30
6. Repeat the above step with the lower terminal block (inlet thermistor).
7. If either of these readings is not consistent with the chart (within ±10,000Ω), replace
that thermistor.
8. If all ohms readings are acceptable, proceed to Check the Flow Meter
.
Check the Flow Meter:
1. Set the unit to diagnostic mode by pressing and releasing the UP and DOWN buttons
simultaneously.
2. Turn on a hot water tap at a fixture that will ensure a good flow rate through the unit.
3. If the flow rate on the display reads ‘F00.0’ then continue with the next step.
Otherwise, proceed to Check the Temperature Controller
.
4. Verify that the wiring from the flow switch is connected to the control board in the
order WHITE/GREEN/BROWN from left to right.
5. With no flow on the unit, using the multi-meter probes with the setting at Volts –
Direct Current, place one probe on the terminal block where the WHITE wire is
connected (F1) and the other probe where the BROWN wire is connected (F3). A
voltage reading in the appropriate range (5V) should be indicated.
6. If the voltage reading is not in the appropriate range (5V), replace the temperature
controller.
7. Turn on a hot water tap at a fixture that will ensure a good flow rate through the unit
and using the multi-meter probes with the setting at Volts – Direct Current, place one
probe on the terminal block where the WHITE wire is connected (F1) and the other
probe where the GREEN wire is connected (F2). A voltage reading in the appropriate
range (2.5V) should be indicated.
8. If the voltage reading is not in the appropriate range (2.5V), replace the flow meter.
9. If all voltage readings are acceptable, proceed to Check the Temperature Controller
.
Check the Temperature Controller:
1. At the top of the temperature controller there are 4 sets of terminal blocks. Verify the
wiring is correct as indicated in the wiring diagram specific to the model.
2. Check the voltage between the terminal block where the RED wire is connected (this
will be the leftmost terminal) and the metal heater chamber cover. A voltage reading
in the appropriate range (120V) should be indicated.
3. If no voltage is present, verify that the RED wire in the terminal block is properly
tightened and verify that the opposite end of the RED wire is properly connected to
the power distribution block, magnetic contactor, or transformer, as applicable.
4. Check the voltage between the terminal block where the BLACK wire is connected at
the second terminal from the left and the metal heating chamber cover. A voltage
reading in the appropriate range (120V) should be indicated. Repeat this step for each
of the BLACK wires.
5. If no voltage is present, verify that the BLACK wire in the terminal block is properly
tightened and verify that the opposite end of the BLACK wire is properly connected
to the power distribution block, magnetic contactor, or transformer, as applicable.
6. If voltage is present where both the RED and BLACK wires connect to the terminals
and there is no display, replace the temperature controller.
7. Check the voltage between each additional BLACK wire from left to right and the
metal heating chamber cover. A voltage reading in the appropriate range (one half of
the incoming power voltage, i.e. if the incoming power is 480V, then the reading
should be 240V) should be indicated.
8. If no voltage is present, verify that the BLACK wires in the terminal block are
properly tightened and verify that the opposite ends of the BLACK wires are properly
jumpered to the previous BLACK wire connection terminal or properly connected the
magnetic contactor, as applicable.
9. Turn on a hot water tap at a fixture that will ensure a good flow rate through the unit
and set the temperature at the highest setting so the unit calls for full power.
To Next Page
Loading...
