Bosch TW Series User manual

Installation, Operation and Maintenance Manual
TW Series
6720220047 (2016/02)
Water to Water

2| Table of contents TW Series Water to Water
TW Series Water to Water6720220047 (2016/02) Subject to change without prior notice
TABLE OF CONTENTS
Key to Symbols..................................................................3
Safety Warnings................................................................3
Model Nomenclature..........................................................4
Standard TW package ........................................................ 5
General Description ..................................................... 5
Moving and Storage........................................................... 5
Initial Inspection.......................................................... 5
Location.....................................................................5
Installation.........................................................................5
Piping...............................................................................6
Electrical .......................................................................... 6
Safety Devices and the UPM Controller ........................... 7
Options.............................................................................9
Heat Recovery Package (HRP) ....................................... 9
DPS Water Flow Proving ............................................... 9
Pump Relay.................................................................9
Comfort Alert Module ................................................... 9
Heat Recovery Package ...................................................10
Water Tank Preparation.............................................. 10
HR Water Piping ........................................................ 10
Water Tank Refill........................................................ 10
Initial Start-Up........................................................... 10
Sequence Of Operation....................................................11
Cooling Mode............................................................ 11
Heating Mode............................................................11
Sequence Of Operation Flow........................................12
Application Considerations .............................................. 13
Well Water Systems ................................................... 13
Cooling Tower/Boiler Systems.....................................13
Geothermal Systems.................................................. 14
System Checkout ............................................................15
Considerations...........................................................15
Unit Start-Up................................................................... 16
Maintenance ...................................................................16
Decommissioning.............................................................16
Water ToWater UnitController..........................................16
Features....................................................................16
Unit Sensors.....................................................................16
Water Sensor.............................................................16
Changeover Sensor.....................................................16
Modes Of Operation..........................................................16
Off Mode...................................................................16
Heating Mode.............................................................16
Cooling Mode.............................................................17
AutoChangeover Mode................................................17
Unit Protection...........................................................17
Manual Lockout................................................................18
Lead-Lag...................................................................18
Pump Cycling.............................................................18
Operating Instructions......................................................18
User Interface............................................................18
UP Button..................................................................18
Down Button..............................................................18
LED Indicators............................................................19
User Adjustable Settings Chart..........................................19
Settingupthecontroller....................................................19
InitialConfiguration..........................................................20
Unit Check-out sheet........................................................21
Troubleshooting ..............................................................22
Unit Troubleshooting...................................................22
Confort Alert Module-Flash Codes.................................23
HRPTroubleshooting...................................................24
Unit Lockouts ............................................................24
Electrical Data Table ........................................................25
UPMBoard LEDIndicators.................................................25
Water Quality Table..........................................................26
Wiring Diagrams..............................................................27
Dimensional Drawings......................................................33
Terminology ....................................................................36

Key to Symbols | 3TW Series Water to Water
6720220047 (2016/02)Revised 02-16
KEY TO SYMBOLS
Warnings
The following keywords are defined and can be used in
this document:
•NOTICE 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
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.
WARNING: 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.
DANGER: Before performing service or
maintenance operations on the system, turn
off main power to the unit. Electrical shock
could cause personal injury or death.
WARNING: When working on equipment,
always observe precautions described in
the literature, tags, and labels attached to
the unit. Follow all safety codes. Wear
safety glasses and work gloves. Use a
quenching cloth for brazing, and place a fire
extinguisher close to the work area.
NOTICE: 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.
NOTICE: To avoid equipment damage, DO
NOT use these units as a source of heating
or cooling during the construction process.
Doing so may affect the unit’s warranty. The
mechanical components and filters will
quickly become clogged with construction
dirt and debris, which may cause system
damage.
NOTICE: 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 proficiency requirements.

4| Model Nomenclature TW Series Water to Water
TW Series Water to Water6720220047 (2016/02) Subject to change without prior notice
MODEL NOMENCLATURE
TW 25-1CSN-FXXXCA-XKGAEXXXX 7X XX
XXXXXX SB A
TW Code String Rev Level
Size Standard/Special
025 SS - Standard
035 049 061
071 X - N/A
122
Controls
Voltage X - Standard
1208-230/60/1 M - DDC - Multi-Protocol (BacNET, Modbus, N2)
L - DDC - LonWorks
Cabinet Con guration
US - Unit Mounted Controller Transformer
CS - Remote Controlled 7 - 75 VA
Source Side Coax Options Refrigeration Circuit Options
C - Copper X - None N - Cupro-Nickel D - Heat Recovery Package
Water Connections General Electrical Options (up to 5 available per unit)
F - Front A - EMS relay
E - Pump/valve rela
y
X - N/A H - Flow proving switch
N - Comfort Alert
Load Side Coax Options X - As default for non used electrical codes
C - Copper
N - Cupro-Nickel Application
G - EXTENDED RANGE (Geothermal)
Revision Level
A - Current
Cabinet Construction
K - Pre Paint Steel / 1/2" Standard 1.5LB Dual Density Fiberglass / EQ
Electric Heat X - None

