Damper Control; Monitor Function Of Damper Limit Sw; Damper Operation By Operating Modes; Main Operation On/Off (With Preheating) - Hitachi RAF-25NH4 Service Manual

amper control
1. Precondition
The damper has 2-directional output and realizes OPEN/CLOSE using a stepping motor.
Damper control functions only when the Air outlet SW is set to Ò
2. OPEN/CLOSE Operation
(1) OPEN operation
Start up the damper towards OPEN direction by overall angle width [DNPALD1]. When the start up completes, turn off
the output.
(2) CLOSE operation
Start up the damper towards CLOSE direction by overall angle width [DNPALD1] + tightening angle [CNPPLS1]. When
start up completes, turn off the output.
3. Initial Operation
Initial operation is performed only once when the main power is switched ON. The damper should be operated as follows
due to its structure.
Damper OPEN (Damper limit SW = OFF signal)
①
Damper CLOSE (Damper limit SW = ON signal)
②
Its travel speed is pulse output speed [DNPPPS].
4. Monitor Function of amper Limit SW
Monitoring of damper limit SW is inhibited during start up and for 2 seconds after starting up the damper, after which the damper
limit SW will be monitored.
(1) Damper limit SW signal at the completion of initial operation is monitored. If the signal is OFF, it is judged as malfunction and the
malfunction mode is entered immediately.
(2) Monitoring of damper limit SW signal is inhibited while the unit is stopped.
(3) Damper limit SW is always monitored while the unit is in operation. Right after the unit operation is started, however, malfunction
judgment is not made and the damper performs the following operation.
When ÒONÓ signal is detected (Normal signal): Start up towards CLOSE direction by tightening angle.
When ÒOFFÓ signal is detected (Abnormal signal): Start up towards CLOSE direction by overall angle width plus tightening angle.
(4) After performing the above operation, malfunction judgment will always be carried out. If abnormality is detected for 4 times
consecutively within 30 minutes, the malfunction mode is entered at the moment the 4th abnormality is detected.
In the case where 3 or less abnormality are detected, retry operation is performed.
Abnormal OPEN location
If the signal is ÒONÓ, the damper is judged to be at CLOSE location (abnormal). The retry operation, which is the same as OPEN
operation by overall angle width, will be performed.
Abnormal CLOSE location
If the signal is ÒOFFÓ, the damper is judged to be at OPEN location (abnormal). The retry operation, which is the same as CLOSE
operation by overall angle width + tightening angle, will be performed.
(5) Self diagnosis mode of the damper is indicated by ÒTimer lamp blinks for 8 timesÓ.
5. amper operation by operating modes
The damper functions only during heating and cooling operation. It stays closed during other operating modes.
Heating mode
The damper is open during normal heating operation (except for 10 seconds after thermo resumes, during sleep operation
and during nice temperature). It is closed during other types of operation.
The damper closes immediately if the damper changeover SW is set to ÒmanualÓ. When the damper is starting up, however,
it closes only after open operation completed.
● Main operation ON/OFF (with preheating)
Main Power
Remote controller operation
Operating condition
Operation lamp
Upper fan
Lower fan
Compressor
Limit SW
Close
(Limit SW is ON)
Open
(Overall angle width)
DNPFLG (0)
DNPFLG (1)
DNPSTS
Note: Regardless of ÒONÓ and ÒOFFÓ of the limit SW, the damper
performs OPEN operation when the power is switched on.
Operation starts
Stop Preheating
ON
Tightening
Initial completed
Overall
angle
Overall angle width
+
width
Tightening angle
0 (Initial period)
1 0 (Closed period)
1 2 0
Ó.
Setting fan speed
ON
angle
1 2 3
Period 1 Period 2 Period 3
Open sequence
176
Normal operation
Setting fan speed
Overall angle width
1 (Initial completed)
1 (Opened period)
4
Operation stop
Stop
ON
Overall angle width
+
Tightening angle
0 (Closed period)
0