Space Pak SCM2-0111 Instruction manual

– 1 – P/N SCM2-0111 Copyright 2011 Mestek, Inc.
SCM2-0111
W30-WG0593
Installation , Operation
& Maintenance Manual
MODEL SCM
Air to Water Heat Pumps
Reverse Cycle Chillers
3 and 5 Ton
IN UNITED STATES: 260 NORTH ELM ST. WESTFIELD, MA 01085 [phone] / FAX [phone]
IN CANADA: 7555 TRANMERE DRIVE, MISSISSAUGA, ONTARIO, L5S 1LR [phone] / FAX [phone]
Qualied installer only —
This product must be installed
only by a qualied service tech-
nician. The installation must be
done using recognized indus-
try practices, and in compli-
ance with this manual and all
applicable codes. Failure to
comply could result in death,
serious injury or substantial
property damage.
For information not included in this
manual, see the following: This manual
includes only basic information for in-
stallation, operation and maintenance of
SpacePak air to water heat pumps. For
more advanced applications and infor-
mation not shown in this manual, contact
SpacePak Technical Support for assis-
tance and supplemental instructions. Call
413-564-5530 in Westeld, MA or visit our
website at www.spacepak.com to send an
e-mail or review technical literature.

Model SCM overview . . . . . . . . . . . . . . . . . . . . . . . . 2



Prepare the unit . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Mounting pad. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Glycol/water system design . . . . . . . . . . . . . . . . . . . . .8
Glycol/water system installation . . . . . . . . . . . . . . . . . . .8

Overcurrent protection & wire sizing . . . . . . . . . . . . . . . . .9
Optional low ambient adjustment . . . . . . . . . . . . . . . . . .9
SpacePak heat pump/chiller wiring . . . . . . . . . . . . . . . . .9
Multiple air handler applications . . . . . . . . . . . . . . . . . . .9

BEFORE starting the unit . . . . . . . . . . . . . . . . . . . . . 11
Start the SpacePak heat pump/chiller . . . . . . . . . . . . . . . 11
Anti-freeze cycle . . . . . . . . . . . . . . . . . . . . . . . . . . 11
24-Hour follow-up . . . . . . . . . . . . . . . . . . . . . . . . . 11


Glycol/water mixture . . . . . . . . . . . . . . . . . . . . . . . . 13
Perform annual inspection . . . . . . . . . . . . . . . . . . . . . 13
Preparing the SCM for shut down . . . . . . . . . . . . . . . . . 13
To restart after shutdown . . . . . . . . . . . . . . . . . . . . . . 13


3-Ton SpacePak chiller. . . . . . . . . . . . . . . . . . . . . . . 15
5-Ton SpacePak chiller. . . . . . . . . . . . . . . . . . . . . . . 15


– 2 – P/N SCM2-0111
Model SCM Air to Water Heat Pump — Installation, Operation & Maintenance Manual
Hazard denitions
The following terms are used throughout this manual to bring
attention to the presence of potential hazards or to important
information concerning the product.
Indicates an imminently hazardous situation which,
if not avoided, WILL result in death, serious injury or
substantial property damage.
Indicates an imminently hazardous situation which,
if not avoided, COULD result in death, serious in-
jury or substantial property damage.
Indicates an imminently hazardous situation which,
if not avoided, MAY result in minor injury or property
damage.
Used to notify of special instructions on installation,
operation or maintenance which are important to
equipment, but not related to personal injury haz-
ards.
Model SCM overview
The SPACE PAK Model SCM Heat pump/chiller is a self
contained reverse-cycle heat-pump that provides a continuous
supply of heated or chilled water for various purposes, such as:
residential or small commercial building heating and cooling;
and specialty applications, such as computer room cooling or
industrial/agricultural conditioning and dehumidication.
Model SCM Chillers are available in three- and ve-ton nominal
capacities. Both use the same general design and operating
principals.
Each chiller contains TWO isolated refrigeration systems of
equal size to cool or heat the delivered water supply. The two
systems can operate individually or in tandem to achieve 50%
or 100% capacity. The major components of each system are:
• A hermetically sealed refrigeration compressor & motor.
• An outside coil to reject heat (in cooling) or absorb heat (in
heating) from the surrounding ambient air.
• A fan and motor to force air over the outside coil; a shell-
and-tube refrigerant-to-water heat exchanger to absorb heat
(in cooling) or supply heat (in heating) to the delivered water
ow.
• An electronic expansion valve to throttle the refrigerant ow
in both heating and cooling modes of operation, responding
to varying load on the system.
• Additionally, each system contains a reversing valve (to se-
lect between heating and cooling operation) and sensors
and safety circuits to monitor and protect the equipment from
potentially damaging or dangerous operating conditions.
A single water circuit connects both internal heat exchangers,
and contains sensors to measure entering and leaving water
temperatures. A mechanical ow switch safety ensures
continuous water ow while either of the two refrigerant systems
is operating. All components are contained within a supporting
structure and enclosure sufcient to allow stand-alone outdoor
installation in all temperate climates.
All operation and protections are managed by a microprocessor
controller which operates the individual systems, determines
all operating parameters, and monitors the condition of each
system. A simple interface communicates with the indoor air
handler, heat exchanger, or other load.

• This product must be installed in accordance with all appli-
cable codes. Where instructions in this manual differ from
specic local requirements, defer to the local codes.
• The electrical installation must also comply with the latest
edition of: in the U. S. — National Electrical Code ANSI/
NFPA No. 70; in Canada — CSA C22.1 Canadian Electrical
Code Part 1. Wiring must be N.E.C. Class 1. Use only cop-
per wire, rated for 120°F and sized for the load listed in this
manual.
• Electrical shock hazard — Disconnect all electrical power
before servicing the unit. Also, the unit must be grounded in
accordance with the Electrical Code listed above.

