for installation as follows:
1. Compare the electrical data on the unit nameplate
Twith ordering and shipping information to verify that
the correct unit has been shipped.
2. Keep the cabinet covered with the shipping packaging
until installation is complete and all plastering, painting,
etc. is nished.
3. Verify refrigerant tubing is free of kinks or dents and
that it does not touch other unit components.
4. Inspect all electrical connections. Connections must be
clean and tight at the terminals.
CAUTION! All three phase scroll compressors must have
direction of rotation veried at start-up. Verication is
achieved by checking compressor Amp draw. Amp draw
will be substantially lower compared to nameplate values.
Additionally, reverse rotation results in an elevated sound
level compared to correct rotation. Reverse rotation will result
in compressor internal overload trip within several minutes.
Verify compressor type before proceeding.
CAUTION! DO NOT store or install units in corrosive
environments or in locations subject to temperature or
humidity extremes (e.g., attics, garages, rooftops, etc.).
Corrosive conditions and high temperature or humidity can
signicantly reduce performance, reliability, and service life.
Always move and store units in an upright position. Tilting
units on their sides will cause equipment damage.
⚠ CAUTION! ⚠
⚠ CAUTION! ⚠
⚠ CAUTION! ⚠
CAUTION! CUT HAZARD - Failure to follow this caution may
result in personal injury. Sheet metal parts may have sharp
edges or burrs. Use care and wear appropriate protective
clothing, safety glasses and gloves when handling parts and
servicing heat pumps.

WATER-SOURCE HEAT PUMPS
JMW-Series
Rev.: February 28, 2023
Installation, Operation, Maintenance
6
Unit Physical Data
Unit Maximum Water Working Pressure
Options Max Working Pressure PSIG [kPa]
Base Unit 300 [2,068]
Motorized Valves 400 [2,758]
Dual isolated compressor mounting
Balanced port expansion valve (TXV)
Insulated Source and Load Water Coils standard
Insulated Refrigerant Circuit standard
Compressor on (green) and fault (red) light
Model JMW036 JMW060 JMW120 JMW170 JMW340
Compressor (qty) Scroll (1) Scroll (2) Scroll (1) Scroll (2)
Factory Charge R410A (lbs) [kg] / Circuit 4.5 [2.04] 5.5 [2.49] 5.5 [2.49] 14.9 [6.75] 14.9 [6.75]
Indoor / Load Water connection sizes FPT (in) 3/4” 1” 1-1/2” 2”
Outdoor / Source Water connection Size FPT (in) 3/4” 1” 1-1/2” 2”
HWG Water In/Out IPT (in) 1/2” N/A
Weight - Operating (lbs) [kg] 348 [158] 360 [163] 726 [329] 790 [358] 1330 [603]
Weight - Shipping (lbs) [kg] 373 [169] 385 [175] 770 [349] 800 [363] 1340 [608]
Water Volume (Source)
Gallons (LIters) 0.96 (3.64) 1.33 (5.04) 2.65 (10.02) 3.50 (13.27) 6.72 (25.44)
Dual isolated compressor mounting
Balanced port expansion valve (TXV)
Compressor on (green) and fault (red) light

JMW-Series
Rev.: February 28, 2023
THE SMART SOLUTION FOR ENERGY EFFICIENCY
Installation, Operation, Maintenance 7
JMW036-120 – Unit Dimensional Data
Water to
Water
Overall Cabinet
Water Connections
Electric Access Plugs
1 2 3 4 5 6
A
Depth
B
Width
C
Height
D
Source
(Outdoor)
Water In
E
Source
(Outdoor)
Water Out
F
Load
(Indoor)
Water In
G
Load
(Indoor)
Water Out
H
HWG
Water In
J
HWG
Water
Out
K
Low
Voltage
L
External
Pump
M
Power
Supply
036-060 in. 30.6 25.4 33 2.7 9.4 19.4 24.5 27.9 30.4 20.9 22.9 30.9
cm. 77.8 64.5 83.8 6.9 23.9 49.3 62.2 70.9 77.2 53.1 58.2 78.5
120 in. 30.6 52.9 37 25.2 25.2 30.1 30.1 34.9 34.9 29.9 31.9 34.4
cm. 77.8 134.4 94 64.0 64.0 76.5 76.5 88.6 88.6 75.9 81.0 87.4
B
C
A
M
L
K
1.0
(2.5 cm)
1
2
3
4
56
J
H
G
F
E
D
1
2
3
4
5
6
Required
Service Access
Optional
Service Access
Required
Service Access
Optional
Service Access
B
C
A
1.8
(4.6 cm)
1.3
(3.3 cm)
2.7
(6.9 cm)
(18.3 cm)
(4.3 cm)
1.0
(2.5 cm)
7.2
1.7
3 Ft
3 Ft
Notes 1 & 2
3 Ft
Notes 1 & 2
Notes 1 & 2
3 Ft
Notes 1 & 2
(7.4 cm)
2.9
(10.1 cm)
4.0
JMW
036-060
JMW 120
K
L
M
B
C
A
M
L
K
1.0
(2.5 cm)
1
2
3
4
56
J
H
G
F
E
D
1
2
3
4
5
6
Required
Service Access
Optional
Service Access
Required
Service Access
Optional
Service Access
B
C
A
1.8
(4.6 cm)
1.3
(3.3 cm)
2.7
(6.9 cm)
(18.3 cm)
(4.3 cm)
1.0
(2.5 cm)
7.2
1.7
3 Ft
3 Ft
Notes 1 & 2
3 Ft
Notes 1 & 2
Notes 1 & 2
3 Ft
Notes 1 & 2
(7.4 cm)
2.9
(10.1 cm)
4.0
JMW
036-060
JMW 120
K
L
M
Notes:
1. Front & side access is preferred for service access.
However, all components may be serviced from
the front access panel if side access is not avail-
able.
2. While clear access to all removable panels is not
required, installer should take care to comply with
all building codes and allow adequate clearance for
future field services.

