Bosch LM024 User manual

Installation, Operation and Maintenance Manual
LM CS Series Heat Pump
8 733 920 847 (2014/01)
LM024 | LM036 | LM048 | LMO60 | LM070

2| LM CS Series Heat Pump
LM CS Series Heat Pump8 733 920 847 (2014/01) Subject to change without prior notice
CONTENTS
CS/AH Pairing ................................................................... 3
Key to Symbols.................................................................. 3
Safety Warnings................................................................ 3
LM CS Standard package.................................................... 4
GENERAL DESCRIPTION .................................................... 4
MOVING AND STORAGE..................................................... 4
INITIAL INSPECTION .......................................................... 4
LOCATION......................................................................... 5
Condensing Section ..................................................... 5
Air Handler ................................................................. 5
INSTALLATION .................................................................. 5
CONDENSATE DRAIN ......................................................... 6
WATER PIPING .................................................................. 6
ELECTRICAL...................................................................... 6
Safety Devices and the UPM Controller ........................... 7
COMFORT ALERT MODULE............................................... 10
OPTIONS......................................................................... 12
Pump Status Switch ................................................... 12
DPS Water Flow Proving ............................................. 12
Valve End Switch ....................................................... 12
Pump Relay............................................................... 12
SEQUENCE OF OPERATION .............................................. 13
Cooling Mode ............................................................ 13
Heating Mode............................................................ 13
APPLICATION CONSIDERATIONS...................................... 15
Well Water Systems ................................................... 15
Cooling Tower/Boiler Systems ..................................... 15
Geothermal Systems .................................................. 17
SYSTEM CHECKOUT ........................................................ 18
UNIT START-UP ............................................................... 18
MAINTENANCE................................................................ 19
UNIT CHECK-OUT SHEET .................................................. 20
TROUBLESHOOTING ........................................................ 21
OPERATING TEMPERATURES AND PRESSURES................. 25
WIRING DIAGRAMS ......................................................... 30
DIMENSIONAL DRAWINGS ............................................... 31
NOTES ............................................................................ 32

CS/AH Pairing | 3LM CS Series Heat
8 733 920 847 (2014/01)Revised 01-14
LM CS MODEL NOMENCLATURE
CS/AH PAIRING
KEY TO SYMBOLS
Warnings
The following keywords are defined and can be
used in this document:
•NOTE indicates a situation that could result in
damage to property or equipment.
•CAUTION indicates a situation that could
result in minor to medium injury.
•WARNING indicates a situation that could
result in sever injury or death.
•DANGER indicates a situation that will result in
severe injury or death.
Important Information
SAFETY WARNINGS
LM 024 - 1 CS C - F
SERIES WATER CONNECTIONS
LM F - Front
SIZE COAX OPTIONS
024 C - Copper
036 N - Cupro-Nickel
048
060 CABINET CONFIGURATION
070 CS - Condensing Section
VOLTAGE DESIGNATIONS
1- 208/1/60 & 230/1/60
Revision Level A
UNIT MODEL Paired Air Handler
Unit 1 Unit 2
LM024-1CSC LM024-1AVX LM024-1AHX
LM036-1CSC LM036-1AVX LM036-1AHX
LM048-1CSC LM048-1AVX LM048-1AHX
LM060-1CSC LM060-1AVX LM060-1AHX
LM070-1CSC LM070-1AVX LM070-1AHX
Warnings in this document are identified by
a warning triangle printed against a grey
background. Keywords at the start of the
warning indicate the type and seriousness
of the ensuing risk if measures to prevent
the risk are not taken.
This symbol indicates important information
where there is no risk to property or people.
Before performing service or maintenance
operations on the system, turn off main
power to the unit. Electrical shock could
cause personal injury or death.
Installation and servicing of this equipment
can be hazardous due to system pressure
and electrical components. Only trained
and qualified personnel should install,
repair, or service the equipment.
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.
R410A is flammable when exposed to open
flame. Recover all refrigerant prior to
brazing.

