Greenheck 474706 Reference Manual page 24

Ddc controller for tempered air products
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Hot Gas Flush Setup
Cycle:
30minutes
Duration:
1minutes
Mod Hot Gas Setup
Minimum ON:
4.0vdc
Maximum ON:
10.0vdc
Supply Reset Control
Integration:
1200s
Band:
10°F
Heat/Cool Delay
Time delay between heating,
cooling &/or economizer
modes. Delay:
180s
Unoccupied Mode Setup
Type:
CycleSupplyFan
Source:
Input ID6
Damper Setup
Allow the dampers to open
for: 10 seconds before
starting the fans.
Fan/Airflow Proving
Alarm delay:
30s
(inputs ID1 & ID5)
24
DDC Controller for Tempered Air Products
T
his screen allows adjusTmenT of The hoT gas flush sysTem
This screen appears if hot gas reheat with flush was provided (except heat pump).
The hot gas flush cycle is designed to provide a momentary flush of the hot
gas reheat system. This prevents the build up of oil in the reheat coil. The
flush sequence starts by fully opening the reheat valve for a period of Duration
(Factory Default = 1 minute). Once the flush duration is complete, the valve
resumes modulation for a period of Cycle (Factory Default = 30 minutes).
T
his screen allows adjusTmenT of The hoT gas reheaT bypass damper
This screen appears if modulating hot gas reheat was provided.
T
his screen allows adjusTmenT of The
r
T
c
.
oom
emp
onTrol
This screen only appears if a Room Temp Sensor is wired to controller terminals
B4 and BC4.
The controller utilizes a PI loop control for supply reset based on room temp.
This allows for less sporadic changes in supply air temperature, resulting in a
smooth reaction to changing conditions. To speed up reaction time, decrease
the integration time. For slower reaction time, increase the integration time.
When making adjustments, make them in small increments and test the system
to determine if the new setting is adequate prior to further adjustment. The
band is the range that the integration will occur between.
T
his screen allows adjusTmenT of The delay beTween heaT and cool modes
This time delay prevents short cycling between heating, cooling and/or
economizer modes.
T
his screen displays whaT The uniT will do in unoccupied mode
Setting the Type to CycleSupplyFan will engage the unit to maintain space
temperature. However, a room temperature sensor must be wired between
controller terminals B4 and BC4. If desired, the Source offers three options to
control occupancy. The factory default is terminal ID6 on the controller.
Input ID6: Typically used with a remote time clock, motion sensor or switch
(default).
BMS: BMS control (see Points List). BMS can be overridden with ID6.
Time Clock: Internal time clock (Scheduler). See Clock/Scheduler menu for
more information. The Scheduler can be overridden with digital
input ID6.
Without the room temperature sensor, the Type will be Unit Off, forcing the unit
off during unoccupied mode.
T
his screen allows adjusTmenT of The fan sTarT delay
This timer allows the damper time to open before the fan start sequence
begins. This prevents the fans from having to overcome higher static pressure
when the damper(s) are opening. (Factory Default = 10 seconds)
T
his screen allows adjusTmenT of The fan airflow proving swiTch Time
.
delay
Since the unit is only part of a complete system, the airflow(s) may momentarily
change (ie. If a downstream damper closes). This delay is intended to prevent
false loss of airflow alarms. (Factory Default = 30 seconds)
.
s
r
pi
upply
eseT
conTrol loop
.
.
,
for
.
.
®

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