WATER-SOURCE HEAT PUMPS
JMW-Series
Rev.: February 28, 2023
Installation, Operation, Maintenance
8
JMW170 & 340 – Unit Dimensional Data
12.3
[313]
15.0
[381]
4.5
[114]
4.3
[108]
Power Supply Wiring
1.375 x 2.0
[ 34.9 x 50.8] Double KO
4.3
[108]
Control Wiring
1.125 x 1.375
[ 28.6 x 34.9] Double KO
4.5
[114]
2” IPT Water Connections
15.0
[381]
5.4
[138]
21.0
[533]
Fault/Run Lights
64.5
[1638]
Left
Side
View
Front
View
Top
View
Load Source
Side
Refrig.
Circuit
Access
Panel
Front
Compressor
Access
Panel
Electrical
Access
Panel
Header
Access
Panel
Top
Notes: 1. Dimensions shown in inches and [millimeters].
2. For multiple units placed side by side, allow
sufficient space front or back to remove unit.
Minimum
3ft. [91cm]
Required Service
Access
NOTE 2
45.1
[1146]
26.3
[669]
Optional (Single Unit)
3ft. (91cm) Additional
Service Access

JMW-Series
Rev.: February 28, 2023
THE SMART SOLUTION FOR ENERGY EFFICIENCY
Installation, Operation, Maintenance 9
Unit Installation
Installation of Supply and Return Piping
Follow these piping guidelines.
1. Install a drain valve at the base of each supply and
return riser to facilitate system ushing.
2. Install shut-off / balancing valves and unions at each
unit to permit unit removal for servicing.
3. Place strainers at the inlet of each system
circulating pump.
4. Select the proper hose length to allow slack between
connection points. Hoses may vary in length by +2%
to -4% under pressure.
5. Exceeding the minimum bend radius may cause the
hose to collapse which reduces water ow rate. Install
an angle adapter to avoid sharp bends in the hose
when the radius falls below the required minimum
and causes a slight kink.
Insulation is not required on loop water piping except
where the piping runs through unheated areas or outside
the building or when the loop water temperature is
below the minimum expected dew point of the pipe
ambient temperature. Insulation is required if loop water
temperature drops below the dew point.
Pipe joint compound is not necessary when Teon
threaded tape is pre-applied to hose assemblies or when
ared-end connections are used. If pipe joint compound
is preferred, use compound only in small amounts on the
pipe threads of the tting adapters. Prevent sealant from
reaching the ared surfaces of the joint.
PIPING INSTALLATION
JMW Unit Location - These units are not designed for
outdoor installation. Locate the unit in an INDOOR area
that allows enough space for service personnel to perform
typical maintenance or repairs.
The installation of water source heat pump units and all
associated components, parts and accessories which
make up the installation shall be in accordance with
the regulations of ALL authorities having jurisdiction
and MUST conform to all applicable codes. It is the
responsibility of the Installing Contractor to determine
and comply with ALL applicable codes and regulations.
Locate the unit in an indoor area that allows easy removal
of access panels, and has enough space for service
personnel to perform maintenance or repair. Provide
sufcient room to make water and electrical connections..
Any access panel screws that would be difcult to remove
after the unit is installed should be removed prior to
setting the unit. These units are not approved for outdoor
installation and, therefore, must be installed inside the
structure being conditioned. Do not locate in areas where
ambient conditions are not maintained within 40-100°F
[4-38°C].
⚠ WARNING! ⚠
WARNING! Piping must comply with all applicable codes.
⚠ WARNING! ⚠
WARNING! Do not bend or kink supply lines or hoses.
Note: When anti-freeze is used in the loop, assure
that it is compatible with Teon tape or pipe joint
compound employed.
Maximum allowable torque for brass ttings is 30 ft-lbs
[41 N-m]. If a torque wrench is not available, tighten
nger-tight plus one quarter turn. Tighten steel ttings
as necessary.

