Carrier 40MAQ Series Service Manual

Also see for 38MAQ Series: Owner's manual Product data Owner's manual Owner's manual

Carrier 40MAQ Series Service Manual Manual pdf 24 page image

24CONTROL SYSTEMThe unit is equipped with a microprocessor control to perform twofunctions:1 Provide safety for the system2 Control the system and provide optimum levels of comfortand efficiencyThe main microprocessor is located on the control board ofoutdoor unit. Outdoor and indoor units have thermistors used tomonitor the system operation to maintain the unit within acceptableparameters and control the operating mode.Indoor fan speed Maximum frequencyHigh speed/turbo function No limitSilent mode FixedIf users switch on AC by remote controller, the compressor will runat the Fmax frequency for 7 minutes according to the outdoorambient temp. During the 7 minutes, the frequency limitation isactive. 7 minutes later, the compressor running frequency will becontrolled as shown below. While the zones of A, B, C… arecorresponding to different compressor running frequency.Fig. 20 – ZonesNOTE: When AC is in “hold” zone for 3 minutes, the compressorfrequency will rise to the higher level.(frequency will increase twiceat most).Fig. 21 – ZonesI3COOL, I2COOL, I1COOL mean different running current value.S Off: Compressor stops.S Decrease: Decrease the running frequency to the lowerlevel.S Hold: Keep the current frequency.S Resume: No limitation for frequency.NOTE: When AC is in “hold” zone for 3 minutes, the compressorfrequency rises to the higher level. (Frequency increases twice atmost).When T1- Ts stays in the same temperature zone for 3 minutes, thecompressor runs according to the following rules:1 Increase the frequency to the higher level until F10.2 Keep the current frequency.3 Decrease the frequency to the lower level until F1.4 Run at F1 for 1h.(if T1- Ts- T>42.8_F(6_C), thecompressor will stop).Meanwhile, the compressor running frequency is limited by thecurrent.Fig. 22 – Running frequencyFig. 23 – Indoor fan running rulesIn the cooling mode, indoor fan runs all the time and the speed canbe selected as high, medium, low, auto and silent mode.