Fans and Motors
All outdoor unit frames <80MBh include one direct drive, variable
speed propeller type fan. All outdoor unit frames >80MBh include two
direct drives, variable speed propeller type fans.
All fan motors have inherent protection, permanently lubricated bear-
ings, and are variable speed with a maximum speed up to 1,100 rpm.
Raised guards are provided to limit contact with moving parts.
All Heat Pump and Heat Recovery outdoor units have vertical
discharge airflow. Optional factory-provided air guides can be field
installed to change discharge airflow from vertical to horizontal.
DIP switch setting to accommodate additional external static pressure.
Both Heat Pump and Heat Recovery outdoor units are available in
choice of 208-230V 60 Hz, 3-phase or 460V, 60 Hz, 3-phase power
supply. The units include over/undervoltage protection.
Multi V Heat Recovery Units
Multi V heat recovery units are for use with Multi V heat recovery
outdoor units to permit simultaneous heating and cooling operation.
Heat recovery units have two (2), three (3), or four (4) ports for con-
nections to indoor units. Each port is capable of connecting from one
(1) indoor unit up to eight (8) indoor units up to a maximum nominal
pacity must use two (2) neighboring heat recovery unit ports twinned
together with a Y-branch kit.
Heat recovery ports can operate in heating or cooling mode inde-
pendently, regardless of the mode of any other port on the unit or in
the system except where heat recovery unit ports are twinned. Heat
recovery units contain one double spiral subcooling heat exchanger
per port, are internally insulated, and do not require a condensate
Casing and Construction
Heat recovery units are completely factory assembled, internally
piped, wired, and are designed for indoor installation. Casing is con-
structed of galvanized steel, and houses piping, valves and controls
to divert refrigerant controlling each port to operate in either heating
or cooling mode. Heat recovery units contain one double spiral sub-
cooling heat exchanger per port, are internally insulated, and do not
require a condensate drain.
Each heat recovery port is circuited with two two-position solenoid
valves to control R410A refrigerant flow path to allow indoor units to
operate in heating or cooling mode.
Units can be piped in series and / or parallel to optimize cost be-
tween material and labor. Up to 16 heat recovery units can be piped
in series, parallel, or a combination of series and parallel to optimize
Multi V IV Outdoor Units / Multi V Heat Recovery Units
Heat pump and heat recovery outdoor units are factory wired with
necessary electrical control components, integral microprocessors,
printed circuit boards, thermistors, sensors, terminal blocks, and
The control circuit between the indoor units, heat recovery unit(s)
(Multi V heat recovery systems only) and the outdoor unit is an
RS-485 daisy chain communication bus. The cable is two conductor,
stranded and shielded, 18 AWG.
Microprocessor-based algorithms provide component protection,
soft-start capability, refrigeration system pressure, temperature,
defrost, and ambient control.
cost between material and labor.
Any series string of heat recovery
ports/units can connect up to
192MBh of indoor unit nominal
• Indoor units up to 131 equiva-
lent feet of piping length from
the Heat Recovery unit to
which it is connected.
• Indoor units up to 295 equiva-
lent feet of piping length from the first branch.
• Difference between highest and lowest elevation indoor units
piped to separate parallel heat recovery units (HRUs) up to 131
feet in elevation.
• Difference between highest and lowest heat recovery units piped
in parallel up to 49 feet in elevation.
• Difference between highest and lowest elevation heat recovery
units piped in series up to 16 feet in elevation.
• Elevation difference of series connected heat recovery units can-
not exceed 16 feet.
All refrigerant lines from the outdoor unit to the heat recovery units,
and from the heat recovery units to the indoor units must be sepa-
rately field insulated.
Heat recovery units require 208-230V, 1-phase, 60 Hz electrical
power, and are capable of operation within ±10% of nominal voltage.
Heat recovery units include factory-installed control boards with
integral microprocessors. Heat recovery unit control boards commu-
nicate with the main control board in the outdoor unit and interface
with the VRF equipment controls system. The control circuit between
the indoor units, heat recovery units and the outdoor unit is RS-
485 daisy chain communication over two-conductor, stranded and
shielded, 18 AWG cable.
Four-port Heat Recovery Unit.
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