Hitachi RAD-25NH5, Service Manual, Page: 218 / 371

The damper has 2-directional output and realizes OPEN/CLOSE using a stepping motor.
Damper control functions onlywhen the Air outlet SW is set to Ò Ó.
(1) OPEN operation
Start up the damper towards OPEN direction byoverall angle width [DNPALD1]. When the start up completes, turn off
the output.
(2) CLOSE operation
Start up the damper towards CLOSE direction byoverall angle width [DNPALD1] + tightening angle [CNPPLS1]. When
start up completes, turn off the output.
Initial operation is performed onlyonce when the main power is switched ON. The damper should be operated as follows
due to its structure.
①
Damper OPEN (Damper limit SW = OFF signal)
②
Damper CLOSE (Damper limit SW = ON signal)
Its travel speed is pulse output speed [DNPPPS].
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 bytightening angle.
When ÒOFFÓ signal is detected (Abnormal signal): Start up towards CLOSE direction byoverall 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
consecutivelywithin 30 minutes, the malfunction mode is entered at the moment the 4th abnormalityis detected.
In the case where 3 or less abnormalityare detected, retryoperation is performed.
Abnormal OPEN location
If the signal is ÒONÓ, the damper is judged to be at CLOSE location (abnormal). The retryoperation, which is the same as OPEN
operation byoverall angle width, will be performed.
Abnormal CLOSE location
If the signal is ÒOFFÓ, the damper is judged to be at OPEN location (abnormal). The retryoperation, which is the same as CLOSE
operation byoverall angle width + tightening angle, will be performed.
(5) Self diagnosis mode of the damper is indicated byÒTimer lamp blinks for 8 timesÓ.
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The damper functions onlyduring heating and cooling operation. It stays closed during other operating modes.
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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 immediatelyif the damper changeover SW is set to ÒmanualÓ. When the damper is starting up, however,
it closes onlyafter open operation completed.
● Main operation ON/OFF (with preheating)
Main Power
Remote controller operation
Operating condition
Operation lamp
Indoor
Upper fan
Lower fan
Compressor
Limit SW
Damper
Close
(Limit SW is ON)
Open
(Overall angle width)
DNPFLG (0)
DNPFLG (1)
DNPSTS
1
1 1
Period 1 Period 2
Open sequence
Period 3
1
1 0
2 2 3 4 0 0
0
0
Operation starts Operation stop
Stop
ON ON ON
Stop Preheating Normal operation
Setting fan speed
Setting fan speed
Initial completed
(Initial completed)
Tightening
angle
Tightening angle
Overall
angle
width
Overall angle width
Overall angle width
+
Tightening angle
Overall angle width
+
(Initial period)
(Closed period) (Closed period) (Opened period)
Note: Regardless of ÒONÓ and ÒOFFÓ of the limit SW, the damper
performs OPEN operation when the power is switched on.
MODEL RAF-25NH5, RAF-35NH5, RAF-50NH5
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