INSTALLATION INSTRUCTIONS
Low−Ambient Kit
NASA201LA, NASA401LA
These instructions must be read and understood completely before attempting installation.
Safety Labeling and Signal Words
DANGER, WARNING, CAUTION, and
NOTE
The signal words DANGER, WARNING, CAUTION, and NOTE are used to identify levels of haz-
ard seriousness. The signal word DANGER is only
used on product labels to signify an immediate hazard. The signal words WARNING, CAUTION, and
NOTE will be used on product labels and throughout this manual and other manuals that may apply
to the product.
DANGER − Immediate hazards which will result in
severe personal injury or death.
WARNING − Hazards or unsafe practices which
could result in severe personal injury or death.
CAUTION − Hazards or unsafe practices which
may result in minor personal injury or product or
property damage.
NOTE − Used to highlight suggestions which will
result in enhanced installation, reliability, or operation.
Signal Words in Manuals
The signal word WARNING is used throughout this
manual in the following manner:
WARNING
!
The signal word CAUTION is used throughout this
manual in the following manner:
!
Signal Words on Product Labeling
Signal words are used in combination with colors
and/or pictures on product labels.
WARNING
CAUTION
!
ELECTRICAL SHOCK HAZARD
Failure to turn off electric power could result in
personal injury or death.
Before installing or servicing system, turn off
main power to the system. There may be more
than one disconnect switch, including accessory
heater(s).
NOTE: Read the entire instruction manual before starting the
installation.
Improper installation, adjustment, alteration, service,
maintenance, or use can cause explosion, fire, electrical
shock, or other conditions which may cause death, personal
injury, or property damage. Consult a qualified installer,
service agency, or your distributor or branch for information
or assistance. The qualified installer or agency must use
WARNING
SAFETY CONSIDERATIONS
factory−authorized kits or accessories when modifying this
product. Refer to the individual instructions packaged with
the kits or accessories when installing.
Follow all safety codes. Wear safety glasses, protective
clothing, and work gloves. Use quenching cloth for brazing
operations. Have fire extinguisher available. Read these
instructions thoroughly and follow all warnings or cautions
included in literature and attached to the unit.. Consult local
building codes and current editions of the National Electrical
Code ( NEC ) NFPA 70. In Canada, refer to current editions
of the Canadian electrical code CSA 22.1.
Recognize safety information. This is the safety−alert symbol
!
!
. When you see this symbol on the unit and in instructions
or manuals, be alert to the potential for personal injury.
Understand the signal words DANGER, WARNING, and
CAUTION. These words are used with the safety−alert
symbol. DANGER identifies the most serious hazards which
will result in severe personal injury or death. WARNING
signifies hazards which could result in personal injury or
death. CAUTION is used to identify unsafe practices which
may result in minor personal injury or product and property
Specifications subject to change without notice.
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damage. NOTE is used to highlight suggestions which will
result in enhanced installation, reliability, or operation.
!
WARNING
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal
injury or death.
Before installing, modifying, or servicing system, main
electrical disconnect switch must be in the OFF
position. There may be more than 1 disconnect switch.
Lock out and tag switch with a suitable warning label.
INTRODUCTION
These instructions cover the installation of Low−Ambient
Pressure Switch Part No. NASA201LA and NASA401LA in
all single−speed air conditioners or heat pumps using R−22
or R−410A refrigerant. This kit is also acceptable for use on
2−stage air conditioners or heat pumps using R−410A and
permanent split capacitor (PSC) fan motors.. Refer to Table
1 for kit usage.
DESCRIPTION AND USAGE
The Low−Ambient Pressure Switch Kit is a long−life pressure
switch which turns the fan on and off as shown in Table 1. It
is wired in series with black fan lead. Sleeve−bearing motors
can be used with this control.
Other accessories may be required. Refer to the Required
Changes for Cooling Units and Heat Pump Units section in
this document for further details.
