42
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1P
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V2
.1
NM
V
-D2
M
-EN
11
-02
-04.
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VAV
– Module NMV-D2M
Legend
Legend
Sequence
a)
Test start ‘Check system supply pressure’
- [System test: Setp
oint V’mid]
- Actual value zero [m
3
/h] / [l/s]
- Damper 100% open
N-P1.7 VAV- / CAV-Box
..........................................................................................
wrong direction of rotation
Suggestion for a remedy
a)
Check direction of rotation (‘Service’ register
‘OPEN’ or ‘CLOSE’ operation)
b) Correct direction of rotation or mount the actuator
correctly (note the mark on the damper blade)
Suitable Test-Sequences
-
BasicTest Max-Min 5m.txt
Note:
The Test-Sequence is discontinued because of the lack of system
supply pressure. Fault alarm: ‘Inadequate supply air pressure’ is given.
Possible faults
- Incorrect direction of rotation
- NMV-D2M shaft connector and damper spindle
installed with offset (90°)
a
S
A
A
D
A
Sequence
a) Step 1: Damper open (uncontrolled)
- Volumetric flow already very high when the
damper is only slightly open !
- Damper 20...100% open
b)
Step 2: V’max
- Actual value not reaching setpoint
- Damper apparently 100% open
c)
Step 3: V’min
- Volume increases despite the damper closing
and being clearly above the setpoint !
- Damper in control range
d) Step 4: Damper closed
- Actual value: Volumetric flow present despite the
damper apparently being closed !
- Damper appears to be closed
Suggestion for a remedy
Remove the NMV-D2M and match the closed position
correctly to that of the closed damper blade.
Suitable Test-Sequences
-
Test 0 CAV (Open-Max-Min-Close) 8m.txt
Note:
If the system does not attain the required supply pressure
– during the
Test start
– the Test-Sequence is discontinued and the fault alarm ‘In-
adequate supply air pressure’ is given.
The spindle is fitted with clear offset in order to record this symptom. As
a result different values of offset can occur on-site in this situation.
Possible fault
0° position of the actuator does not correspond to that
of the closed damper blade. This produces offset, i.e.
the damper remains open although the actuator is
closed. When the actuator is 100% open the damper
is already moving back in the ‘Close’ direction (90°).
a
b
d
N-P1.8 VAV- / CAV-Box
.................................................................
leakage air with VAV controller closed
S
A
A
D
A
c
NMV-D2M
– Diagnosis
