Johnson Controls Low Ambient Pressure Kit - Manual

Johnson Controls Unitary Products

513433-UAI-A-0509

ACCESSORY KIT INSTALLATION MANUAL

LOW AMBIENT PRESSURE KIT MODEL 2LA06700224 & 2LA06700424

FOR MODELS: SPLIT SYSTEM AIR CONDITIONERS AND HEAT PUMPS

GENERAL INFORMATION

The low ambient pressure switch kit (2LA06700224) for R-22
models and 2LA06700424 for R-410A models) are designed to
regulate condenser liquid pressure at low outdoor ambient tem-
peratures by controlling the airflow over the condenser. The low
ambient pressure kit will energize the outdoor motor when the
liquid line pressure reaches 300 +/-10 PSIG for R-22 models
and 360 +/-10 PSIG for R-410A models, it will stop the motor
when the pressure falls below 150 +/- PSIG for R-22 models
and 240 +/- PSIGfor R-410A models.

The supplied relay has a normally-closed contact. As the liquid
pressure falls below the low setting of the pressure switch, the
relay will energize and open the normally-closed contact, thus
breaking the circuit of the fan motor, causing it to stop.As the
liquid pressure increases above the high pressure setting of the
pressure switch, the relay will de-energize and close the nor-
mally-closed contact, re-energizing the fan. Heat pumps use
the 4-way reversing valve power for the control circuit of the low
ambient kit in the order to disable low ambient fan cycling in the
heat mode.

When applying this kit, a TXV must be used on the indoor coil-
and a crankcase heater should be added. This will guard
against liquid migration and hard starts which could lead to pre-
mature failure of the compressor.

PRE-INSTALLATION INFORMATION AND

INSTRUCTIONS

1.

With this kit, only use motors that are single phase, perma-

nent split, capacitor type or shaded pole motors.

2.

Line Voltage Range: 120 to 600 Volts AC.

3.

Wiring must comply with all local and national electric

codes.

4.

Crankcase heater should be applied in conjunction with

this kit.

INSPECTION

The following list details the parts included in this kit. Inspect
the kit to ensure that all the parts are included.

INSTALLATION

1.

Disconnect power to the unit.

2.

Remove the control access panel.

3.

Locate the liquid line base valve and remove the cap off the

schrader valve.

4.

Attach the tee fitting and pressure switch to the liquid line

base valve , as shown in Figure 1.

5.

Tighten all connections using a 9/16” wrench. Check the

connections between the switch and schrader valve for
leaks.

6.

Route the pressure switch wires through the grommet

located on the bottom of the control box. Secure the wires
away from hot refrigerant lines with a wire tie.

7.

Secure the relay with #10 screws included in the kit. Use

the relay to mark and drill two (9/64 inch) holes so that the
relay is 1/2 inch away from high voltage wiring and compo-
nents.

8.

To wire the low ambient pressure kit:

a.

For 1 and 3 phase AC, use Figure 2.

b.

For 1 and 3 phase HP, use Figure 3*.

*To connect wires to “O” and “C” in the low voltage box, cut off
wire connections from the additional black wires provided in kit
and strip insulation from wire. Use existing wire nuts to connect
into “O” and “C” junction.

9.

Replace the control access panel and restore power to the

unit.

10. With the unit running in the cooling mode, make sure the

outdoor fan operates properly and replace all schrader
valve caps.

Improper installation, adjustment service, or mainte-
nance can cause injury or property damage; there-
fore, only a qualified installer or qualified service
personnel should perform the conversion.

TABLE 1:

Source 1

ITEM

QTY.

PART NO.

DESCRIPTION

1

1

513033

Pressure Switch

2

1

473-19101-000

Relay

3

2

—

Black Wire

4

1

—

Black Wire

5

2

021-17310-000

Screw #10-16x3/8

6

2

—

Wire Tie

7

1

6666

Tee Fitting

8

1

1216-175

Line Splice Connection

Make sure the electric power is shut-off. Failure to dis-
connect the electric power could result in electric
shock and severe injury from the outdoor fan.

FIGURE 1:

Pressure Switch Assembly

T

O LOW VOL

T

AGE BOX

PRESSURE
SWITCH

FLARE
FITTING

TEE FITTING
ASSEMBLY

VALVE
CAP

FLARE FITTING
WITH DEPRESSOR

BRASS REFRIGERANT
VALVE (Liquid)