Vfd-Ready' For Customer-Installation; Optional Hot Gas Bypass (Hgbp) - York SUNLINE MagnaDRY WR300 Installation Manual

284813-YIM-C-1008
Once the appropriate relay and capacitor are obtained,
install the capacitor across LR terminals '3' & '4' and
make the following wiring connections:
• LR '1' to BAS controller
• LR '2' to BAS controller
• LR '3' to UCB 'X'
• LR '4' to UCB 'C'

'VFD-READY' FOR CUSTOMER-INSTALLATION

Units configured as 'VFD-ready' provide provisions for
a customer-installed drive. The physical dimensions of
VFDs can vary greatly among manufacturers, horse-
power ratings and voltage requirements. Keep in mind
that drive manufacturers also require various minimum
clearances to allow for adequate internal cooling of the
drive during operation.
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 applications13" H x 6" W x 7" D
For 7.5 thru 15-hp motor applications13" 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.
20
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.
Do not connect AC power to the T1, T2, T3
drive terminals to prevent damage to the VFD.
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.
Johnson Controls Unitary Products