Manual 2100-568A
Page 12 of 23
WirinG – main POWer
Refer to the unit rating plate for wire sizing information
and maximum fuse or “HACR” type circuit breaker
size. Each outdoor unit is marked with a “Minimum
Circuit Ampacity”. This means that the field wiring
used must be sized to carry that amount of current.
Depending on the installed KW of electric heat, there
may be two field power circuits required. If this is the
case, the unit serial plate will so indicate. All models
are suitable only for connection with copper wire. Each
unit and/or wiring diagram will be marked “Use Copper
Conductors Only”. These instructions
must be
adhered
to. Refer to the National Electrical Code (NEC) for
complete current carrying capacity data on the various
insulation grades of wiring material. All wiring must
conform to NEC and all local codes.
The electrical data lists fuse and wire sizes (75° C copper)
for all models including the most commonly used heater
sizes. Also shown are the number of field power circuits
required for the various models with heaters.
The unit rating plate lists a “Maximum Time Delay
Relay Fuse” or “HACR” type circuit breaker that is to
be used with the equipment. The correct size must be
used for proper circuit protection and also to assure that
there will be no nuisance tripping due to the momentary
high starting current of the compressor motor.
The disconnect access door on this unit may be locked
to prevent unauthorized access to the disconnect. To
convert for the locking capability, bend the tab located
in the bottom left-hand corner of the disconnect
opening under the disconnect access panel straight
out. This tab will now line up with the slot in the door.
When shut, a padlock may be placed through the hole
in the tab preventing entry.
See “Start Up” section for important information on
three phase scroll compressor start ups.
See Tables 3 & 4 for Electrical Specifications.
low Voltage connection
These units use a 24-volt AC low voltage circuit.
The “
R
” terminal is the
hot
terminal and the “
C
”
terminal is
grounded
.
“
G
” terminal is the
fan input
.
“
Y
” terminal is the
compressor input for cooling
1-Stage units only
“
W1
” terminal is the
1st stage electric heat
.
“
W2
” terminal is the
2nd stage heat
(if equipped).
“
E
”, “
F
”, “
Y2
” & “
A
” Used with ECONWMT Economizer.
“
1
” NO (normally open) lockout alarm.
“
2
” NC (normally closed) lockout alarm.
“
3
” COM lockout alarm.
“
4
” & “
5
” dirty filter alarm NC (normally closed).
“
6
” Used with MD4000 only; do not use for anything else!
“
Y1
” & “
7
” Used with ECONWMT Economizer; do
not use for anything else!
“
8
” & “
9
” ECON Fail Alarm.
WirinG – lOW VOltaGe WirinG
230/208V, 1 phase and 3 phase equipment dual primary
voltage transformers. All equipment leaves the factory
wired on 240V tap. For 208V operation, reconnect
from 240V to 208V tap. The acceptable operating
voltage range for the 240 and 208V taps are:
taP ranGe
240
253 – 216
208
220 – 187
NOTE: The voltage should be measured at the field
power connection point in the unit and while
the unit is operating at full load (maximum
amperage operating condition).
For wiring size and connections, refer to MV4000
Controller Manual 2100-571.
dirtY filter sWitch & relaY
These units include a dirty filter switch and relay. The
alarm output of relay is normally closed, open on alarm
and is connected to terminals 4 and 5 of the unit low
voltage terminal block.
ecOnOmizer fail time delaY relaY
NOTE: Applies only to units with economizers.
These units employ a time delay relay used in
conjunction with the 100% Economizers to provide an
economizer fail alarm. The alarm output is connected
to terminals 8 and 9 of the low voltage terminal block.
The time delay should be set to no less than 3 minutes
to ensure no nuisance alarms.
MIS-3054
timer tO be
set here