Service Manual

Outline of Control (Indoor Unit) SiUS281811E
110 Part 4 Functions and Control
Note(s)
6.11 3-Step Thermostat Processing (FTQ-TA Models)
Outline
The thermostat ON/OFF for the indoor unit is controlled in accordance with Thermostat step 1.
The heater ON/OFF operation during heating is controlled as follows.
Thermostat step 2, 3: Auxiliary electric heater control
Thermostat step 1, 2: Heat pump lockout control
For more details of the heater, refer to Heater Control (FTQ-TA Models) on page 106.
Detail
&
• No errors (except errors in which the system keeps operating)
has occurred.
• Remote controller ON
•
Thermostat step 1: OFF
• Thermostat step 2: OFF
• Thermostat step 3: OFF
Other conditions
Perform the processing in
the following chart. (∗5)
gnitaeH )2(gnilooC )1(
Thermostat step 2
Thermostat step 1
ON
OFF
ON
OFF
2+S
(∗1)
4+S (∗1)
A (∗4) B (∗4)
Controlled temperature
(Tcon)(˚C)
Set temperature (Ts’)
Thermostat step 3
Thermostat step 2
Thermostat step 1
ON
OFF
ON
OFF
ON
OFF
1.5
1.5
Toff+S (∗1,2,3)
Ton+S
(∗1,2,3)
A
(∗4)B (∗4)
Set temperature (Ts’)
Controlled
temperature
(Tcon)(˚C)
1. S value varies automatically based on the room temperature trend.
2. Ton + S > –B (°C), Toff + S < A (°C)
3. For parameters, refer to page 125.
4. A and B values vary automatically based on the field setting 12 (22)-2.
5. If, directly after a change in conditions, it is such that the thermostat could be either ON or
OFF (controlled temperature is within ranges A and B), the thermostat will be switched to
ON.