Bosch TRONIC 6000C WH17 Technical Document

[en] Installation Manual and Operating Instructions
Tankless electric whole house water heaters
TRONIC 6000C
Models: WH17 / WH27
6 720 646 951 (2015/04) US

6 720 646 951 (2015/04) Tronic 6000C
2 | Table of contents
Table of contents
1 Explanation of symbols and safety instructions . . . . 2
1.1 Key to symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2 IMPORTANT SAFETY INSTRUCTIONS . . . . . . . . . . 3
2 General information . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1 Disclaimer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1.1Approval number . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.2 Technical identification code . . . . . . . . . . . . . . . . . 4
2.3 Model name and number identification . . . . . . . . . 4
2.4 Package contents . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.5 Components Diagram . . . . . . . . . . . . . . . . . . . . . . . 5
2.6 Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.7 Wiring diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.8 Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.9 Technical specifications . . . . . . . . . . . . . . . . . . . . . 9
3 Regulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.1 Important information . . . . . . . . . . . . . . . . . . . . . . 10
4.2 Selection of place of installation . . . . . . . . . . . . . 10
4.2.1Freeze prevention . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.2.2Recommended minimum
clearances for servicing . . . . . . . . . . . . . . . . . . . . 11
4.3 Mounting the water heater . . . . . . . . . . . . . . . . . . 11
4.4 Water connections . . . . . . . . . . . . . . . . . . . . . . . . 11
4.4.1Water quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.5 Electrical connections . . . . . . . . . . . . . . . . . . . . . . 12
4.6 Starting up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
4.6.1Checking for leaks and purging air . . . . . . . . . . . . 15
4.6.2Adjusting the temperature dial . . . . . . . . . . . . . . . 15
4.6.3Adjusting the flow . . . . . . . . . . . . . . . . . . . . . . . . . 15
5 Operation instructions . . . . . . . . . . . . . . . . . . . . . . . . . 16
5.1 Before using the water heater . . . . . . . . . . . . . . . 16
6 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
7 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
8 Spare Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
1 Explanation of symbols and safety
instructions
1.1 Key to symbols
Warnings
The following keywords are defined and can be used in this
document:
•DANGER indicates a hazardous situation which, if not
avoided, will result in death or serious injury.
•WARNING indicates a hazardous situation which, if not
avoided, could result in death or serious injury.
•CAUTION indicates a hazardous situation which, if not
avoided, could result in minor to moderate injury.
•NOTICE is used to address practices not related to
personal injury.
Important information
Additional symbols
Warnings in this document are identified by
a warning triangle printed against a grey
background.
Keywords at the start of a 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 people or property.
Symbol Explanation
▶ Step in an action sequence
Cross-reference to another part of the
document
• List entry
– List entry (second level)
Table 1

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Explanation of symbols and safety instructions | 3
1.2 IMPORTANT SAFETY INSTRUCTIONS
When using this electrical equipment, basic safety precautions
should always be followed, including the following:
▶READ AND FOLLOW ALL INSTRUCTIONS.
▶ This appliance must be grounded.
▶ Disconnect this product from the electrical supply before
cleaning, servicing or removing the cover.
▶ To reduce the risk of injury, close supervision is necessary
when the product is used near children or elderly persons.
▶ Warning: Mount the unit onto a flat section of wall, well
away from any potential splashes of water or spray and
away from areas where direct moist or wet contact could
occur.
▶ Warning: Indoor installation only, where it will NOT be
exposed to freezing.
▶ Warning: Do not install a check valve or any other type of
back flow preventer within ten feet of the cold water inlet.
▶ The electrical installation must conform to current National
Electrical Codes.
▶ Warning: Do not switch the heater on if you suspect that it
may be frozen. Wait until you are sure that it has completely
thawed out.
▶ The Tronic 6000C is designed to heat potable cold water
for domestic purposes. The heater is not designed to
accept inlet water temperatures above 86° F. The water
heater is not designed for preheated water or recirculation
applications. Contact Bosch Thermotechnology Corp.
before specifying or installing the appliance in any other
application.
IMPORTANT SAFETY INSTRUCTIONS
▶ ADDITIONAL CANADIAN SAFETY INSTRUCTIONS:
– AspertheCanadianElectricalCode,C22.1-02Section
26-744, an auxiliary terminal block must be fitted to
the unit before connecting to the electrical supply (Kit
Part N° “AE Canada Kit”).
(See Fig. 9 and Fig. 10).
– A green terminal (or a wire connector marked “G,”
“GR,” “GROUND” or “GROUNDING”) is provided within
the control. To reduce the risk of electrical shock,
connect this terminal or connector to the grounding
terminal of the electrical service of supply panel with a
continuous copper wire in accordance with the
Canadian Electrical Code, Part I.
– This product shall be protected by a Class A ground
fault circuit interrupter.
SAVE THESE INSTRUCTIONS
▶ Keep this manual in a safe place once the unit has been
installed as it may be needed for future reference.
Safety of electrical appliances for domestic use and similar
purposes
Product installation and use must be in accordance with EN
60335-1 in order to prevent hazards from occurring when
using electrical appliances.

