SiUS281811E
6.9
Heater Control (Except FTQ-TA Models)
Note(s)
Optional PCB KRP1B... is required for heater control.
Heater control is conducted in the following manner.
Normal control
While in heating operation, heater control (ON/OFF) is
conducted as shown on the right.
Overload control
When the system is overloaded in heating operation,
the heater will be turned OFF in the following two manners.
(1) Heater control (ON/OFF) is conducted through the
liquid pipe temperature (R2T) of the indoor unit.
(2) Heater control (ON/OFF) is conducted by
converting the heater temperature into the
condensing pressure equivalent saturated
temperature (Tc) according to the temperature
detection through the high pressure sensor
(S1NPH) of the outdoor unit.
Fan residual operation
When the heater turns OFF, in order to prevent the activation of the thermal protector, the fan
conducts residual operation for a given period of time after the heater turns OFF. (This operation is
conducted regardless of whether or not a heater is equipped.)
Residual operation time: 100 seconds on ceiling suspended type or 60 seconds on other types
Part 4 Functions and Control
O
N
2ºC
(3.6˚F)
43ºC
ON
(109.4˚F)
50ºC
(122˚F)
ON
S
t e
e t
m
p
e
a r
u t
e r
OFF
2ºC
(3.6˚F)
50ºC
(122˚F) Liquid pipe temperature
OFF
60ºC
(140˚F)
Condensing pressure
equivalent saturated
temperature
OFF
Outline of Control (Indoor Unit)
105