Daikin CTXU25G2V1B Service Manual page 34

Main Functions
How to Check the You can check whether the humidifying unit is in good working order. If you set HUMID HEAT
test operation (refer to the installation manual for details), you can check even beyond the range
Motion of
of the conditions for humidifying operation.
Humidifying
1. Hygroscopic fan .......................... Air is exhaled from the front exhaust outlet of outdoor unit.
Operation
2. Humidifying fan/heater/damper ... Warm air is blown from the duct of outdoor unit.
3. Humidification rotor ..................... The rotor is rotating with top panel off.
As for the performance, estimate from psychrometric chart with the measured temperature and
humidity of the outdoor air and of the humidified air (in front of the indoor outlet) using thermal
hygrometer.
Humidity At HUMID HEAT operation, as room temperature rises, relative humidity is temporarily lowered.
This is because as room temperature rises, relative humidity is lowered even if the moisture
Fluctuation by
content is the same.
Temperature
Settings
e.g.) The rise in the room temperature from 15°C to 25°C results in the fall in humidity from
40%RH to about 22%RH.
As humidifying operation starts concurrently with heating, humidity rises gradually as shown in
the figure below.
Some room conditions (floor space, ventilation frequency, number of residents, etc.) and
temperature settings (mostly higher settings) may result in unsatisfactory humidity settings.
Humidity
23
3
Airflow rate (m /min)
0.38
Humidity Fluctuation on HUMID HEAT Operation
(%)
100
90
"HUMID HEAT" start
80
When room temperature rises,
70
relative humidity is lowered
even if the moisture content is
same.
60
50
40
30
20
10
0
20
Measurement Conditions
Outdoor temp.: 7
HUMID HEAT operation setting:
Temp.; each setting as below, Humidity; "CONT" (Continuous)
Airflow rate setting: H tap
Area of the room: 26.4 m²
Humidifying hose length: 4.0 m
Ventilation: 0.75 times/hour
0.5 times of natural ventilation
0.25 times of humidity absorption by a carpet, a curtain, etc.
40 60
SiBE12-908
Setting temp.
17
20
23
Humidity rises
gradually.
Heating without
humidifying setting
temp. 23
80 100 Time (min.)
(R9411)
Function and Control