Greenheck Microprocessor Controller (474706 IOM) TAP v1.04 June 2011 (ERCH, ERH, APEX, VER, ERT) User Manual
Page 14
14
DDC Controller for Tempered Air Products
u
sers
can
choose
eiTher
The
conTroller
or
The
bms
To
deTermine
s
upply
a
ir
s
eT
p
oinT
during
operaTion
.
This screen only appears if the controller was supplied with BMS capability.
Local means the controller set point will be used during operation. (Outdoor Air
Reset or Room Reset)
BMS means that the BMS set point will be used during operation.
T
his
screen
displays
The
room
seT
poinTs
for
heaTing
and
cooling
operaTion
during
unoccupied
mode
.
This screen only appears if the unoccupied mode is set to “Cycle on Room”
instead of “Unit Off”. A room temp sensor must be wired into the controller. For
energy recovery units, a Night Set-Back Damper must be installed.
In unoccupied mode when the temperature falls below the room Heating set
point, the supply fan and heating will turn on. If the unit is an Energy Recovery
unit, the Night Set-Back Damper will also open. The unit will discharge the
Supply Max temperature per the Supply Reset Limits screen, until the room
set point is satisfied. Unit will then shut down. When the temperature rises
above the Cooling set point, the unit will discharge the Supply Min temperature
per the Supply Reset Limits screen until the room temperature set point is
satisfied. Unit will then shut down.
The differential acts as a hysteresis to keep the heating and cooling from
cycling too often. For example, on a call for heating, the unit turns on at 60°F
and turns off at 65°F. For cooling, the unit turns on at 85°F and turns off at 80°F.
T
his
screen
displays
The
TemperaTure
aT
which
The
uniT
will
enable
frosT
conTrol
mode
if
necessary
. (f
acTory
d
efaulT
= 5°f)
This screen only appears if the unit has an energy recovery wheel and a frost
control method was provided with the unit.
Upon sensing a high differential pressure across the energy wheel, the unit will
go into defrost if the outside air temperature is below this temperature setting.
T
his
screen
displays
The
low
supply
air
TemperaTure
limiT
.
If the unit supply air temperature falls below Supply Air Low Limit for a period
of Alarm Delay, the unit will shut down and an alarm will be signaled. The
purpose of the supply low limit is to protect the building and contents from
cold supply air. It is NOT designed to protect the air-handling unit.
If the unit does not have chilled water (CW) or hot water (HW) coils, it should
not need additional protection from freezing. If the unit does have CW or HW
coils, field provided coil freeze protection may be necessary.
e
conomizer
lockouT
prevenTs
The
uniT
from
going
inTo
economizer
mode
when
The
ouTdoor
air
condiTions
are
Too
cold
.
This screen only appears if economizer was provided with the unit.
The lockout prevents outdoor air from: (1) entering the space at too cold of a
temperature or (2) entering heating or cooling coils at conditions that could
freeze the coils. Built-in hysteresis of 2°F. The hysteresis is similar to a dead-
band above and below the lockout set point. Example: If Lockout = 40°F,
economizer is locked out below 38°F and enabled above 42°F outside air
temperature.)
T
his
screen
displays
The
TemperaTure
difference
aT
which
The
dehumidificaTion
mode
is
locked
ouT
. (f
acTory
d
efaulT
= 10°f)
This screen only appears if the unit is equipped with cooling.
This setting prevents the unit from operating in dehumidification mode when the
outdoor air conditions are relatively cool. Example: If the cold coil set point is
55°F, dehumidification mode cannot operate until the outdoor air is at least 65°F.
Dehumidification lock
Lockout dehumidification until
outside air is 10.0°F above
cold coil set point.
Economizer Lockout
Lockout econo when outside
below:
40.0°F
Hysteresis
2.0°F
Supply air low limit
Alarm when supply is
below:
35.0°F
Alarm delay:
300s
Set Point Source
Use local set point, or BMS
interface set point? Local
Defrost
Allow wheel defrost
mode when outside
is below:
05.0°F
UnOcc Fan Cycle Setup
Unit will energize to maintain
unocc room set points.
Heating:
65.0°F
Cooling:
80.0°F
Differential:
5.0°F
®