Wiring Diagram; Sequence Of Operation - Vulcan-Hart VHU Series Service Manual

VHU INSULATED HUMIDIFIED CABINETS - ELECTRICAL OPERATION

SEQUENCE OF OPERATION

1. Conditions.
A. Unit connected to correct voltage and is
properly grounded.
B. Power switch is off.
2. Power switch turned on.
A. Relays K1, K2 and K3 are de-energized
(contacts N.O.).
B. Controller board performs diagnostic test
and verifies temperature and humidity input
signals are present.
C. If no errors codes display, the temperature
and humidity settings flash in each display
window.
3. Fan relay K2 is energized, K2 contacts close and
power the fans.
4. Based on temperature and humidity settings, the
board determines whether K1 relay will be
energized to power element 1 (dry air); or K3
relay will be energized to power element 2 (humid
air).

WIRING DIAGRAM

Fig. 31
NOTE: When temperature or humidity settings are
changed, after a brief pause, both element relays (K1
& K3) will be de-energized and return to N.O. position.
Heating and humidity generation stop. The relay
numbers will flash in each display window. Based on
temperature and humidity level in cabinet vs. setting,
the controller board determines which relay to
energize. The number of the energized relay will flash
in display window.
5. Adjust temperature and humidity to desired
levels.
6. Turn power switch off stops heating cycle.
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