35
electric Heat Applications
Units with electric heat utilize control relay located on the
air handlers control board in the control box.
Auto-reset limit switch located on heater end plate or
on heater assembly interrupts power to heater should
overheat condition occur.
Each electric heat assembly is also equipped with one-time
fuse link. Should electric heat temperatures rise above auto
resetting limit switch, non-resetting, one-time fuse link
opens and heater remains off. To restart, new fuse link is
required.
5 kw = 22.3 Amps
3 kw = 13.5 Amps
Units With Condensate pumps
EMI air handlers are available with optional condensate
pump. Condensate pumps are recommended when it is not
possible to gravity drain condensate from indoor unit.
Maximum lift for pumps will vary. Consult pump
instructions for maximum lift.
Condensate generated by air handlers will collect in pump’s
reservoir.
• When water level is high enough, pump motor
energizes clearing water from the reservoir.
• If water exceeds either drain pan upper limit or
condensate pump reservoir's upper limit, compressor
shuts down, preventing generation of additional
condensate.
Interconnect Wiring
See “Electrical Wiring” on page 13 for interconnect wiring
diagrams, both unit mounted and optional wired wall
thermostat.
Checking Voltage
can be accomplished at either indoor or
outdoor unit.
24v transformer located in indoor air handler unit provides
low volt control power to both indoor air handler and
outdoor condenser between SC and 24vDC(-) terminals.
This is DC voltage use proper scale on meter.
Cooling
EMI heat pump systems utilize Reversing valve energized
in Cooling mode and de-energized in Heating mode. When
24 volts
AC
exists between Rv and Rv (either indoors or
outdoors) system is in cooling mode. As long as system
is in Cooling mode, 24 volt power exists between Rv and
Rv terminals. When zero (0) volts AC exists between Rv
and Rv, system is either in Heating mode or there is open
circuit to reversing valve in Cooling mode.
• EMI heat pump systems utilize a reversing valve is
that is energized in the cooling mode.
• It should remain energized constantly as long as the
indoor unit or thermostat remains in cooling mode.
Heating
Heat pump systems accommodate two-stage heating when
optional electric heater is present in combination with heat
pump condenser. First stage consists of heat pump alone
and second stage consists of heat pump and electric heat
both operating simultaneously.
To verify heating operation, place Amp meter on indoor
incoming power line. Mode should be heating, with
temperature set 1° above current room temperature.
• Compressor starts and delivers heat to conditioned
space, Amp meter registers fraction of Amp (blower
motor only).
• Set temperature 2° continues to run delivering heat to
conditioned space, and electric heat energizes.
Amp meter reads 7 to twenty 23 Amps at 230 volts
AC
depending on electric heater capacity and line voltage
supplied to air handler.
TROUbLeSHOOTIng