4| LM CS Standard package LM CS Series Heat Pump
LM CS Series Heat Pump8 733 920 847 (2014/01) Subject to change without prior notice
LM CS STANDARD PACKAGE
Figure # 1
[1] LM Split Series Water-to-Air Heat Pump
Condensing Section
[2] Installation and Operation Manual
GENERAL DESCRIPTION
LM Split Series Water-to-Air Heat Pumps provide
the best combination of performance and
efficiency available. All units are performance
certified to American Heating and Refrigeration
Institute (AHRI) ISO Standard 13256-1. All LM
Water-to-Air Heat Pumps conform to UL1995
standard and are certified to CAN/CSA C22.1 No
236 by Intertek-ETL.
Split system heat pumps consist of two
independently installed sections allowing for
centralized air distribution while remotely locating
the section containing the compressor and water-
to-refrigerant heat exchanger.
In the cooling mode, the air coil in the air handler
section serves as an evaporator and the water-to-
refrigerant heat exchanger serves as a condenser.
In the heating mode, their roles are reversed.
In cooling mode, the refrigerant lines connecting
the two sections consist of one line carrying liquid
refrigerant and another carrying refrigerant vapor.
The liquid carrying line will be referred to as the
liquid line while the vapor carrying line will be
referred to as the suction line.
The Water-to-Air Heat Pumps are designed to
operate with entering fluid temperature between
20°F to 80°F in the heating mode and between
50°F to 110°F in the cooling mode.
Several factory installed options are available:
Differential Pressure Switch (DPS) Water Flow
Proving Switch, Auxiliary Pump Relay, Zone Valve
and Internal Water Pump. See Pg#12 for more
detail.
Safety devices are built into each unit to provide
the maximum system protection possible when
properly installed and maintained.
MOVING AND STORAGE
If the equipment is not needed for immediate
installation upon its arrival at the job site, it should
be left in its shipping carton and stored in a clean,
dry area. Units must only be stored or moved in the
normal upright position as indicated by the “UP”
arrows on each carton at all times.
INITIAL INSPECTION
Be certain to inspect all cartons or crates on each
unit as received at the job site before signing the
freight bill. Verify that all items have been received
and that there are no visible damages; note any
shortages or damages on all copies of the freight
bill. In the event of damage or shortage, remember
that the purchaser is responsible for filing the
necessary claims with the carrier. Concealed
damages not discovered until after removing the
units from the packaging must be reported to the
carrier within 24 hours of receipt.
1
2
50°F Minimum Entering Water Temperature
(EWT) for well water applications with sufficient
water flow to prevent freezing. Antifreeze
solution is required for all closed loop
applications.
Cooling Tower/Boiler and Geothermal
applications without antifreeze must have
means to protect against extreme conditions
and equipment failure. Frozen water coils are
not covered under warranty. Other equivalent
methods of temperature control are acceptable.

Location | 5LM CS Series Heat
8 733 920 847 (2014/01)Revised 01-14
LOCATION
To maximize system performance, efficiency and
reliability, and to minimize installation costs, it is
always best to keep the refrigerant lines as short
as possible. Every effort should be made to locate
the air handler and the condensing section as
close as possible to each other.
Condensing Section
Locate the condensing section in an area that
provides sufficient room to make water and
electrical connections, and allows easy removal of
the access panels, for service personnel to
perform maintenance or repair.
The condensing section is designed for indoor use;
however, if the condensing section must be
installed in an outdoors location where ambient
temperatures can fall below freezing, some form of
freeze protection should be employed such as a
freeze-stat and/or a pump timer/starter to prevent
possible condenser freeze-up and to optimize
overall system performance.
Air Handler
Locate the air handler unit in an indoor area that
allows easy removal of the filter and access panels,
and has enough room for service personnel to
perform maintenance or repair. Provide sufficient
room to make electrical and duct connections. If
the unit is located in a confined space such as a
closet, provisions must be made for return air to
freely enter that space.
INSTALLATION
Condensing Section
The condensing section should be mounted on a
vibration absorption pad on a cement slab or
similar support to provide a good base and some
degree of levelness. The cement pad should not
come in contact with the foundation or side of the
dwelling, because sound may be transmitted into
the residence. See Figure #2 below.
Figure # 2
Reference the Factory Manual for your AH, or
Air Handler section of this manual for detailed
installation and operation.
Loosen compressor mounting bolts.
NOTE: The installer should comply with all
local codes and regulations which govern
the installation of this type of equipment.
Local codes and regulations take precedent
over any recommendations contained in
these instructions. In lieu of local codes, the
equipment should be installed in
accordance with the recommendations
made by the National electric code, and in
accordance with the recommendations
made by the National Board of Fire
Underwriters.
DO NOT remove the protective caps or plugs
from the service valves until the refrigerant
lines are run and ready for final connections.
Vibration Pad is
recommended

6| Condensate Drain LM CS Series Heat Pump
LM CS Series Heat Pump8 733 920 847 (2014/01) Subject to change without prior notice
CONDENSATE DRAIN
Figure # 3
A drain line must be connected to the air handler
and pitched away from the unit a minimum of 1/8”
per foot to allow the condensate to flow away from
the unit.
This connection must be in conformance with local
plumbing codes. A trap must be installed in the
condensate line to insure free condensate flow.
A vertical air vent is sometimes required to avoid
air pockets. The length of the trap depends on the
amount of positive or negative pressure on the
drain pan. A second trap must not be included.
WATER PIPING
Supply and return piping must be as large as the
unit connections on the heat pump (See manual
Pg#10 for any line size at installation length longer
than 25 feet).
LM units are supplied with either a copper or
optional cupro-nickel condenser. Copper is
adequate for ground water that is not high in
mineral content.
In conditions anticipating moderate scale
formation or in brackish water a cupro-nickel heat
exchanger is recommended.
Both the supply and discharge water lines will
sweat if subjected to low water temperature.
These lines should be insulated to prevent damage
from condensation. All manual flow valves used in
the system must be ball valves. Globe and gate
valves must not be used due to high pressure drop
and poor throttling characteristics.
Flexible hoses should be used between the unit
and the rigid system to avoid possible vibration.
Ball valves should be installed in the supply and
return lines for unit isolation and unit water flow
balancing.
ELECTRICAL
Refer to electrical component box layout.
(Figures #5,6)
Drain Pan is not internally sloped.
Never use flexible hoses of a smaller inside
diameter than that of the fluid connections
on the unit.
Proper testing is recommended to assure the
well water quality is suitable for use with water
source equipment.
Use cupra-nickel condenser in ground
water application due to possibility of
containing high mineral and corrosive
properties
Never exceed the recommended water flow
rates, as serious damage or erosion of the
water-to-refrigerant heat exchanger could
occur.
Teflon tape sealer should be used when
connecting water piping connections to the units
to insure against leaks and possible heat
exchanger fouling.
Field wiring must comply with local and
national electric codes. Properly sized fuses
or HACR circuit breakers must be installed
for branch circuit protection. See unit
nameplate for maximum fuse or breaker
size.
Power to the unit must be within the
operating voltage range indicated on
the unit nameplate or on the
performance data sheet.
Operation of unit on improper line
voltage or with excessive phase
imbalance will be hazardous to the unit,
constitutes abuse and may void the
warranty.