• Refrigeration system is factory charged with R410A refriger-
ant, and requires no additional service during installation. Any
repair, diagnosis or maintenance service to the refrigeration
system must be performed by a qualied technician. No alter-
nate refrigerants, lubricants or additives are approved for this
unit. Any use of alternate or non-approved materials in the re-
frigeration system may result in personal injury or equipment
damage, and will void the manufacturer’s warranty.

• The uid in the liquid side of the Model SCM must be
an anti-freeze/water mix. The antifreeze percentage must
be at least 10%. Follow guidelines in this manual to nd the
required antifreeze mix for the application. Thoroughly ush
the system before lling.
• The system must be supplied with a pump sized to provide
the minimum ow rates specied in this manual. Pump selec-
tion must consider the pressure loss through the system and
its components plus the pressure loss through the SCM’s
heat exchanger and internal components. The pump must
be rated for use with chilled water/glycol mixture.
• Install a y-strainer at the liquid input of the heat pump as
shown in this manual to prevent damage to the heat ex-
changer from sediment.
• DO NOT use for potable water heating. The single-wall
heat exchanger is not suitable for the application.

• See information in this manual for heating and cooling per-
formance versus ambient temperature.
• For applications requiring cooling at outdoor temperatures
below 55°F, contact SpacePak Technical Support for assis-
tance.
• DO NOT disconnect power in cold temperatures. Power
must be on to allow the anti-freeze cycle to operate.

• The SCM electronic controller is factory congured. DO NOT
adjust the control settings. If special operating characteris-
tics are required, contact SpacePak Technical Support for
availability and instructions.
Failure to comply with all of the guidelines BE-
LOW could result in death, serious injury or
substantial property damage.


– 3 –P/N SCM2-0111
Model SCM Air to Water Heat Pump — Installation, Operation & Maintenance Manual
Figure 1 Model SCM rating data
Item Units SCM-036 SCM-060 Item Units SCM-036 SCM-060
Cooling capacity (Note 2) Btuh / KW 34,000 / 10.0 46,000 / 13.5 Supply voltage VAC 230/1/60 230/1/60
Heating capacity (Note 3) Btuh / KW 44,000 / 13.0 60,000 / 17.0 Running current,
cooling (Note 1) Amps 17.6 26.4
Fan speed RPM 850 850 Running current,
heating (Note 1) Amps 13.1 21.3
Noise level dB(A) 56 56 MCA (Note 1) Amps 19.7 30.3
Water volume Gallons 2 2.5
Supply connection Inches NPT 1 1 Return connection Inches NPT 1 1
Minimum supply
temperature °F 36 36 Maximum supply temperature °F 125 125
Minimum ow GPM 7 10 Maximum ow GPM 12 15
Pressure drop at
minimum ow Feet WC 8 17 Pressure drop at maximum ow Feet WC 21 28
Net weight Lbs 337 386 Operating weight Lbs 354 407
Shipping weight Lbs 346 395 Shipping dimensions Inches 47 x 18 x 60 47 x 18 x 60
Note 1:
Note 2:
Note 3:
Electrical ratings DO NOT include water pump amp draw. This pump is supplied by the installer. Add the current draw of the pump to
the values listed above. Adjust the MCA accordingly.
Performance at 95° ambient temperature, 45° water
Performance at 47° ambient temperature, 115° water
Figure 2 Model SCM coding
Typical model S C M 0 6 0 A 4
Position 1 2 3 4 5 6 7 8
Designation Unit Type Capacity Series Refrigerant
type
Values SCM = SpacePak Heat Pump/Chiller Module 036 = 3 ton nominal
060 = 5 ton nominal A = Series “A” 4 = R410A
Examples SCM-036-A-4 = 3 ton nominal, series A, using R410A referigerant, SpacePak Heat Pump/Chiller Module
SCM-060-A-4 = 5 ton nominal, series A, using R410A referigerant, SpacePak Heat Pump/Chiller Module

• Heat pump/chiller, including two refrigeration systems, fac-
tory-programmed controller, fans and all required internal
components
• Powder-coated enclosure

• Auxiliary electric immersion heater (3 KW, 230V/1/60) — re-
quires separate electrical power circuit, 15-amp minimum
breaker

• Pump and piping by others
• Zone valves (must be 3-way, NOT 2-way) or zone pumps for
multi-zone
• Expansion tank (10 gallon minimum)
• SpacePak Chiller Interface Module


– 4 – P/N SCM2-0111
Model SCM Air to Water Heat Pump — Installation, Operation & Maintenance Manual

Figure 3 Model SCM dimensions (ALL DIMENSIONS IN INCHES)
Model
A B D D1 D2 E F G H J K W W1 W2
Leg
height
Front to
return
Cabinet
depth
Mounting
lug
depth
Mounting
lug
centers
Bottom
to
return
Bottom
to
supply
Base to
bottom edge
of lower fan
Overall
Height
Return
connec-
tion
Supply
connec-
tion
Overall
width
Mounting
lug
centers
Lug
center
to edge
SCM-036 1 10 17 3
/
417 3
/
815 3
/
45 1
/
215 1
/
425 53 1” NPT 1” NPT 43 3
/
827 1
/
27 15
/
16
SCM-060 1 10 17 3
/
417
3
/
815 3
/
45 1
/
215 1
/
425 53 1” NPT 1” NPT 43 3
/
827 1
/
27 15
/
16

– 5 –P/N SCM2-0111
Model SCM Air to Water Heat Pump — Installation, Operation & Maintenance Manual

