valent VX Series - Optional Component Operation; EC Condenser Fan Operation; Air-Source Heat Pump Operating Conditions

Dedicated Outdoor Air Unit16
Optional Component Operation
Electronically Commutated (EC)
Condenser Fans with Standard Scroll or
Digital Scroll Compressors
The EC condenser fan will
modulate up and down to
maintain the highest liquid
line pressure. The factory
set points are: Set (left
dial): 23 barg; Diff (right
dial): 5 barg.
Fan operation with these
set points are as follows.
The fan will be at max
speed (~1140 rpm) when
the highest liquid line
saturation temperature
is 118°F (410psig, 28
barg). The fan remains at
max speed if the pressure is higher than 410psig (28
barg). The fan will be at min speed (~180rpm) when
the highest liquid line saturation temperature is 105°F
(340 psig, 23 barg). Below this pressure, the fan will be
off. The fan modulates linearly between the min and
max speeds. If unit is selected with inverter compressor
or air-source heat pump, reference the supplemental
Reference Guide for Microprocessor Controller.
Air-Source Heat Pump
Operating Conditions and Limitations
To operate in Cooling mode, the following conditions
must be true:
1. Supply air temperature above minimum low supply
temperature limit (35°F)
2. Outside air temperature above the cooling ambient
lockout (55°F, adj.)
To operate in Heating mode, the following conditions
must be true:
1. Supply air temperature below maximum high
supply temperature limit (120°F)
2. Supply air temperature above 35°F
3. Outside air temperature above the low ambient
lockout (10°F, adj.)
For more information on air-source heat pump
operation, reference the supplemental Reference Guide
for Microprocessor Controller.
Set (left dial): 23 barg;
Diff (right dial): 5 barg
IMPORTANT
Air-source heat pumps are equipped with a defrost
cycle to remove ice from the outdoor coil. During
defrost cycles, melted water may drip from the
bottom of the refrigeration section under the outdoor
coil. In cold climates, proper drainage/heat tape must
be installed under the outdoor coil to prevent the
buildup of ice on the roof.
IMPORTANT
Melted water from snow accumulation on the unit
roof can be sucked into outdoor fans, resulting in ice
formation on fan blades under certain conditions.
Remove snow accumulation from the unit roof and
outdoor coil section after snow storms.