Merco MHU63SST2N, Руководство по обслуживанию

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5-8
Troubleshooting Section 5
Heater/Thermocouple Troubleshooting
Thermocouple Reading is Below or Above Set Point -
Zone Error is displayed on screen
1. Document all temperature readings for unit, each zone,
upper and lower.
2. If the zone probes are switched, there will be two
errors, one high and one low.
3. Check the I/O boards where the probes with errors
plug in. Check that the probes alternate (yellow brown
yellow brown) and are plugged in properly.
4. Heater outputs could be swapped, there will be two
errors.
5. The I/O board triac could be shorted or open. An
orange LED is associated with each triac, it signals if the
triac should be on or off.
6. Isolate each triac wire and check the amperage.
• If the triac is supposed to be open and there is
no current, the problem could be a heater. Check
continuity through heating element.
• If the triac light does not match the amperage,
the triac is failing and the I/O board needs to be
replaced.
• Check input and output of triac, this could signal an
I/O board failure.
The heater thermocouple (brown wire) is under the same
tape as the heater. Failed thermocouples require a heater
replacement.
Check ohm resistance on heater pad. The ohms and part
number are below.
o 8076230 - 6x3 144.5 Ω (137 Ω – 152 Ω)