Heat Controller VMH12SC-1 Main Protection, VMH Series, Temperature protection of compressor top

Service Manual VMH Series Heat Controller, Inc.

8.3 Main Protection

8.3.1 Three Minute Time Delay at restart for compressor.

1 minute delay for 1st time start-up and 3 minute delay for others.

8.3.2 Temperature protection of compressor top.

Protector cuts off compressor for 30 seconds and restarts after 3 minute delay.

8.3.3 Temperature protection of compressor discharge.

When the compressor discharge temperature increases, the compressor frequency will be limited as indicated below:

•Compressor discharge temp. T5>239°F/115°C for 5 seconds, compressor stops.

•If T5<239°F/115°C, decreases compressor frequency to the lower level every 3 minutes.

•T5>194°F/90°C, cancels the frequency limit control and restarts the compressor.

8.3.4 Fan Speed is out of control.

When indoor fan speed is lower than 300 RPM for 50 second, the whole unit stops and LED displays error code E3, and the unit will not resume operation automatically.

8.3.5 Inverter module Protection.

Inverter module protection has a protection function against current, voltage and temperature. If any of these conditions occur, the corresponding code will display on indoor unit LED and A/C will stop. Once the code is cleared unit will restart after the 3 min delay.

8.3.6 Indoor fan delayed open function

When the system starts up, the louver will be active immediately and the indoor fan will open 10 seconds later.

If the system is in heating mode, the anti-cold wind function has priority.

8.3.7Compressor preheating functions. Preheat conditions:

•If the main relay closes, T4＜37°F/3°C and the unit is powered on, or T4＜37°F/3°C and compressor has stopped over 3 hours, the compressor heating cable will operate.

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