WATER-SOURCE HEAT PUMPS
JMW-Series
Rev.: February 28, 2023
Installation, Operation, Maintenance
10
Piping Installation
JMW Unit Load Plumbing - The applications are too
varied to describe in this document. However, some basic
guidelines will be presented. Much of the discussions
on water loop applications would be valid for the load
plumbing discussion as well. All plumbing should conform
to local codes with the following considerations:
Wide temperature variation applications such as
heating/cooling coils:
- Employ piping materials that are rated for the
maximum temperature and pressure combination.
This excludes PVC for most heating applications.
- Insure that load water ow in high temperature
heating applications is at least 3 gpm per ton [3.9 l/m
per kW] to improve performance and reduce nuisance
high pressure faults.
- DO NOT employ plastic to metal threaded joints
- Utilize a pressure tank and air separator vent system to
equalize pressure and remove air.
Swimming Pool Hot Tub Applications:
- Load coax should be isolated with secondary heat
exchanger constructed of anti-corrosion material in all
chlorine/bromine uid applications.
Potable Water Applications:
- Potable water systems require eld supplied external
secondary heat exchanger.
- Insure load water ow in high temperature heating
applications is at least 3 gpm per ton to improve
performance & reduce nuissance to high pressure faults.
LOAD PLUMBING INSTALLATION
Optional pressure-rated hose assemblies designed
specically for use with Johnson Controls units are available.
Similar hoses can be obtained from alternate suppliers.
Supply and return hoses are tted with swivel-joint ttings
at one end to prevent kinking during installation.
Refer to Figure 1 for an illustration of a Supply/Return
Hose Kit. Male adapters secure hose assemblies to the
unit and risers. Install hose assemblies properly and
check them regularly to avoid system failure and reduced
service life.
⚠ CAUTION! ⚠
CAUTION! Corrosive system water requires corrosion
resistant ttings and hoses and possibly water treatment.
Figure 2: Typical Water Loop Application
Load Connections
(Hot Water/Chilled Water)
Source Connections
(Boiler/Tower,
Geothermal Loop)
Power Disconnect
Figure 1: Supply/Return Hose Kit
Rib Crimped
Length
(2 ft [0.6m] Length Standard)
Swivel
Brass
Fitting
Brass
Fitting
MPT
Reborde Acanalado
Longitud
(Long. Estándar de 2 pies)
Accesorio
Giratorio
de Bronce
Accesorio
de Bronce
MPT
MPT
MPT
Rib Crimped
Length
(0.6m Length Standard)
Swivel
Brass
Fitting
Brass
Fitting
MPT
MPT
Note: The manufacturer strongly recommends all piping
connections, both internal and external to the unit, be
pressure tested by an appropriate method prior to any
nishing of the interior space or before access to all
connections is limited. Test pressure may not exceed the
maximum allowable pressure for the unit and all components
within the water system. The manufacturer will not be
responsible or liable for damages from water leaks due to
inadequate or lack of a pressurized leak test, or damages
caused by exceeding the maximum pressure rating during
installation.
WARNING! Polyolester Oil, commonly known as POE oil, is
a synthetic oil used in many refrigeration systems including
those with HFC-410A refrigerant. POE oil, if it ever comes
in contact with PVC or CPVC piping, may cause failure of
the PVC/CPVC. PVC/CPVC piping should never be used
as supply or return water piping with water source heat
pump products containing HFC-410A as system failures and
property damage may result.
⚠ WARNING! ⚠

JMW-Series
Rev.: February 28, 2023
THE SMART SOLUTION FOR ENERGY EFFICIENCY
Installation, Operation, Maintenance 11
Water-Loop Heat Pump Applications
Commercial systems typically include a number of units
plumbed to a common piping system. Any unit plumbing
maintenance work can introduce air into the piping system,
therefore air elimination equipment is a major portion of the
mechanical room plumbing. In piping systems expected to
utilize water temperatures below 50°F [10°C], 1/2" [13mm]
closed cell insulation is required on all piping surfaces to
eliminate condensation. Metal to plastic threaded joints
should never be employed due to their tendency to leak
over time. Teon tape thread sealant is recommended for
FPT water connections (commercial class) to minimize
internal fouling of the heat exchanger. Do not overtighten
connections and route piping so as not to interfere with
service or maintenance access. Hose kits are available
from Johnson Controls in different congurations as shown
in Figure 2 for connection between the JMW Series and
the piping system. The hose kits include shut off valves,
P/T plugs for performance measurement, high pressure
stainless steel braid hose, "Y" type strainer 20 mesh
(841 micron) [0.84mm]) with blowdown valve, and "J"
type swivel connection. Balancing valves to facilitate the
balancing of the system, and an external low pressure
drop solenoid valve for use in variable speed pumping
systems, may also be included in the hose kit. The piping
system should be ushed to remove dirt, piping chips,
and other foreign material prior to operation. See Piping
System Cleaning and Flushing Procedures later in this
document. The ow rate is usually set between 2.25 gpm
and 3 gpm per ton [2.9 l/m and 4.5 l/m per kW] of cooling
capacity. Johnson Controls recommends 2.5 gpm per ton
Air Pad or
Extruded
polystyrene
insulation board
Unit Power
Disconnect
Pressure
Tank
Flow
Regulator
Water
Control
Valve
P/T Plugs
Water Out
Shut-Off
Valve
Boiler
Drains
Water In
Optional
Filter
Thermostat Wiring
⚠ WARNING! ⚠
⚠ CAUTION! ⚠
CAUTION! Many units are installed with a factory or eld
supplied manual or electric shut-o󰀨 valve. DAMAGE WILL
OCCUR if shut-o󰀨 valve is closed during unit operation. A
high pressure switch must be installed on the heat pump side
of any eld provided shut-o󰀨 valves and connected to the
heat pump controls in series with the built-in refrigerant circuit
high pressure switch to disable compressor operation if water
pressure exceeds pressure switch setting. The eld installed
high pressure switch shall have a cut-out pressure of 300
psig and a cut-in pressure of 250 psig. This pressure switch
can be ordered from Johnson Controls with a 1/4” internal
are connection as part number 39B0005N02.
[3.2 l/m per kW] for most applications of water loop heat
pumps. To insure proper maintenance and servicing, P/T
ports are imperative for temperature and ow verication,
as well as performance checks.
Cooling Tower/Boiler Systems typically utilize a
common loop maintained 60-90°F [16-32°C]. The use
of a closed circuit evaporative cooling tower with a
secondary heat exchanger between the tower and the
water loop is recommended. If an open type cooling tower
is used continuously, chemical treatment and ltering will
be necessary.
Low Water Temperature Cutout Setting - CXM2 or
DXM2.5 Control: When an antifreeze is selected, the
LT1 jumper (JW3) should be clipped to select the low
temperature (Antifreeze 15°F [-9.4°C]) setpoint to avoid
nuisance faults. See Figure 4: Low Water Temperature
Cutout - LT1.
WARNING! Never jumper terminal “A” from CXM2 or
DXM2.5 board #1 to CXM2 or DXM2.5 board #2 on multi-
compressor/control bound units. See Figure 5 in electrical
section of this document for motorized valve wiring.
Figure 3: Typical Open Loop/Well Application