Standard TW Package | 5TW Series Water to Water
6720220047 (2016/02)Revised 02-16
STANDARD TW PACKAGE
Figure # 1
[1] TW Series Water-to-Water
[2] Installation and Operation Manual
General Description
TW Series Water-to-Water 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 13256-2. All
TW Water-to-Water Heat Pumps conform to UL1995
standard and are certified to CAN/CSA C22.2 No 236 by
Intertek-ETL. The Water-to-Water Heat Pumps are
designed to operate with entering fluid temperature
source between 30°F to 90°F in the heating mode and
between 50°F to 110°F in the cooling mode on the
source side
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.
Location
Locate the unit in an indoor area that allows easy access
to the panels, and has enough room for service
personnel to perform maintenance or repair. Provide
sufficient room to make fluid and electrical
connection(s).
INSTALLATION
The TW series unit should be mounted level on a
vibration absorbing pad slightly larger than the base to
minimize vibration transmission to the building
structure, It is not necessary to anchor the unit to the
floor.(Figure #2).
Figure # 2
Heat Pump operating under extreme conditions will
have limitation on fluid flow rates and/or
temperatures.
50°F Minimum Entering Water Temperature (EWT)
is recommended 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
should have sufficient antifreeze solution to protect
against extreme conditions and equipment failure.
Frozen water coils are not covered under warranty.
Other equivalent methods of temperature control are
acceptable.
1
2
WARNING: For Storage if unit stacking is
required, stack unit as follows:
Do not stack units larger than 6 tons. For
units less than 6 tons, no more than three
high
NOTICE: These units are not approved for
outdoor installation; therefore, they must
be installed within a conditioned space
inside the structure. Do not locate in areas
that are subject to freezing.
VIBRATION
PAD FULL

6| Piping TW Series Water to Water
TW Series Water to Water6720220047 (2016/02) Subject to change without prior notice
PIPING
Supply and return piping must be as large as the unit
connections on the heat pump (larger on long runs).
TW units are supplied with either a copper or optional
cupro-nickel Water to refrigerant Heat Exchanger.
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.
Always check carefully for water leaks and repair
appropriately. Units are equipped with female pipe
thread fittings. Consult Unit Dimensional Drawings.
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. (See Water
Quality Table on Page#26)
ELECTRICAL
Refer to electrical component box layout. (Figure #3)
Properly sized fuses or HACR circuit breakers must be
installed for branch circuit protection. See unit
nameplate for maximum fuse or breaker size.
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 on
Pg#27 To 34).
Figure # 3
[1] Comfort Alert Module (Option)
[2] Compressor contactor
[3] Capacitor
[4] Auxiliary Relay (DP/DT)
[5] Unit Protection Module (UPM)(CS Option)
NOTICE: 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. When in doubt, use cupro-nickel.(See
Water Quality Table on page #28)
NOTICE: 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.
NOTICE: Do not overtighten the
connections.
NOTICE: Field wiring must comply with
local and national electric codes.
WARNING: Power to the unit must be
within the operating voltage range indicated
on the unit nameplate or on the
performance data sheet.
WARNING: 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.
1
2
3
4
5
6
5

Electrical | 7TW Series Water to Water
6720220047 (2016/02)Revised 02-16
Safety Devices and the UPM Controller
Figure # 4
[1] Board Power Indicator
[2] UPM Status LED Indicator
[3]Water Source Coil Freeze Protection Temperature
Selection [R30]
[4] Load Water Coil Freeze Protection Temperature
Selection [R24]
[5] UPM Board Settings
[6] Source Coax Freeze Connection (Freeze 1)
[7] Load Coax Freeze Connection (Freeze 2)
[8] LCD Unit Display 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 (not applicable on
TW)
[16] Dry Contact
[17] UPM Ground Standoff
The TW Series has an optional factory installed 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 26°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 #4, item [3] for resistor location), Refer to
Figure #5 for sensor location
.
Figure # 5
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 #4.
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.
1
2
3
4
5
6
7910
11
1213
17
14
15
16
8
If the thermostatis 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)
NOTICE: If unit is employing a fresh water
system (no anti-freeze protection), it is
extremely important to have the Freeze1
R30 resistor set to 26°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.
For Reference
only

8| Electrical TW Series Water to Water
TW Series Water to Water6720220047 (2016/02) Subject to change without prior notice
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. After 2 minutes if 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 L.E.D Fault Indication below for blink code
explanation. The remote device must have a
malfunction detection capability when the UPM
board is set to "PULSE".
•DISPLAY OUTPUT: The Display output is a pulse
output connected to the Unit Diagnostic Display
(UDD) and it pulses 24VAC when the unit is in an
lockout alarm condition.
•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 26°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 load side 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 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
UPM Board Factory Default Settings
TEMP 26°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.
NOTICE: 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.

