Friedrich MW12C1H, MW09C1H, MR09C1H, MR12C1H manual Function and Control

FUNCTION AND CONTROL

Protection

Protection is the same as that under the cooling mode.

(3) Heating Mode

Working conditions and process of heating

If Tamb.≤Tpreset+36°F, the unit enters heating mode, in which case the four-way valve, the compressor and the outdoor fan will operate simultaneously, and the indoor fan will run at preset speed in the condition of preset cold air prevention.

If T amb≥T. preset+41°F, the compressor will stop, the outdoor fan will stop with a time lag of 30s, and the indoor fan will stop after 60-second blow at low speed

If Tpreset+36°F<T amb<. Tpreset +41°F, the unit will maintain its original operating status.

Under this mode, the four-way valve is energized and temperature can be set within a range of 61 - 86°F . The operating symbol, the heating symbol and preset temperature are revealed on the display.

Condition and process of defrost

When duration of successive heating operation is more than 45 minutes, or accumulated heating time more than 90 minutes, and one of the following conditions is reached, the unit will enter the defrost mode after 3 minutes.

a.Toutdoor amb.≥A°F, Toutdoor tube ≤W°F;

b.A°F≤Toutdoor amb.<B°F, Toutdoor tube ≤X°F;

c.B°F≤Toutdoor amb.<C°F, Toutdoor tube ≤Y°F;

d.Touter amb.<C°F, Touter tube ≤Z°F

At that time, the indoor fan stops and the compressor stops, and after 30 seconds the outdoor fan will stop, and then after 30 seconds, the four-way valve will stop. After 30 seconds, thecompressor is initiated for raising the frequency to defrost frequency.

When the compressor has operated under defrost mode for 7.5 minutes, or Touter tube ≥E°F, the compressor will be converted to 53Hz operation. After 30 seconds, the compressor will stop. And after another 30 seconds, the four-way valve will be opened, and after 60 seconds, the compressor and the outdoor fan will be started, the indoor fan will run under preset cold air prevention conditions, and H1 will be displayed at temperature display area on the display panel. Defrost frequency is 70Hz.

3.Protection

Cold air prevention

The unit is started under heating mode (the compressor is ON):

In the case of Tindoor amb.<75°F : if T tube ≤104°F and the indoor fan is at stop state, the indoor fan will begin to run at low speed with a time lag of 2 minutes. Within 2 minutes, if Ttube >40, the indoor fan also will run at low speed; and after

1-minute operation at low speed, the indoor fan will be converted to operation at preset speed. Within 1-minute low speed operation or 2-minute non-operation, if Ttube >108°F , the fan will run at present speed.

In the case of Tindoor amb.≥75°F: if Ttube ≤108°F, the indoor fan will run at low speed, and after one minute, the indoor fan will be converted to preset speed. With in one-minute low speed operation, if Ttube >108°F , the indoor fan will be converted

to preset speed.

Note: Tindoor amb.1 2 refers to, under initially heating mode, the indoor ambient temperature before the

command to start the compressor is performed according to the program, or after the unit is withdrawn from defrost, the indoor ambient temperature before the defrost symbol is cleared.

Total current up and frequency down protection

If the total current Itotal ≤W, frequency rise will be allowed; if Itotal ≥X, frequency rise will not be allowed; if Itotal ≥Y, the compressor will run at reduced frequency; and if Itotal ≥Z, the compressor will stop and the outdoor fan will stop with a time lag of 30s.

(4) Fan Mode

Under the mode, the indoor fan will run at preset speed and the compressor, the outdoor fan, the four-way valve and the electric heater will stop.

Under the mode, temperature can beset within a range of 61°F - 86°F.

(5) AUTO Mode

Working conditions and process of AUTO mode

Under AUTO mode, standard cooling temperature Tpreset is 77°F and standard heating temperature Tpreset is 64.4°F.

a.Once energized, if Tamb.≤68°F, the unit will be started under heating mode; if 68°F < Tamb.< 77°F, the unit will run

under fan mode and the operation indicator lamp will be bright; and if Tamb.≥77°F, the unit will be started under cooling mode.

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