Electrical | 7LM CS Series Heat
8 733 920 847 (2014/01)Revised 01-14
The unit is provided with a concentric knock-out
for attaching common trade sizes of conduit, route
power supply wiring through this opening.
Always connect the ground lead to the grounding
lug provided in the control box and power leads to
the line side of compressor contactor as indicated
on the wiring diagram (Figures#17 through #25,
Pg#30 through Pg#40).
Figure # 4 - Single Phase unit
Figure # 5 EBox Cover
[1] Compressor contactor
[2] Energy Management System Relay (Option)
[3] Hot Gas Reheat Relay (Option)
[4] Cooling Relay
[5] Unit Protection Module (UPM)
[6] Terminal block Low-Voltage
[7] Auxiliary Relay (Option)
[8] Capacitor
[9] ECM Interface Board(Option, mounts on E-Box
cover)
[10] Comfort Alert Module (Option)
[11] DDC (Option)
[12] LonWorks Card (Option)
[13] Input Expansion Module (Option)
[14] Smart Start Assist (Option)
[15] Ground Lug
Safety Devices and the UPM Controller
Figure # 6 Typical UPM Board
[1] Board Power Indicator
[2] UPM Status LED Indicator
[3] Water Coil Freeze Protection Temperature
Selection [R30]
[4] Air Coil Freeze Protection Temperature
Selection
[5] UPM Board Settings
[6] Water Coil Freeze Connection
[7] Air Coil Freeze Connection
[8] LED Status-Diagnostic Connection
[9] 24VAC Power Input
[10] Compressor Contact Output
[11] High Pressure Switch Connection
[12] Call for Compressor Y1
[13] Low Pressure Switch Connection
[14] 24VAC Power Common
[15] Condensate Overflow Sensor
[16] Dry Contact
[17] UPM Ground Standoff
4
5
3
2
15 67
8
1
10
12
14
13
11
9
1
2
3
4
5
6
78 910
11
1213
17 14
15 16

8| Electrical LM CS Series Heat Pump
LM CS Series Heat Pump8 733 920 847 (2014/01) Subject to change without prior notice
Each unit is factory provided with a Unit Protection
Module (UPM) that controls the compressor
operation and monitors the safety controls that
protect the unit.
Safety controls include the following:
• High pressure switch located in the refrigerant
discharge line and wired across the HPC
terminals on the UPM
• Low pressure switch located in the unit
refrigerant suction line and wired across
terminals LPC1 and LPC2 on the UPM.
• Water side freeze protection sensor, mounted
close to condensing water coil, monitors
refrigerant temperature between condensing
water coil and thermal expansion valve. If
temperature drops below or remains at freeze
limit trip for 30 seconds, the controller will
shut down the compressor and enter into a
soft lockout condition. The default freeze limit
trip is 30°F, however this can be changed to
15°F by cutting the R30 or Freeze1 resistor
located on top of DIP switch SW1. Refer to
Figure #6, item [3] for resistor location. (Refer
to Figure #7 for sensor location)
Figure # 7
• The condensate overflow protection sensor is
located in the drain pan of the unit and
connected to the ‘COND’ terminal on the UPM
board. (Figure #8)
Figure # 8
If the unit is being connected to a thermostat
with a malfunction light, this connection is made
at the unit malfunction output or relay. Refer to
Figure #6.
If the thermostat is provided with a malfunction
light powered off of the common (C) side of the
transformer, a jumper between “R” and “COM”
terminal of “ALR” contacts must be made.
If the thermostat is provided with a malfunction
light powered off of the hot (R) side of the
transformer, then the thermostat malfunction
light connection should be connected directly to
the (ALR) contact on the unit’s UPM board.
UPM Board Dry Contacts are Normally Open
(NO)
If unit is employing a fresh water system (no
anti-freeze protection), it is extremely
important to have the Freeze1 R30 resistor
set to 30°F in order to shut down the unit at
the appropriate leaving water temperature
and protect your heat pump from freezing if
a freeze sensor is included.

