Daikin VRV IV+ Service Manual page 208

3 | Components
Service manual
208
When outdoor temperature does not allow the unit to run in cooling or heating
mode
INFORMATION
Follow this procedure when the outdoor temperature is outside the temperature
range for one of the operation modes (Heating or Cooling). The unit CANNOT
operate in the mode for which the outdoor temperature is outside its temperature
range. See the databook on Business Portal for the temperature range of the
operation modes.
9 Connect the 4‑way valve connector to the appropriate PCB.
10 Turn ON the power using the respective circuit breaker.
11 With the unit operating, connect the service monitoring tool to the unit and
check whether the unit is in one of the following operation modes in which
the 4-way valves are energized:
Y3S valve:
▪ Cooling mode
▪ Oil Return Operation in Cooling
▪ Defrost/Oil Return Operation in Heating
Y4S valve:
▪ Heating mode
▪ Low load Cooling mode
▪ Simultaneous Cooling/Heating operation
▪ Defrost operation
Y5S valve:
▪ Heating mode*
▪ Oil Return Operation in simultaneous Cooling/Heating mode
* Y5S may also be OFF if low load condition
Is this the case?
No
Yes
12 With the 4‑way valve connector connected to the PCB, measure the voltage
on the 4‑way valve connection of the PCB.
Result: The measured voltage MUST be 230 V AC.
Is the measured voltage correct?
Yes
No
13 If, according to the service monitoring tool, the unit is in one of the following
operation modes in which the 4-way valves are NOT energized:
Y3S valve:
▪ Heating mode
▪ Simultaneous Cooling/Heating operation
▪ Oil Return Operation in Simultaneous Cooling/Heating mode
Action
Skip the next step of this procedure.
Perform the next step of this procedure.
Action
Perform a position check of the 4-way
valve, see "3.1.1 Checking
4
procedures" [ 206].
Perform a check the main PCB, see
4
"3.11 Main PCB" [ 290].
REYQ8~20+REMQ5U7Y1B
VRV IV+ Heat Recovery
ESIE18-15B – 2020.05