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device is functioning correctly.
8. Replacing the varistors
The GTW1500 HF is a complex high-technology device. As a result, the possibilities for
fixing faults on site are limited to just a few items. Please don't try to carry out repairs other
than those described here. Use the ProVista’s service and repair service instead.
If the red LED on the status display glows continuously during operation, you should
first of all make sure that there is no earth fault in the PV generator
1. Disconnect the GTW1500 HF from the low voltage grid (switch the line circuit breaker to
its "off" position or pull out the AC plug). Make sure the grid cannot be
inadvertently reconnected.
2.
Disconnect the DC plug connectors for all
3.
strings. Make sure you note the order of the
individual inverter inputs so you can put them back
in the right place later!
4.
Taking one DC plug connector at a time,
measure
the voltages between one DC plug connector of a
string and earth potential. Pay attention to the safety
warnings!
Warning
！
Dangerous high voltages may be present. Danger of death!
5. the measured voltages are constant and if their total is roughly the same as the open circuit
voltage of the string then there is a earth fault in this string. Its approximate location can be
deduced from the relationships between the voltages
6. Repeat points 3 and 4 for each string
If you found a earth fault, it is probably not necessary to replace the varistors. Instead, make
sure the ground fault is fixed. Generally the PV generator's installation engineer should
be hired for this job. In this case continue as described under point 10, but
without reconnecting the faulty string. Protect its DC plug against accidental touch contact
(e.g. by fitting the protective caps or using sufficient high-voltage insulating tape).
If you did not find any earth fault in the PV generators, it is likely that one of the thermally
monitored varistors has lost its protective function. These components are wearing parts.