Nortec 132-3091 Using The Wiring Diagram, Electronics, Yellow and Green Status Lamps Both On

Supply water pressure is too low (less than 30 psig).

7. Electronics

Symptom(s) Diagnosed: When on/off/drain switch is switched on, green status lamp does not come on.

Probable Cause(s): Green status lamp is damaged. (Long life LED should never burn out.) NHB electronic board assembly was damaged in shipment or installation. Electronics need to be replaced.

8. Yellow and Green Status Lamps Both On

Symptom(s) Diagnosed: Water has reached the top of the cylinder and activated the high water sensor circuit. Note: This is normal on startup and at end of cylinder life.

Probable Cause(s): Normal on startup with a new cylinder. Can last for several hours until cylinder reaches optimum contained water conductivity or 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.

USING THE WIRING DIAGRAM

Fixed to the inside of each unit’s door is a wiring diagram showing all of the internal (and most of the external) wiring details. Additional external wiring details can also be found with any electrical accessories purchased from NORTEC.

The following is a detailed explanation of how the NH humidifier (with and without options) operates. Direct reference is made to the wiring diagram. Reviewing the proper function in detail will make it easier to troubleshoot if something goes wrong.

The wiring diagram details a 24 Vac control circuit and a primary voltage circuit.

NHMC/NHP

A primary-to-24 Vac 75 VA transformer, tapped from the primary, powers the 24 Vac control circuit. One leg of the secondary is connected to ground and terminals 6 and 46 on the electronics. The “hot leg” finds its way to the electronics via the following in series: the external on/off controls (if present), terminals 8-10, the blower pack mounted on/off

humidistat (if present), terminals 84-85 and finally the cabinet mounted on/off humidistat (if present). 24 Vac arrives at the electronics’ terminals 10 (hot) and 6 (ground). A second “hot leg” takes a more direct route to terminals 8, 18, 34, 38, 44 on the electronics via the “on switch” and the door interlock switch in series.

The primary voltage circuit is what turns the water in the cylinder to steam for humidification. The internal primary fuses (if present) are followed by the primary contactor(s). When the 24 Vac coil is powered, the contactor “makes”. One primary leg is routed through the core of the linear Hall Effect current sensing circuit on the electronics, then it goes to the cylinder. The high water sensor board has a primary voltage side. One leg connects to the primary leg; one leg connects to the short sensor pin in the top of the cylinder. A potential, somewhat less than primary, is picked up by the sensor at high water level, which “makes” the red/black circuit on the low voltage side. This creates a resistive loop across terminals 42-48 on the electronics which stops the fill valve until water boils down below the sensor pin.

Back at the electronics, the contactor receives its “hot leg” from terminal 12. The fill receives its “hot leg” from terminal 14. The drain receives its “hot leg” from terminal 16. Unlike the contactor and fill, the drain gets its “ground leg” directly from the transformer. It does not depend on the air proving switch to activate.

The yellow and green unit status lamps are LED’s. Polarity is important. Terminal 4 is positive dc supply. Terminals 22 and 24 are switched dc grounds for yellow and green respectively.

NHB

A primary-to-24 Vac 75 VA transformer, tapped from the primary, powers the 24 Vac control circuit. One leg of the secondary is connected to ground and terminal 6 on the electronics. The “hot leg” finds its way to the electronics via the following in series: the external on/off controls (if present), terminals 8-10, the blower pack mounted on/off humidistat (if present), terminals 84-85 and finally the cabinet mounted on/off humidistat (if present). 24 Vac arrives at the electronics’ terminals 10 (hot) and 6 (ground). An onboard 3.15 amp glass fuse protects the circuit. A second “hot leg” takes a more direct route to terminals 8 and 18 on the electronics via the “on switch” and the door interlock switch in series.

The primary voltage circuit is what turns the water in the cylinder to steam for humidification. The internal primary fuses (if present) are followed by the primary contactor(s). When the 24 Vac coil is powered, the contactor “makes”. One primary leg is routed through the core of the linear Hall Effect current sensing circuit on the electronics, then it goes to the cylinder. The

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