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4 | General information
2 General information
2.1 Disclaimer
2.1.1 Approval number
Commonwealth of Massachusetts
In the Commonwealth of Massachusetts a licensed plumber
and electrician must perform the installation.
2.2 Technical identification code
[EI] Electronic Instantaneous
[17/27] Maximum output (kW)
[E/M] Electronic / mechanical temperature control
[W] Wall hung
[I] Indoor
[H] Horizontal installation
[B] Water connections
2.3 Model name and number identification
2.4 Package contents
• Tankless electric water heater.
• 4 screws.
• Installation Manual.
• Warranty Registration Card.
• Warranty Statement.
EI 17 E/M W IHB
EI 27 E/M W IHB
Table 2
Model Name Model Number
WH17 EI 17 E/M W I H B
WH27 EI 27 E/M W I H B
Table 3

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General information | 5
2.5 Components Diagram
Fig. 1
[A] Heating module
[B] Heating element assembly
[C] Heating module PCB
[D] Double pole thermal cut-off (WH27).
Single pole thermal cut-off (WH17).
[E] 6 way terminal block (WH27).
4 way terminal block (WH17).
[F] Temperature sensor
[G] Terminal block (CANADA ONLY)
[H] Flow transducer
[I] Control PCB
[J] Cold water inlet
[K] Hot water outlet
[L] Display PCB
[M] Display DIP switch

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2.6 Dimensions
Fig. 2
[1] Outlet ¾ " NPT (hot water)
[2] Inlet ¾ " NPT (cold water) Dimensions
(inches) WH17 / WH27
A (Width) 15 ¼ "
B (Height) 12 ½ "
C (Depth) 4 ½ "
D 12 5/8"
E 12 5/8"
F 2 ½ "
G 3 ½ "
H6
1/8"
I5
3/4"
J1
3/4"
Water connections ¾ "
Table 4 Dimensions

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General information | 7
2.7 Wiring diagram
Fig. 3 Internal wiring schematic for single phase WH17 unit.
DANGER: Risk of electric shock!
▶ Always switch off the electricity supply
to the unit before any intervention in the
heater.

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8 | General information
Fig. 4 Internal wiring schematic for single phase WH27 unit.
2.8 Function
How the water heater works:
• The Tronic 6000C heats water continuously as it flows
through the 2 heater modules.
• The electronic control PCB monitors the flow rate and the
incoming water temperature and then switches on the
required number of heater elements to reach the
temperature set by the temperature adjustment dial.
• The temperature dial sets the heater set-point
temperature. Please note heat loss, pipe run, and other
factors affect the outlet temperature at end use.
• As the flow rate or the incoming water temperature
changes, the electronic control adjusts the number of
heater elements used so that the outlet temperature is
maintained.
• The outlet water temperature can change slightly as the
flow rate changes due to the steps in power as different
heater elements are switched on and off.
• The outlet water temperature can also vary if the maximum
flow rate is exceeded (see Fig. 11) or if the supply
voltage changes.
• Each heater module is protected by an electro-mechanical
thermal cut-out. This cut-out will only trip in exceptional
circumstances.
Contact Technical Support 800-798-8161 for further
instruction.
• The WH17 unit is supplied from two independent voltage
supplies and the WH27 unit from three independent
voltage supplies. (In Canada the unit has just one voltage
supply).
• Depending on the region of the country, the temperature of
the water supply can vary between an average of 40 °F in
winter to 70 °F in summer, with an average of 55 °F. The
output temperature and maximum flow of the heater is
dependent on inlet water temperature.

