Daikin GYEQ20AN Service Manual page 111

SiAUY361411EA
[1.1 System Control Overview] See the Basic heating control section.
When the outdoor air temperature rises to 26°C or higher during heating and the "Overload
Capacity" control function (for heating) cannot control high-side pressure 1, this function is
activated to lower the operable range of outside air temperatures by temporarily stopping the
outdoor unit.
(Cooling/heating) This control function determines the outside air temperature threshold (35°C
to 26°C) for the "Inhibit" control function (for cooling/heating) to be activated.
When the outdoor heat exchanger is frosted and its temperature drops, this function is activated
to defrost the heat exchanger by turning ON SV3A/3B/3C/3D and turning OFF SV3E/3F so that
gas is discharged.
• Activation conditions
• Deactivation conditions
When the number of engine speed steps is the maximum standard value, high-side pressure 1
is equal to or lower than the high-side pressure set point, and the outdoor air temperature is 6°C
or lower, this function is activated to enhance heating performance by increasing the number of
engine speed steps.
[1.1 System Control Overview] See the Basic heating control section.
1 hour after starting the outdoor unit and at every cumulative 8 hours after this, or when the oil
separator oil level is at or below the detection level, this function sets the outdoor unit circuit and
BS circuit to the cooling circuit and performs the oil return operation.
If refrigerant accumulates in an inactive indoor unit, this function increase the expansion valve
opening degree to perform a refrigerant recovery operation.
You can select the energy saving mode by configuring the memory switches with the onboard
checker of the main circuit board as shown in the table below. The energy saving mode works
by restricting the engine speed upper limit to reduce gas consumption regardless of whether the
load is low or high.
[Note] Cooling/heating performance is more or less sacrificed when energy saving mode is
[Configuring the energy saving mode]
Control and Functionality
(Heating) "Overload Capacity" control function
(Heating) "Inhibit Operation under Overload" control function
(Heating) "Defrost" control function
The control function is activated when intake temperature 1 is lower than -3°C and the
difference between the outdoor air temperature and intake temperature 1 stays constant for
10 minutes or longer.
When the specified time period or longer has elapsed after turning ON SV3A/3B/3C/3D and
turning OFF SV3E/3F or when high-side pressure 1 has risen to the specified pressure or
higher, the defrosting process is complete, and SV3A/3B/3C/3D are returned to the OFF
position and SV3E/3F are returned to the ON position.
(Heating) "Enhance Performance at Low Outdoor Air Temperatures" control function
(Heating) "Avoid High-Side Pressure Rise during Transition" control function
(Heating) "Oil Return" control function
(Heating) "Indoor Unit Refrigerant Recovery" control function
(Cooling) (Heating) "Energy Saving Mode" control function
configured, possibly resulting in "Cannot Get Cool/Warm" complaints from end users.
Memory switch
Cooling CH4-No.4
Heating CH4-No.6
Normal operation mode
OFF
OFF
Outdoor Unit Control
Energy saving mode
ON
ON
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