SCXF-SVX01T-EN
57
bypass valve either towards open or towards closed
respectively. Eventually a balance will be reached until the
saturated condenser temperatures change again. Both
valves close whenever mechanical cooling is not required,
and in the event of a power failure.
If the unit does not have a waterside economizer then
variable water flow is automatically active with intermediate
piping.
Figure 33. Basic water piping, constant water flow
Condenser 1
Condenser 2
Condenser 3
Condenser 4
Figure 34. Intermediate water piping, variable water
flow (L) and Intermediate piping with waterside
economizer, variable or constant water flow (R)
Condenser 1
Condenser 2
Condenser 3
Condenser 4
V2
V2
Condenser 1
Condenser 2
Condenser 3
Condenser 4
V1
Economizer
Variable Water Flow Waterside Economizer
Variable or Constant Water Flow
Unit Airside Components
The air delivery system consists of dampers, enthalpy
switch option, airside economizer option, filters, low
ambient sensors, and factory mounted single or double
wall plenums.
Supply Air Fan
The unit has two supply fans on a single shaft that run at a
constant speed (CV). However, the fans may have the VFD
option with supply air temperature control (VAV) that
modulates airflow based on supply air duct static pressure.
Pressing the stop key on the HI will turn the supply fan off.
The fan is on continuously when a CV unit is in occupied
mode and except when a unit is in the night heat/morning
warm-up mode. During the night heat and setback mode
the fan cycles on and off in response to a call for heat.See
supply fan table below for available fan horsepower.
Table 30. Supply fan horsepower selections
Unit Model HP
SXRF SXWF 5 7.5 10 15 20 25 30 40 50 60
20, 22, 25
X X X X X
25, 29 29, 32
X X X X X
30, 35 35, 38
X X X X X X
40
42, 46
X X X X X X
50
52, 58, 65
X X X X X X
Operating Principles
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