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Regulations | 9
2.9 Technical specifications
3 Regulations
Any federal, state, and local codes and regulations pertaining
to installation and use of electric water heating appliances must
be observed. Please refer to the laws that should be attended
in your area.
• The electrical installation must conform to current National
Electrical Codes.
• As per the Canadian Electrical Code, C22.1-02 Section 26-
744, an auxiliary terminal block must be fitted to the unit
before connecting to the electrical supply (Kit Part N° “AE
Canada Kit”).
• A green terminal (or wire connection marked “G”, “GR”,
"GND", “GROUND” or “GROUNDING”) is provided within
the control box. Additional Canadian safety instructions, to
reduce the risk of electrical shock, connect this terminal or
connector to the grounding terminal of the electrical
service of supply panel with a continuous copper wire in
accordance with the Canadian Electrical Code, Part I.
• In Canada this product shall be protected by a Class A
ground fault circuit interrupter.
• In the Commonwealth of Massachusetts a licensed
plumber and electrician must perform the installation.
(Approval number: P1-09-25).
• In the Commonwealth of Massachusetts a pressure relief
valve shall be installed on the cold water side by a licensed
plumber. (MGL 142 Section 19, Approval number P1-09-
25).
• The unit must be wired by a qualified electrician, in
accordance with the current version of the National
Electrical Code (US) or Canadian Electric Code (Canada).
• When the heater is not within sight of the electrical circuit
breakers, a circuit breaker lockout or additional local
means of disconnection for all non-grounded conductors
must be provided that is within sight of the appliance. (Ref
NEC 422.31.).
• The power cable size and the installation must be in
accordance with the US National Electrical Code or the
Canadian Electrical Code, C22.1-02.
Technical characteristics Units WH17 WH27
Voltage supply V 2 X 240VAC (Canada 240VAC) 3 X 240VAC (Canada 240VAC)
Amperage A 2 X 40A (Canada 1 x 80A) 3 X 40A (Canada 1 x 120A)
Maximum output kW 17.25kW 26.85kW
Temperature control range 95 °F to 131 °F 95 °F to 131 °F
Minimum water pressure psi 15psi 15psi
Maximum water pressure psi 150psi 150psi
Minimum flow rate gal/min 0.6 US gal / min 0.6 US gal / min
Maximum flow rate (refer to Fig. 11) (refer to Fig. 11)
Weight (without water) lbs 20 lbs 22 lbs
The unit will work at lower supply voltages but the following changes will apply:
Maximum output 15kW at 220V 22.5kW at 220V
13kW at 208V 20kW at 208V
Maximum flow rate
(refer to Fig. 11)
84% of maximum at 220V 84% of maximum at 220V
75% of maximum at 208V 75% of maximum at 208V
Table 5

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4 Installation
4.1 Important information
Please follow these instructions. Failure to follow instructions
may result in:
• Damage or injury.
• Improper installation/operation.
• Loss of warranty.
4.2 Selection of place of installation
• If being used in a public place, locate the heater out of easy
reach to discourage vandalism.
• Mount the unit onto a flat section of wall, well away from
any potential splashes of water or spray and away from
areas where direct moist or wet contact could occur.
• Install the heater in a place that provides easy access for
any service or maintenance.
4.2.1 Freeze prevention
Introduction
Please note that the installation manual states that the water
heater must not be installed in a location where it may be
exposed to freezing temperatures. If the heater must be left in
a space that is likely to experience freezing temperatures, all
water must be drained from the heater.See Section 6.
Freeze damage is not covered under the warranty.
DANGER: Risk of electric shock!
▶ For safety reasons, disconnect the
power supply to the heater before any
service or testing is performed.
WARNING:
▶ This heater must be electrically
grounded in accordance with the most
recent edition of the National Electrical
Code. NFPA 70. In Canada, all electrical
wiring to the heater must be in
accordance with local codes and the
Canadian Electrical Code, CSA C22.1
Part 1.
DANGER:
▶ The installation must only be performed
byaqualifiedpersoninaccordancewith
these instructions.
▶ Bosch Thermotechnology Corp. is not
responsible for improperly installed
appliances.
WARNING:
▶ The heater must only be mounted in a
horizontal position with the water
fittings located at the bottom of the
heater. Under no circumstances should
the heater be mounted differently.
WARNING:
▶ The appliance should be located in an
area where leakage of the heater or
connections will not result in damage to
the area adjacent to the appliance or to
lower floors of the structure.
WARNING: Risk of freezing!
▶ Do not install the water heater in an area
where there is a chance of freezing.
Damage to the water heater as a result
of freezing will not be covered under
warranty.
DANGER:
▶ ELECTRICITY IS EXTREMELY
DANGEROUS. TAKE EXTRA
PRECAUTIONS AND ENSURE ALL
CIRCUIT BREAKERS ARE OFF BEFORE
PERFORMING ANY WORK TO THE
HEATER.
WARNING:
▶ Indoor installation only, where it will
NOT be exposed to freezing.
Use of chemical agents such as anti-freeze
are not allowed as they may cause damage to
the water heater’s internal components.

