Freeze Prevention; Heater Control - Daikin VRV III RXYQ5-54PY1 Service Manual

Outline of Control (Indoor Unit)
6.8

Freeze Prevention

Freeze When the temperature detected by liquid pipe temperature thermistor (R2T) of the indoor unit
heat exchanger drops too low, the unit enters freeze prevention operation in accordance with
Prevention by Off
the following conditions, and is also set in accordance with the conditions given below.
Cycle (Indoor
Unit)
Conditions for starting freeze prevention: Temperature is -1°C or less for total of 40 min., or
temperature is -5°C or less for total of 10 min.
Conditions for stopping freeze prevention: Temperature is +7°C or more for 10 min.
continuously
Ex: Case where temperature is -5°C or less for total of 10 min.
6.9

Heater Control

The heater control is conducted in the following manner.
[Normal control]
While in heating operation, the 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) The heater control (ON/OFF) is
136
conducted through the liquid
pipe temperature (R2T) of the
indoor unit.
ON
2ºC
ON 43ºC
Si34-601A
Set temperature
OFF
2ºC
50ºC Liquid pipe temperatur
OFF
Function