Mits. Electr MAC-397IF-E

[Peter_1]

Anyone experience with this interface?
SW500, dip switch 4-5-6 ON.
Roomsensor replaced with a fix resistance of 5k4 (= 24°C)
CN591: 1+2 bridged is system ON
What happens when you bridge 1 with 4 and 5 and you then bridge 1 with 3 and 4 and leave 5 open?
Are these settings taking over the settings of the PAR21 controller?
Do you in fact still need the PAR21 controller, perhaps to control the fan speed or can you also alter DIP switches to control fan speed?
What happens if you bridge 1-2 and set the PAR21 off? Does the PAR21 switches on automatically? Will the display of the PAR21 show the working mode of the outdoor unit?

[JoeAT50A]

Hi Peter,

All these preset temperatures are available, not fan speeds. You will still need either wired (PAR21) or wireless RC.

Take a look my two slides below and study. I did not quite understand your questions. Hope this
help somewhat I guess.
8744

8745

[Peter_1]

Joe, thanks. Do we need the fixed resistor then?Most of my questions are answered.
What happens if the customer changes changes his temperature on the PAR21 of is this then overruled by the MAC-397. What happens when the PAR21 is switched off? IS 1/2 taking this over then, even with a shut down PAR21?Will the display of the PAR21 show the working mode of the outdoor unit?

[Peter_1]

Joe, thanks. Do we need the fixed resistor then?Most of my questions are answered.
What happens if the customer changes changes his temperature on the PAR21 of is this then overruled by the MAC-397. What happens when the PAR21 is switched off? IS 1/2 taking this over then, even with a shut down PAR21?Will the display of the PAR21 show the working mode of the outdoor unit?

[Peter_1]

Joe, why we use this: the fixed resistor of 5k4 simulates 24°C. We've installed a neutral zone thermostat with a DT of only 0.5K to regulate temperature in a room at 24°C. AT 24°C, we bridge 1/5, and when 23.5, we bridge 1 with 6, 3,4 and 5 (=heat on and 30°C) If room is at 24.5, we bridge 1/6 (= cool for 16°C)
If room reaches 24°C, we bridge 1-5 (=24°C) and 1/6. Does it matter in this case if we bridge 1-6 or open 1-6?

Additional question: if we have 23.5°C in the room and we bridge 1-6 (=heat) but we bridge 1-5 (=26°C) instead of 1 with 3-4-5 (=30°C), will the inverter then choose a lower speed due to the smaller DT (compared to 30°C in the first case)? This should be handy because a colleague of my installed this several years ago and the room needs +/- 4 kW and he installed 14 kW. With the standard thermostat they use now, we have an overshoot each time.

[JoeAT50A]

Hi Peter,
MAC-397IF fixed the value by bridging and override the PAR-21MA I think (not 100% sure) otherwise no point having a preset temperature function. And tolerances and response times of normal RTD sensor are uncertain. There is very difficult to precise the temperature. However aside from response times and tolerances, our LEVs are acting according to your set temperature.

For example : Set temperature 24C
Room Temperature detect 23.8C (LEV close >> Cool OFF)
Room Temperature detect 24.2C (LEV open >> Cool ON)
You can see from Maintenance Tool of course.
Compressor speed is based on total (all indoor units) LEV openings requirements.
For 1 to 1 system >> LEV closed >> compressor stopped.

even Pt100 or Pt1000 can't help much to precise the room temperature ( I mean difficult).