Failure to comply with all of the guidelines IN
THE FOLLOWING could result in death, seri-
ous injury or substantial property damage.
The installation must comply with all applicable lo-
cal codes.
Prepare the unit
• Inspect the unit for shipping damage. DO NOT use if there is
a risk that the damage could affect unit operation.
• Make sure all required components are available.
• Install optional immersion heater, if used. See instructions
provided with the heater.
Location
• DO NOT locate where the unit could be sprayed by sprin-
klers.
• DO NOT locate near swimming pools, spas or any location
that could cause chlorine or other contaminant to enter the
unit.
• DO NOT locate where water run-off from adjacent structures
could impinge on the unit.
• Maintain the clearances shown in Figure 5.
• LOW AMBIENT conditions — Contact SpacePak Technical
Support to obtain low ambient adjustment instructions if cool-
ing operation below 55°F is required.
• CORROSIVE ENVIRONMENTS — Do not install the unit in
an area subject to sea air or other potential corrosive con-
taminants.
• INDOOR INSTALLATION — If the unit is installed inside a
building, the building must be equipped with air openings
sufcient to ensure free discharge of heated (or cooled) air
generated by the heat pump/chiller. All clearances must be
maintained to ensure free air ow into and out of the enclo-
sure. Make sure no other equipment located in the space will
be affected by the unit’s air ow.
Handling
• See Figure 4.
• Place padding at pressure points to prevent damage to the
enclosure.
• Use caution when handling. The unit is heavy and could
cause severe injury or damage if dropped or handled incor-
rectly.
Figure 4 Handling with cables
Figure 5 Maintain clearances below
Minimum clearances (inches)
S T U V
20 59 40 20
Mounting pad
• The SpacePak heat pump/chiller must be mounted on a level
corrosion- and weather-resistant mounting surface, prefer-
ably concrete. The structural support must be suitable for the
operating weight of the unit and attached components, its
mounting pad, snow loading and any other expected loads.
• The mounting pad must not be attached directly to a struc-
ture where noise transmission would be objectionable.
• Vibration isolators supplied with the chiller may be installed
when desired to reduce transmitted vibration.
• The unit must be bolted securely to the pad. Where required
by local jurisdiction, the mounting must also be analyzed for
seismic loading capability.
• The mounting must ensure that there will be no debris ac-
cumulation which might block air ow through the enclosure
openings. 

.
• There must be no accumulation of water that could reach the
bottom of the unit’s enclosure.

– 6 – P/N SCM2-0111
Model SCM Air to Water Heat Pump — Installation, Operation & Maintenance Manual
Figure 6 SpacePak Chiller with single air handler (see page 8 for instructions)
10 Supply connection, 1” NPT
11 Return connection, 1” NPT
12 Pressure gauge
13 Balancing valves (2 per air handler) — see
Figure 7, page 7
14 3-way valves (1 per air handler) — see
Figure 7, page 7

15 (Not shown) — Install a hose bibb valve
at a convenient location in the system.
Use this valve to ll the system with the
required glycol/water mixture.
1 SpacePak heat pump/chiller
2 Pump (by installer) — see instruc-
tions in this manual for sizing infor-
mation
3 Drain valve
4 Isolation valve, typical — install
where shown
5 Y-strainer — must be installed
where shown to prevent sediment
from damaging or clogging the
chiller heat exchanger
6 Expansion tank (diaphragm or blad-
der type)
7 Air separator with automatic air vent
— install in two locations, as shown
8 Purge valve (external valve required
only when purge valve is not integral
to the air handler
9 Air handler — Make sure the chiller/
heat pump is sized for the air han-
dler load
16 Manual air vent.

– 7 –P/N SCM2-0111
Model SCM Air to Water Heat Pump — Installation, Operation & Maintenance Manual
(continued)
Figure 7 SpacePak Chiller with two air handlers (parallel piping) (see page 8 for instructions) — see legend on page 6

– 8 – P/N SCM2-0111
Model SCM Air to Water Heat Pump — Installation, Operation & Maintenance Manual
(continued)
Glycol/water system design
1. SpacePak heat pump/chiller capacity — The SCM capacity
is reduced as glycol percentage increases. Multiply the rated
capacity by the multiplier listed in Figure 8, page 8.
2. Select the recommended piping layout from either Figure 6,
page 6 or Figure 7, page 7.
For system designs not covered in this manual,
contact SpacePak Technical Support for further in-
formation.
3. Other equipment in the system — Make sure the system
design meets the requirements of air handlers, boilers and
other components in the system.
4. Existing systems — Modify existing system piping and com-
ponents as needed to comply with the recommendations in
this manual.
5. Automatic ll — SpacePak recommends NOT installing an
automatic ll line except where required by local codes.
Where required, connect the ll line to the expansion tank.
6. Size the piping and select the system pump using the ow
rate and pressure drop given in Figure 1, page 3. Adjust the
pressure drop through piping and chiller using the glycol cor-
rection multipliers in Figure 8, page 8.
7. Expansion tank — All systems require an expansion tank
with a minimum of ten gallons capacity. The total system vol-
ume must be at least 5 gallons per single system capacity
(1/2 nominal unit capacity if the smallest chiller in the sys-
tem). As an example, a 5 ton chiller consists of two 2 ½ ton
systems. A single 5 ton chiller installation would require a
minimum of 2 ½ x 5, or 12 ½ gallons. A combined system
with one 5 ton and one 3 ton chiller would require a minimum
system capacity of 1 ½ x 5, or 7 ½ gallons.
8. Air vents — Locate high-efciency air vents as shown in the
piping to prevent air from pocketing.
9. Dielectric unions — Install a dielectric union at the supply
and return connections to the SCM to prevent possibility of
galvanic corrosion that might occur with dissimilar piping ma-
terials in the system.
Glycol/water system installation
1. Obtain all components specied in Figure 6, page 6 or Fig-
ure 7, page 7. Make sure all components and piping comply
with applicable local codes.
DO NOT use galvanized pipe anywhere in the sys-
tem. Galvanizing will react with the glycol and can
cause glycol degradation and sludge in the system.
2. Charge the expansion tank to 15 PSIG (with no water or
pressure in the system).
3. Install the system piping. DO NOT connect the SpacePak
unit to the system piping until the system has been cleaned
as required below.