Options | 9TW Series Water to Water
6720220047 (2016/02)Revised 02-16
evaporator coil as shown in Figure #5. 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 (six (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.
•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.
•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”.
OPTIONS
Number of factory installed options are available on TW
Series of Heat Pumps. The following details the purpose,
function and components of each option.
Heat Recovery Package (HRP)
The heat recovery package is a factory installed option
on TW series heat pumps. The HRP can be used to heat
potable water during unit operation using waste heat
from the compressor discharge gas. In some cases the
HRP can provide most or all of the hot water
requirements for a typical home.
The HRP consists of three major components:
• Double wall, vented refrigerant to water heat
exchanger
• Circulating pump
• Control circuit
The heat exchanger is rated for use with potable water
and is acceptable for use as a domestic water heating
device in most building codes.
The pump circulates water between the domestic hot
water tank and HRP heat exchanger in the Heat Pump.
The control circuit ensures that the HRP only operates
when there is available heat from the compressor and
when the water is within a safe temperature range of
below 140 deg F.
When the heat pump compressor operates, the HRP will
monitor the temperature of the discharge gas from the
compressor. Once discharge gas is hot enough to
provide useful heat to the domestic water tank, the
circulating pump will be enabled, drawing water from
the tank, through the HRP heat exchanger and then
depositing the heated water back into the tank. If the
water temperature reaches 140 deg F, the circulating
pump is disabled to prevent over heating of the
domestic water. The HRP is provided with an on/off
switch in case the end user desires that the HRP be
inactivated (typically during the winter months when
space heating is most important).
DPS Water Flow Proving
The DPS water flow proving switch is a factory installed
option available for the WW 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 refrigerant heat exchanger.
When the pressure drop between the water in and water
out lines reaches a pre-set value, compressor operation
is enabled.
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.
Comfort Alert Module
The Comfort Alert diagnostics module (CADM) is a
breakthrough innovation for troubleshooting heat pump
system failures. (Figure #6)
Figure # 6
NOTICE: Freeze sensor will not guard
against the loss of water. Flow switch is
recommended to prevent unit from running
if water flow is lost or reduced.
NOTICE: If heat recovery unit is installed in
an area where freezing may occur, the unit
must be drained during winter months to
prevent heat exchanger damage. Heat
exchanger ruptures that occur due to
freezing will void the heat recovery package
warranty along with the heat pump
warranty.

10 | Heat Recovery Package TW Series Water to Water
TW Series Water to Water6720220047 (2016/02) Subject to change without prior notice
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.Heat Recovery Package
HEAT RECOVERY PACKAGE
Water Tank Preparation
1. Turn off electrical or fuel supply to the water heater.
2. Attach garden hose to water tank drain connection
and run other end of hose out doors or to an open
drain.
3. Close cold water inlet valve to water heater tank.
4. Drain tank by opening drain valve on the bottom of
the tank, then open pressure relief valve or hot
water faucet.
5. Once drained the tank should be flushed with cold
water until the water leaving the drain hose is clear
and free of sediment.
6. Close all valves and remove the drain hose.
7. Install HR water piping.
HR Water Piping
All hot water piping MUST be a minimum of 3/8t O.D.
copper tube to a maximum distance of fifteen (15) feet.
For distances beyond fifteen feet but not exceeding sixty
(60) feet use 1/2” copper tube. Separately insulate all
exposed surface of both connecting water lines with 3/
8” wall closed cell insulation. Install isolation valves on
supply and return to the heat recovery. (Figure # 7)
Water Tank Refill
1. Open the cold water supply to the tank.
2. Open a hot water faucet to vent air from the system
until water flows from the faucet, then close.
3. Depress the hot water tank pressure relief valve
handle to ensure there is no air remaining in the
tank.
4. Carefully inspect all plumbing for water leaks.
Correct as required.
5. Purge all air from HR by depressing the schrader
valve on the HR Unit. Allow all air to bleed out until
water appears at the valve.
6. Before restoring the power or fuel supply to the
water heater, adjust the temperature setting on the
tank thermostat(s) to ensure maximum utilization of
the heat available from the refrigeration system and
conserve the most energy. On tanks with both upper
and lower elements and thermostats, the lower
element should be turned down to 100° F, while the
upper element should be adjusted to 120° F.
Depending upon the specific needs of the customer,
you may need to adjust the upper element
differently. On tanks with a single thermostat lower
the thermostat setting to 120° F or the “LOW”
position. After thermostat adjustments are
completed, replace access cover and restore
electrical or fuel supply to water heater.
Initial Start-Up
1. Turn on the heat pump. The HR pump should not run
if the compressor is not running
2. Turn HR switch to the “ON” position. The pump will
operate if entering water temperature to HR is
below 120° F.
3. The temperature difference between the water
entering and leaving the heat recovery should be 5°
to 15° F.
4. Allow the unit to operate for 20 to 30 minutes to
ensure it is functioning properly. The pump should
shut off when the water temperature entering the
heat recovery reaches 120°F.
This module does not provide safety protection! The
Comfort Alert module is a monitoring device and
cannot shut down the compressor directly.
Concentric water fitting (p/n 8733907119) is
recommended.
(See Figure # 7)
NOTICE: All piping from HRP to domestic
water tank must be copper or any metal of
stronger alloy.
NOTICE: Make sure all valves in heat
recovery water piping system are open.
NEVER OPERATE HR PUMP DRY.

