Lennox XC21, Installation Instructions Manual

Page 19

XC21 SERIES

IMPORTANT

Use a thermocouple or thermistor electronic vacuum
gauge that is calibrated in microns. Use an instrument
capable of accurately measuring down to 50 microns.

WARNING

Danger of Equipment Damage. Avoid deep vacuum
operation. Do not use compressors to evacuate a
system. Extremely low vacuums can cause internal
arcing and compressor failure. Damage caused by
deep vacuum operation will void warranty.

Evacuating the system of non−condensables is critical for
proper operation of the unit. Non−condensables are

defined as any gas that will not condense under
temperatures and pressures present during operation of
an air conditioning system. Non−condensables and water
suction combine with refrigerant to produce substances
that corrode copper piping and compressor parts.

Electrical

In the U.S.A., wiring must conform with current local codes
and the current National Electric Code (NEC). In Canada,
wiring must conform with current local codes and the current
Canadian Electrical Code (CEC).
Refer to the furnace or blower coil installation instructions
for additional wiring application diagrams and refer to unit
nameplate for minimum circuit ampacity and maximum
overcurrent protection size.

24VAC TRANSFORMER

Use the transformer provided with the furnace or air
handler for low-voltage control power (24VAC − 40 VA
minimum)

Refer to the unit nameplate for minimum circuit ampacity, and
maximum fuse or circuit breaker (HACR per NEC). Install power
wiring and properly sized disconnect switch.

NOTE  Units are approved for use only with copper conductors.
Ground unit at disconnect switch or to an earth ground.

SIZE CIRCUIT AND INSTALL DISCONNECT
SWITCH

1

NOTE  24VAC, Class II circuit connections are made in the control
panel.

Install room thermostat (ordered separately) on an inside wall
approximately in the center of the conditioned area and 5 feet
(1.5m) from the floor. It should not be installed on an outside wall
or where it can be affected by sunlight or drafts.

THERMOSTAT

5 FEET

(1.5M)

INSTALL THERMOSTAT

2

SERVICE

DISCONNECT

SWITCH

WARNING

Electric Shock Hazard. Can cause injury or death. Unit must be grounded in accordance with national and
local codes.

Line voltage is present at all components when unit is not in operation on units with single-pole contactors.
Disconnect all remote electric power supplies before opening access panel. Unit may have multiple power
supplies.

CAUTION

ELECTROSTATIC DISCHARGE

(ESD)

Precautions and Procedures

Electrostatic discharge can affect electronic components. Take precautions
during unit installation and service to protect the unit’s electronic controls.
Precautions will help to avoid control exposure to electrostatic discharge by
putting the unit, the control and the technician at the same electrostatic potential.
Neutralize electrostatic charge by touching hand and all tools on an unpainted unit
surface before performing any service procedure.