- 7 -
CONTROLS
ELECTRIC REACTIVATION CONTROLS:
Dehumidifiers with electric reactivation incorporate an air proving pressure switch and two adjustable
temperature limit devices. All three of these devices must be energized to allow the reactivation heaters to
be energized. One temperature limit automatically resets and the second is manual reset. The manual reset
limit may have to be reset upon start-up.
The reactivation temperature limits are safety limits only and are not operating controls!
If
on-off cycling of the heater occurs due to the entering air temperature reaching the auto reset
temperature limit set-point the limit set-point should be verified (set-point not to exceed 320
°
F) and the
reactivation air flow verified and increased if necessary to achieve the design reactivation inlet
temperature as specified on the dehumidifier set-up sheet provided in this manual. The manual reset limit
is a fail-safe device with a set point no higher than 350
°
F.
NOTE:
The dial indication (on the manual reset Hi-Limit) is for reference only. The actual set-point
value may differ slightly. To check the calibration, turn the knob to a lower setting until the
heaters cut off, then increase the setting until the heaters come on. Compare the dial setting
with the digital display on the auto-reset hi-limit to verify calibration.
A fan control
(VFB-3 ONLY)
is utilized to cool down the heaters when the dehumidifier is turned off.
CAUTION-
disconnecting main power defeats this device. The reactivation fan may start any time there is
residual heat. Disconnect power before servicing fan.
A time delay type of cool down circuit
(VFB-6, 9,12,18,24,36,50,75,100,150,200 & 300)
is used to
cool down the heaters when the dehumidifier is turned off.
Caution – disconnecting main power defeats
this circuit.
Disconnect power before servicing fan.
The airflow section of this manual will provide the information on adjusting airflow through the
dehumidifier. This is extremely important because the electric heaters are sized for a temperature rise based
on design air volume. Consult the dehumidifier set-up sheet or system flow schematic included in this
manual for the proper reactivation temperature. This temperature is achieved through the proper air volume
and is measured at the dry-bulb temperature test ports in the reactivation inlet. See dehumidifier set-up
sheet for more information.
NOTE:
It is important to insure the reactivation airflow is sufficient before adjusting limit set points.
