The Ductless Split System of Choice
Made in Rome, New York, USA
3
approximately 20 seconds. At that point the unit will enter
defrost mode for approximately 2 seconds. During this time
the condenser fan will switch off, the reversing valve will
energize and the defrost board will energize the indoor
electric heat relay through the W terminal. After the 2
second defrost cycle is complete, the unit will switch back
to heating operation for another twenty seconds. This process
will repeat until the jumpers are removed from the test pins.
NOTE:
If the condenser coil is heavily frosted
with ice, it is likely that the Defrost Sensor is
already closed so the R and DFT jumper can
be eliminated. To initiate defrost, momentarily
jump DFT TST until the defrost cycle begins
but DO NOT leave the jumper in place. The
unit will remain in defrost mode until the
condenser coil is defrosted and will then
resume heating mode.
L
IMITED
R
ANGE
H
EAT
P
UMP
A limited range heat pump is a model that does not
utilize a defrost sequence in heating mode since this unit
will not operate during periods of outdoor temperatures
below 35° F.
The EMI limited range heat pumps are designed to
cease operation at 35° F. (+/- 3° F) and automatically switch
into electric resistance or hydronic heating only, as long as
the evaporator has been supplied with supplemental heat
from the factory (it is recommended that supplemental heat
be ordered as an option with ALL heat pump evaporators).
The specific control that is used to monitor the extreme
cold conditions and break power to the compressor is called
a Changeover Thermostat (C.O. Tstat on wire diagram).
This device has a long sensing bulb on its body that is
strategically placed from the factory for best sensing
capability.
The EMI MH2 & MH4 series condensers are
manufactured as limited range heat pumps. The
capacities available range from 9,000 BTU/h up to 30,000
BTU/h nominal capacity.
MIXING & MATCHING EQUIPMENT IN A
SPLIT SYSTEM (STRAIGHT COOL ONLY)
It is possible to mate EMI air handlers and condensing
units with other manufacturers products in
Straight Cool
Applications
if the following conditions are met properly
(see EMI Policy Bulletin #910503).
All equipment capacities must have the same BTU/h
rating and efficiency rating (SEER).
A transformer must be added to the outdoor unit if
not standard.
If a thermostat is not supplied by EMI it must have
an independent Gsignal capability to operate the fan.
EMI must test and/or approve any non-EMI equip-
ment if heat pump applications require manufacturer
mixing.
NOTE:
If EMI equipment is installed in a mixed
equipment system without prior approval, EMI
will void ALL warranties.
GENERAL WIRING PROCEDURES
EMI systems require the following electrical wiring
for proper operation:
24v transformer (standard in all EMI condensers).
NOTE:
It may be necessary to install a trans-
former if using another manufacturers straight
cool condenser (see Mixing & Matching Equip-
ment in this guide.)
Indoor and outdoor unit high-voltage supply and ac-
companying wiring must match unit specifications.
If optioned, low voltage thermostat wiring must run
between the indoor and outdoor units (also wall-
mounted thermostat NEC class II wiring).
EMI
AmericaSeries
condensers are designed to oper-
ate with EMI
AmericaSeries
evaporators. Both the condenser
(outdoor unit) and evaporator (indoor unit) have a
high volt
service connection and are intended to be independently con-
nected to the electrical service panel (see the unit name plate
for correct breaker types and sizes).
The outdoor and indoor units are also connected to
each other through
low volt
interconnect wiring. A 24v trans-
former located in the condensing unit provides the low volt
power source.
The control circuit operates on a 24v a/c power sup-
ply. Control of the condenser is provided either by the
indoor evaporator unit or a wall mounted remote ther-
mostat.
For example, Model SHC condensing units are de-
signed to independently connect to a high volt power supply
(see name plate for required voltage and circuit breakers).
The high volt connection is made through three 6-inch lead
wires located in the control section (refer to wiring diagram).
Wiring connections must abide by NEC and any local elec-
trical codes.
Low volt connections are made through the 5-posi-
tion terminal located in the control section. This circuit is an
NEC Class-II low volt circuit. The low volt terminal block
is labeled C, Y, O, W2, and R.