Electrical | 9LM CS Series Heat
8 733 920 847 (2014/01)Revised 01-14
The UPM Board includes the following features:
•ANTI-SHORT CYCLE TIMER: 5 minute delay on
break timer to prevent compressor short cycling.
•RANDOM START: Each controller has an unique
random start delay ranging from 270 to 300 seconds
on initial power up to reduce the chance of multiple
unit simultaneously starting at the same time after
power up or after a power interruption, thus
avoiding creating large electrical spike.
•LOW PRESSURE BYPASS TIMER: If the
compressor is running and the low pressure switch
opens, the controller will keep the compressor ON
for 120 seconds. If, after 120 seconds the low
pressure switch remains open, the controllers will
shut down the compressor and enter a soft lockout.
The compressor will not be energized until the low
pressure switch closes and the anti-short cycle time
delay expires. If the low pressure switch opens 2-4
times in 1 hour, the unit will enter a hard lockout. In
order to exit hard lockout power to the unit would
need to be reset.
•BROWNOUT/SURGE/POWER
INTERRUPTION PROTECTION: The brownout
protection in the UPM board will shut does the
compressor if the incoming power falls below 18
VAC. The compressor will remain OFF until the
voltage is above 18 VAC and ANTI-SHORT CYCLE
TIMER (300 seconds) times out. The unit will not go
into a hard lockout.
•MALFUNCTION OUTPUT: Alarm output is
Normally Open (NO) dry contact. If pulse is
selected the alarm output will be pulsed. The
fault output will depend on the dip switch
setting for "ALARM". If it is set to "CONST", a
constant signal will be produced to indicate a
fault has occurred and the unit requires
inspection to determine the type of fault. If it is
set to "PULSE", a pulse signal is produced and
a fault code is detected by a remote device
indicating the fault. See LED Fault Indication
below for blink code explanation. The remote
device must have a malfunction detection
capability when the UPM board is set to
"PULSE".
•TEST DIP SWITCH: A test dip switch is provided
to reduce all time delays settings to 10 seconds
during troubleshooting or verification of unit
operation.
•FREEZE SENSOR: The default setting for the
freeze limit trip is 30°F (sensor number 1); however
this can be changed to 15°F by cutting the R30
resistor located on top of the DIP switch SW1. The
default setting for the freeze limit trip is 30°F
(sensor number 1); however this can be
changed to 15°F by cutting the R24 resistor
located on top of the DIP switch SW1. Since
freeze sensor 2 is dedicated to monitor the
evaporator coil it is recommended to leave the
factory default setting on the board. The UPM
controller will constantly monitor the
refrigerant temperature with the sensor
mounted close to the condensing water coil
between the thermal expansion valve and
water coil. If temperature drops below or
remains at the freeze limit trip for 30 seconds,
the controller will shut the compressor down
and enter into a soft lockout condition. Both
the status LED and the Alarm contact will be
active. The LED will flash (three (3) times) the
code associated with this alarm condition. If
this alarm occurs 2 times (or 4 if Dip switch is
UPM Board Factory Default Settings
TEMP 30°F
LOCKOUT 2
RESET Y
ALARM PULSE
TEST NO
UPM DIP SWITCH DEFAULT POSITION
lockout 42
reset RY
alarm Cont pulse
test yes no
If 24 VAC output is needed R must be wired to
ALR-COM terminal; 24 VAC will be available o
the ALR-OUT terminal when the unit is in the
alarm condition.
Operation of unit in test mode can lead to
accelerated wear and premature failure of
components. The "TEST" switch must be set
back to "NO" after troubleshooting/
servicing.

10 | Comfort Alert Module LM CS Series Heat Pump
LM CS Series Heat Pump8 733 920 847 (2014/01) Subject to change without prior notice
set to 4) within an hour the UPM controller will
enter into a hard lockout condition. It will
constantly monitor the refrigerant temperature
with the sensor mounted close to the
evaporator between the thermal expansion
valve and evaporator coil as shown in Figure
#4. If temperature drops below or remains at
the freeze limit trip for 30 seconds, the
controller will shut the compressor down and
enter into a soft lockout condition. Both the
status LED and the Alarm contact will be
active. The LED will flash (three (6) times) the
code associated with this alarm condition. If
this alarm occurs 2 times (or 4 if Dip switch is
set to 4) within an hour the controller will enter
into a hard lockout condition.
Refer to page #10 for more information.
•INTELLIGENT RESET: If a fault condition is
initiated, the 5 minute delay on break time
period is initiated and the unit will restart after
these delays expire. During this period the
fault LED will indicate the cause of the fault. If
the fault condition still exists or occurs 2 or 4
times (depending on 2 or 4 setting for Lockout
dip switch) before 60 minutes, the unit will go
into a hard lockout and requires a manual
lockout reset. A single condensate overflow
fault will cause the unit to go into a hard
lockout immediately, and will require a manual
lockout reset.
•LOCKOUT RESET: A hard lockout can be reset
by turning the unit thermostat off and then
back on when the “RESET” dip switch is set to
“Y” or by shutting off unit power at the circuit
breaker when the “RESET” dip switch is set to
“R”.
COMFORT ALERT MODULE
The Comfort Alert diagnostics module (CADM) is a
breakthrough innovation for troubleshooting heat
pump system failures. (Figure #9)
Figure # 9
By monitoring and analyzing data from the
compressor and the thermostat demand, the
module can accurately detect the cause of
electrical and system related failures without any
sensors. A flashing LED indicator communicates
the ALERT code and guides the service technician
more quickly and accurately to the root cause of a
problem.
When an abnormal system condition occurs, the
Comfort Alert module displays the appropriate
ALERT and/or TRIP LED.
The yellow ALERT LED will flash a number of times
consecutively, pause and then repeat the process.
To identify a Flash Code number, count the
number of consecutive flashes.
• Every time the module powers up, the last
ALERT Flash Code that occurred prior to shut
down is displayed for one minute.
Freeze sensor will not guard against loss of
water. Flow switch is recommended to
prevent unit from running, if water flow is
lost or reduced.
The blower motor will remain active during a
lockout condition.
This module does not provide safety protection!
The Comfort Alert module is a monitoring device
and cannot shut down the compressor directly.

