284806-YIM-B-0707
Unitary Products Group
21
The unit comes with a mounting bracket installed in the
Blower Access compartment which may accommodate
other vendor's drives depending on their size. In order
to utilize the unit's mounting bracket, the maximum rec-
ommended drive dimensions are as follows:
For 5-hp motor applications....................... 10" H x 6" W x 7" D
For 7.5 thru 15-hp motor applications........ 13" H x 8" W x 8" D
If the drive will not fit in the allotted space, then it will
need to be mounted elsewhere; either within the build-
ing on a perpendicular wall which is not subjected to
excessive temperature, vibration, humidity, dust, corro-
sive gas, explosive gas, etc., or within an appropriate
enclosure rated for outside installation to safeguard
against moisture, dust and excessive heat.
The power leads to the drive (L1, L2, L3) and from the
motor (T1, T2, T3) along with the respective ground
wires are supplied with the unit and need to be con-
nected after the drive is installed.
A terminal block located in the control box is provided
for field connection of the VFD speed reference signal
(2-10 VDC) and to the normally-open, run-permit auxil-
iary contact. The use of shielded cable is recom-
mended for the above control wiring connections.
For VFD-ready units also equipped with gas/electric
heat, a terminal block located in the unit's control box
and connected to the VAV board's "VAV BOX" termi-
nal, must be field wired to the building's VAV boxes to
ensure fully open dampers during heating operation.
OPTIONAL HOT GAS BYPASS (HGBP)
To allow for low cooling load operation, a direct-acting,
pressure-modulating bypass control valve installed on
the system #1 discharge line is used to divert high tem-
perature, high pressure refrigerant around the TXV in
order to maintain a desired minimum evaporator pres-
sure.
The opening pressure of the bypass valve is fully
adjustable between 0 and 80 psig with a factory-setting
of 60 psig. HGBP is standard on all units with VAV and
optional with CV units.
Do not connect AC power to the T1, T2, T3
drive terminals to prevent damage to the VFD.
