4.6. Relay Board
Subject
Description
Function of Part
Commissioning the resistors by making the last stage switching and
meeting the heating request.
Impact in Case of Malfunction
1- The device does not heat or heats below its capacity.
2- If it is stuck in the transmission, it can heat even though there is no
heating request, and if there is no water circulation, it may cause an
overheating error.
3- If there is a short-circuit between the relay coils, it will draw excessive
current and damage the mainboard.
Main Associated Error Codes
E03
Diagnostics and Test Method
Coil resistance measurement, resistance measurement between contacts
while they are on and off.
Maintenance Requirement
There is no special maintenance requirement.
Test definition
Test Method
Resistance measurement
between coils.
Resistance between the coil terminals of the relay board is measured.
When measuring between terminal no. 4 and other terminals, the short-
circuit value should not be read. If the short-circuit value is read, there will
be a risk of damaging the relay board to the mainboard. In such a case, the
relay board must be replaced absolutely. Before the relay board
replacement, the test specified in "Voltage measurement over the cable"
should be applied in order to investigate the root cause and it should be
determined that the problem is not caused by the cable. If the problem is
caused by the cable, the cable should also be replaced.
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