1. The SCM must NOT be connected to the system during this
process.
2. Connect a hose from a fresh water supply to the system
ll hose bibb. The hose bibb valve (not shown in piping
diagrams) should be located low in the system near to the
SpacePak connection.
3. Open the purge valve, (may be inside the air handler) while
slowly lling the system. Close the valve when air is removed
from the system and water begins to ow out of the valve.
4. Fill the system with fresh water and run water until the sys-
tem has been thoroughly ushed clean.

1. Add water to the system as needed to raise the pressure to
35 PSIG (verify that all system components are suitable for
this pressure). Verify that the pressure remains constant for
at least one hour. Locate and correct any leaks.
2. After successfully testing,drain the system and removed the
fresh water hose.

1. After testing and draining the system, apply pipe insulation.

1. Calculate the system volume. (Find the SCM water volume
in Figure 1, page 3.)
2. See Figure 8, page 8 for required glycol concentration for the
minimum expected outside temperature.
3. Obtain the required volume  glycol/water solution
premixed or mix in a clean container. (The glycol must con-
tain an inhibitor to prevent metal corrosion.)
4. Pump the glycol/water solution into the system, allowing air
to escape through the purge valve(s).
5. After lling the system, sample the system uid and verify
glycol and inhibitor percentages, following instructions pro-
vided with the glycol.
Figure 8 SCM glycol concentration (10% min, 50% max)
Ethylene glycol % 10 20 30 40 50
Min ambient temp, °F 23 14 2 –13 –36
SpacePak capacity multiplier .98 .96 .93 .91 .89
Pressure drop multiplier (cooling) 1.06 1.12 1.16 1.25 1.36
Pressure drop multiplier (heating) 1.06 1.12 1.16 1.22 1.28
Propylene glycol % 10 20 30 40 50
Min ambient temp, °F 26 18 8 –7 –29
SpacePak capacity multiplier .99 .98 .96 .93 .88
Pressure drop multiplier (cooling) 1.10 1.20 1.34 1.50 1.65
Pressure drop multiplier (heating) 1.10 1.20 1.34 1.46 1.50

– 9 –P/N SCM2-0111
Model SCM Air to Water Heat Pump — Installation, Operation & Maintenance Manual

The electrical installation must comply
with the latest edition of: in the U. S. — Na-
tional Electrical Code ANSI/NFPA No. 70;
in Canada — CSA C22.1 Canadian Elec-
trical Code Part 1. Wiring must be N.E.C.
Class 1. Use only copper wire, rated for
120°F and sized for the load listed in this
manual.
Electrical shock hazard — Disconnect
all electrical power before servicing the
unit. Also, the unit must be grounded in
accordance with the Electrical Code listed
above.
Overcurrent protection & wire
sizing
• Protect each circuit with a breaker or fuse rated for
the load given in Figure 1, page 3.
The electrical loads given in Figure 1,
page 3 allow for a pump load of no more
than 5 amps at 110 VAC (2.5 amps at
230 VAC). If the pump load exceeds this,
provide a separate power source to the
pump. DO NOT feed power to the pump
from the SpacePak air handler panel.
• Optional electric immersion heater — Provide a
separate power source and overcurrent protection
for the optional heater, if used. Refer to the Installa-
tion and Operation Manual supplied with the heater
kit.
Optional low ambient
adjustment
• If cooling is desired in low ambient conditions, fol-
low the instructions supplied by SpacePak Techni-
cal Support.
SpacePak heat pump/chiller
wiring
• Connect single air handler to chiller as shown in
Figure 9, page 9.
• Connect multiple air handlers to chiller via
SpacePak Chiller Interface Module as shown in
Figure 10, page 10.
• See Figure 11, page 11, for chiller electrical ladder
diagram.
Figure 9 SpacePak Heat Pump/Chiller eld wiring — SINGLE air han-
dler (see Figure 11, page 11 for ladder wiring diagram)

– 10 – P/N SCM2-0111
Model SCM Air to Water Heat Pump — Installation, Operation & Maintenance Manual
(continued)
Figure 10 SpacePak Heat Pump/Chiller eld wiring — Multiple air han-
dlers (see Figure 11, page 11 for ladder wiring diagram)
Multiple air handler applications
• See Figure 10, page 10.
• For multiple air handler applications, provide a
3-way valve to control water ow to the air handler.
• When the zone thermostat activates the SCM,
the valve will be activated by the SpacePak air
handler.
• The valve load must not exceed 20 va at 24
VAC. If the valve load is higher, connect a relay
coil to the air handler terminals. Feed 24 VAC
power to the valve through the relay from a
separate 24-VAC transformer.
• As an option, the air handlers can be installed on
secondary circuits with a zone pump for each air
handler.

