Room thermostat, Fig. э—wiring harness 16-ptn plug, Viii. accessories – Bryant FA4A User Manual

Page 14: Thermostatic expansion valves (txv), Accessories, Thermostatic expansion valveis (txv), Зиши, Utc tech pub

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A П П G / 1 4 / 2 0 0 8 / T H U 0 3 : 4 8

UTC TECH PUB

F A X N o , 3 1 7 2 4 0 5 6 6 2

0 1 4

+ ROOM THERMOSTAT

- Remove thetrtiOStst 'wires from the circuit board,

- Jumper screw terminais (J at & time) R-G, R-Y/Y2, R-YJ^

and R-W2, If motor runs in all cases, thermostat is bad.

Replace thermostat. If motor does not run, or runs in some
cases but not in others, continue by checking the wiring

harness.

+ WIRING HARNESS

- Shut off power to unit.

- Remove 5-pin plug from motor.

CAUTION:

Never remove 5-pin high voltage plug from

the motor with the power on.

Remove 16-pin plug from motor. ,

Replace 5-pin plug and turn on power.

Check for 24v between pin-1 and pin-12 on the l6-pin plug.

If rm voltage is present, replace wiring'harness. (See Fig, 9.)

If voltage is present, jumper screw terminal R-Y/Y2 on
circuit board and check for 24v between pjh-1-2 and pin-14 on
16-pin plug. (See Fig. 9 ) If no voltage is present, replace
harness.

H 24v is present, the motor is bad. Replace motor.

16 15 14 13 12

ЗИШИ

16-PIN PLUG

A94375

Fig. Э—Wiring Harness 16-Ptn Plug

VIII. ACCESSORIES

A. Electronic Air Cleaner (EAC)

Familiar

230-vac

EAC control/power signal EACl and БАС2 is

not available, because the ICM2 blower motor used in the FK4B

Fan Coil is controlled by low-voUsgc signals. This signal is
replaced by a

24“Vdc

signal which is provided at circuit board

terminals AUXl and AUX2, (See Fig 6.)

This signal is present when either G or W is present and' is active

in all heating and cooling modes. Because 24-vdc relays may not
be readily available to installer, a kit exists, KFAJROIOIACR,
containing a 24-vdc relay which mounts directly inside EAC

cabinet. User-supplied 110 vac is switched by relay to power air
cleaner when G or W arc present. (See Fig. 10 and 11.)

In heat pump applications, the G signal is present in both cooling
and heating modes, permitting НАС to be controlled from G signal
only. For this application, a user-supplied 24-vac relay can be
driven by G terminal eliminating need for relay kit.

B. FK4B De-Hufflidify Mode

NOTE:

Humidistat must open cm humidity rise.

Latent capacities for

systems

using the FK4B Fan Coil are better

than average systems. If increased latent capacity is an application

requirenjeut, the FK4B can be wired to

provide

this requirement by

adjusting its airflow in response to standard humidistat input. Fig.
12 illustrates the wiring connections to activate de-huraidify mode.
Carefully consult product airflow data for cooling and dehumidi-

iying mode,

THERMOSTATIC EXPANSION VALVES (TXV)

The FC4B and FK4B Fan Coils are factory equipped with a hard
shutoff (HSO) TXV,

A9321S

Fig. 10—Mounting KFAIRO101ACR Relay Kit

FK4B

AUXl AUX2

110 VAC BRANCH CKT

GND HOTNËUT

Fig. 11—KFAlROlOIACR Relay Kit Wiring

Schematic

HUMIDISTAT

RED WIRE Г Л

FROM ЮМ2 -f-i-

MOTÛR

TO PCB TERMINAL

MARKED 'RED'

HUMIDISTAT

wiring

FOR

DE-HUMlDiFY MODE

A93215

Fig. l3“HumIdIstat Wiring for De-Humidify Mode

The hard shutoff TXV has no bleed port and allows no bleed-
through after system is shutdown. No pressure equalization occurs.

A start capacitor and relay must be installed on single-phaSc
reciprocating compressors to boost torque to compressor motor so
it may overcome the unequalized system pressures.

This manual is related to the following products:

FC4B FB4A