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SK2017 AHRI PFWSL-V/P-AECM-001
D.5.
Control Logics For 4-Pipe System
Note: 4-pipe system must always be equipped with 2 valves.
COOL MODE
a)
MTV2, AUX1 and Electrical Heater always off.
b)
If Tr ≥ Ts+1.8 ºF (or +7.2 ºF if economy contact is activated), cool operation is activated, MTV1 and AUX2 are turned on.
Indoor fan runs at set speed.
c)
If Tr < Ts, cool operation is terminated, MTV1 and AUX2 are turned off. Indoor fan runs at set speed.
d)
The range of Ts is 61-86 ºF
e)
Indoor fan speed can be adjusted for low, medium, high and auto.
f)
When turned on, MTV1 requires 30 seconds before it is fully open.
g)
When turned off, MTV1 requires 120 seconds before it is fully closed.
h)
When the unit is turned off, indoor fan will delay for 5 seconds before it is turned off.
LOW TEMPERATURE PROTECTION OF INDOOR COIL
a)
If Ti1 ≤ 36 ºF for 2 minutes, MTV1 and AUX2 are turned off. If indoor fan is set for low speed, it will run at medium speed.
If it is set at medium or high speed, it will keep running at the same speed.
b)
If Ti1 ≥ 41 ºF for 2 minutes, MTV1 and AUX2 are turned on. Indoor fun runs at set speed.
FAN MODE
a)
Indoor fan runs at the set speed while heater, MTV1, MTV2, AUX1 and AUX2 are turned off.
b)
Indoor fan speed can be adjusted for low, medium and high.
HEAT MODE
Without Electrical Heater
a)
MTV1, AUX2 and heater always off.
b)
If Tr ≤ Ts-1.8 ºF (or -7.2 ºF if economy contact is activated), heat operation is activated, MTV2 and AUX1 are turned on.
Indoor fan runs at the set speed.
c)
If Tr > Ts, heat operation is terminated, MTV2 and AUX1 are turned off. Indoor fan runs at 200rpm.
d)
The range of Ts is 61-86 ºF.
e)
Indoor fan speed can be adjusted for low, medium, high and auto.
f)
MTV2 will delay for 30 seconds before it is turned on.
g)
MTV2 will delay for 120 seconds before it is turned off.
With Electrical Heater as Booster
a)
MTV1 and AUX2 are always off.
b)
If Tr ≤ Ts-1.8 ºF (or -7.2 ºF if economy contact is activated), heat operation is activated, MTV2 and AUX1 are turned on.
Indoor fan runs at the set speed.
c)
If Tr > Ts, heat operation is terminated, MTV2 and AUX1 are turned off. Indoor fan runs at 200rpm.
d)
If Ti2 < 104 ºF, the electrical heater is turned on. If 104 ºF ≤ Ti2 < 113 ºF, the electrical heater is kept original state. If Ti2 ≥
113 ºF, the electrical heater is turned off.
e)
The range of Ts is 61-86 ºF
f)
Indoor fan speed can be adjusted for low, medium, high and auto.
g)
MTV2 will delay for 30 seconds before it is turned on.
h)
MTV2 will delay for 120 seconds before it is turned off.
PRE-HEAT
Without Electrical Heater
a)
If Ti2 < 97 ºF [or 82 ºF depends on DIP setting], when MTV2 and AUX1 are on, indoor fan remains off.
b)
If Ti2 ≥ 100 ºF [or 86 ºF depends on DIP setting], when MTV2 and AUX1 are on, indoor fan runs at set speed.
c)
If indoor coil temperature sensor is damaged, pre-heat time is set for 2 minutes and indoor fan runs at set speed.
With Electrical Heater
a)
If indoor fan speed ≥ 300 rpm, electrical heater is turned on