Comfort Alert Module | 11LM CS Series Heat
8 733 920 847 (2014/01)Revised 01-14
Figure 10: Refrigerant Charge, Line Sizing and Capacity Multiplier Chart
SYSTEM
MODEL
Factory
R410A
Charge
(Oz)*
Refrigerant Line O.D. Size (Based on Equivalent Line Length) Suct. Line
Riser Max.
25 FT. 35 FT. 45 FT. 50 FT. 75 FT
LIQ. SUC. LIQ. SUC. LIQ. SUC. LIQ. SUC. LIQ. SUC.
LM024 80 3/8 3/4 3/8 3/4 3/8 3/4 3/8 3/4 3/8 7/8 3/4
LM036 86 3/8 3/4 3/8 3/4 3/8 3/4 3/8 7/8 3/8 7/8 3/4
LM048 93 3/8 7/8 3/8 7/8 3/8 7/8 3/8 7/8 3/8 7/8 7/8
LM060 115 3/8 1-1/8 3/8 1-1/8 3/8 1-1/8 3/8 1-1/8 3/8 1-1/8 7/8
LM070 127 3/8 1-1/8 3/8 1-1/8 3/8 1-1/8 3/8 1-1/8 3/8 1-1/8 7/8
CAPACITY MULTIPLIER 1.00 .995 0.990 0.990 0.980
Example 1:
Model LM036 with 45ft of equivalent length of 3/8” O.D Liquid
Line. Total system charge= Factory charge + (45ft - 25 ft) x .60
oz/ft Total System Charge = 93 oz + (20ft x .60 oz/ft) = 105 oz.
Additional 12 oz of R410A refrigerant required.
Example 2:
Model LM060 with 10ft of equivalent length of 3/8” O.D
Liquid Line. Total system charge= Factory charge + (25ft -
10ft) x .60 oz/ft Total System Charge = 150 oz + (15ft x .60
oz/ft) = 141 oz. Additional 12 oz of R410A refrigerant
required.
Figure 11: Liquid Line Charge Per Linear Foot
Liquid Line Size, O.D.
1/4 5/16 3/8 1/2 5/8
R410A oz per foot .25 .44 .60 1.15 1.95

12 | Options LM CS Series Heat Pump
LM CS Series Heat Pump8 733 920 847 (2014/01) Subject to change without prior notice
OPTIONS
Number of factory installed options are available
on LM CS Series of Heat Pumps. The following
details the purpose, function and components of
each option.
Pump Status Switch
The pump status switch is a Current Transformer
(CT) that monitors the current flow from the
condenser pump motor. It’s default is Normally
Open (NO) when the motor is not running, and
closes once it senses current flow.
DPS Water Flow Proving
The DPS water flow proving switch is a factory
installed option available for the LM series. The
DPS prevents compressor operation if there is
inadequate water flow through the water to
refrigerant heat exchanger in the heat pump.
The DPS operates by monitoring the water side
pressure drop across the water to the refrigerant
heat exchanger. When the pressure drop between
the water in and water out lines reaches a pre-set
value, compressor operation is enabled.
Valve End Switch
The leaving water valves are all equipped with
Valve End Switches (VES) and it is a factory
installed option available for the LM series.
The VES prevents compressor operation if the
valve is not fully open. This prevents short-cycling
due to low water through the water-to-refrigerant
heat exchanger in the heat pump.
The VES only closes once the leaving water valve is
fully open. The valve is activated by the
compressor call (Y1) signal.
Pump Relay
The factory installed pump relay can be used to
energize a supply pump or solenoid valve when
there is a call for compressor operation. This relay
can be used to switch either high or low voltage
power.