– 11 –P/N SCM2-0111
Model SCM Air to Water Heat Pump — Installation, Operation & Maintenance Manual
(continued)
Figure 11 SpacePak Heat Pump/Chiller electrical ladder diagram
24V
315 mA
230VAC
C1/2
NO3NO2
NO1 C5
NO5
C3/4
NO4 X
C3/4
C1/2 X
CAREL µC
2
T+ GND
TLAN
GND
B2
GNDG
G0 B1
ID4GNDY
B3 ID3ID5
ID2
ID1
NO7
NO6
NO9NO8 X
C6/7C6/7
X
C8/9
NO10
C10
CAREL
GNDG YGND ID9GND ID7
B7B5G0 B6 ID8ID10 ID6
GND
T+
TLAN
1234
765 8
GND
TLAN/485
T+ T-
DI/AI/P
V+GND B4
V+B4
DI/AI/P
GND T-GND
TLAN/485
T+
C8/9
21 24 25 44 5 17
GND
TERMINAL
STRIP
GND
13 8 41 29 STRIP
TERMINAL
TERMINAL
STRIP
1
1216
GND GND
28 9 20
TERMINAL
STRIP
TERMINAL
STRIP
12 TERMINAL
STRIP
EXPANSION BOARD
K1
K5
K4
KT
K3
K6
K2
RELAY OUTPUTS
SOFT START
COMP2-IN
COMP1-IN
AC-N1
AC-N2
COMP1
START C1
AC-L
COMP1
CS
CRCC
68k C1
K1
CC CR
CS
C2
COMP2
START C2
COMP2
K2
FM1
FM2
C3
C4
OS1
OS2
CONDENSER FAN 1
& OVERLOAD RELAY
& OVERLOAD RELAY
CONDENSER FAN 2
COMPRESSOR 1
COMPRESSOR 2
CONTROL
TRANSFORMER
68k
GND
MODE
+12V
NET
C6
12V
CN1
12V
NET
GND
ET4
ET3 ET2
ET1
AT
EOT4
EIT4
EOT3
EIT3
EOT2
EIT2
EOT1
EIT1
CN2 CN3
CN4
EEV1 EEV2
K6
K5
6.8k
EXPANSION VALVES
& SUPERHEAT CONTROLLER
33
36
40
41
43
37
32
41
12V
230VAC
CONTROL
TRANSFORMER
ELECTRONIC
LEGEND:
4VI - REVERSING VALVE 1
4V2 - REVERSING VALVE 2
HP1 - HIGH PRESSURE CUTOUT
SW.
HP2 - HIGH PRESSURE CUTOUT
SW.
LP1 = LOW PRESSURE CUTOUT
SW.
LP2 - LOW PRESSURE CUTOUT SW.
FS - WATER FLOW SWITCH
.
OT - LEAVING WATER TEMP.
CT11 - OUTSIDE COIL TEMP.
CT21 - OUTSIDE COIL TEMP.
AT - AMBIENT TEMPERATURE
CT12 - INSIDE COIL TEMP.
SUT1 - SYSTEM 1 SUCTION TEMP.
CT22 - INSIDE COIL TEMP
.
SUT2 - SYSTEM 2 SUCTION TEMP.
1 2
4V1
1
4V2
3
L2
L1
4V1
4
L2
5
HP1
5
5
6
HP1
GND
1 2
7 8
8
89
9
HP2
9
10
HP2
GND
11 12
12
13
12
13
LP1
13
14
LP1
GND
15
LP2
16
LP2
17
16
17
FS
17
18
FS
GND
19
GND
20
20 21
21
IT
21
22
IT
OPEN=COOLING
CLOSED=HEATING
REMOTE OPERATION
OT
OT
CT11
CT11 CT21 CT21 AT AT CT12 CT12 SUT1 SUT1 CT22 CT22 SUT2 SUT2
CLOSED=POWER ON
REMOTE OPERATION
OPEN=POWER OFF
GND GNDGND GND GND GND GND
2 16 20
24 25
2524
28 29
2928
32 33
3332
36 37
3736
40 41
4140
43 44
4443
23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44
L2L4
L12L11
L22L21PENL2L1
K3
KT K7
K7
M
M
HEATER ELEMENT
3 kW
OPTIONAL ACCESSORY
3kW IMMERSION HEATER
*CAUTION: ELECTRIC
HEATER MUST BE
POWERED BY A
DEDICATED CIRCUIT
PROTECTED BY A 15A
BREAKER
LINE VOLTAGE
208-240VAC
CONTROL VOLTAGE
12/24 VAC
SIGNAL
~5VDC
FIELD INSTALLED WIRING
TEMPERATURE LIMIT SWITCH
OPEN ON RISE AT 170°F
POWER SUPPLY
230VAC 60 Hz
K4
L3L
SUPPLY POWER
230V 60Hz 15A
AUX. HEATER
N
OPTIONAL ACCESSORY
USED WITH OPTIONAL HEATER
L1
L2
WATER PUMP
(230 OR 115VAC)

– 12 – P/N SCM2-0111
Model SCM Air to Water Heat Pump — Installation, Operation & Maintenance Manual

BEFORE starting the unit
Electrical shock hazard — Disconnect all electri-
cal power before proceeding with the following.
❑Verify that the system and all components have been in-
stalled in accordance with this manual and all applicable
codes and instructions.
❑Inspect the SpacePak heat pump/chiller and all other system
components. All components should be in good condition
and operational.
❑Inspect the water piping for any signs of leakage.
Repair all system leaks. Leakage will cause pressure
to drop, preventing the heat pump/chiller from oper-
ating. Leaks also allow introduction of excess make-
up water, whether lled automatically or manually.
❑Check system pressure. The pressure should be at least
15 PSIG with heat pump/chiller not in operation.
❑Check all wiring connections to ensure terminal connections
are tight and all wiring is in place.
Start the SpacePak heat pump/chiller

1. Apply power to the unit
2. The display (Figure 12, page 13) should show the start se-
quence — uC2, then 2.0, then the current water tempera-
ture. No other symbol should appear.
3. When the display shows only temperature, lower the thermo-
stat setpoint below the current room temperature.
4. This begins a call for cooling, and the pump symbol will begin
to ash.
5. After 1 to 2 minutes, the pump symbol will change to con-
stant display, and the pump will begin circulating.
6. Assuming the water is outside of the cooling temperature
range (above 42 deg) the refrigeration system will initiate
and the 1, or 3, or both numerals will begin ashing.
7. After 1 to 2 minutes, the 1, or 3, or both numerals will change
to constant, the compressor symbol will turn on and one or
both compressors will start.
8. Observe for any alarms, errors, or faulty operation (noises,
vibration, etc)
9. When operation is deemed satisfactory, raise the thermostat
set-point or turn it off.
10. The pump will run for approximately two minutes after the
compressor shutdown.

