Bosch Tronic 5000C Reference manual

Technical Service Bulletin:
Polypropylene Heating Canister Replacement
Models: Bosch Tronic 5000C/6000C (WH27 Model Only) Electric Tankless Water Heater
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Please read this entire document prior to proceeding with any work.
WARNING:
This bulletin is intended to provide technical guidance
to a professional who is qualified to work on 240V
electrical equipment. If you are not qualified to work on
such equipment, please obtain the services of such a
professional.
DANGER: HAZARDOUS VOLTAGE
The electrical supply to the water heater MUST be shutoff
and isolated prior to commencing work!
NOTICE: PROPERTY DAMAGE
The water supply to the water heater must be shut off and
residual water drained prior to commencing work.
These directions assume that the product is installed in a location that
provides the installer with sufficient access to work. If that is not the case,
it may be necessary to uninstall the water heater completely prior to
commencing work.
Part Numbers
Description Part Number
Left Heating Canister Assembly 7738007199
Right Heating Canister Assembly 7738007198
Table 1
Replacing The Right-Hand Polypropylene Canister
1. Remove the two Phillips screws that secure the brass outlet water connector
to the water heater’s chassis (Fig.1).
Figure 1
2. Unscrew and remove the brass outlet water connector from the left black
polypropylene canister’s outlet pipe (Fig.2).
Figure 2
3. Remove the two Phillips screws and washers that secure the brass inlet water
connector to the water heater’s chassis (Fig.3).

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Technical Service Bulletin
2 | Tronic 5000C/6000C Polypropylene Heating Canister Replacement
Figure 3
4. Firmly hold the clear flow transducer in place, and separate the brass water
inlet connector from it by gently pulling it down through the water heater’s
chassis (Fig.4). Be aware that an o-ring that is located at the bottom of
the flow transducer will be creating some friction with the brass inlet
connection.
Figure 4
5. Remove the slotted brass screw and washer to disconnect the red wire from
the left tab of the thermal cutout switch that is mounted on top of the right
brass heating element assembly (Fig. 5).
Figure 5
6. Remove the two screws and washers that secure the thermal cutout switch
to the right brass heating element assembly (Fig.6).
Figure 6
7. Disconnect the short gray wire from the single TRIAC circuit board that is
mounted to the top of the right brass heating element assembly (Fig.7).
Figure 7
8. Disconnect the short pink wire and the short black wire from the dual TRIAC
circuit board that is mounted to the top of the right brass heating element
assembly (Fig.8).

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Technical Service Bulletin Tronic 5000C/6000C Polypropylene Heating Canister Replacement | 3
Figure 8
9. Remove the three screws and washers that secure the TRIAC circuit boards
to the top of the right brass heating element assembly (Fig.9).
Figure 9
10. Remove the TRIAC circuit boards and bracket from the top of the right brass
heating element assembly
Figure 10
11. Unplug the two circled wire connectors from the main circuit board that is
located in the lower-right corner of the water heater (Fig.11).
Figure 11
12. Remove the clear flow transducer by pulling it down from the polypropylene
canister pipe, and remove the black temperature probe by removing two
screws and pulling the component out of the black pipe (Fig.12).
Figure 12
13. The black polypropylene canisters are secured to the chassis by five M4
flange nuts (example shown in Fig.13). Remove all five nuts from the
threaded studs.
Figure 13

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Technical Service Bulletin
4 | Tronic 5000C/6000C Polypropylene Heating Canister Replacement
14. Separate the two black canisters from each other by rotating at the joint to
disengage the connection, and then pulling them apart (Fig.14).
Figure 14
15. Ensure that the o-ring is in place on the new right canister’s connector pipe
(Fig.15) and lubricate it with a small amount of silicone grease.
Figure 15
16. Connect the new right canister to the existing left canister and rotate to lock
into place (Fig.16).
Figure 16
17. Using the five M4 flange nuts that were removed in Step 13, secure the
black polypropylene canisters back to the chassis’ threaded studs (Fig.17).
Figure 17
18. Insert the flow transducer into the inlet connection pipe on the new
right black polypropylene canister, taking care to ensure that the flow
transducer’s arrow is pointing UP in the direction of water flow, and reinstall
the black temperature sensor using the two screws removed in Step 12 to
secure in place (Fig.18).
Figure 18
19. Plug the two wire connectors back into the main circuit board (Fig.19).