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4.2.2 Recommended minimum clearances for servicing
Should it be necessary to service the Tronic 6000C, observe
the following clearances. These are not required clearances,
but would facilitate any service work.
Fig. 5 Recommended minimum clearances
4.3 Mounting the water heater
▶ Undo the retaining screws on the front cover. Remove the
temperature knob by pulling up with slight force. Place
knob and white bushing aside, and take the cover off the
heater. Hold the back plate in position against the wall and
mark the four mounting holes.
▶ Drill the holes and secure the heater using the four wood
screws supplied.
Fig. 6 Vertical mounting position
4.4 Water connections
▶ The heater must be connected directly to the main cold
water supply and not to pre-heated water. (The inlet water
temperature must not be greater than 86 °F).
▶ The heater must be installed with shutoff valves on both the
inlet and outlet connections.
▶ It is recommended that you use ¾ inch or ½ inch copper.
▶ Do not use plastic piping within 3 feet on either side of
heater.
WH17 WH27
Top (A) 12" 12"
Sides 0" 0"
Bottom (B) 6" 6"
Front (C) 12" 12"
Table 6 Recommended minimum clearances
WARNING:
▶ The heater must only be installed in the
orientation shown in Fig. 6 i.e.,
mounted in a horizontal position with
the water fittings located at the bottom
of the heater. Under no circumstances
should the heater be mounted
differently.
WARNING:
▶ Do not install a non-return check valve
within 10 feet of the inlet.
WARNING:
▶ Do not apply heat or solder to
connections or pipe if they are already
connected to the unit.
NOTICE: Disclaimer
▶ In the Commonwealth of Massachusetts
a pressure relief valve shall be installed
on the cold water side by a licensed
plumber. (MGL 142 Section 19).

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12 | Installation
▶ Use Teflon tape for sealing pipe threads. Do NOT use pipe
dope.
▶ Remember to keep the hot water pipe runs as short as
possible.
▶ After flushing and filling the heater with water, (with power
off) disconnect the inlet connection and inspect the filter
screen for any debris that may have been flushed through
the system.
▶ Check the pressure of the main water supply. To operate
correctly, the heater needs the running pressures
mentioned in Tab. 5.
4.4.1 Water quality
Water quality can have an impact on appliance longevity and
may not be covered under the manufacturer's warranty.
▶ For water analysis data call your local water department, or
if on a well, have well water analyzed periodically.
If water quality exceeds one or more of the values specified
below, Bosch recommends consulting a local water
treatment professional for water softening/conditioning
options.
4.5 Electrical connections
US wiring
• The minimum recommended wire size is 8 AWG. (The
terminal block will accept cables up to 6 AWG size).
• The cable entry is via the 1¼ inch cable entry hole on the
bottom right hand edge of the back plate.
• Strip back the insulation on the power wires about ½ inch.
Connect the live wires to the terminals marked “L1” and
“L2.” There are two pairs of live wires in the WH17 and
three pairs of live wires in the WH27. (See Fig. 7 and
Fig. 8, page 13).
• Any insulation on the ground wires should be stripped back
about ¾ inch. The ground leads must be connected to the
pillar terminal marked “GR”. (See Fig. 7 and Fig. 8, page
13).
• Make sure the terminal block screws are tightened
securely. Loose connections can cause wires to heat up.
• Make sure that the ground wires are wrapped around its
terminalstudandinto the saddle washer. The nut should be
tightened securely.
• Attach the front cover, replace the white bushing with flat
end facing up, replace the knob in any orientation by
pushing down to secure and tighten the retaining screws.
After the heater has been plumbed, and
before you wire it, flush it with water to
remove any debris or loose particles. Heater
must be full of water and air purged before
power is turned on. Failure to do so may
result in damage to the product that is not
covered by warranty.
The inlet and outlet connections are clearly
marked on the heater. They each have a
¾ inch male NPT connector.
Description Max. Levels
pH pH 6.5 - 8.5
TDS (total Dissolved Solids) mg/l or ppm 500
Total hardness mg/l or ppm 100
(6 grains)
Aluminum mg/l or ppm 2.0
Chlorides mg/l or ppm 250
Copper mg/l or ppm 1.0
Iron mg/l or ppm 0.3
Manganese mg/l or ppm 0.05
Zinc mg/l or ppm 5.0
Table 7
WARNING:
▶ The unit must be wired by a qualified
electrician, in accordance with the
currentversionoftheNationalElectrical
Code US) or Canadian Electric Code
(Canada).
When the heater is not within sight of the
electrical circuit breakers, a circuit breaker
lockout or additional local means of
disconnection for all non-grounded
conductors must be provided that is within
sight of the appliance. (Ref NEC 422.31.).
As per the Canadian Electrical Code, C22.1-
02 Section 26-744, an auxiliary terminal
block must be fitted to the heater before
connecting to the electrical supply. This is
available as a kit from Bosch
Thermotechnology Corp. Part Number “AE
Canada Kit”. (Contact 800-798-8161).