WATER-SOURCE HEAT PUMPS
JMW-Series
Rev.: February 28, 2023
Installation, Operation, Maintenance
12
Ground-Water Heat Pump Applications
Typical open loop piping is shown in Figure 3. Shut off
valves should be included in case of servicing. Boiler
drains or other valves should be ‘tee’d’ into the line to
allow acid ushing of just the heat exchanger. Pressure
temperature plugs should be used so that ow and
temperature can be measured. Supply and return water
piping materials should be limited to copper, PE, or similar
material. PVC or CPVC should never be used as they
are incompatible with the POE oils used in HFC-410A
products and piping system failure and property damage
may result.
Water quantity should be plentiful and of good quality.
Consult Table 1 for water quality guidelines. The unit can
be ordered with either a copper or cupro-nickel water
heat exchanger. Copper is recommended for closed loop
systems and open loop ground water systems that are
not high in mineral content or corrosiveness. In conditions
anticipating heavy scale formation or in brackish water, a
cupro-nickel heat exchanger is recommended.
In ground water situations where scaling could be heavy
or where biological growth such as iron bacteria will
be present, a closed loop system is recommended. It is
recommended to install an intermediate heat exchanger
to isolate an open loop from the heat pump loop on
open well systems. Heat exchangers may over time lose
heat exchange capabilities due to a build up of mineral
deposits inside. These can be cleaned only by a qualied
service mechanic as acid and special pumping equipment
are required.
In areas with extremely hard water, the owner should be
informed that the heat exchanger may require occasional
acid ushing.
Expansion Tank and Pump - Use a closed, bladder-
type expansion tank to minimize mineral formation due
to air exposure. The expansion tank should be sized
to handle at least one minute run time of the pump to
prevent premature pump failure using its drawdown
capacity rating. Discharge water from the unit is not
contaminated in any manner and can be disposed of
in various ways depending on local building codes; i.e.
recharge well, storm sewer, drain eld, adjacent stream
or pond, etc. Most local codes forbid the use of sanitary
sewer for disposal. Consult your local building and zoning
department to assure compliance in your area.
WARNING! Polyolester Oil, commonly known as POE oil, is
a synthetic oil used in many refrigeration systems including
those with HFC-410A refrigerant. POE oil, if it ever comes
in contact with PVC or CPVC piping, may cause failure of
the PVC/CPVC. PVC/CPVC piping should never be used
as supply or return water piping with water source heat
pump products containing HFC-410A as system failures and
property damage may result.
⚠ WARNING! ⚠
⚠ WARNING!
WARNING! Never jumper terminal “A” from CXM2 or
DXM2.5 board #1 to CXM2 or DXM2.5 board #2 on multi-
compressor/control bound units. See Figure 5 in electrical
section of this document for motorized valve wiring.
Low Water Temperature Cut-Out Setting - For all open
loop systems the 35°F [1.7°C] LT1 setting (factory setting-
water) should be used to avoid freeze damage to the unit.
See Figure 4: “Low Water Temperature Cutout - LT1”.
Water Control Valve - Note the placement of the water
control valve. Always maintain water pressure in the
heat exchanger by placing water control valves at the
outlet of the unit to prevent mineral precipitation. Pilot
operated or Taco slow closing valve’s solenoid valves are
recommended to reduce water hammer. If water hammer
persists, a mini-expansion tank can be mounted on the
piping to help absorb the excess hammer shock. Insure
that the total ‘VA’ draw of the valve can be supplied by
the unit transformer. For instance the Taco slow closing
valve can draw up to 35VA. This can overload smaller 40
or 50 VA transformers depending on the other controls
employed. A typical pilot operated solenoid valve draws
approximately 15VA.

