Carrier 38HD018 - Control Circuit Wiring; Control Circuit Details; Service Safety Warning; Blower Safety Precaution

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ARRANGEMENT A-(COOLlNG ONLY)
J
ARRANGEMENT B-ONE TRANSFORMER
(COOLING AND ONE-STAGE HEATING)
rHr
ARRANGEMENT C-ONE TRANSFORMER
(COOLING AND TWO-STAGE HEATING)
*IFR and IFM are located in furnace on heating-cooling applica¬
tions If accessory IFR is required for cooling-only applications,
locate (IFR) in fan coil
c
— Contactor (12-va)
-— Field Wiring
HC
— Heating Control
IFM
— Indoor Fan Motor
IFR
— Indoor Fan Relay
Trans — Transformer
NOTE Refer to unit wiring label for wire colors CtoGandCtoY
connections
Fig. 6 — Typical Control Circuit Connections
CONTROL CIRCUIT WIRING — Control voltage is
24 volts (40 va minimum). See Fig. 6 and unit label
diagram for field-supplied wiring details. Route control
wires through opening in unit side panel to connection in
unit control box.
TB — Terminal Board
■ O - TB Connections
-Field Wiring
. Factory Wiring
Fig. 7 — Line Power Connections
NOTE: For wire runs up to 50 ft, use no. 18 AWG insu¬
lated wire (35 C minimum). For 50 to 75 ft, use no. 16
AWG insulated wire (35 C minimum). For over 75 ft, use
14 AWG insulated wire (35 C minimum).
NOTE: Operation of unit on improper line voltage con¬
stitutes abuse and could affect Carrier warranty See
Table 3. Do not install unit in system where voltage may
fluctuate above or below permissible limits.
See Table 3 for recommended fuse sizes. When making
electrical connections, provide clearance at unit for refrig¬
erant piping connections
Use furnace oi fan coil transformer as 24-v (40-va
minimum) supply for system as shown in Fig. 7 or use
accessory transformer.
A WARNING
To avoid personal injury, be sure indoor blower has
stopped before attempting service or maintenance.
Operating voltage to compressor must be within
voltage range indicated on unit nameplate. On 3-phase
units voltages between phases must be balanced within
2% U se the following formula to determine the % voltage
imbalance.
% Voltage Imbalance
^ max voltage deviation frqm average voltage
~~ average voltage
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