8
Specifications subject to change without notice. IM-KSAIC03-03
SCENARIO 4: SINGLE ZONE OUTDOOR
UNIT 38MA*R WITH APPROVED MULTI-
FAMILY 24V FAN COILS FMA/FMC/FMU
For the correct combinations, review the compatibility chart in “APPENDIX
1 - COMPATIBILITY AND FAN SPEED WIRING” on page 15.
Installation Steps:
1. Remove the TXV/Piston on the indoor unit.
2. Run the interconnecting piping from the outdoor unit to the indoor
unit using the outdoor piping size and brazing to the adapter for the
mechanical fitting from which the TXV was removed (Part number
331831-701) (available through RCD). If required, use the
Bushing/Reducers data (review “APPENDIX 2 - PIPING
ADAPTER BUSHINGS/REDUCERS” on page 16).
3. Suction and liquid refrigerant lines must be properly insulated and
separated from each other to prevent condensation and energy loss.
4. Disconnect and remove the 24V transformer from the 24V interface
kit. Run a 2-conductor wire from the 24 volt side of the indoor unit
transformer to CN16 and CN17.
5. Run the interconnecting wiring from the outdoor unit to the 24V
interface using terminal connections L1, L2, S and G. Separate
power supplies are required for the outdoor unit and the indoor unit.
6. Run the thermostat wiring from the thermostat to the 24V interface
using connection R and C on CN15 and Y, W, G on CN19.
7. Run the thermostat wiring from the 24V interface to the indoor unit
using output connections G1 (Low), G1+G2 (Medium),
G1+G2+G3 (High) on the 24V interface and connect according to
the installation manual for these fan coils.
8. Install the T1 sensor on CN5 on the 24V interface and place on the
return of the indoor unit.
9. Configure the dip switches on the 24V interface accordingly.
10. Configure the thermostat to operate as a single stage cooling and
heating (
DO NOT
configure the thermostat as Heat Pump).
NOTES:
Follow the indoor and outdoor unit's general installation
instructions.
The T1 (Return air temperature) sensor should be near or on the unit
on the air inlet side. The thermistor should be installed pointing down
into the duct between 2.5ft. (0.762m) and 4ft. (1.2m) from the return
side of the fan coil. Use a 1/2” drill and insert the thermistor no less
than 6 in. (15.24cm) into the duct and seal air tight around cable.
Auxiliary Heater on an FMA/FMC/FMU:
Refer to and follow the steps of the FMA/FMC/FMU Fan Coil
Installation Instructions manual and wiring diagram:
1. Wire W2 from the thermostat directly to the FMA/FMC/FMU fan
coil as listed on the indoor unit wiring diagram.
2. Re-configure the wall thermostat to control the electric heat as a
2nd stage heat W2.
3. Follow the standard wiring practices of the FMA/FMC/FMU to
connect the Auxiliary Electric Heater element.
NOTE:
When an auxiliary electric heater is connected and active by
W2 from the thermostat, the fan coil keeps blowing air regardless if
the outdoor unit is operating under
DEFROST
mode.
Fig. 12 — Wiring Diagram for Conventional 24V Fan Coil Indoor Unit
When the outdoor unit is matched with a Multi-Family or Residential fan
coil and brazing the piping on the fan coil side is required, it is
NECCESSARY to flow nitrogen into the system while brazing the line
set since a filter drier is not recommended for use with these condensing
CAUTION
The conventional thermostat must be configured for use with a single
stage air conditioner (Y output ONLY) and a single stage heating (W)
system.
CAUTION
Thermostat
70
Transformer
L1
L2
Red dash means
disconnect
transformer
Power supply from outdoor unit disconnect.
Two wires are line voltage and the other is a ground wire.
Power supply from indoor unit
1 2 3 4 5
N G
L
C
GROUND
NOTE: Dashed Lines indicate
OPTIONAL COMPONENTS
BUS BAR
G
G
