Bryant LEGACY 213R Service Manual download pdf (Page 14)

High--Pressure Switch (AC &

HP)

The high--pressure switch is located in liquid line and protects

against excessive condenser coil pressure. It opens around 610 psig

for Puron and 400 psig for R22 (+/-- 10 for both). Switches close

at 298 (+/-- 20) psig for R--22 and 420 (+/-- 25) psig for Puron.

High pressure may be caused by a dirty condenser coil, failed fan

motor, or condenser air re-- circulation.

To check switch:

1. Turn off all power to unit.

2. Disconnect leads on switch.

3. Apply ohmmeter leads across switch. You should have

continuity on a good switch.

NOTE: Because these switches are attached to refrigeration system

under pressure, it is not advisable to remove this device for

troubleshooting unless you are reasonably certain that a problem

exists. If switch must be removed, remove and recover all system

charge so that pressure gauges read 0 psi. Never open system

without breaking vacuum with dry nitrogen.

PERSONAL INJURY HAZARD

Failure to follow this caution may result in personal injury .

Wear safety glasses, protective clothing, and gloves when

handling refrigerant.

CAUTION

To replace switch:

1. Apply heat with torch to solder joint and remove switch.

PERSONAL INJURY HAZARD

Failure to follow this caution may result in personal injury .

Wear safety glasses when using torch. Have quenching

cloth available. Oil vapor in line may ignite when switch is

removed.

CAUTION

2. Braze in 1/4--in. flare fitting and replace pressure switch.

Loss of Charge Switch (HP

Only)

Located on liquid line of heat pump only, the liquid line pressure

switch functions similar to conventional low--pressure switch.

Because heat pumps experience very low suction pressures during

normal system operation, a conventional low-- pressure switch

cannot be installed on suction line. This switch is installed in liquid

line instead and acts as loss--of-- charge protector. The liquid-- line is

the low side of the system in heating mode. It operates identically

to low--pressure switch except it opens at 23 (+/-- 5) psig for Puron

and 7 (+/-- 5) psig for R22 and closes at 55 (+/-- 5) psig for Puron

and 22 (+/-- 5) for R22 Two-- stage heat pumps have the

low--pressure switch located on the suction line. The two--stage

control board has the capability to ignore low--pressure switch trips

during transitional (defrost) operation to avoid nuisance trips.

Troubleshooting and removing this switch is identical to

procedures used on other switches. Observe same safety

precautions.

Tech Assist

The TechAssist is a service board incorporated in the outdoor unit.

The Tech Assist board is found on Legacy Line AC units built

before March, 2008. It incorporates a series of LED’s to identify

components that have power through them. These components

include both high and low voltage. Low voltage components

indicated are 24 volts, low pressure switch and high pressure

switch. The high voltage components indicated are 230 volts,

contactor and compressor.

Troubleshooting using the Tech Assist should reduce service time

as it quickly identifies where a problem may exist using a

hopscotch method.

ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal

injury or possible equipment damage.

This tool does not replace the necessity to utilize proper

service meters. Always verify power is removed before

servicing equipment.

WARNING

The Tech Assist does not lock out any components and has no

effect on operation. It simply provides indication of power with

closed contacts or completed circuit through particular

components.

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Bryant LEGACY 213R Service Manual Page 14

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