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Installation | 13
The WH17 requires two independent 240V AC circuits protected by two separate and independent double pole breakers (as
shown) rated at 40A each.
Fig. 7 WH17 terminal block connection (U.S.A. only)
The WH27 requires three independent 240V AC circuits protected by three separate and independent double pole breakers (as
shown) rated at 40A each.
Fig. 8 WH27 terminal block connection (U.S.A. only)

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14 | Installation
Canada Wiring - auxiliary terminal block and connections
Fitting the auxiliary terminal block (see diagram below).
Fig. 9 For Canada only (Not for U.S.A.)
Fig. 10 For Canada only (Not for U.S.A.)
▶ Connect the red wires from the left hand terminal of the
new block to the L1 terminals in the unit. (There are two red
wires required in the WH17 and three in the WH27).
▶ Connect the blue wires from the right hand terminal of the
new block to the L2 terminals in the unit. (There are two
blue wires required in the WH17 and three in the WH27).
▶ Mount the auxiliary terminal block onto the provided
backplate using the mounting holes.
Connecting the supply cable - Canada only - not for the USA.
• The power cable size and the installation must be in
accordance with the Canadian Electrical Code, C22.1-02.
• The incoming hole diameter on auxiliary terminal block can
accept up to 1/0 AWG size cables.
• The cable entry is via the 1 ¼ inch cable entry hole on the
bottom right hand edge of the backplate.
• Strip back the insulation on the power wires about ½ inch.
Connect the ungrounded conductors to the terminals “L1”
and “L2” on the auxiliary terminal block.
• Any insulation on the ground wire should be stripped back
about ¾ inch. The ground lead must be connected to the
pillar terminal marked “GR.”
• Make sure the terminal block screws are tightened
securely. Loose connections can cause wires to heat up.
• Make sure that the ground wire is wrapped around its
terminalstudandinto the saddle washer. The nut should be
tightened securely.
• Attach the front cover, replace the white bushing with flat
end facing up, replace the knob in any orientation by
pushing down to secure and tighten the retaining screws.
The WH17 requires an 80A 240V AC
single phase supply protected by an 80A
double pole circuit breaker.
The WH27 requires a 120A 240V AC
single phase supply protected by a 120A
double pole circuit breaker.