Sequence of operation | 11TW Series Water to Water
6720220047 (2016/02)Revised 02-16
Figure # 7
SEQUENCE OF OPERATION
Cooling Mode
Energizing the “O” terminal energizes the unit reversing
valve thus placing the unit into cooling mode. T
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. Once the thermostat is satisfied, the
compressor shuts down accordingly
Heating Mode
The first two stages of heating (Y1 & Y2) operate in the
same manner as cooling, but with the reversing valve de-
energized. Once the thermostat is satisfied, the
compressor shuts down,
NOTE: Diagram for illustration purposes only.
Ensure access to Heat Pump is not restricted.

12 | Sequence of Operation flow TW Series Water to Water
TW Series Water to Water6720220047 (2016/02) Subject to change without prior notice
SEQUENCE OF OPERATION FLOW
Figure # 8
CC
LOCKOUT CAN BE SET
TO 4 VIA DIP SWITCH
BLINK CODE ON STATUS LED
SOFT LOCKOUT
RECORD ALARM
START COUNTER (IF APPLICABLE)
CC OUTPUT = ON
NO
YES
LPC
=CLOSED
FRZ >TEMP
LIMIT
Y1 = ON
TIME > 30
SEC
CON > 0
POWER/ SWITCHES/SENSOR
STATUS CHECK
START
TIMER
NO
YES
NO
YES
NO
YES
T > ASC OR
RS SEC
YES
NO
NO
YES
START
ANTI SHORT CYCLE
INITIAL
POWER UP
YES
NO
START
RANDOM START UP
START
COUNTER
NEEDED?
YES
COUNT = 2
OR
COUNT = 4
BLINK CODE ON STATUS LED
DISPLAY OUTPUT = PULSE
ALR OUTPUT = ON/PULSE
NO
YES
HARD
LOCKOUT?
CC OUTPUT = OFF
V > 18VAC
NO
YES YES
NO
BLINK CODE
ON STATUS LED
NO
RESET ON
Y
CLEAR FAULTS
R = 24VAC
NO
YES NO
YES
NO
YES
HPC =
CLOSED
RESET ON R
CC OUPUT=
ON
NO
YES
TIME >
120 SEC
START
TIMER
NO
YES
CNT = CNT+1

Application Considerations | 13TW Series Water to Water
6720220047 (2016/02)Revised 02-16
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 #9)
Figure # 9 Example System Set-up
[1] Pressure Tank
[2] Ball Valves
[3] Solenoid Valve
[4] Hose kit
[5]P/T Kit
[6] Load Side Connections
[7] Low Voltage Control Connection
[8] Vibration Pad
[9] Line Voltage Control Connection
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.
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.