JMW-Series
Rev.: February 28, 2023
THE SMART SOLUTION FOR ENERGY EFFICIENCY
Installation, Operation, Maintenance 13
Ground-Water Heat Pump Applications, Cont’d.
⚠ CAUTION! ⚠
CAUTION! Low temperature limit system will not allow leaving
load water temperature (cooling mode) or leaving source water
temperature (heating mode) to be below 42 ° F [5.6 ° C].
⚠ CAUTION! ⚠
CAUTION! Many units are installed with a factory or eld
supplied manual or electric shut-o󰀨 valve. DAMAGE WILL
OCCUR if shut-o󰀨 valve is closed during unit operation. A
high pressure switch must be installed on the heat pump side
of any eld provided shut-o󰀨 valves and connected to the
heat pump controls in series with the built-in refrigerant circuit
high pressure switch to disable compressor operation if water
pressure exceeds pressure switch setting. The eld installed
high pressure switch shall have a cut-out pressure of 300
psig and a cut-in pressure of 250 psig. This pressure switch
can be ordered from Johnson Controls with a 1/4” internal
are connection as part number 39B0005N02.
Flow Regulation - Flow regulation can be accomplished
by two methods. First, most water control valves have
a built in ow adjustment. By measuring the pressure
drop through the unit heat exchanger, ow rate can be
determined and compared to Tables 7 and 8. Since the
pressure is constantly varying, two pressure gauges
might be needed. Simply adjust the water control valve
until the desired ow of 1.5 to 2 gpm per ton is achieved.
Secondly, a ow control device may be installed. The
devices are typically an orice of plastic material that
is designed to allow a specied ow rate. These are
mounted on the outlet of the water control valve. On
occasion, these valves can produce a velocity noise that
can be reduced by applying some back pressure. This
is accomplished by slightly closing the leaving isolation
valve of the well water setup.

WATER-SOURCE HEAT PUMPS
JMW-Series
Rev.: February 28, 2023
Installation, Operation, Maintenance
14
Ground-Loop Heat Pump Applications
Pre-Installation - Prior to installation, locate and mark
all existing underground utilities, piping, etc. Install loops
for new construction before sidewalks, patios, driveways,
and other construction has begun. During construction,
accurately mark all ground loop piping on the plot plan as an
aid in avoiding potential future damage to the installation.
Piping Installation - All earth loop piping materials should
be limited to only polyethylene fusion for inground sections
of the loop. Galvanized or steel tting should not be used at
any time due to their tendency to corrode. All plastic to metal
threaded ttings should be avoided due to their potential
to leak in earth coupled applications and a anged tting
substituted. P/T plugs should be used so that ow can be
measured using the pressure drop of the unit heat exchanger
in lieu of other ow measurement means. Earth loop
temperatures can range between 25 to 110°F [-4 to 43°C],
and 2.25 to 3 gpm of ow per ton [2.9 l/m to 3.9 l/m per kW]
of cooling capacity is recommended in these applications.
Upon completion of the ground loop piping, pressure test the
loop to assure a leak free system. Horizontal Systems: Test
individual loops as installed. Test entire system when all loops
are assembled. Vertical U-Bends and Pond Loop Systems:
Test Vertical U-bends and pond loop assemblies prior to
installation with a test pressure of at least 100 psi [689 kPa].
Flushing the Earth Loop - Upon completion of system
installation and testing, ush the system to remove all
foreign objects and purge to remove all air. Flush the loop
rst with the unit isolated to avoid ushing debris from the
loop into the unit heat exchanger.
Table 2: Antifreeze Percentages by Volume
Antifreeze - In areas where minimum entering loop
temperatures drop below 40°F [5°C] or where piping will
be routed through areas subject to freezing, anti-freeze
is needed. Alcohols and glycols are commonly used as
antifreezes, however your local sales manager should
be consulted for the antifreeze best suited to your area.
Low temperature protection should be maintained to
15°F [9°C] below the lowest expected entering loop
temperature. For example, if 30°F [-1°C] is the minimum
expected entering loop temperature, the leaving loop
temperature would be 25 to 22°F [-4 to -6°C] and low
temperature protection should be at 15°F [-10°C] e.g. 30°F
- 15°F = 15°F [-1°C - 9°C = -10°C]. All alcohols should
be premixed and pumped from a reservoir outside of the
building when possible or introduced under water level to
prevent fuming. Initially calculate the total volume of uid
in the piping system. Then use the percentage by volume
shown in Table 2 for the amount of antifreeze. Antifreeze
concentration should be checked from a well mixed
sample using a hydrometer to measure specic gravity.
Low Water Temperature Cut-Out Setting -
CXM2 or DXM2.5 Control: When an antifreeze is selected,
the LT1 jumper [JW3] should be clipped to select the low
temperature (Antifreeze 15°F [-9.4°C]) setpoint to avoid
nuisance faults. See Figure 4.
⚠ CAUTION! ⚠
CAUTION! The following instructions represent industry
accepted installation practices for Closed Loop Earth
Coupled Heat Pump Systems. They are provided to assist
the contractor in installing trouble free ground loops. These
instructions are recommendations only. State and Local
Codes MUST be followed and installation MUST conform to
ALL applicable Codes. It is the responsibility of the Installing
contractor to determine and comply with ALL applicable
Codes and Regulations.
Type
Minimum Temperature for Low Temperature Protection
10°F [-12.2°C] 15°F [-9.4°C] 20°F [-6.7°C] 25°F [-3.9°C]
Methanol
100% USP food grade Propylene Glycol
Ethanol*
25%
38%
29%
21%
25%
25%
16%
22%
20%
10%
15%
14%
* Must not be denatured with any petroleum based product

