482 01 2231 02
3
Specifications are subject to change without notice
ATTACH FUSE BOX OR CIRCUIT BREAKER BOX
1. For 15kW and 20kW fused models:
After installing heater assembly, attach fuse assembly to side of
fan coil unit by inserting fuse box tab between insulation and to
left side of unit and fan deck. Mount front of assembly to side
flange with two (2) screws provided. On fan coil units size 4200
and larger, remove wire tie that shortens wire length between
heater and fuses. Fuse cover is closed by engaging dimples in
fuse box. (See Figure 2)
2. For 24kW and 30kW fused models:
Fuse assembly is mounted on heater. Be sure fuse cover is
closed by engaging clip latch on unit top panel. (See Figure 1)
ELECTRICAL SHOCK.
Failure to follow this warning could result in death and/or
personal injury.
Close fuse box before power is turned to ON position.
!
WARNING
3. For 5kW through 20kW circuit breaker models:
After installing heater assembly, attach circuit breaker assembly
to unit with screws provided. (See Figure. 3) On fan coil units
size 4200 and larger, remove wire tie that shortens wire length
between heater and circuit breaker assembly to allow mounting
of circuit breaker assembly. (See Figure 3)
4. Circuit breaker models require installing a bezel in unit door to
provide safe access to circuit breakers. Bezel mounts on inside
of blower door. (See Figure 4)
Figure 2
Fused Model Installation
a. Cut insulation away from access hole in blower access panel.
Slide bezel flanges under insulation. Lip on bezel must protrude
inward toward unit.
b. Secure bezel to panel with two (2) No. 6 hex head screws. Insert
screws through original cover plate holes on access panel and
drive into engagement holes on bezel flanges.
ELECTRICAL CONNECTIONS
Refer to unit instructions for recommended wiring procedures.
Install wiring in accordance with all applicable local and national
codes.
Connect heater wiring harness plug to receptacle on fan control
board or wire harness. A positive connection must be made
between plug and receptacle. Plug will interlock with receptacle
when properly seated. Harness contains both 24V control and
high
−
voltage wiring. Blower power is provided through heater
harness.
NOTE:
Units with or without electric heaters require a minimum
CFM. Refer to unit wiring label to ensure the fan speed selected with
electric heaters is equal to or greater than the minimum fan speed
indicated. The minimum CFM for cooling is determined by the
outdoor unit requirements. Use the higher of the two for year
−
round
operation.
Figure 3
Circuit Breaker Model Installation
A. Wire 24V Control Systems
1. Connections to unit
Use No. 18 AWG color
−
coded, insulated (35 Deg. C minimum)
wire to make low
−
voltage connections between thermostat, fan
coil unit, and outdoor unit. If thermostat is located more than 100
ft. from unit (as measured along the low
−
voltage wire), use No.
16 AWG color
−
coded, insulated (35 Deg. C minimum) wire. All
wiring must be separated from line voltage power leads. Refer
to outdoor unit wiring instructions for additional wiring procedure
recommendations.
2. Transformer
Transformer is factory wired for 230V operation. For 208V ap-
plications, disconnect black wire on transformer 230V terminal
and reconnect it to 208V terminal. (See Figure 5) The secondary
circuit of transformer is protected by a 5
−
amp fuse mounted on
fan control board.
3. Heater staging
The units are shipped circuited for single stage operation and
the Observer Wall Control only supports single stage operation.
4. Rectifier and Time Delay Boards
Each heater element is controlled by a relay mounted on the
heater panel. The relay has a 24V DC coil. Each relay has a
small rectifier board attached directly to relay coil terminals. The
rectifier board converts incoming 24V AC control signal to DC.
Some heaters may have up to three relays. These relays are for
future use with a control capable of staging the electric heat. The
second and/or third relay rectifier board also has a time delay
feature and a small jumper wire built into it. With the jumper un-
cut, the time delay allows the second stage heat to be energized
approximately five (5) seconds after the first stage. On 24kW,