14 | Application Considerations TW Series Water to Water
TW Series Water to Water6720220047 (2016/02) Subject to change without prior notice
Consult the specification sheets for piping sizes.
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.
See specification sheets for water flow vs. pressure drop
information.
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 # 10
1. Ball Valves.
2. Hose kits.
3. P/T Plugs
4. Load Side Connections.
5. Low Voltage Control Connections.
6. Vibration Pad.
7. Line Voltage Disconnect.
8. Supply and Return lines of central system.
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 #11)
NOTICE: Water piping exposed to extreme
low ambient temperatures is subject to
freezing.
Teflontape sealershould beusedwhenconnectingto
the unit to insure against leaks and possible heat
exchanger fouling.
Do not overtighten the connections. Flexible hoses
should be used between the unit and the rigid system
to avoid possible vibration

System Checkout | 15TW Series Water to Water
6720220047 (2016/02)Revised 02-16
Figure # 11
[1] Polybutylene or Polyethelene with insulation
[2] Ground loop pumping package (GLP)
[3] Ground loop connection kit.
[4] P/T Plugs
[5]Load side connection
[6]low voltage control connection
[7] Vibration Pad
[8] Line Voltage disconnect
SYSTEM CHECKOUT
After completing the installation, and before energizing
the unit, the following system checks should be made:
1. Verify that the supply voltage to the heat pump is in
accordance with the nameplate ratings.
2. Make sure that all electrical connections are tight
and secure.
3. Check the electrical fusing and wiring for the correct
size.
4. Verify that the low voltage wiring between the
thermostat and the unit is correct.
5. Verify that the water piping is complete and correct.
6. Check that the water flow is correct, and adjust if
necessary.
7. Verify that vibration isolation has been provided.
8. Unit is serviceable. Be certain that all access panels
are secured in place.
Considerations:
• 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.
• 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.
• We 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.
• Do not apply additional controlled devices to the
control circuit power supply without consulting the
factory. Doing so may void equipment warranties.
• Check with all code authorities on installation
criteria.
DANGER: Ensure cabinet and Electrical Box
are properly grounded.

16 | Unit Start-up TW Series Water to Water
TW Series Water to Water6720220047 (2016/02) Subject to change without prior notice
UNIT START-UP
1. Set the thermostat to the highest setting.
2. Set the thermostat system switch to “COOL”, . The
reversing valve solenoid should energize. The
compressor should not run.
3. Reduce the thermostat setting approximately 5
degrees below the room temperature.
4. Verify the heat pump is operating in the cooling
mode.
5. Turn the thermostat system switch to the “OFF”
position. The unit should stop running and the
reversing valve should de energize.
6. Leave the unit off for approximately (5) minutes to
allow for system equalization.
7. Turn the thermostat to the lowest setting.
8. Set the thermostat switch to “HEAT”.
9. Increase the thermostat setting approximately 5
degrees above the room temperature.
10. Verify the heat pump is operating in the heating
mode.
11. Set the thermostat to maintain the desired space
temperature.
12. Check for vibrations, leaks, etc.
MAINTENANCE
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.
INFORMATION ON DECOMMISSIONING
Only authorized technicians are allowed to
decommission and dispose of equipment following
applicable requirements and local codes.
WATER TO WATER UNIT CONTROLLER
Bosch water heat pump controller offers a low cost,
simple solution to the control of a water to water heat
pump unit. The control is configurable to provide cooling
only, heating only or auto change over control strategies
based on the application of the unit in a given system.
Features:
• Selectable mode of operation. Cooling, Heating or
Auto Changeover.
• Adjustable temperature differential for heating and
cooling set point.
• Adjustable auto changeover set point with
adjustable dead band setting.
• Intelligent auto reset of a fault condition avoids
nuisance hard lockouts.
• LED display of control temperature and set points.
• F° or C° Display.
• 50/60 Hertz operation.
• Pump operation configurable for continuous or
cycling operation with the compressor.
• Compressor lead-lag operation on units with dual
compressors.
• Malfunction output and service LED can be set to
steady or pulsing to indicate fault condition.
• Color LED’s indication of mode of operation.
• Set point retention in non volatile memory in the
event of a power failure.
• Five minute delay on break or power interruption for
compressor short cycling protection.
• Brown out low voltage protection.
UNIT SENSORS
The unit controller is provided with two sensors:
Water sensor:
This sensor will control unit operation in the cooling or
heating mode based on the water temperature on the
load side. It may be field mounted for example on the
return water line or in a water tank when provided with
a field supplied inversion well. The location will depend
on the specific requirements of the job.
Changeover Sensor
This sensor will put the unit in either the heating or
cooling mode depending on the set point. It maybe
mounted in a location that would be indicative if the unit
should be in either the heating or cooling mode, for
example outdoors.
The sensor may be located up to 1000 feet from the unit
(additional field supplied wiring required).
MODES OF OPERATION
The controller will memorize the last mode used before
power is removed and will run in that mode after is
turned on. In all modes the control will display
temperature degree differential setting for five seconds
once it is powered and this setting for five seconds once
it is powered and this settings may be adjusted during
this time. Thereafter the display will switch to the
monitored water temperature. When switching from one
mode to another the set point (the decimal point is used
to distinguish it from water temperature) for the new
mode is displayed for 5 seconds and the monitored
water temperature. During this time the set point may be
adjusted.
Off Mode
In the OFF MODE all outputs are disabled and mode
indication LED’s will be off.
WARNING: Decommissioning of this
equipment can be hazardous due to system
pressure and electrical components. Only
trained and qualified personnel should
install, repair, or service or decommission
the equipment.