JMW-Series
Rev.: February 28, 2023
THE SMART SOLUTION FOR ENERGY EFFICIENCY
Installation, Operation, Maintenance 15
Ground-Loop Heat Pump Applications, Cont’d.
⚠ WARNING! ⚠
⚠ CAUTION! ⚠
CAUTION! Many units are installed with a factory or eld
supplied manual or electric shut-o󰀨 valve. DAMAGE WILL
OCCUR if shut-o󰀨 valve is closed during unit operation. A
high pressure switch must be installed on the heat pump side
of any eld provided shut-o󰀨 valves and connected to the
heat pump controls in series with the built-in refrigerant circuit
high pressure switch to disable compressor operation if water
pressure exceeds pressure switch setting. The eld installed
high pressure switch shall have a cut-out pressure of 300
psig and a cut-in pressure of 250 psig. This pressure switch
can be ordered from Johnson Controls with a 1/4” internal
are connection as part number 39B0005N02.
WARNING! Never jumper terminal “A” from CXM2 or
DXM2.5 board #1 to CXM2 or DXM2.5 board #2 on multi-
compressor/control bound units. See Figure 5 in electrical
section of this document for motorized valve wiring.
ELECTRICAL LINE VOLTAGE
All eld installed wiring, including electrical ground, must
comply with the National Electrical Code as well as all
applicable local codes.
Refer to the unit wiring diagrams for fuse sizes and a
schematic of the eld connections which must be made
by the installing (or electrical) contractor.
Consult the unit wiring diagram located on the inside of
the compressor access panel to ensure proper electrical
hookup. All nal electrical connections must be made
with a length of exible conduit to minimize vibration and
sound transmission to the building.
General Line Voltage Wiring - Be sure the available
power is the same voltage and phase as that shown on the
unit serial plate. Line and low voltage wiring must be done
in accordance with local codes or the National Electric Code,
whichever is applicable.
JMW Power Connection - Line voltage connection is
made by connecting the incoming line voltage wires to L1,
L2, and L3 on power distribution block. Consult electrical
data table for correct fuse size.
208 Volt Operation - All 208-230 Volt units are factory
wired for 208 Volt. The transformers may be switched to
230V operation as illustrated on the wiring diagram by
switching the Red (208V) and the Orange (230V) at the
contactor terminal L2.
⚠ WARNING! ⚠
WARNING! To avoid possible injury or death due to electrical
shock, open the power supply disconnect switch and secure
it in an open position during installation.
⚠ CAUTION! ⚠
CAUTION! Use only copper conductors for eld installed
electrical wiring. Unit terminals are not designed to accept
other types of conductors.
⚠ WARNING! ⚠
WARNING! Disconnect electrical power source to prevent
injury or death from electrical shock.
Water Control Valve - Note the placement of the water
control valve. Always maintain water pressure in the heat
exchanger by installing water control valves at the source
out of the unit to prevent mineral precipitation. Position
water high pressure switch between unit and valve. Pilot
operated or slow closing valves are recommended to
reduce water hammer. If water hammer persists, a mini-
expansion tank can be mounted on the piping to help
absorb the excess hammer shock. Insure that the total ‘VA’
draw of the valve can be supplied by the unit transformer.
For instance, some slow closing valves can draw up to
35VA. This can overload smaller transformers depending
on the other controls employed. A typical pilot operated
solenoid valve draws approximate ly 15VA.
Flow Regulation - Install on source in of unit. Flow
regulation can be accomplished by two methods. First,
most water control valves have a built in ow adjustment.
By measuring the pressure drop through the unit heat
exchanger, ow rate can be determined and compared
to Table 6. Since the pressure is constantly varying, two
pressure gauges might be needed. Simply adjust the water
control valve until the desired ow of 2.5 to 3 gpm per ton
[2.0 to 2.6 l/m per kW] is achieved. Secondly, a ow control
device may be installed. The devices are typically an orice
of plastic material that is designed to allow a specied ow
rate. These are mounted on the outlet of the water control
valve. On occasion, these valves can produce a velocity
noise that can be reduced by applying some back pressure.
This is accomplished by slightly closing the leaving isolation
valve of the well water setup.