1. When the pump has stopped, change the thermostat to
Heating (if applicable) and raise the set point above current
room temperature.
2. This initiates a call in Heating mode. The pump symbol will
begin ashing.
3. After 1 to 2 minutes, the pump symbol will change to con-
stant display, and the pump will begin circulating.
4. Assuming the water is outside of the heating temperature
range (below 120 deg) the refrigeration system will initiate
and the 1, or 3, or both numerals will begin ashing.
5. After 1 to 2 minutes, the 1, or 3, or both numerals will change
to constant, the compressor symbol will turn on and one or
both compressors will start.
6. Observe for any alarms, errors, or faulty operation (noises,
vibration, etc).
Anti-freeze cycle
1. Should the water temperature drop to 34°F during periods of
non-use, the pump will start and the antifreeze heater (op-
tional, when installed) will energize and continue to operate
until the temperature reaches 38°F.
2. If the water temperature continues to fall and reaches 33°F,
the Alarm symbol and Fault Code AL will be displayed, and
the unit will automatically start in heating mode. It will con-
tinue to run until the water temperature reaches 38°F.
3. NOTE: This provides the maximum level of protection in all
cases, but may use energy unnecessarily when a suitable
concentration of glycol anti-freeze is installed. When freeze
protection is sufcient, these value can be adjusted to low-
er temperatures. Contact technical support for guidance in
re-conguring these parameters, however it must be under-
stood that the installer is responsible for ensuring sufcient
freeze protection to the lowest temperature allowed.
24-Hour follow-up
Approximately 24 hours after start-up and testing, return to the
installation to verify proper operation. Perform the following
checks.
❑Check system pressure. Add additional glycol/water mixture
if needed to restore pressure. (Pressure can drop as air is
removed from the system by the air vents.)
❑Sample the glycol/water mixture in the system. Verify inhibi-
tor and glycol levels.
❑Inspect the piping and components to ensure there are no
leaks. Repair any leaks immediately.
❑Close the isolation valves on either side of the y-strainer at
the SpacePak heat pump/chiller return connection. Remove
the screen and inspect for sediment. Clean if necessary.
• If the strainer has become clogged with sediment, deter-
mine whether the system needs to be drained, cleaned
and re-lled. Excessive sediment accumulation in the
strainer will reduce ow and cause the unit to shut down.
❑Cycle the system on heating and cooling. Verify that all com-
ponents operate correctly.

– 13 –P/N SCM2-0111
Model SCM Air to Water Heat Pump — Installation, Operation & Maintenance Manual
Figure 12 Controller display
(continued)

– 14 – P/N SCM2-0111
Model SCM Air to Water Heat Pump — Installation, Operation & Maintenance Manual

Figure 13 Troubleshooting suggestions
Condition Possible Causes Verication Solution
Unit will not start
Incorrect power supply Check power supply Supply correct power
Loose or broken wires Check wiring Repair or replace wiring
Circuit breaker interrupted Check for short
Compressor running - insufcient
cooling/heating
Insufcient pipe insulation Check insulation Add/repair insulation
Dirty coil Check coil Clean Coil
Low water ow Look for alarm symbol and FL
fault code
Clean strainer screen
Clear blockage
Remove air in piping
Verify operation/condition of
water pump
High compressor discharge pres-
sure in cooling
Insufcient pipe insulation Check charge Add/repair insulation
Dirty coil Check coil Clean Coil
High compressor discharge pres-
sure in heating Low water ow Measure water ow through heat exchanger
Flow should be a minimum of 11
GPM for SCM060 or 8 GPM for
SCM036
Low compressor suction pres-
sure in cooling
Insufcient/no water ow Look for alarm symbol and FL
fault code
Clean strainer screen
Clear blockage
Remove air in piping
Verify operation/condition of
water pump
Cooling operation in low ambient
Conrm outdoor ambient is lower
than typical for cooling operation,
e.g. <55°
If low ambient cooling is desired,
contact Technical Support for
procedure to modify fan operat-
ing parameters.
Compressor will not run
Power supply failure Supply correct power
Failed compressor contactor Replace contactor
Loose power cable Check power cable Tighten power cable
Compressor limit exceeded
Check for compressor symbols 1
and/or 3. If symbol is displayed
but compressor is inactive, ther-
mal overload has been tripped.
This will reset, however root
cause must be determined
Incorrect return water tempera-
ture setting
Check return water temperature
setting
Adjust return water temperature
setting
Low glycol/water ow Look for alarm symbol and FL
fault code Clean strainer screen
Clear blockage
Remove air in piping