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4.6 Starting up
4.6.1 Checking for leaks and purging air
▶ Verify all circuit breakers supplying power to the water
heater are turned off.
▶ Open all hot water taps supplied by the water heater and
inspect all water connections for leaks.
▶ With all hot water taps still open, inspect each tap to ensure
all air in the lines has been purged out.
▶ Close all hot water taps and proceed to the next section.
4.6.2 Adjusting the temperature dial
▶ The temperature dial sets the heater set-point
temperature. Please note heat loss, pipe run, and other
factors affect the outlet temperature at end use.
▶ The temperature adjustment is made using the dial on the
front cover of the unit. the adjustment is between
approximately 95 °F and 131 °F. Turning the dial clockwise
increases the temperature setting, as indicated by the
increasing temperature displayed on the unit.
4.6.3 Adjusting the flow
▶ Open fully both inlet and outlet shut-off valves at the
heater, then:
▶ Turn on fully the highest flowing hot water faucet (e.g.,
bathtub) served by the water heater.
▶ Adjust the inlet shut-off valve until the water flow rate from
the hot faucet corresponds to the value given in Fig. 11
below.
▶ For a licensed electrician, the unit has capability of
displaying the flow rate on the front cover display. To do
this, shut the circuit breakers off and remove the cover.
– Setthesmall dip-switches on the display printed circuit
board in fig. 12 to display flow in the units desired.
The display will show these measurements as shown in
table 8. Once the switch has been changed to display
flow rate, place the unit cover back on and turn on the
electrical breakers.
– Fully turn on the highest flowing hot water faucet (e.g.
bathtub) served by the water heater.
– Adjust the inlet shut-off valve until the water flow rate
displayed on the unit corresponds to the value given in
fig. 11 below, noting any derate due to supply voltage.
Derate for 208 and 220V is noted at the bottom of
Table 5.
– Shut off the hot water faucet and turn off all breakers.
– Remove front cover by undoing the retaining screws on
the front. Remove the temperature knob by pulling up
with slight force. Place knob and white bushing aside,
and take the cover off the heater. Then reset the circuit
board switches to display temperature, as shown in
fig. 12 below.
– Place front cover back on the unit. Reinstall white
bushing with flat end facing up. Attach knob in any
orientation and push down to secure. Tighten cover
retaining screws. Then and turn on the electrical
breakers. Utilize the front knob to set the setpoint
temperature of the unit.
Fig. 11

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16 | Operation instructions
For example, calculations for desired outlet temperature of
125F and supply voltage of 240VAC. Please look at Table 5
for derates of various supply voltages:
• For the WH17 unit, using the inlet valve, ensure the flow
rate does not exceed 1.7 gallons/minute.
• For the WH27 unit, using the inlet valve, ensure the flow
rate does not exceed 2.6 gallons/minute.
These figures are based on an inlet water temperature of 55 °F
and a supply voltage of 240 volts. If the inlet water temperature
is lower than 55 °F, or if the supply voltage is less than 240
volts, then the outlet temperature will be lower than what is
shown in Fig. 11. If a higher outlet water temperature is
desired, then reduce the flow rate and/or supply the unit with
240 volts. Please review Table 5 for derate percentage for
supply voltage of 208VAC and 220VAC.
Fig. 12 Display DIP Switch
[1] Metric units °C & liters per min
[2] Display Temp
[3] American units °F & GPM
[4] Display Flow
5 Operation instructions
5.1 Before using the water heater
▶ Check that the power is switched on at the circuit breaker
panel.
▶ Turn on the hot water faucet FULLY.
• If the unit has been used recently, run the water through for
a few seconds to let the temperature cool down. You may
initially get a short burst of very hot water that was in the
plumbing lines from previous use.
• If a second outlet connected to the unit is also turned on,
the hot water will be shared between the two.
Before leaving the site, the installer should
demonstrate the unit to the user and give
them this manual.
American units: 95 °F (Degrees,
Temperature)
1.5G (GPM flow
rate)
Metric units: 35 °C (Degrees,
Temperature)
5.7L (L/min flow
rate)
Table 8 Appliance Display of Units
The temperature output will be reduced if the
voltage is lower than 240 volts and you may
not achieve the desired output temperature.
WARNING:
▶ Do not use the unit if you think it may be
frozen, as this could result in serious
damage to the unit. Wait until you are
sure that it has completely thawed out
before you switch it on.
The hot water temperature can be changed
by adjusting the heater set-point
temperature dial on the front of the unit.
(The dial adjusts the temperature typically
between95°Fand 131°F, as displayed inthe
display screen. The factory sets the
temperature dial at the lowest position).