WATER-SOURCE HEAT PUMPS
JMW-Series
Rev.: February 28, 2023
Installation, Operation, Maintenance
16
Water Quality Standards
pH - Chilled Water 0.7F°58< to 9.0 7.0 to 9.0 7.0 to 9.0 7.0 to 9.0
pH - Heated Water 0.8F°58> to 10.0 8.0 to 10.0 8.0 to 10.0 8.0 to 10.0
Alkalinity
(
HCO3
)
ppm - CaCO
3
equiv. 50 to 500 50 to 500 50 to 500 50 to 500
Calcium (Ca)ppm <100 <100 <100 <100
Magnesium (Mg)ppm <100 <100 <100 <100
Total Hardness (CaCO3)ppm - CaCO3 equiv. 30 to 150 150 to 450 150 to 450 150 to 450
Langelier Satura�on Index LSI -0.5 to +0.5 -0.5 to +0.5 -0.5 to +0.5 -0.5 to +0.5
Ryznar Stability 5.6ISRxednI to 8.0 6.5 to 8.0 6.5 to 8.0 6.5 to 8.0
Total Dissolved Solids (TDS) ppm - CaCO
3
equiv. <1000 <1000 <1000 <1500
Sulfate (SO
4
2-
)ppm <200 <200 <200 <200
Nitrate(NO
3
-
)001<001<001<001<mpp
Chlorine (free)(Cl) ppm <0.5 <0.5 <0.5 <0.5
Chloride (water < 80°F) ppm <20 <20 <150 <150
Chloride (water > 120°F) ppm <20 <20 <125 <125
Hydrogen Sulfideα(H
2
S) 5.0<5.0<5.0<5.0<bpp
Carbon Dioxide (CO
2
)ppm 0 <50 10 to 50 10 to 50
Iron Oxide (Fe) ppm <1.0 <1.0 <1.0 <0.2
Manganese (Mn)ppm < 0.4 <0.4 <0.4 <0.4
Ammonia (NH
3
)ppm <0.05 <0.1 <0.1 <0.1
Chloramine (NH
2
CL) ppm 0 0 0 0
Iron 0000Lm/sllecairetcaB
Slime Forming 0000Lm/sllecairetcaB
Sulfate reducing 0000Lm/sllecairetcab
Suspended Solidsβ01<01<01<01<mpp)SST(
Earth Ground Resistanceχ0smhO Consult NEC & local electrical codes for grounding requirements
Electrolysis Voltageδ003<Vm Measure voltage internal water loop to HP ground
Leakage Currentδ51<Am Measure current in water loop pipe
Building Primary Electrical Ground to unit, must meet local diameter and penetra�on length requirements
WATER QUALITY REQUIREMENTS
For Closed-Loop and Open-Loop Systems
All Heat Exchanger
Types
COAXIAL HX Copper
Tube in Tube
COAXIAL HX
Cupronickel
Brazed Plate HX
316 SS
Symbol UnitsDescrip�on
Electrolysis
All HX types Scaling Poten�alCorrosion Preven�on
(Cl
-
)
Fouling &
Biological
Do not connect heat pump to steel pipe unless dissimilar materials are separated by using Di-electric unions. Galvanic corrosion of heat
pump water pipe will occur.
Heat Exchanger Type
Closed Loop
Recircula�ng Open Loop, Tower, Ground Source Well
-
Table 2: Water Quality Standards
Clean water is essential to the performance and life span of water source heat pumps. Contaminants, chemicals, and
minerals all have the potential to cause damage to the water heat heat exchanger if not treated properly. All closed water
loop systems should undergo water quality testing and be maintained to the water quality standards listed in this table.

JMW-Series
Rev.: February 28, 2023
THE SMART SOLUTION FOR ENERGY EFFICIENCY
Installation, Operation, Maintenance 17
Water Quality Standards, Cont’d.
1. The Water Quality Table provides water quality
requirements for coaxial & brazed plate heat
exchangers.
2. The water must be evaluated by an independent
testing facility comparing site samples against
this Table. When water properties are outside of
these parameters, the water must either be treated
by a professional water treatment specialist to
bring the water quality within the boundaries of
this specication, or an external secondary heat
exchanger must be used to isolate the heat pump
water system from the unsuitable water. Failure to
do so will void the warranty of the heat pump system
and will limit liability for damage caused by leaks or
system failure.
3. Regular sampling, testing and treatment of the water
is necessary to assure that the water quality remains
within acceptable levels thereby allowing the heat
pump to operate at optimum levels.
4. If closed‐loop systems are turned off for extended
periods, water samples must be tested prior to
operating the system.
5. For optimal performance, it is recommended that the
closed‐loop piping systems are initially lled with de‐
ionized water.
6. Well water with chemistry outside of these
boundaries, and salt water or brackish water requires
an external secondary heat exchanger. Surface/Pond
water should not be used.
7. If water temperature is expected to fall below 40°F,
antifreeze is required. Refer to the heat pump IOM for
the correct solution ratios to prevent freezing.
αHydrogen Sulde has an odor of rotten eggs. If one
detects this smell, a test for H2S must be performed.
If H2S is detected above the limit indicated,
remediation is necessary (Consult with your Water
Testing/Treatment Professional) or a secondary heat
exchanger is required using appropriate materials as
recommended by the heat exchanger supplier.
βSuspended solids and particulates must be ltered
to prevent fouling and failure of heat exchangers.
Strainers or particulate lters must be installed to
provide a maximum particle size of 600 micron (0.60
mm, 0.023 in.) using a 20 to 30 mesh screen size.
When a loop is installed in areas with ne material
such as sand or clay, further ltration is required to a
maximum of 100 micron. Refer to the Strainer / Filter
Sizing Chart to capture the particle sizes encountered
on the site.
χ An electrical grounding system using a dedicated
ground rod meeting NEC and Local Electrical
codes must be installed. Building Ground must not
be connected the WSHP piping system or other
plumbing pipes.
δ Refer to IOM for instructions on measuring resistance
and leakage currents within water loops.
Do not use PVC pipe for water loop (compressor POE
oil and glycols damage PVC) use of HDPE pipe is
recommended.
Strainer / Filter Sizing
Mesh Size Particle Size
Microns MM Inch
20 840 0.840 0.0340
30 533 0.533 0.0210
60 250 0.250 0.0100
100 149 0.149 0.0060
150 100 0.100 0.0040
200 74 0.074 0.0029
ppm = parts per million
ppb = parts per billion

