Bosch TRONIC 6000C WH17 Installation Manual And Operating Instructions page 20

20 | Troubleshooting
Cold water only – Neon light off
Premature element failure
Table 11
Water not hot enough - Neon light on
The water supply is connected to
the outlet of the unit
One or more of the heating
module thermal cut-outs has
tripped
Temperature dial is turned too
low
Water flow is too high
Plumbing crossover
Table 12
Water flow too low
There are restrictions in the
plumbing
Water supply pressure too low
Inlet shut-off valves are set too
low
Table 13
6 720 646 951 (2015/04)
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.
Verify plumbing connections are correct (See Fig. 2). Reconnect the water supply to the
inlet of the unit (marked blue).
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.
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.
Adjust water flow to stay within the water heater's specifications. See Fig. 11 of this
manual.
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).
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.
Verify incoming water supply is at least 15psi. For people on well systems, the recommended
pressure range is 30-50psi.
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.
Tronic 6000C