Electric Reheat Dehumidification Operation; Figure 49 Electric Reheat Dehumidification; Figure 50 Dehumidification Control (°F) - Bard MEGA-TEC W090A Service Instructions Manual

5. Press ENTER key to scroll to Enable.
6. Press UP or DOWN keys to change the value from
Yes to No.
FIGURE 49
Electric Reheat Dehumidification
An electric reheat capable unit will allow for concurrent
operation of compressor and electric heat. This allows
the compressor to operate which will remove moisture
from the indoor air while the electric heat keeps the
space temperature from dropping during this operation.
The cooling capacity of the MEGA TEC is much greater
than its capacity to heat with either the 9kw or 18kw
option. In order to extend the compressor run times
and prevent the unit from overcooling the space, the
cooling capacity will be limited during dehumidification
operation (see Table 11).
Heat
Limitation
Option
Compressor
9 Kw
1 Part Load
Compressor
18 Kw
1 Full Load
* Capacities listed are nominal and don't reflect actual performance.
Cool
Reheat
58
Manual 2100-671C
Page 34 of 59
Cooling Capacity Limitation
Heat
Capacity*
7.5 Ton Cooling Capacity
30,709 29,700
61,418 45,000
FIGURE 50
Dehumidification Control (°F)
59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79

Electric Reheat Dehumidification Operation

The unit will utilize electric reheat dehumidification
when it receives an active dehumidification call from
the LC6000 supervisory controller. During the active
dehumidification call, the unit status message will
show "Active Dehum". An LC6000 equipped with
and indoor humidity sensor is required to utilize
dehumidification.
When the command is received from the LC6000, or
generated by unit with stand-alone display, the wall
unit will engage the compressor to begin removing
moisture from the space and turn on the electric
heat to extend the run time of the cooling cycle while
mitigating the cooling done by the compressor. If/
when the return temperature falls to 2° above heating
setpoint, the compressor will be disabled until the
temperature is increased to 2° below the cooling
setpoint and then compressor will be re-energized (see
Figure 50). If/when the temperature reaches 4° below
the cooling setpoint, the electric heating elements will
be energized. The electric heating elements will be
disabled 2° below the cooling setpoint. The system will
continue the dehumidification process until either the
heating or cooling setpoint are reached again or the
active dehumidification command has been removed.
A heating or cooling call will disable the
dehumidification call. Dehumidification can only
take place when the system is not actively heating or
cooling.
For more information on dehumidification staging, see
latest version of LC6000 Service Instructions manual
2100-669.
TABLE 11
Cooling Capacity*
10 Ton Cooling Capacity
39,600
60,000
12.5 Ton Cooling Capacity
49,500
75,000