WATER-SOURCE HEAT PUMPS
JMW-Series
Rev.: February 28, 2023
Installation, Operation, Maintenance
18
Water Quality Standards, Cont’d.
OHM meter
Measuring Earth Ground Resistance
0.02�
Building
Ground Rod
Well Casing
Measure the earth ground bond using an Ohm meter between the building's ground rod and the steel well casing.
The resistance measured should be zero Ohms. The NEC allows a resistance to ground up to 20 Ohms. Any
resistance above zero, indicates a poor earth ground which may be the result of a hot neutral line or that
conduc�ve water is present. Both of these may lead to electrolysis and corrosion of the heat pump piping. A check
for both should be performed and resolved.
Note if the well casing is plas�c, a conduc�ve path can be achieved by inser�ng a #6 AWG bare copper wire into the
well water. Remove the temporary conductor when finished.

JMW-Series
Rev.: February 28, 2023
THE SMART SOLUTION FOR ENERGY EFFICIENCY
Installation, Operation, Maintenance 19
Water Quality Standards, Cont’d.
Measuring Electrolysis Voltage and Current
Volt Meter
300mV
Heat Pump
Wire Electrode inserted into port for
Voltage measurement
Pete's Port
HP Piping
Amp Sensor to VOM for Current
Water-in
Water-out
Measure the electrolysis voltage using a volt meter between the heat pump ground and a #14 AWG solid copper
wire electrode inserted into the water using a Pete’s style access port.
The HP must be opera�ng and the water stream flowing.
The voltage measured should be less than 300mV (0.300 V). If higher than 500mV electrolysis will occure and
corrosion will result.
If voltage is measured, the cause is a high resistance earth ground or current on the neutral conductor. Remedial
measures should be performed.
Measure the current flowing through the piping system by using an amp clamp probe on the water-in line. The HP
must be opera�ng and the water stream flowing.
There should be zero amps measured. If current is present, there is leakage current to the plumbing system and it
must be rec�fied to prevent pipe corrosion.

WATER-SOURCE HEAT PUMPS
JMW-Series
Rev.: February 28, 2023
Installation, Operation, Maintenance
20
Electrical – Line Voltage
JMW Electrical Data
ELECTRICAL - LOW VOLTAGE
Thermostat Connections - The aquastat/thermostat
should be wired directly to the CXM2/DXM2.5 board #1.
Note: The JMW second stage is wired directly to the CXM2
#2.
Low Water Temperature Cutout - LT1 - The CXM2/
DXM2.5 control allows the eld selection of source uid
low temperature cutout points. The factory setting of
LT1 is set for water (35°F [1.7°C]). In cold temperature
applications jumper JW3 (LT1- antifreeze 15°F [-9.4°C])
should be clipped as shown in Figure 4 to change the
setting to 10°F [-12.2°C], a more suitable temperature
when using antifreezes. Never clip JW3 prior to antifreeze
being added to the loop.
Figure 4: Changing LT1-Low Water Temperature
Cutout Setpoint
Model Voltage
Code Volatge Voltage Min/Max
Compressor Total
Unit FLA
Min
Circuit
Amps
SCCR
rms
Symetrical
SCCR
Volts
Maximum
Max
Fuse/
HACR
Qty RLA LRA
JMW036
G208-230/60/1 187/254 116.7 79 16.7 20.8 5 600 35
E265/60/1 239/292 113.5 72 13.5 16.8 5 600 30
H208-230/60/3 187/254 110.4 73 10.4 13.1 5 600 20
F460/60/3 414/506 15.8 38 5.8 7.2 5 600 15
N575/60/3 518/633 13.8 36.5 3.8 4.7 5 600 15
JMW060
G208-230/60/1 187/254 126.3 134 26.3 32.9 5 600 50
H208-230/60/3 187/254 115.6 110 15.6 19.5 5 600 35
F460/60/3 414/506 17.8 52 7.8 9.8 5 600 15
JMW120
G208-230/60/1 187/254 226.3 134 52.6 59.2 5 600 80
H208-230/60/3 187/254 215.6 110 31.2 35.1 5 600 50
F460/60/3 414/506 27.8 52 15.6 17.6 5 600 25
JMW170
H208-230/60/3 187/254 153.6 245 53.6 67.0 5 600 110
F460/60/3 414/506 120.7 125 20.7 25.9 5 600 45
N575/60/3 518/633 116.4 100 16.4 20.5 5 600 35
JMW340
H208-230/60/3 187/254 253.6 245 107.2 120.6 5 600 150
F460/60/3 414/506 220.7 125 41.4 46.6 5 600 60
N575/60/3 518/633 216.4 100 32.8 36.9 5 600 50