Sequence of Operation | 13LM CS Series Heat
8 733 920 847 (2014/01)Revised 01-14
SEQUENCE OF OPERATION
Cooling Mode
Energizing the “O” terminal energizes the unit
reversing valve thus placing the unit into cooling
mode. The fan motor starts when the “G” terminal
is energized.
When the thermostat calls for first stage cooling
(Y1) the loop pump or solenoid valve if present is
energized and the first stage of compressor
capacity starts.
When the thermostat calls for second stage
cooling (Y2) the second stage (or full compressor
capacity) is initiated. The fan ramps up to full
cooling air flow.
Once the thermostat is satisfied, the compressor
shuts down and the fan ramps down to either fan
only mode or off over a span of 30 seconds.
Heating Mode
The first two stages of heating (Y1 & Y2) operate in
the same manner as cooling, but with the reversing
valve de-energized. On a call for auxiliary heat
(W1), the fan ramps up to auxiliary heat air fl ow
immediately and the electric heater package is
energized along with the compressor. As the
thermostat is satisfied, the heaters will shut off as
soon as W1 is de-energized, and the compressors
will remain on until the thermostat stages are
satisfied.
Once the thermostat is satisfied, the compressor
shuts down and the fan ramps down either fan only
mode or off over a span of 30 seconds. If
thermostat has two different output points one for
Auxiliary heat and a different one for Emergency
heat the two outputs must be terminated on W1
units equipped with one stage of Electric heat.
(Figure #12)
The fan motor will take 30 seconds to ramp up
to operating speed and will run at fan only rated
air flow, as long as there is no call for
compressor or heater operation.
Some options will have a built in delay, and
hence, compressor operation is not immediate.
See ‘Options’ section for more detail.
A fault condition initiating a lockout will de-
energize the compressor irrespective of which
stage is engaged.
If the unit compressor lock out for any reason at
this time, the electric heaters will continue to
function normally.
When using a 2-cool, 3-heat thermostat both the
W1 & W2 on the Heat Pump and W2 & EM on
the thermostat must be connected together via
a jumper. (See Figure#22)

14 | Sequence of Operation LM CS Series Heat Pump
LM CS Series Heat Pump8 733 920 847 (2014/01) Subject to change without prior notice
Figure # 12
UPM Sequence of Operation (SOO) Flow Chart
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
Y1=1
V
>
18VAC
HPC = 1
LPC = 1
FRZ
> TEMP
LIM
CON
> 0
INITIAL
POWER UP T
>
ASC OR
RS SEC
TIME
> 30
SEC
TIME
> 120
SEC
COUNT = 2
Start Timer
Start Timer
CC Output = On
CC Output = Off
Blink Code On Status LED
Report Alarm Fault
Hard Lockout
ALR Output = On/Pulse
Blink Code On Status LED
Soft Lockout
Record Alarm
Start Counter (If Applicable)
Start
Anti Short Cycle
Start
Random Start Up
Lockout Can Be Set To
4 Via Dip Switch
Power/Switchs/Sensor
Status Check
LEGEND:
HPC - HIGH PRESSURE CUTOUT
LPC - LOW PRESSURE CUTOUT
FRZ - FREEZE PROTECTION CONDITION
CON - CONDENSATE OVERFLOW CONDITION
CC - COMPRESSOR COIL
ASC - ANTI SHORT CYCLE
RS - RANDDOM START

Application Considerations | 15LM CS Series Heat
8 733 920 847 (2014/01)Revised 01-14
APPLICATION CONSIDERATIONS
Well Water Systems
Copper is adequate for ground water that is not
high in mineral content. Should your well driller
express concern regarding the quality of the well
water available or should any known hazards exist
in your area, we recommend proper testing to
assure the well water quality is suitable for use
with water source equipment. In conditions
anticipating moderate scale formation or in
brackish water a cupro-nickel heat exchanger is
recommended. In well water applications water
pressure must always be maintained in the heat
exchanger. This can be accomplished with either
control valve or a bladder type expansion tank.
When using a single water well to supply both
domestic water and the heat pump care must be
taken to insure that the well can provide sufficient
flow for both. In well water applications a slow
closing solenoid valve must be used to prevent
water hammer. Solenoid valves should be
connected across Y1 and C1 on the interface board
for all. Make sure that the VA draw of the valve
does not exceed the contact rating of the
thermostat. (Figure #13)
Figure # 13 Example System Set-up
[1] Flex Duct Connection
[2] Low Voltage Control Connection
[3] Vibration Pad
[4] Ball Valves
[5] Solenoid Valve Slow Closing
[6] Condensate Drain Connection
[7] Drain Valves
[8] Hose Kits (optional)
[9] Pressure Tank (optional)
[10] P/T Ports (optional)
[11] Line Voltage Connection
[12] Electric Heater Line Voltage Disconnect
[13] Unit Line Voltage Disconnect
Cooling Tower/Boiler Systems
The cooling tower and boiler water loop
temperature is usually maintained between 50° F
to 100 ° F to assure adequate cooling and heating
performance.
In the cooling mode, heat is rejected from the unit
into the water loop. A cooling tower provides
evaporative cooling to the loop water thus
maintaining a constant supply temperature to the
unit. When utilizing open cooling towers, chemical
water treatment is mandatory to ensure the water
is free from corrosive elements. A secondary heat
exchanger (plate frame) between the unit and the
open cooling tower may also be used.
1
2
3
4
5
6
7Typical Installation shown for
illustration purposes only.
9
8
10
11
12
13

