Greenheck Microprocessor Controller (475595 IOM) TAP v2.10 April 2014 (RVE, ERCH-01, ERT-01) - Manual (Page 17)

T
HIS SCREEN DISPLAYS THE HEATING LOCKOUT
.
This screen only appears if the unit the unit is equipped with heating.
There is a built in hysteresis of 2°F which prevents the heating from short cycling.
The hysteresis is similar to a dead-band above and below the lockout set point.
(Example: If Lockout = 70°F, heating is locked out above 72°F and enabled below
68°F outside air temperature.)
Heating Lockout
Lockout heating when outside
above:
70.0°F
Differential: 2.0°F
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.
T
HIS SCREEN DISPLAYS THE
E
CONOMIZER LOCKOUTS
.
This screen only appears if economizer functionality was provided with the unit.
The lockouts determine when economizer is available, based on the outdoor
air temperature or outdoor air temperature and humidity. The low temperature
lockout prevents outdoor air from entering the unit at too cold of a temperature
that could freeze coils. There is a built in differential that is similar to a deadband,
above and below the lockout set point.
If an outdoor relative humidity sensor was provided with the unit, the user can
change the economizer lockout control type.
Possible Control Types:
DryBulb – The economizer will be locked out based on the outdoor dry-bulb
temperature.
DryBulb+DewPoint (preferred) – The economizer will be locked out based on the
outdoor dry-bulb temperature and a calculated outdoor air dew point.
DryBulb+Enthalpy – The economizer will be locked out based on the outdoor
dry-bulb temperature and a calculated outdoor enthalpy.
DryBulb+WetBulb – The economizer will be locked out based on the outdoor dry-
bulb temperature and a calculated outdoor air wet-bulb temperature.
Economizer Lockout
Type: DryBulb+DewPoint
Below: 40.0°F (Dry Bulb)
Above: 75.0°F (Dry Bulb)
Above: 55.0°F (Dew PT)
Differential: 2.0°F
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.
Supply air low limit
Alarm when supply is
below:
35.0°F
Alarm delay: 300s
T
HIS SCREEN DISPLAYS THE COOLING LOCKOUT
.
This screen only appears if the unit is equipped with cooling.
There is a built in hysteresis of 2°F which prevents the cooling from short cycling.
The hysteresis is similar to a dead-band above and below the lockout set point.
(Example: If Lockout = 55°F, cooling is locked out below 53°F and enabled above
57°F outside air temperature.)
Cooling Lockout
Lockout cooling when outside
below:
55.0°F
Differential: 2.0°F
17 DDC Controller for Tempered Air Products
®