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50VG-K: Installation Instructions
Selection of Proper Fan Speeds for Operation Modes:
Low Stage Cooling (All Models): Using
external static pressure drops for wet coil, economizer, and filter, and
add them to dry coil measured on the system. Using this total static
pressure, look up
Table 5
to find the airflows available at the total static
pressure. For 208/230 VAC models, connect the chosen fan speed wire
to "LO COOL" connection on the IFB Board (see
models, connect the chosen fan speed wire to "LOW" connection on the
IFB (see
Fig.
11).
High Stage Cooling (All Models): Using
external static pressure drops for wet coil, economizer, and filter, and
add them to dry coil measured on the system. Using this total static
pressure, look up
Table 5
to find the airflows available at the total static
pressure. The speed chosen must provide airflow of between 350 to 450
CFM per ton of cooling. For 208/230 VAC models, connect the chosen
fan speed wire to "HI COOL" connection on the IFB Board (See
Fig.
11). For 460 VAC models, connect the chosen fan speed wire to
"HIGH" connection on the IFB (see
High Stage Enhanced Dehumidification Cooling (208/230 VAC
Models): Using the total static pressure for selecting the high stage
cooling speed, look up
Table 5
that total static pressure. All airflows highlighted in
acceptable for the Dehum speed. The speed chosen must provide airflow
of between 320 to 400 CFM per ton of cooling. To activate the high
stage enhanced dehumidification cooling mode, the shunt jumper must
be moved from the "No DH" to the "DH" selection. (See
up.) For 208/230 VAC models, connect the chosen fan speed wire to
"DHUM" connection on the IFB Board (see
Continuous Fan (All Models): Continuous fan speed is the same speed
as Low Stage Cooling.
To activate the high stage enhanced dehumidification cooling mode, the
shunt jumper in
Fig. 11
must be moved from the No DH to DH selection
(See
Fig.
11, close up).
Using the Same Fan Speed for More than One Mode: Some fan speeds
are ideal for more than one mode of operation. It is permissible to use a
field-supplied jumper wire to connect one speed tap wire to two or more
speed connections on the Interface Fan Board (IFB). Jumper wires must
use 18 AWG wire with at least 2/64" insulation.
Cooling Sequence of Operation
a. Continuous Fan
(1.) Thermostat closes circuit R to G energizing the blower
motor for continuous fan. The indoor fan is energized on
low speed.
b. Cooling Mode
(1.) Low Stage: Thermostat closes R to G, R to Y1. The
compressor and indoor fan are energized on low speed. The
outdoor fan is also energized
(2.) High Stage: Thermostat closes R to G, R to Y1, R to Y2.
The compressor and indoor fan are energized on high speed.
The outdoor fan is also energized.
c. Electric Heating Mode
(1.) Thermostat closes circuit R to W2 or W3, and R to G. There
are no on or off delays.
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
Table 7
-
Table 9
Fig.
11). For 460 VAC
Table 7
-
Table
9, find the
Fig.
11).
to find lower speed/airflows available at
Table 5
Fig.
Fig.
11).
find the
are
11, close
07
QIL
D5 D3
15
208/230 VAC Models
HIGH
LOW
QC5
QC4
KZ
KL
R13 C8
R11
Q1
09
0L0
08
D2
ALO
Q3
C9
C4
G1
G2
Z2
06
04
A7
R9
AB A15
Z1
U1
C3
C7
JWZ
JW5
R3 R5 R6
R2
P2
JW3
QCB
Y
R W2 Y
C
W3 W3 W2 W2 C
JW4
SSTZ-8
P1
Y2
Y1
W3
W2
DH G
C R
Y
460 VAC Models
Fig. 11 – Interface Fan Board (IFB)
A12571
COM
QC3
DCR
QCR
C
QC1
AL2
RL
01
C0
F1
R4
RL4
P4
A09059
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