Bosch WH36, Installation Manual And Operating Instructions

Page: 17 / 64

6 720 647 022 (2013/04) Tronic 5000C
Troubleshooting | 17
Cold water only – Neon light on
One or more of the
heating module thermal
cut-outs has tripped Shut off the power to the unit, remove the cover and locate thermal cutouts on the top of each
heating module. Try resetting each cutout by pushing the reset button located in the center of the
cutout. Determine and fix the cause of the overheating. Obstructions in the water path can restrict
the flow of water through the heater causing it to overheat. 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 a cold water feed only. If thermal cut out does not reset,
check for continuity through each cutout (Less than 0.5 Ohms). If any cutout reads more than 0.5
Ohms or open, then it may be defective and should be replaced.
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 WH36 models are rated for 240V and will also operate at 220V or 208V with reduced
output. The output will vary in accordance with the ratios, mentioned in table 9.
The inlet water
temperature is too cold Verify the heater is sized appropriately for it’s geographic location. Turn temperature knob located on
the bottom of the water all the way clockwise for maximum temperature setting. Ensure flow rates are
within the heater’s specifications. Refer to Fig. 8 on page 13 of the manual. Use of an isolation valve
on the hot water outlet 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 on
page 10 of this manual.
Premature element failure Shut off power to the unit and remove cover. Use an ohmmeter to verify correct resistance on each
element. If readings are different than listed specifications on page 15, contact Technical Support
800-798-8161 for further instruction.
Table 11
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 thermal cutouts on the top of each heating
module. Try resetting each cutout by pushing the reset button located in the center of the cutout.
Determine and fix the cause of the overheating. Obstructions in the water path can restrict the flow of
water through the heater causing it to overheat. 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 a cold water supply only. If thermal cut out does not reset, check for continuity
through each cutout (less than 0.5 Ohms). If any cutout reads more than 0.5 Ohms or open, then it may
be defective and should be replaced.
Temperature dial is
turned too low Turn the temperature dial located on the bottom of the water heater clockwise for hotter temperatures.
Refer to Fig. 8 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. 8 of this manual.
Table 12