Mitsubishi Heavy Industries FDUA160AVSAVH Service Manual page 14

(5) Hot start (Cold draft prevention at heating)
(a) Operating conditions
When either one of following conditions is satisfied, the hot start control is performed.
(i) From stop to heating operation
(ii) From cooling to heating operation
(iii) Form heating thermostat OFF to ON
(iv) After completing the defrost operation (only on units with thermostat ON)
(b) Contents of operation
(i) Indoor fan motor control at hot start
1) Within 7 minutes after starting heating operation, the fan mode is determined depending on the condition of
thermostat (fan control with heating thermostat OFF).
a) Thermostat OFF
i) Operates according to the fan control setting at heating thermostat OFF.
ii) Even if it changes from thermostat OFF to ON, the fan continues to operate with the fan control at thermostat
OFF till the heat exchanger temperature sensor (Thi-R1 or R2, whichever higher) detects 35°C or higher.
iii) When the heat exchanger temperature sensor (Thi-R1 or R2, whichever higher) detects 35°C or higher, the fan
operates with the set air flow volume.
b) Thermostat ON
i) When the heat exchanger temperature sensor (Thi-R1 or R2, whichever higher) detects 25°C or lower, the fan is
turned OFF and does not operate.
ii) When the heat exchanger temperature sensor (Thi-R1 or R2, whichever higher) detects 25°C or higher, the fan
operates with the fan control at heating thermostat OFF.
iii) When the heat exchanger temperature sensor (Thi-R1 or R2, whichever higher) detects 35°C or higher, the fan
operates with the set air flow volume.
c) If the fan control at heating thermostat OFF is set at the "Set air flow volume" (from the remote control), the fan
operates with the set air flow volume regardless of the thermostat ON/OFF.
2) Once the fan motor is changed from OFF to ON during the thermostat ON, the indoor fan motor is not turned OFF
even if the heat exchanger temperature sensor detects lower than 25°C.
Note (1) When the defrost control signal is received, it complies with the fan control during defrost operation.
3) Once the hot start is completed, it will not restart even if the temperature on the heat exchanger temperature sensor
drops.
(ii) During the hot start, the louver is kept at the horizontal position.
(iii) When the fan motor is turned OFF for 7 minutes continuously after defrost operation, the fan motor is turned ON re-
gardless of the temperatures detected with the indoor heat exchanger temperature sensors (Thi-R1, R2).
(c) Ending condition
(i) If one of following conditions is satisfied during the hot start control, this control is terminated, and the fan is operated
with the set air flow volume.
1) Heat exchanger temperature sensor (Thi-R1 or R2, whichever higher) detects 35°C or higher.
2) It has elapsed 7 minutes after starting the hot start control.
(6) Hot keep
Hot keep control is performed at the start of the defrost operation.
(a) Contents of operation
(i) When the indoor heat exchanger temperature (detected with Thi-R1 or R2) drops to less than 35°C, the speed of indoor
fan follows fan setting at the time of thermostat OFF.
(ii) During the hot keep, the louver is kept at the horizontal position.
13
- -
'21 • PAC-SM-398