!
CAUTION
CUT HAZARD
Failure to follow this caution may result in personal
injury.
Sheet metal parts may have sharp edges or burrs. Use
care and wear appropriate protective clothing and
gloves when handling parts.
INSTALLATION
The pressure switch is mounted inside the outdoor unit
cabinet by using adapter tube supplied. The adapter tee is
mounted to liquid service valve and tube is either routed
through one of the knockout holes in unit cabinet (vertical
discharge product) or through one of the service valve holes
in unit cabinet (horizontal discharge product). From inside
cabinet, the flare nut is attached to extender tube. (See Fig.
1.) The pressure switch is wired in series with black or
common fan lead.
WIRING FOR ALL VOLTAGES OF COOLING UNITS
A. Single− And Two−Stage Non−Communicating
Capable
For all voltages of cooling units, refer to Fig. 2 and wire
low−ambient pressure switch as follows:
1. Disconnect black fan lead from contactor and connect
this lead to yellow or violet wire from low−ambient
pressure switch using connector supplied.
NOTE: To ensure electrical isolation and strain relief, it is
recommended to wrap connector with UL approved electrical
2 482 01 5121 01
Specifications subject to change without notice.
tape overlapping the wires on each side by a minimum of 1
inch.
2. Connect remaining blue wire from low−ambient
pressure switch to contactor terminal from which black
fan lead was removed.
B. Single− And Two−Stage Communicating Capable
For all stages of cooling units, refer to Fig. 3 and use
Low−Ambient Pressure Switch as follows:
1. Disconnect black fan lead from control board and
connect it it to yellow or violet wire from low ambient
pressure switch connector supplied.
NOTE: To ensure electrical isolation and strain relief, it is
recommended to wrap connector with UL approved electrical
tape overlapping the wires on each side by a minimum of 1
inch.
2. Connect blue wire from low−ambient pressure switch
to control board terminal from black fan lead was
removed.
WIRING FOR HEAT PUMPS
Heat pumps require a normally closed Isolation Relay (Part
No. NASA00101IK or equivalent) with the 24v coil connected
to the C and O terminals of defrost board or control board.
A 208/230v Applications
For 208/230v heat pump applications, refer to Fig. 4 and wire
low−ambient pressure switch as follows:
1. Remove black lead of outdoor fan motor connected to
defrost board OF2 or control board ODF depending on
type of unit.
2. Install piggyback female terminal on violet wire
harness (provided in isolation relay kit) to tab 1 of
isolation relay. Connect non−piggyback female
termination of same violet wire to one side of provided
connector. Connect the female termination of violet (or
yellow) lead of low ambient pressure switch to the
other side of the provided connector. Connect the
female termination of the black fan motor lead to the
male piggy back terminal located at tab 1 of relay.
NOTE: To ensure electrical isolation and strain relief it is
recommended to wrap connector with UL approved electrical
tape overlapping the wires on each side by a minimum of 1”.
3. Install piggyback female terminal on black wire
harness (provided in isolation relay kit) to tab 2 of
relay. Connect non−piggyback female termination of
same black wire to OF2 on defrost board or ODF on
control board. Connect the female termination of blue
lead of low ambient pressure switch to the male piggy
back terminal located at tab 2 of relay.
4. Install orange wire (provided in isolation relay kit) to
one side of the relay coil. Connect the other side to
the O wire coming from defrost board or control board.
5. Install black wire (provided in isolation relay kit) to
opposite side of the relay coil. Connect the other side
to the C wire coming from defrost board or control
board.
6. Reinstall control box cover and reconnect power to
unit.
B. 460v Applications
For 460v heat pump applications, refer to Fig. 5 and wire
low−ambient pressure switch as follows:
1. Remove black lead of outdoor fan motor connected to
outdoor fan relay terminal 3.
2. Install piggyback female terminal on violet wire
harness (provided in isolation relay kit) to tab 1 of