Filter
Top Products
9. Phase Interrupt - Error 8 (NHMC only)
Symptom(s) Diagnosed:
The 24 VAC to the main
PCB, across terminals 44 and 46 is interrupted.
Probable Cause(s):
a) A wiring problem leading to an interruption of
the 24 VAC to terminals 44 and 46 of the
main PCB.
b) A problem with the main PCB.
Corrective Action:
1. With the unit switched on, measure across
terminals 44 and 46 of the main PCB for 24 VAC.
If not present, find the cause of interruption. If
present, the problem is with the main PCB.
Response:
See Figure #2, NHMC System
Messages
10. Cyl. Lifespan End - Error 9
Symptom(s) Diagnosed:
The criteria for
diagnosing Cylinder Spent - Error 4 has expired
and cylinder has not been replaced. Humidifier
has shut down to avoid unsafe operation.
Probable Cause(s):
Refer to Error 4.
Corrective Action:
Refer to Error 4.
Response:
See Figure #2, NHMC/NHP System
Messages.
Troubleshooting Dual Cylinder Units
Double units, NHMC-150 and 200, are two circuits
in one cabinet sharing one LCD display. A ribbon
cable between the RS232 ports links the two circuits.
The left circuit is the master. [1] on the display means
left side. [2] on the display means right side.
Refer to double unit operation on in the NHMC
Installation and Operation Manual.
When a fault occurs on the right side of a double
unit, both sets of lamps (and remote relays) will come
on indicating that a fault has occurred. The left side
(master) will display its own faults as well.
The LCD will indicate which fault has occurred and
on which side of the unit, [1] or [2]. The side not
faulted will continue to operate as usual.
The side which has shut down on fault can be
treated as a single circuit using the same
troubleshooting guidelines as previously described.
NHB
The NHB checks the status of the electrical
circuits to the fill valve, drain valve, primary voltage
contactor, high water sensor and steam cylinder. The
manual capacity setting, if reduced, is taken into
consideration. When problem symptoms are found,
the NHB will, if necessary, respond by shutting itself
down.
The NHB communicates its findings to the user by
way of the unit’s status lamps and a 24 Vac (maximum
100 mA maximum) signal sent to the terminal strip for
optional external remote indication.
The signal for remote indication comes in
response to the following symptoms. In each case,
the NHB shuts itself down. The green status lamp
goes off, but the yellow status lamp (and remote fault
relay) remain on.
NHB Explanation of Automatic Shutdowns
1. Excess Current
Symptom(s) Diagnosed:
Current in steam
cylinder increases beyond the fill off and
emergency drain on triggers. Current reaches
150% of FLA (i.e. 134% of fill off rated amps; i.e.
134% of amps on spec. label) for 1 second.
Probable Cause(s):
Blocked drain due to blocked
cylinder strainer or blocked drain valve or blocked
external drain line. No power to drain valve at
emergency drain on trigger. Power remains on fill
valve at fill off trigger. Wrong steam cylinder (too
conductive). Wrong fill valve (orifice too big).
Wrong supply voltage (too high). Supply water too
conductive. Contained water too conductive.
100% softened supply water is often too
conductive. Measure conductivity and report
findings to factory if suspected. Mineral bridge
between electrodes.
Unit Takes Self-Corrective Action:
It has already
tried to control current with fill off and emergency
drain on triggers. It then responds as shown
below.
Response:
UNIT STATUS LAMPS REMOTE
INDICATION
(24 Vac to:)
UNIT
CONTACTOR
YELLOW GREEN 61-20
“YELLOW”
OFF ON OFF ON
-19-