16 | Application Considerations LM CS Series Heat Pump
LM CS Series Heat Pump8 733 920 847 (2014/01) Subject to change without prior notice
It is imperative that all air be eliminated from the
closed loop side of the heat exchanger to insure
against fouling. In the heating mode, heat is
absorbed from the water loop. A boiler can be
utilized to maintain the loop at the desired
temperature.
Do not overtighten the connections. Flexible hoses
should be used between the unit and the rigid
system to avoid possible vibration. Ball valves
should be installed in the supply and return lines
for unit isolation and unit water flow balancing.
Pressure/temperature ports are recommended in
both supply and return lines for system flow
balancing. Water flow can be accurately set by
measuring the water-to-refrigerant heat
exchangers water side pressure drop.
No unit should be connected to the supply or
return piping until the water system has been
completely cleaned and flushed to remove any dirt,
piping chips or other foreign material. Supply and
return hoses should be connected together during
this process to ensure the entire system is
properly flushed.
After the cleaning and flushing has taken place the
unit may be connected to the water loop and
should have all valves wide open. (Figure #14)
Figure # 14
[1] Line voltage disconnect (unit)
[2] Low voltage control connection
[3] P/T ports (optional)
[4] Hose kits (optional)
[5] Ball valves
[6] Supply and return line of central system
[7] Flex duct connection
[8] Hanging bracket assembly
[9] Threaded rod
[10] Hanging bracket assembly
Water piping exposed to extreme low
ambient temperatures is subject to
freezing.
Consult the specification sheets for piping
sizes. Teflon tape sealer should be used
when connecting to the unit to insure
against leaks and possible heat exchanger
fouling.
See specification sheets for water flow vs.
pressure drop information.
Note: Diagram shows typical
installation and is for illustration
purposes only. Ensure access to Heat
Pump is not restricted.

Application Considerations | 17LM CS Series Heat
8 733 920 847 (2014/01)Revised 01-14
Geothermal Systems
Closed loop and pond applications require
specialized design knowledge. No attempt at these
installations should be made unless the dealer has
received specialized training. Utilizing the Ground
Loop Pumping Package (GLP), makes the
installation easy. Anti-freeze solutions are utilized
when low evaporating conditions are expected to
occur. Refer to the GLP installation manuals for
more specific instructions. (Figure #16)
Figure # 15
[1] Line voltage disconnect (unit)
[2] Flex duct Connection
[3] Low voltage control connection
[4] Line voltage connection (unit)
[5] P/T ports
[6] Vibration pad
[7] Condensate drain connection
[8] Ground loop connection kit
[9] Ground loop pumping package
[10] Polyethylene with insulation
[11] Line voltage disconnect (electric heater)
Note: Diagram shows typical
installation and is for illustration
purposes only. Ensure access to Heat
Pump is not restricted.

18 | System Checkout LM CS Series Heat Pump
LM CS Series Heat Pump8 733 920 847 (2014/01) Subject to change without prior notice
SYSTEM CHECKOUT
After completing the installation, and before
energizing the unit, the following system checks
should be made:
• Verify that the supply voltage to the heat pump
is in accordance with the nameplate ratings.
• Make sure that all electrical connections are
tight and secure.
• Check the electrical fusing and wiring for the
correct size.
• Verify that the low voltage wiring between the
thermostat and the unit is correct.
• Verify that the water piping is complete and
correct.
• Check that the water flow is correct, and
adjust if necessary.
• Check the blower for free rotation, and that it
is secured to the shaft.
• Verify that vibration isolation has been
provided.
• Unit is serviceable. Be certain that all access
panels are secured in place.
Considerations:
1. Always check incoming line voltage power
supply and secondary control voltage for
adequacy. Transformer primaries are dual
tapped for 208 and 230 volts. Connect the
appropriate tap to ensure a minimum of 18
volts secondary control voltage. 24 volts is
ideal for best operation.
2. Long length thermostat and control wiring
leads may create voltage drop. Increase wire
gauge or up-size transformers may be required
to insure minimum secondary voltage supply.
3. FHP recommends the following guidelines for
wiring between a thermostat and the unit: 18
GA up to 60 foot, 16 GA up to 100 ft and 14 GA
up to 140 ft.
4. Do not apply additional controlled devices to
the control circuit power supply without
consulting the factory. Doing so may void
equipment warranties.
5. Check with all code authorities on
requirements involving condensate disposal/
over flow protection criteria.
UNIT START-UP
1. Put the UPM board in “test” mode.
2. Set the thermostat to the highest setting.
3. Set the thermostat system switch to “COOL”,
and the fan switch to the “AUTO” position. The
reversing valve solenoid should energize. The
compressor and fan should not run.
4. Reduce the thermostat setting approximately 5
degrees below the room temperature.
5. Verify the heat pump is operating in the cooling
mode.
6. Turn the thermostat system switch to the
“OFF” position. The unit should stop running
and the reversing valve should de energize.
7. Leave the unit off for approximately (5)
minutes to allow for system equalization.
8. Turn the thermostat to the lowest setting.
9. Set the thermostat switch to “HEAT”.
10. Increase the thermostat setting approximately
5 degrees above the room temperature.
11. Verify the heat pump is operating in the heating
mode.
12. Set the thermostat to maintain the desired
space temperature.
13. Check for vibrations, leaks, etc.
Ensure cabinet and Electrical Box are
properly grounded.

