Section 3 – SR-2 Software Description
FreshSet High Speed Modulation
Micro Rev
All
HMI Rev
All
Choices
Off or On
Factory Set
Off
Exceptions Only appears if Modulation Control
= On.
Description This feature turns High Speed
Modulation on or off. High Speed Modulation
provides precise modulation control with increased
air-flow and capacity under high cooling load
conditions. Air flow is increased by operating the
unit in high speed. The increased air flow reduces
the rise in the return air temperature above setpoint
under high cooling load conditions. The discharge
air temperature is controlled to the programmed floor
limit during high speed operation.
If this feature is On the unit will automatically enter
high speed operation under high load conditions.
The unit will automatically switch back to low speed
operation when conditions allow. High speed
operation only occurs when necessary to minimize
fuel consumption and high speed operating hours.
FreshSet High Speed Modulation Ceiling
Micro Rev
All
HMI Rev
All
Choices
2.0°F (1.0°C) to 10.0°F (5.5°C)
Factory Set
3.0°F (1.7°C)
Exceptions Only appears if High Speed Mod-
ulation = On.
Description This switch point determines the
number of degrees above setpoint the temperature
must rise before high speed modulation is allowed.
A lower setting will result in tighter control to setpoint
but increases high speed operation time. A higher
setting will result in looser temperature control but
reduces high speed operation time for additional fuel
savings.
When the temperature rises to the Modulation
Ceiling + 2°F (-17°C) the unit will run in high speed
modulation until the temperature falls back to the
Modulation Ceiling.
For example, if the setpoint is 35°F (1.7°) and the
High Speed Modulation Ceiling is 3°F (1.7°C), the
Modulation Ceiling is 38°F (3.4°C). If the
temperature reaches 40°F (4.4°C) as determined by
a Modulation Ceiling of 38°F (3.4°C) + 2°F (1.0°C),
the unit will switch to high speed modulation. The
unit will run in high speed modulation until the
Modulation Ceiling of 38°F (3.4°C) is reached. The
unit will then switch back to low speed modulation.
3-39
31 January 2005
To Next Page
Loading...
