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SK2017 AHRI PFWSL-V/P-AECM-001
D.4.
Control Logics for 2-Pipe System
With Valve Configuration
COOL MODE
a)
MTV2, AUX1 and electric heater are always off.
b)
If Tr ≥ Ts+1.8ºF (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 61-86ºF
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 ≤ 35.6 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 ≥ 41ºF 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
Heat mode without electrical heater
a)
MTV2, AUX2 and electric heater are always off.
b)
If Tr ≤ Ts-1.8ºF (or -7.2ºF if economy contact is activated), heat operation is activated, MTV1 and AUX1 are turned on.
Indoor fan runs at the set speed.
c)
If Tr > Ts, heat operation is terminated, MTV1 and AUX1 are turned off. Indoor fan runs at 200rpm.
d)
The range of Ts is 61-86ºF
。
e)
Indoor fan speed can be adjusted for low, medium, high and auto.
f)
MTV1 will delay for 30 seconds before it is turned on.
g)
MTV1 will delay for 120 seconds before it is turned off.
Heat mode with electrical heater as booster
a)
MTV2 and AUX2 are always off.
b)
If Tr ≤ Ts-1.8ºF (or -7.2ºF if economy contact is activated), heat operation is activated, MTV1 and AUX1 are turned on.
Indoor fan runs at the set speed.
c)
If Tr > Ts, heat operation is terminated, MTV1 and AUX1 are turned off. Indoor fan runs at 200rpm
d)
If Ti1 < 104ºF, the electrical heater is turned on. If 104ºF ≤ Ti1 < 113 ºF, the electrical heater is kept original state. If Ti1 ≥
113 ºF, the electrical heater is turned off.
e)
The range of Ts is 61-86ºF
f)
Indoor fan speed can be adjusted for low, medium, high and auto.
g)
MTV1 will delay for 30 seconds before it is turned on.
h)
MTV1 will delay for 120 seconds before it is turned off.
Heat mode with electrical heater as primary heat source
a)
MTV1, MTV2, and AUX2 are always off
b)
If Ti2 ≤ 86ºF (or Ti2 is damaged or disconnected), AND if Tr ≤ Ts-1.8ºF (or -7.2ºF if economy contact is activated), heat
operation is activated, electrical heater and AUX1 are turned on. Indoor fan runs at set speed.
c)
If Tr > Ts, heat operation is terminated, Electrical heater and AUX 1 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.
Over-heat protection of indoor coil in heat mode
a)
If Ti1 ≥ 167 ºF, MTV1, AUX2 and EH are turned off, indoor fan runs at high speed, even in standby mode.
b)
If Ti1 < 158ºF, unit will keep at original state.
c)
If indoor coil temperature sensor is damaged, the protection mode will be overridden and the Pre-heat and Post-heat
set times will be used instead.