Duty Cycle; Maintenance; Fuse On Powered Type; Electric Heaters - Bryant 551K 04N Series Service And Maintenance Instructions

Single package rooftop cooling only/electric heat unit with puron (r-410a) refrigerant 3 to 5 nominal tons
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UNIT
CONNECT
VOLTAGE
AS
L1: RED +YEL
208, 230
240
L2: BLU + GRA
L1: RED
460
480
Splice BLU + YEL
L2: GRA
L1: RED
575
600
L2: GRA
Fig. 30 — Powered Convenience Outlet Wiring

Duty Cycle

The unit-powered convenience outlet has a duty cycle limita-
tion. The transformer is intended to provide power on an inter-
mittent basis for service tools, lamps, etc; it is not intended to
provide 15A loading for continuous duty loads (such as electric
heaters for overnight use). Observe a 50% limit on circuit load-
ing above 8A (i.e., limit loads exceeding 8A to 30 minutes of
operation every hour).

Maintenance

Periodically test the GFCI receptacle by pressing the TEST
button on the face of the receptacle. This should cause the in-
ternal circuit of the receptacle to trip and open the receptacle.
Check for proper grounding wires and power line phasing if
the GFCI receptacle does not trip as required. Press the RESET
button to clear the tripped condition.

Fuse on Powered Type

The factory fuse is a Bussmann Fusetron
screw-in (Edison base) type plug fuse.
USING UNIT-MOUNTED CONVENIENCE OUTLETS
Units with unit-mounted convenience outlet circuits will often
require that two disconnects be opened to de-energize all pow-
er to the unit. Treat all units as electrically energized until the
convenience outlet power is also checked and de-energization
is confirmed. Observe National Electrical Code Article 210,
Branch Circuits, for use of convenience outlets.

ELECTRIC HEATERS

The 551K units can be equipped electric heaters as a field-
installed accessory. The heaters are modular in design, with heat-
er frames holding open coil resistance wires strung through ce-
ramic insulators and control contactor(s), using a combination of
24-v control side break/auto-reset or line-break/auto-reset limit
switches and a pilot-circuit/manual reset limit switch to protect
1. Bussmann and Fusetron are trademarks of Cooper Technologies
Company.
PRIMARY
TRANSFORMER
CONNECTIONS
TERMINALS
H1 + H3
H2 + H4
H1
H2 + H3
H4
H1
H2
1
T-15, non-renewable
the unit against over-temperature situations. All 551K Model
electric heaters are one module containing either one or two
banks of electric heat coils.
Heater modules are installed in the compartment below the in-
door (supply) fan outlet. Access is through the indoor access
panel. Heater modules slide into the compartment on tracks
along the bottom of the heater opening. See Fig. 31-33.
Fig. 31 — Typical Access Panel Location
Not all available heater modules can be used in every unit. Use
only those heater modules that are UL listed for use in a specif-
ic size unit. Refer to the label on the unit cabinet regarding ap-
proved heaters.
OPTIONAL
FACTORY-
MAIN
INSTALLED
CONTROL
DISCONNECT
BOX
CONTROL WIRE
TERMINAL BLOCK
Fig. 32 — Typical Component Location
Fig. 33 — Typical Module Installation
18
INDOOR
ACCESS
PANEL
CONTROL BOX
ACCESS PANEL
SINGLE
CENTER
VANE AXIAL
POINT
POST
INDOOR FAN
BOX
SYSTEM
HEATER
HEATER
MOUNTING
COVER
BRACKET
MANUAL
RESET
LIMIT
SWITCH
HEATER
MODULE

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