– 15 –P/N SCM2-0111
Model SCM Air to Water Heat Pump — Installation, Operation & Maintenance Manual
(continued)
Figure 13 Troubleshooting suggestions (continued)
Condition Possible Causes Verication Solution
Noisy compressor Liquid returning to compressor Replace compressor
Compressor failure
Fan will not run Fan relay failure Replace fan relay
Fan motor failure Replace fan motor
Compressor runs - no heating/
cooling
No refrigerant charge Check for leaks Add appropriate refrigerant
Damaged heat exchanger Check for glycol/water leaks
and/or refrigerant leaks Replace heat exchanger
Compressor failure Replace compressor
Low outlet glycol/water tempera-
ture in cooling
Improper temperature control
setting
Check cooling temperature
setpoint and differential
Contact Technical Support for
instructions to reset cooling
setpoints
No load/rapid temperature drop
Ensure compressors are al-
lowed to run a minimum of three
minutes before reaching desired
temperature
Verify cooling fuction when there
is sufcient heat load to allow
continuous operation.
Low outlet glycol/water tempera-
ture in heating
Dirty coil, damaged or improperly
operating fans
Visually inspect coil condition and
fan operation
Clean coil, repair fan blade or
motor as necessary.
Extremely low ambient tempera-
ture
Heating performance falls con-
siderable as temperatures drop
below 20-25°F
Install supplemental heating for
extreme low ambient conditions.
Low glycol/water ow
Damaged or blocked plumbing or
air handler
Check for blockage and/or air in
piping, check operation/condition
of water pump
Clean strainer screen
Clear blockage
Remove air in piping
Defective or improper pump
Verify pump operation/condition.
Measure water ow through the
heat exchanger
Replace or re-size pump to
obtain a minimum of 11 GPM for
SCM060 or 8 GPM for SCM036

– 16 – P/N SCM2-0111
Model SCM Air to Water Heat Pump — Installation, Operation & Maintenance Manual
(continued)
Figure 14 Fault codes
FAULT
CODE MALFUNCTION REASON ACTION
E1 Water Inlet Temperature Sensor
Failure
Short Circuit or Sensor Open Check/Replace Sensor
E2 Water Outlet Temperature Sensor
Failure
Short Circuit or Sensor Open Check/Replace Sensor
E3 Evaporator Sensor Failure Short Circuit or Sensor Open Check/Replace Sensor
AL Anti-Freeze Cycle Error / Cooling Water Temperature has Fallen
Below Antifreeze Protection
Setpoint
Check Flow Rate
Check For Blockage in Piping
FL Flow Switch Error Inadequate Water Flow Rate Verify or Increase Glycol Concentration
and Contact Mestek Technical Support for
Instructions to Lower Alarm Setpoint
HP1/HP2 High Pressure Alarm
System1/System2
Discharge Pressure Exceeds
Maximum Allowable
Cooling Mode:
Check for Dirty Coil
Check for Restricted Air Flow
Check for Excessive Ambient Temperature
Heating Mode:
Check for Sufcient Water Flow Rate
LP1/LP2 Low Pressure Alarm
System1/System2
Suction Pressure Below
Minimum Allowable
Cooling Mode:
Check for Sufcient Water Flow Rate
Heating Mode:
Check for Dirty Coil
Check for Restricted Air Flow
Check for Low Ambient Temperature

– 17 –P/N SCM2-0111
Model SCM Air to Water Heat Pump — Installation, Operation & Maintenance Manual

Glycol/water mixture
The water system must contain a mixture of inhib-
ited glycol and water with thermal protection suf-
cient for the coldest expected temperature for the
installation. The inhibitor level can degrade over
time, and may need to be adjusted periodically.
The inhibitor is essential to prevent the glycol from
accelerating corrosion of metal components in the
system. The glycol and inhibitor levels must be
checked regularly (no less than once annually).
1. At least once annually, sample the system uid to verify that
the glycol concentrations meets the minimum value given in
Figure 8, page 8. Also test the inhibitor concentration. Add
glycol and inhibitor as needed to return the system to the
correct concentrations.

1. Check the glycol/water system pressure. Operating pressure
should be between 15 and 25 PSIG. Adjust uid volume if
needed to restore pressure.
2. If pressure is low, check system for evidence of leaks. Repair
all leaks immediately.
Perform annual inspection
Electrical shock hazard — Disconnect all electri-
cal power before proceeding with the following.
1. At least once annually, perform a complete inspection of the
system, including at least the following.
❑Inspect the SCM for signs of dirt or debris accumulation. Re-
move any debris and notify the building owner that the unit
must be kept clean and unobstructed.
❑Inspect glycol/water system piping and components. Repair
or replace any defective components. Repair all leaks im-
mediately.
❑Close the isolation valves on either side of the y-strainer at
the SpacePak heat pump/chiller return connection. Remove
the screen and inspect for sediment. Clean if necessary.
• If the strainer has become clogged with sediment, deter-
mine whether the system needs to be drained, cleaned
and re-lled. Excessive sediment accumulation in the
strainer will reduce ow and cause the unit to shut down.
❑Inspect all wiring and wiring connections. Tighten connec-
tions if needed. Correct any problems found.
❑Check the fuses or breakers to ensure they are correctly
sized and properly installed.
❑Clean the SCM heat exchangers and air openings.
❑Cycle the system on heating and cooling. Verify that all com-
ponents operate correctly.
Preparing the SCM for shut down
DO NOT turn off power to the SCM heat pump/chill-
er in the winter or any time when there is a possibil-
ity of freezing. Power must be ON for the automatic
anti-freeze operation to occur. See information be-
low for preparing the unit for shut down.
1. When the water temperature drops below 34 deg F during
periods of non-use, the pump will start and the antifreeze
heater (optional, when installed) will energize and continue
to operate until the temperature reaches 38 deg F.
2. If SCM must be turned off or left idle during periods when
freezing is possible, one of the following must be done:
a. Verify that sufcient glycol solution is present to protect
against most extreme anticipate conditions
b. — OR — Drain chiller and external piping completely
To restart after shutdown
1. If unit was drained, rell.
2. Follow start up procedure on page 12.