Maintenance | 19LM CS Series Heat
8 733 920 847 (2014/01)Revised 01-14
MAINTENANCE
1. Filter changes or cleanings are required at
regular intervals. The time period between
filter changes will depend upon type of
environment the equipment is used in. In a
single family home, that is not under
construction, changing or cleaning the filter
every 60 days is sufficient. In other
applications such as motels, where daily
vacuuming produces a large amount of lint,
filter changes may need to be as frequent as
biweekly.
2. An annual “checkup” is recommended by a
licensed refrigeration mechanic. Recording the
performance measurements of volts, amps,
and water temperature differences (both
heating and cooling) is recommended. This
data should be compared to the information on
the unit’s data plate and the data taken at the
original startup of the equipment.
3. Lubrication of the blower motor is not
required, however may be performed on some
motors to extend motor life. Use SAE-20 non-
detergent electric motor oil.
4. The condensate drain should be checked
annually by cleaning and flushing to insure
proper drainage.
5. Periodic lockouts almost always are caused by
air or water flow problems. The lockout
(shutdown) of the unit is a normal protective
measure in the design of the equipment. If
continual lockouts occur call a mechanic
immediately and have them check for: water
flow problems, water temperature problems,
air flow problems or air temperature problems.
Use of the pressure and temperature charts for
the unit may be required to properly determine
the cause.
Equipment should never be used during
construction due to likelihood of wall board
dust accumulation in the air coil of the
equipment which permanently affects the
performance and may shorten the life of the
equipment.
Figure 16: Water side pressure drop in PSIG
Series GPM Water PD @ 77°EWT
with Water
LM024
30.7
41.2
51.7
62.4
73.2
84.0
LM036
61.1
81.8
10 2.7
12 3.7
14 4.9
16 6.2
LM048
61.1
81.8
10 2.7
12 3.7
14 4.9
16 6.2
LM060
7.5 1.1
10 1.9
12.5 2.8
15 3.9
17.5 5.2
20 6.6
LM070
7.5 1.1
10 1.9
12.5 2.8
15 3.9
17.5 5.2
20 6.6

20 | Unit Check-Out Sheet LM CS Series Heat Pump
LM CS Series Heat Pump8 733 920 847 (2014/01) Subject to change without prior notice
UNIT CHECK-OUT SHEET
Customer Data
Customer Name _____________________________________________ Date ___________________________________
Address ______________________________________________________
_______________________________________________________________
Phone _______________________________________________________ Unit Number ___________________________
Unit Nameplate Data
Unit Make _________________________________________
Model Number ____________________________________ Serial Number ____________________________________
Refrigerant Charge (oz) __________________________
Compressor: RLA ____________________ LRA ___________________________
Blower Motor: FLA (or NPA) ___________ HP ____________________________
Maximum Fuse Size (Amps) ____________
Maximum Circuit Ampacity _____________
Operating Conditions
Cooling Mode Heating Mode
Entering / Leaving Air Temp _______________ / _____________ _______________ / _____________
Entering Air Measured at: ______________________________ ______________________________
Leaving Air Measured at: ______________________________ ______________________________
Entering / Leaving Fluid Temp _______________ / _____________ _______________ / _____________
Fluid Flow (gpm) ______________________________ ______________________________
Compressor Volts / Amps _______________ / _____________ _______________ / _____________
Blower Motor Volts / Amps _______________ / _____________ _______________ / _____________
Source Fluid Type ______________________________ ______________________________
Fluid Flow (gpm)* ______________________________ ______________________________
Fluid Side Pressure Drop* ______________________________ ______________________________
Suction / Discharge Pressure (psig)* _______________ / _____________ _______________ / _____________
Suction / Discharge Temp* _______________ / _____________ _______________ / _____________
Suction Superheat* ______________________________ ______________________________
Entering TXV / Cap Tube Temp* ______________________________ ______________________________
Liquid Subcooling* ______________________________ ______________________________
* Required for Troubleshooting ONLY
Auxiliary Heat
Unit Make __________________________________
Model Number: ______________________________ Serial Number _____________________________
Max Fuse Size (Amps) _______________________
Volts / Amps _______________________________
Entering Air Temperature _____________________
Leaving Air Temperature ______________________
Bosch Group
601 NW 65th Court
Fort Lauderdale, FL 33309
Phone: [phone]
Fax: [phone]
MAIL TO: Bosch.Fhp.TechSuppo[email protected]
or scan the QR code and attach picture of this form with
the information requested.