6 720 646 951 (2015/04)Tronic 6000C
Maintenance | 17
6 Maintenance
Draining the heater
Due to the shape of the heat exchangers and connecting pipe,
it is extremely difficult to get all of the water out of the heater.
Follow the procedure below to best minimize the chance of
freeze damage:
▶ Disconnect electric supply.
▶ Disconnect cold and hot water pipes from fittings on
bottom of heater. Allow water to drain out (have a catch
basin ready).
Remember, these suggestions are only made to help minimize
the potential for freeze damage and are not to be construed as
the guaranteed method for dealing with freeze possibilities.
Check inlet water filter screen once a year
▶ Check that the power is switched off at the circuit breaker
panel.
▶ Shut off the installer supplied cold water isolation valve to
the heater. If one is not installed, install before proceeding.
▶ Open nearest hot water tap to relieve pressure in the
plumbing lines.
▶ Position a bucket under the cold water inlet connection of
the heater to catch any water that may drain.
▶ Disconnect the cold water plumbing connection from the
inlet (bottom right of heater) to access filter screen.
▶ Remove filter, clean with water and inspect for damage. If
the filter is at all damaged, it should be replaced.
▶ Replace the filter into the inlet housing
▶ DO NOT leave the filter out.
▶ DO NOT remove the flow regulator (located behind the
filter).
▶ DO NOT clear the filter by back flushing.
▶ NEVER use an air line to blow out the heater (the flow
transducer will be permanently damaged).
▶ Before switching power back on, reconnect cold water
plumbing connection and open all hot water taps and
inspect each tap to ensure all air in the lines has been
purged out. With the air purged and taps still flowing, turn
on all circuit breakers supplying the water heater.
▶ Close all hot water taps and proceed for normal operation.
▶ The maximum flow rate may need to be set again. See
section 4.6.3 for details.

6 720 646 951 (2015/04) Tronic 6000C
18 | Maintenance
Using an ohm meter to check for premature element failure
Fig. 13 Heating elements
On WH17 model, there is no middle element
Meter probes Ohm Readings
Outer to Outer 10.5 ± 0.6 Ohms
Middle to Middle 11.7 ± 0.8 Ohms
Inner to Inner 15.1 ± 1 Ohms
Table 9
Meter probes Ohm Readings
Outer to Outer 10.5 ± 0.6 Ohms
Middle to Middle 11.7 ± 0.8 Ohms
Inner to Inner 21.0 ± 1.2 Ohms
Table 10

6 720 646 951 (2015/04)Tronic 6000C
Troubleshooting | 19
7 Troubleshooting
Important: If you are unable to perform the tasks listed below,
or need additional assistance please contact your original
installer/licensed electrician.
DANGER: Risk of electric shock!
▶ Always switch off the electricity supply
to the unit before you remove the cover.
Cold water only – Neon light off
Flow rate is too low Verify the flow rate out of fixture is at or above the minimum activation rate required for the
unit to activate. (Activation rates: WH17 = 0.6 GPM, WH27 = 0.6 GPM).
Plumbing crossover To test for a plumbing crossover, turn off power supply to the heater. Close installer supplied
cold water shut off valve (if none installed, install before proceeding). Open all hot water taps
supplied by the heater. Wait 5 minutes and check all taps. Any water running is a sign of a
plumbing crossover. Consult a local plumber or service person for help in correcting a
plumbing crossover. To return the heater to service, reinstall cover, open the inlet water
supply to the heater and open all hot water taps. Let all taps run until there is no air coming out
of the fixtures. Shut off all hot water taps. Turn power supply on to the heater. Return heater to
service. (This procedure will prevent the heating elements from burning out).
The flow transducer is not
spinning
Turn off the power supply to the heater and remove the cover. Observe if the flow transducer
"spins" when the water is turned on. Please note the flow transducer spins at a high speed and
can appear to be stopped when actually spinning. It is recommended to observe the flow
transducer without water flowing, then turn on a hot water tap while observing the flow
transducer. If the flow transducer is not spinning, remove and flush flow transducer, noting
the Do's and Dont's in section 6 Maintenance. See the technical support section of
www.bosch-climate.us for more detailed instruction on removing the flow transducer.
No electricity at the heater or one
of the supplies has failed
Have a licensed electrician verify proper wiring and adequate voltage on the terminal block
inside the water heater. See the “Electrical connections” section in section 4.5 Electrical
Connections, of this manual.
One or more of the heating
module thermal cut-outs has
tripped
Turn off the power to the heater, remove the cover and locate the thermal cutouts on the top of
each heating module. Check for continuity through each cutout. (Less than 0.5 Ohms). A
continuity value greater than 0.5 Ohms indicates that the cutout has tripped or is faulty. A
cutout will only trip in exceptional circumstances and it is essential that the cause is
determined and resolved. Verify the heater's inlet filter screen and all outlets served by the
heater are clear of debris. Ensure the heater is not being fed preheated water. This water
heater is designed for cold water feed only.
Contact Technical Support 800-798-8161 for further instructions.
The power supply voltage has
dropped
This is likely an issue with the incoming power supply. Have a qualified electrician measure
voltage on the water heater’s terminal block while operating at maximum flow and maximum
temperature setting. The WH17 & WH27 models are rated for 240V and will also operate at
220V or 208V with reduced maximum flow rate.
The inlet water temperature is
too cold
Verify the heater is sized appropriately for it’s geographic location. Turn temperature knob
located on the front of the water all the way clockwise for maximum temperature setting.
Ensure flow rates are within the heater’s specifications. Refer to Fig. 11 in section 4.6
Starting Up of the manual. Use of an isolation valve on the cold water inlet to control flow rate
is recommended.
One of the power supplies is not
on
Have a licensed electrician verify adequate voltage on the terminal block inside the water
heater. Verify circuit breakers serving the heater are not tripped. See the “Electrical
connections” section in section 4.5 Electrical Connections of this manual.
Table 11

