Lennox MPC User Manual

93
23. Specications and Operations
Table 2. Electronic Functions Abbreviations
T1 Indoor ambient temperature
T2 Coil temperature of indoor heat exchanger
T2B Coil temperature of indoor heat exchanger outlet. (Located in outdoor unit)
T3 Pipe temperature of outdoor heat exchanger
T4 Outdoor ambient temperature
T5 Compressor discharge temperature
Table 3. Electronic Control Working Environment
Input voltage: 230V
Input power frequency: 60Hz
Indoor fan normal working amp. is less than 1A
Outdoor fan normal working amp is less than 1.5A
Four-way valve normal working amp is less than 1A
Table 4. Main Protection
Three minutes delay at restart for compressor
One minute delay for the rst time start-up and three minutes delay for others
Temperature protection of compressor discharge
When the compressor discharge is getting higher, the running frequency will be limited as below rules:
If 215.6°F (102°C) < T5 < 244.4°F (115°C), decrease the frequency to the lower level every two minutes until to F1.
If T5 < 244.4°F (115°C) for ten seconds, the compressor will stop and restart till T5 < 194°F (90°C)
Table 5. Indoor/Outdoor Units Communication Protection
If the indoor units cannot receive the feedback signal from the outdoor units for two minutes, the unit will stop and display failure.
High Condenser Col Temp
Protection
When T3>149°F (65°C) for three seconds, the compressor will stop while the indoor fan and outdoor fan will
continue.
When T3<125.6°F (52°C), the protection will release and the compressor will restart after three minutes.
Outdoor Unit Anti-Freezing
Protection
When T2B< 32°F (0°C) for 250 seconds, the indoor unit capacity demand will be zero and resume to normal when
T2B> 50°F (10°C).
Running Rules
1. If the compressor frequency keeps lower than RET_OIL_FREQ1_ADD for RET_OIL_TIME1_ADD,the AC will rise
the frequency to RET_OIL_FREQ2_ADD for RET_OIL_TIME2_
2. During the oil return process, the EXV will keep 300p while the indoor units will keep the current running mode.
Table 6. Compressor Preheating Functions
Preheating permitting
condition
If T4 (outdoor ambient temperature)< 37.4°F (3°C) and newly powered on or if T4<37.4°F (3°C) and compressor has
stopped for over 3 hours, the compressor heating cable will work.
Preheating Mode
A weak current ow through the coil of compressor from the wiring terminal of compressor, then the compressor is
heated without operation.
Preheating Release
Condition
If T4>41°F (5°C) or the capacity demand isn’t zero, preheating function will stop.
Table 7. Compressor Crankcase Heater
Preheating permitting
condition
When T4< 37.4°F (3°C) within 5 seconds of being plugged in, the crankcase heater will be active.
When T4< 37.4°F (3°C) and the compressor is not running for 3 hours, the crankcase heater will be active.
Preheating Release
Condition
If T4>41°F (5°C) or the indoor has capacity demand, the crankcase heater will stop work.

Lennox MPC Specifications

General

Brand	Lennox
Model	MPC
Category	Air Conditioner
Language	English