Modes Of Operation | 17TW Series Water to Water
6720220047 (2016/02)Revised 02-16
The control will first display temperature differential
setting with the ability for the user to adjust it and then
will display “OFF” and finally water temperature.
Heating Mode
When the unit is operated in the heating mode and the
controlled water temperature is below the set point
minus the differential setting is below the set point
minus the differential setting, terminal Y1 will close and
the unit will operate (first stage compressor in a two
stage unit). When the set point is satisfied the
compressor is turned off.
In a two stage unit after the first activation if the water
temperature drops an additional two degrees below the
set point, the second stage (terminal Y2) will be
activated (if control is configured for both
compressors). Both stages will be on until the set point
is satisfied.
When the units runs after power is applied or the mode
is changed from cooling to heating, if the fluid
temperature is below set point and does not change for
3 minutes, the second stage of heating will be activated.
This only applies for a two stage machine.
There will be 5 minutes delay on a break after the unit
cycles off on temperature, a power interruption or
because of a fault condition.
at any point in time the control will ignore a low pressure
switch condition for 120 seconds before turning off the
compressor.
Cooling Mode
When the unit is operated in the cooling mode and the
leaving water temperature is above temperature set
point plus the differential setting, terminals Y1 will close
(first stage compressor of a two stage unit) and the unit
will operate in the cooling mode. When the set point is
satisfied the compressor is turned off. The reversing
valve is always activated when the unit is in the cooling
mode.
On two stage units, after first stage activation if water
temperature increases two degrees above the set point,
the second stage (terminal Y2) will be activated (if
control is configured for both compressors). Both stages
will remain on until the set point is satisfied.
when the unit runs after power is applied or the mode is
changed from heating to cooling, if fluid temperature is
above cooling point and does not change for 3 minutes,
the second stage of cooling will be activated. this only
applies for a two stage machine.
There will be 5 minute delay on break after the unit
cycles off on temperature, a power interruption or
because of a fault condition.
Auto Changeover Mode
The controller’s auto change over mode control feature
will switch from the heating mode to cooling mode and
vice versa based on the setting of the change over
sensor. There will be a dead-band where the control will
not call for either heat or cool. The dead -band setting is
adjustable in the configuration mode. When the auto
changeover mode is selected the changeover set point
will be displayed for 5 seconds, however this point is
only adjustable when the controller is in the
configuration mode. Once the controller has switched to
either heating or cooling mode, pressing the up or down
buttons will display the set point for that particular
mode.
When the reading from the changeover sensor is above
the change over set point plus the dead-band setting,
the unit will operate in the cooling mode and will
maintain the cooling set point temperature. While in the
cooling mode the user can adjust the cooling set point.
Likewise when the change over sensor is below the
changeover set point minus the dead-band setting, the
unit will switch to the heating mode and will maintain
the heating set point temperature. While in the heating
mode the user can adjust the heating set point.
Once the reading from the sensor enters the
dead-band zone it will terminate the call for cooling or
heating even if the set points are not satisfied.
Mode switching will be HEAT – COOL – OFF in a closed
loop. If the changeover sensor is shorted when the
control is in Auto changeover mode then the control will
switch to the OFF mode. If no sensor is connected the
controller will indicate a sensor error code.
Unit Protection
The unit controller will protect the unit against a
high or low pressure condition and brownout. To
avoid nuisance lockouts an intelligent reset
function is built into the controller to allow the unit
to restart one time in the event of a fault condition.
If a fault condition is initiated on any circuit the
corresponding compressor will be turned off and
the 5 minute delay on break time period timer is
initiated. After the delay expires the unit will attempt to
restart. If the fault condition still exists or reoccurs
within the next 60 minutes, the unit will go into a hard
lockout and requires a manual lockout reset. During this
period the fault LED will indicate the cause of the fault.
A 120 second time delay is built into the low pressure
switch to avoid nuisance trips with low fluid
temperatures.
While in a soft lockout condition the display will
show the specific fault (for example LP1) and the
“service” LED will turn on according to the malfunction
mode. If the setting for malfunction
mode is “steady,” the service LED will turn and
remain on. If the setting is “pulse,” the service LED
will blink according to the blink code as follows:

18 | Manual Lockout TW Series Water to Water
TW Series Water to Water6720220047 (2016/02) Subject to change without prior notice
Brownout Protection
The control will disable all outputs if the supply
voltage drops below 17 VAC. The outputs will be
enabled if the supply voltage rises and remains
above 17 VAC for the 5 minutes time delay. During
that time control will display “bro.”
MANUAL LOCKOUT
The unit or refrigeration circuit will go into a manual
lockout if the HPS or LPS opens (LPS open more than
120 seconds each time) twice within one hour. During
manual lockout the compressor(s) is turned off and
locked out and the display will show the fault (for
example LP1) and the “service” LED “malfunction”
output will either be steady or blink according to the
malfunction mode as described above.
If selection for compressor is “Du” (see configuration)
and one compressor has locked out, the control will
switch the call to the other compressor. If compressor
setting is “Si”, the control shall not switch the call to the
other compressor
Lead-Lag (only for TW122 units)
The Controller has the capability to lead-lag
compressors on a dual compressor unit.
The lead-lag between the compressors is active
only when both compressors are in use (and the
compressor setting is “Du”).
When the setting for lead-lag is other than 00,
compressor setting is “Du” and one compressor
has locked out; control will switch the call to the
other compressor and stop the timing for lead-lag.
The lead lag setting remains in the memory.
If control has called for the second stage three
times in a row, and compressor setting is “Du”;
regardless of the lead-lag setting control will switch the
call to the other compressor. The lead-lag timer is reset
and the lead-lag setting still applies.
Pump cycling
When ordered with the optional pump relay the
controller will cycle either the load, source or both
pumps with the compressor operation. Please see
the typical wiring diagram for details.
OPERATING INSTRUCTIONS
Please refer to figure # 12
Figure # 12
User Interface
The following parameters are displayed on the
screen:
• Control fluid temperature when in normal mode
• Settings within the configuration mode
• Individual operating mode temperature set points
• Fault display
UP Button:
• Press once to display the current set point
temperature.
• After current set point temperature is displayed,
pressing again will increment the set point 1
degree for every push. Pressing and holding the
up button will increment the set point at a rate of
4 degrees per second.
• When pressed with the down arrow for
5-seconds, the control will display the current
temperature scale (Fahrenheit or Celsius).
• Used to change the settings for: temperature
scale, dead band, test mode, initial delay,
compressor, pump, and malfunction settings.
DOWN Button:
• Press once to display the current set point
temperature.
• After current set point temperature is displayed,
Blink Code Fault Condition
ONE BLINK High pressure circuit 1
TWO BLINKS Low pressure circuit 1
THREE BLINKS high pressure circuit 2
FOUR BLINKS Low pressure circuit 2
To reset a unit after a hard lockout the user needs to
recycle power or switch the controller to the OFF
mode.

User Adjustable Settings Chart | 19TW Series Water to Water
6720220047 (2016/02)Revised 02-16
pressing again will decrement the set point 1
degree for every push. Pressing and holding the
down button will decrement the set point at a
rate of 4 degrees per second.
• When pressed with the up arrow for 5- seconds,
the control will display the current temperature
scale (Fahrenheit or Celsius).
• Used to change the settings for: temperature
scale, dead band, test mode, initial delay,
compressor, pump, and malfunction settings.
LED Indicators
USER ADJUSTABLE SETTINGS CHART
SETTING UP THE CONTROLLER
On unit power up the LED display will show the
software version, temperature differential setting
with the ability for the user to change it for ten
seconds then will display “OFF” and then finally
will display the control temperature of the fluid
being measured (entering fluid, leaving fluid, tank,
etc.) The default setting of the differential is 1°F
and can be adjusted from 1 – 10° F at start up.
The differential setting is the differential between
set point temperature and actual on\off
temperature of the machine.
For example:
Cooling set point = 45˚F
Differential = 1˚F
The heat pump will cycle on in cooling at 46˚F. If a
two stage machine, stage 2 will come on at 48˚F or
2˚F degrees above set point and one degree
differential. The unit will shut off at set point.
Heating set point = 120˚F
Differential = 1˚F
Stage one will come on at 119˚F and stage 2 will
come at 117˚F. Both stages will remain running
until set point is achieved. Stage 1 and stage 2 will
cycle on and off according to the lead\lag
programmed interval.
Whenever there is a demand for heating and cooling and
during the first stage of operation the
temperature isn’t changing, then the control will
activate the second stage after a three minute delay from
the first stage activation. This logic will apply when the
control is powered up, on a power
interruption, when the mode function is set to OFF
and then back to either HEAT or COOL and when
switching from heating to cooling or vice versa in
the auto changeover mode.
Heating and cooling set points are adjusted by
selecting each mode on the key pad and then using
the up-down arrows to select the set point. Thus,
push cool mode button and use down arrow to 45˚F.
Push heat mode button and use up arrow to 120˚F.
The controller can be set to control heating only,
Mode Indication
HEAT Red LED to indicate that the control is
in the HEATING mode
COOL Green LED to indicate that the control
is in the COOLING mode
AUTO Yellow LED to indicate that the control
is in AUTO mode
COM Red LED to indicate that pump(s) are
selected for continuous operation
CYC Red LED to indicate that pump(s) are
selected for cycling operation
SERVICE Red LED will turn steady on or blink to
indicate that a pressure switch has
opened
Settings Range Default
TEMP SETTING 40-120°F Heating
and Cooling
DIFFERENTIAL 1-10°F 1°F
MODE Heat, Cool, Auto,
Off Off
TEMP SCALE F°, C ° F
PUMP MODE Con (continuous),
Cyc (cycle) Von
DEAD BAND 1-6 ° F 3° F
AUTO CHANGE
OVER 55-85 ° F 65 ° F
TEST MODE De (delay), or
Nd (No delay) De
COMPRESSOR Si (Single),
Du (Dual) Si
LEAD LAG 0-14 Days 0
MALFUNCTION St (Steady),
Pu (Pulsing) St
Settings Range Default

