satisfied and stops again. The resultant short-cycling is easily overcome.

A manual capacity adjustment potentiometer

(“pot”) is provided on the SGH main pc board for that purpose. It is marked “CAPACITY ADJUST” and is adjustable from 25 to 100% of rating.

Modulation Control

The SGH humidifier, utilizing modulation control, does not have the same problems of over sizing. It reacts to the modulation signal and varies its capacity automatically. However, if you wish to turn down the capacity, use the manual capacity adjustment potentiometer (“pot”).

OTHER POTENTIOMETERS

Do not adjust any other potentiometers (“pots”) on the pc board(s). They are factory-set and not meant to be user-set.

DETECTING WATER SUPPLY DEFICIENCY

Knowing how long it normally takes to fill each size steam cylinder, each humidifier’s pc board is factory configured to an acceptable maximum filling time. If it is filling too slowly, when the time expires the electronics stops the humidifier. To indicate this, the green light goes out and the yellow light goes on.

REMOTE INDICATION

Every SGH comes factory wired as a set of dry contacts at 61-20 on the control terminal strip. The user can connect an indicator externally to 61-20. It will automatically be activated any time a fault is detected.

DOUBLE UNIT OPERATION

Turn both switches on. If there is a demand for humidity, the green status lamp will indicate that the circuit is operating.

BLOWER PACK OPERATION

Blower packs are equipped with a control thermostat mounted on the steam distributor. As soon as humidifier generates steam, the contact is closed and the fan is started. When steam is no longer being generated, the fan cuts out with a delay.

If blower packs get overheated (malfunction of the air circulation), the manual reset safety thermostat interrupts the steam generation. To reset, switch off the humidifier and wait until the steam distributor cools down. Then remove left-hand side intake air filter and,

using a screwdriver, press the reset button (marked with a red dot) inside the blower packs.

Units are also equipped with speed select switch. The switch is located on the right-hand side of the blower, inside the blower pack. To access the switch, remove right-hand side intake air filter.

To avoid condensation on the cabinet parts, run blower pack on high speed when humidifier delivers more than 50 lbs/hr of steam.

- 12 -

Page 14
Image 14
Liebert SL-14050 Other Potentiometers, Detecting Water Supply Deficiency, Remote Indication, Double Unit Operation