– 18 – P/N SCM2-0111
Model SCM Air to Water Heat Pump — Installation, Operation & Maintenance Manual

Figure 15 Replacement parts
PART NUMBER DESCRIPTION VENDOR PART NUMBER
SCS036 SCS060
20000-320009 Carel Temperature Sensor NTC015WP00 (IP68,-55F to 212F, 5 Ft., 10K Ohm)
20000-360006 Compressor Contactor HCC-1NU04AA
45W14RWG0061-01 Transformer BE321650GBA0015
2000-3136 Fan Motor On/Off Contactor (Carel) CONVON/OFF
2000-3137 Carel Expansion Module MCH2000020
2000-3138 Carel Controller MCH2000010
2000-3157 Soft Start PCB 2000-3157
2000-3501 Fan Motor Overload CBB61 (35μF/450VAC)
2000-3603 Low Pressure Switch H20PS (0.02MPa/0.15MP)
2000-3606 Water Flow switch HF68P/1"NPT
2000-3619 Relay JQX-105F-4 (220-240V, 30A)
2000-3711 Transformer 41X26.5F (220~230VAC,50/60Hz, 11.5VAC,0.6A)
2001-3605 High Pressure Switch H20PS (3.2MPa/4.4MPa)
2001-3608 Overload Pressure Switch H20PS (2.8MPa/3.6MPa)
2003-1402 Electronic Modulating Valve SPF-16D32 (9.5kW)
2004-1437 4-Way Valve C03C01S/SHF-9H-35U / STF-0203G (R410A)
3404-3301 Fan Motor GAL045H6-225-K01/ YDK-45X-6D
3500-2701 Propeller Fan 440×152 AS+20%GF
20000-110058 Compressor PA291X3CS-3MTU
20000-110068 Compressor PA200M2CS-3MUU1
2000-3504 Compressor Capacitor CBB65 (35μF/450V)
2000-3505 Compressor Capacitor CBB65 (50μF/450V)
35018-120010 Heat Exchanger GAH04-CM×2
35018-120012 Heat Exchanger GAH03-CMF×2
35036-120011 Condenser Coil - Left 3 rows, Φ7.94mm
35036-120012 Condenser Coil - Right 3 rows, Φ7.94mm
40000-120006 Condenser Coil - Left 3 rows, Φ7.94mm
40000-120007 Condenser Coil - Right 3 rows, Φ7.94mm

– 19 –P/N SCM2-0111
Model SCM Air to Water Heat Pump — Installation, Operation & Maintenance Manual

3-Ton SpacePak chiller

Ambient
Temp
Capacity Chiller
Power
Chiller
COP
Chiller
EER
Deg F BTU/hr Watts
82 38,553 2,523 4.47 15.28
95 29,694 3,873 2.25 7.67
105 22,880 4,912 1.36 4.66

Ambient
Temp
Water
Supply
Temp
Capacity Chiller
Power
Chiller
COP
Deg F Deg F BTU/hr Watts
45 115 35,536 3,855 2.70
32 110 26,295 3,472 2.22
20 105 20,245 3,103 1.91
5-Ton SpacePak chiller

Ambient
Temp
Capacity Chiller
Power
Chiller
COP
Chiller
EER
Deg F BTU/hr Watts
82 61,526 5,150 3.50 11.95
95 54,621 5,881 2.72 9.29
105 45,668 6,643 2.01 6.87

Ambient
Temp
Water
Supply
Temp
Capacity Chiller
Power
Chiller
COP
Deg F Deg F BTU/hr Watts
45 115 60,256 6,919 2.55
32 110 42,770 5,927 2.11
20 105 24,769 4,125 1.76

– 20 – P/N SCM2-0111
Model SCM Air to Water Heat Pump — Installation, Operation & Maintenance Manual

Air to Water Heat Pump / Reverse Cycle Chiller
The “Manufacturer” warrants to the original owner at the original installation site that the Air to
Water Heat Pump / Reverse Cycle Chiller (the “Product”) will be free from defects in material or
workmanship for a period not to exceed one (1) year (parts) or two (2) years (compressor) from the
startup. If upon examination by the Manufacturer the Product is shown to have a defect in material
or workmanship during the warranty period, the Manufacturer will repair or replace, at its option, that
part of the Product which is shown to be defective.
This limited warranty does not apply:
a) if the Product has been subjected to misuse or neglect, has been accidentally or
intentionally damaged, has not been installed, maintained or operated in accordance
with the furnished written instructions, or has been altered or modied in any way.
b) to any expenses, including labor or material, incurred during removal or reinstallation of
the defective Product or parts thereof.
c) to any workmanship of the installer of the Product.
This limited warranty is conditional upon:
a) shipment, to the Manufacturer, of that part of the Product thought to be defective. Goods
can only be returned with prior written approval from the Manufacturer. All returns must
be freight prepaid.
b) determination, in the reasonable opinion of the Manufacturer, that there exists a defect
in material or workmanship.
Repair or replacement of any part under this Limited Warranty shall not extend the duration of the
warranty with respect to such repaired or replaced part beyond the stated warranty period.
THIS LIMITED WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES, EITHER EXPRESS OR
IMPLIED, AND ALL SUCH OTHER WARRANTIES, INCLUDING WITHOUT LIMITATION IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, ARE
HEREBY DISCLAIMED AND EXCLUDED FROM THIS LIMITED WARRANTY. IN NO EVENT
SHALL THE MANUFACTURER BE LIABLE IN ANY WAY FOR ANY CONSEQUENTIAL, SPECIAL,
OR INCIDENTAL DAMAGES OF ANY NATURE WHATSOEVER, OR FOR ANY AMOUNTS IN
EXCESS OF THE SELLING PRICE OF THE PRODUCT OR ANY PARTS THEREOF FOUND TO
BE DEFECTIVE. THIS LIMITED WARRANTY GIVES THE ORIGINAL OWNER OF THE PRODUCT
SPECIFIC LEGAL RIGHTS. YOU MAY ALSO HAVE OTHER RIGHTS WHICH MAY VARY BY EACH
JURISDICTION.