20 | Initial Configuration TW Series Water to Water
TW Series Water to Water6720220047 (2016/02) Subject to change without prior notice
cooling only, or auto change modes. The mode
button is pushed until the circular LED is lit next to
the chosen control mode.
INITIAL CONFIGURATION
After power up and the steps above are completed
the configuration default settings may be changed.
Holding down the up and down arrow buttons
simultaneously for 10 seconds will put the
controller into the configuration mode. This mode
will be exited if no other commands are given
within a 10 second period.
Please review all the following steps and enter the
values you want to set at each display field to avoid
a time out period while configuring. This will also
provide a record of the initial configuration settings.
First display field
Temperature scale OC or OF. This is selectable by
using the up or down arrows. Once selected hit
“mode” key to advance.
Scale: ______________________
Second display field
Pump operation: Continuous or cyclic. This is the
load or source or both pumps output relay. This
may be set to continuous pump or cyclic pump
mode to cycle with the compressor by using the up
or down arrows. Once selected hit “mode” key to
advance.
Mode:______________________
Third display field
Change over dead band setting: This is selectable
from 1 to 6 degrees. This is adjustable from 1-6
degrees by using the up or down arrows. The dead
band setting is only used in the auto change mode
and defines the band where the unit will not
operate. This helps eliminate the possibilities of the unit
cycling from one mode to the other too quickly.
For example, on a heating \cooling residential
application this could be set as wide as 6 degrees.
On a pool heater application this could be set as
tight as 1 degree. Once selected hit the “mode” key
to advance.
Value:______________________
Fourth display field
Auto change over set point (S2). Adjustable from 55 to
85 degrees. Use up or down arrows to adjust. Hit the
“mode” key to advance. The auto changeover sensor
should be located in an area that will be indicative of
whether the unit should be in the heating or cooling
mode.
Value:______________________
Fifth display field
Test mode setting, (DE) delay or (ND) no delay: This
is utilized for testing the outputs of the controller
by eliminating the time delays. Use the up or down
arrows to select. The controller will automatically
revert to DE after one cycle to insure safety timings
are restored if installer \commissioner forgets to
reset to DE. The ND setting could be selected at
start-up to avoid prolonged waiting periods during
commissioning.
Once selected hit the “mode” key to advance.
Setting:______________________
Sixth display field
Compressor setting, (Si) single or (Du) dual. Use
the up or down arrows to select. Hit the “mode” key
to advance. This is only applicable on multi stage
units. If set to Si on a dual circuit unit the second
stage will not come on. Must be set to “DU” for al
TW models.
Setting:______________________
Seventh display field
Lead \ lag setting (dual compressor only). Set point is 0
to 14 days on lead compressor rotation
sequence. Use up or down arrows to select. Hit
“mode” key to advance. Must be set to “0” for all
TW models.
Setting:______________________
Eighth display field
Malfunction output setting, (Pu) pulsed or (St)
standard constant on. This sets the malfunction
output relay to mimic the fault blink code that is
causing the safety lock-out. This can be used for
remote monitoring and remote trouble shooting.
Use the up or down arrows to select. Hit the
“mode” key to advance.
Setting:______________________
The controller is now configured and is fully
operational.
A copy of this configuration sheet should be
left with the home owner or building manager
for their records of initial control settings.