Nortec 132-3091 Nhmc/Nhp, Maximal Level Shown on NHMC LCD display only, Excess Current - Error

Clean the drain valve; start with a fresh cylinder. Then measure the manual drain time with and without the external drain connected. Is the external drain impeding flow? NORTEC recommends an open external drain line. See Form #XX-161.

NHMC/NHP

The self-diagnostic system built into the NHMC is continually checking the status of the electrical circuits to the fill valve, drain valve, primary voltage contactor, high water sensor and steam cylinder. The modulating signals from external humidistats and reduced manual capacity settings are taken into consideration. When problem symptoms are found, the NHMC/NHP will take self-corrective actions, if applicable. It will, if necessary, respond by shutting itself down.

The NHMC/NHP communicates its findings to the user by way of the unit’s status lamps and signals sent to the terminal strip for optional external remote indication. Even more directly, the NHMC has an alphanumeric system message to the user via the LCD (liquid crystal display).

All of this is summarized for each system message in the following easy-to-follow format.

NHMC/NHP Explanation of System Messages and Responses —- EPROM : 2.XXN

1.Maximal Level (Shown on NHMC LCD display only)

Symptom(s) Diagnosed: Water has reached the top of the cylinder and activated the high water sensor circuit. This is not an error or fault diagnostic. Note: This is normal on start-up and at end of cylinder life before Error 4 shows.

Probable Cause(s): Normal on startup with a new cylinder or a cylinder that has been completely drained because of an extensive off period. Can last for several hours until the water in the cylinder has concentrated or the electrodes can no longer provide rated capacity (or adjusted capacity). Water level automatically rises to seek out fresh electrode surface to meet the demand.

Unit Takes Self-Corrective Action: Yes. It stops the fill valve to prevent overfilling.

2. Excess Current - Error 1

Symptom(s) Diagnosed: Current drawn on monitored primary lead to cylinder has reached or exceeded 125% of its rated amps. The unit will have tried to self-correct prior to system shutdown by draining water from the cylinder or

de-energizing the contactor momentarily while it drains.

Probable Cause(s):

1.Cylinder water is over-concentrated (too conductive) due to restricted drain, short-cycling by controls, supply water not within acceptable limits (too conductive), improper fill rate, incorrect cylinder being used.

2.Water level too high due to leaking fill valve, excess condensate return from steam line.

Corrective Action:

1.Note water level.

2.Manually drain cylinder while checking drain rate (refer to Figure #7 for proper drain times). If too slow correct cause.

3.Turn unit back on and check the fill rate (1 - 1-1/2 inches per minute)

4.Once RH% set point is attained, monitor cycle time.

Response: See Figure #2, NHMC/NHP System Messages

3. No Current - Error 2

Symptom(s) Diagnosed: Full cylinder (MAXIMAL

LEVEL) detected with no current draw sensed by the electronics on monitored primary lead to cylinder.

Probable Cause(s):

1.No current being drawn, specifically on the monitored primary lead to the cylinder, or the actual current not being sensed.

2.False detection of a full cylinder (water level within inches of cylinder top) due to foaming, wiring/connection problem, circuit board failure.

Corrective Action: Check water level in cylinder.

1.If full (within 4" of top) disconnect white sensor plug on cylinder, reset unit and check monitored primary lead to cylinder for current with amp clamp. If current present, determine why main PCB does not sense the current. If no current, present determine cause of primary voltage interruption.

2.If not full disconnect white sensor plug on cylinder, reset unit. If error 2 does not reoccur within two minutes, cylinder was likely foaming and should be flushed. If error 2 does reoccur within two minutes, there is a problem with the high water sensor PCB. If error 2 occurs with the high water sensor PCB disconnected, there is a problem with the main PCB.

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