6 720 646 951 (2015/04) Tronic 6000C
20 | Troubleshooting
Premature element failure Have a licensed electrician Shut off power to the unit and remove cover. Use an ohm meter to
verify correct resistance on each element in Section 6 Maintenance. If readings are
different than listed specifications on in Section 6 Maintenance, tables 11 and 12, contact
Technical Support 800-798-8161 for further instruction.
Water not hot enough - Neon light on
The water supply is connected to
the outlet of the unit
Verify plumbing connections are correct (See Fig. 2). Reconnect the water supply to the
inlet of the unit (marked blue).
One or more of the heating
module thermal cut-outs has
tripped
Turn off the power to the heater, remove the cover and locate the thermal cutouts on the top
of each heating module. Check for continuity through each cutout. (Less than 0.5 Ohms). A
continuity value greater than 0.5 Ohms indicates that the cutout has tripped or is faulty. A
cutout will only trip in exceptional circumstances and it is essential that the cause is
determined and resolved. Verify the heater's inlet filter screen and all outlets served by the
heater are clear of debris. Ensure the heater is not being fed preheated water. This water
heater is designed for cold water feed only.
Contact Technical Support 800-798-8161 for further instructions.
Temperature dial is turned too
low
Turn the temperature dial located on the front of the water heater clockwise for hotter
temperatures. Refer to Fig. 11 for outlet temperature vs. flow rate variance.
Water flow is too high Adjust water flow to stay within the water heater’s specifications. See Fig. 11 of this
manual.
Plumbing crossover To test for a plumbing crossover, turn off power supply to the heater. Close installer supplied
cold water shut off valve (if none installed, install before proceeding). Open all hot water taps
supplied by the heater. Wait 5 minutes and check all taps. Any water running is a sign of a
plumbing crossover. Consult a local plumber or service person for help in correcting a
plumbing crossover. To return the heater to service, reinstall cover, open the inlet water
supply to the heater and open all hot water taps. Let all taps run until there is no air coming out
of the fixtures. Shut off all hot water taps. Turn power supply on to the heater. Return heater
to service. (This procedure will prevent the heating elements from burning out).
Table 12
Water flow too low
There are restrictions in the
plumbing
Obstructions in the water path can restrict the flow of water through the heater. Verify the
heater’s inlet filter screen, faucet aerators, showerheads and whole house filters are clear of
debris. Verify proper flow on the inlet side of the heater with the hot water pipe disconnected.
Maximum flow rates for each unit are as follows. WH17 = 2.3gpm, WH27 = 3.5gpm.
Water supply pressure too low Verify incoming water supply is at least 15psi. For people on well systems, the recommended
pressure range is 30-50psi.
Inlet shut-off valves are set too
low
Adjust installer supplied inlet valve as described below:
• Completely open both installer supplied inlet and outlet shut-off valves at the heater. (if
none installed, install before proceeding).
• Completely open hot water on the highest flowing hot water fixture served by the heater
(i.e. bathtub).
• Slowly close the inlet shut-off valve, slowing the water flow rate until the temperature at
the hot water faucet corresponds to the values given on Fig. 11 of the manual, or
desired water temperature is reached.
Table 13
Cold water only – Neon light off
Table 11