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Technical Service Bulletin Tronic 5000C/6000C Polypropylene Heating Canister Replacement | 5
Figure 19
20. Heat sink paste was supplied with the new black polypropylene canister,
apply it to the brass element assembly cap at the three locations outlined
below (Fig.20).
Figure 20
21. Place the triac circuit board back on top of the brass element assembly,
ensuring that the correct wires pass through the correct slots (Fig.21).
Figure 21
22. Secure the TRIAC circuit boards to the brass element assembly (Fig. 22)
using the three screws and washers that were removed in Step 9.
Figure 22
23. Reconnect the short pink wire and the short black wire to the dual TRIAC
circuit board (Fig.23).
Figure 23
24. Reconnect the short gray wire to the single TRIAC circuit board (Fig.24).
Figure 24

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Technical Service Bulletin
6 | Tronic 5000C/6000C Polypropylene Heating Canister Replacement
25. Use the two screws and washers that were removed in Step 6 to secure
the thermal cut out switch back on top of the right brass heating element
assembly, ensuring that ground wire is reconnected correctly (Fig.25).
Figure 25
26. Using the slotted brass screw and washer that was removed in Step 5,
reconnect the red wires to the left wiring tabs on the thermal cut out switch
(Fig.26).
Figure 26
27. Insert the brass outlet water connection fitting up through the chassis and
screw it into the left black polypropylene pipe. Insert the brass inlet water
connection fitting up through the chassis, apply some plumbers grease to
the o-ring that is located at the bottom of the flow transducer, and gently
push the brass connector up to fully connect it to the flow transducer (Fig.
27).
Figure 27
28. Use the two Phillips screws and washers that were removed in Step 3 to
secure the brass inlet water connection to the chassis (Fig.28).
Figure 28
29. Use the two Phillips screws and washers that were removed in Step 1 to
secure the brass outlet water connection to the chassis (Fig.29).
Figure 29
30. Reconnect the plumbing piping to the brass inlet and outlet water
connections, turn on the water supply, and check for leaks. If any are found,
shut the water supply off and correct the leak before turning on the power
supplies and putting the water heater back into operation.
31. Run the hot water for a few minutes to ensure correct operation.

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Technical Service Bulletin Tronic 5000C/6000C Polypropylene Heating Canister Replacement | 7
Replacing The Left-Hand Polypropylene Canister
1. Remove the two Phillips screws that secure the brass outlet water connector
to the water heater’s chassis (Fig.30).
Figure 30
2. Unscrew and remove the brass outlet water connection from the left black
polypropylene canister connection (Fig.31).
Figure 31
3. Remove the two Phillips screws and washers that secure the brass inlet
water connector to the water heater’s chassis (Fig.32).
Figure 32
4. Separate the brass inlet water connection from the clear flow transducer by
gently pulling it down through the water heater’s chassis (Fig.33). Be aware
that an o-ring that is located at the bottom of the flow transducer will be
creating some friction with the brass inlet connection.
Figure 33
5. Remove the slotted screw and washer to disconnect the red wires from the
left tabs of the thermal cutout switch that is mounted on top of the left brass
heating element assembly (Fig. 34).
Figure 34
6. Remove the two screws and washers that secure the thermal cutout switch
to the left brass heating element assembly (Fig.35).
Figure 35

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Technical Service Bulletin
8 | Tronic 5000C/6000C Polypropylene Heating Canister Replacement
7. Disconnect the short gray wire from the single TRIAC circuit board that is
mounted to the top of the left brass heating element assembly (Fig.36).
Figure 36
8. Disconnect the short pink wire and the short blue wire from the dual TRIAC
circuit board that is mounted to the top of the left brass heating element
assembly (Fig.37).
Figure 37
9. Remove the three screws and washers that secure the two TRIAC circuit
boards to the top of the left brass heating element assembly (Fig.38).
Figure 38
10. Remove the TRIAC circuit boards and bracket from the top of the left brass
heating element assembly (Fig.39).
Figure 39
11. The black polypropylene canisters are secured to the chassis by five M4
flange nuts (example shown in Fig.40). Remove all five nuts from the
threaded studs.
Figure 40

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Technical Service Bulletin Tronic 5000C/6000C Polypropylene Heating Canister Replacement | 9
12. Separate the two black canisters from each other by rotating at the joint to
disengage the connection, and then pulling them apart (Fig.41).
Figure 41
13. Ensure that the o-ring is in place on the existing right canister’s connector
pipe (Fig.42) and lubricate it with a small amount of silicone grease.
Figure 42
14. Connect the new left canister to the existing right canister and rotate to lock
into place (Fig.43).
Figure 43
15. Using the five M4 flange nuts that were removed in Step 11, secure the
black polypropylene canisters back to the chassis’ threaded studs (Fig.44).
Figure 44
16. Heat sink paste was supplied with the new black polypropylene canister,
apply it to the brass element assembly cap at the three locations outlined
below (Fig.45).
Figure 45

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Technical Service Bulletin
10 | Tronic 5000C/6000C Polypropylene Heating Canister Replacement
17. Place the TRIAC circuit boards back on top of the brass element assembly,
ensuring that the correct wires pass through the correct slots (Fig.46).
Figure 46
18. Secure the TRIAC circuit boards to the brass element assembly (Fig. 47)
using the three screws and washers that were removed in Step 9.
Figure 47
19. Reconnect the short pink wire and the short blue wire back to the dual TRIAC
circuit board (Fig. 48).
Figure 48
20. R econnect the short gray wire back to the single TRIAC circuit board (Fig. 49).
Figure 49
21. Use the two screws and washers that were removed in Step 6 to secure
the thermal cut out switch back on top of the right brass heating element
assembly, ensuring that ground wire is reconnected correctly (Fig.50).
Figure 50