Bryant LEGACY PURON 704D Series Installation Instructions Manual Download Page 18

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COOLING SEQUENCE OF OPERATION

With the room thermostat SYSTEM switch in the COOL position

and the FAN switch in the AUTO position, the cooling sequence of
operation is as follows:
When the room temperature rises to a point that is slightly above
the cooling control setting of the thermostat, the thermostat

completes the circuit between thermostat terminal R to terminals Y
and G. These completed circuits through the thermostat connect

contactor coil (C) (through unit wire Y) and time delay relay

(TDR) (through unit wire G) across the 24--V secondary of
transformer (TRAN).
The normally open contacts of energized contactor (C) close and
complete the circuit through compressor motor (COMP) to

condenser (outdoor) fan motor (OFM). Both motors start instantly.
The set of normally open contacts of energized relay TDR close
and complete the circuit through evaporator blower (indoor) fan

motor (IFM).

NOTE

: Once the compressor has started and then has stopped, it

should not be started again until 5 minutes have elapsed.
The cooling cycle remains on until the room temperature drops to a

point that is slightly below the cooling control setting of the room
thermostat. At this point, the thermostat breaks the circuit between

thermostat terminal R to terminals Y and G. These open circuits
deenergize contactor coil C and relay coil TDR. The condenser and

compressor motors stop. After a 60--second delay, the blower

motor stops. The unit is in a standby condition, waiting for the next
call for cooling from the room thermostat.

MAINTENANCE

To ensure continuing high performance, and to minimize the
possibility of premature equipment failure, periodic maintenance

must be performed on this equipment. This cooling unit should be
inspected at least once each year by a qualified service person. To

troubleshoot unit, refer to Table 7, Troubleshooting Chart.
NOTE TO EQUIPMENT OWNER: Consult your local dealer
about the availability of a maintenance contract.

PERSONAL

INJURY

AND

UNIT

DAMAGE

HAZARD

Failure to follow this warning could result in personal

injury or death and possible unit component damage.
The ability to properly perform maintenance on this

equipment requires certain expertise, mechanical skills,

tools and equipment. If you do not possess these, do not

attempt to perform any maintenance on this equipment,

other than those procedures recommended in the Owner’s

Manual.

WARNING

ELECTRICAL SHOCK HAZARD

Failure to follow these warnings could result in personal

injury or death:

1. Turn off electrical power to the unit and install lockout

tag before performing any maintenance or service on this
unit.

2. Use extreme caution when removing panels and parts.
3. Never place anything combustible either on or in contact

with the unit.

WARNING

UNIT OPERATION HAZARD

Failure to follow this caution may result in equipment

damage or improper operation.
Errors made when reconnecting wires may cause improper

and dangerous operation. Label all wires prior to

disconnecting when servicing.

CAUTION

The minimum maintenance requirements for this equipment are as

follows:

1. Inspect air filter(s) each month. Clean or replace when

necessary.

2. Inspect indoor coil, drain pan, and condensate drain each

cooling season for cleanliness. Clean when necessary.

3. Inspect blower motor and wheel for cleanliness each

cooling season. Clean when necessary.

4. Check electrical connections for tightness and controls for

proper operation each cooling season. Service when
necessary.

5. Ensure electric wires are not in contact with refrigerant

tubing or sharp metal edges.

AIR FILTER

IMPORTANT

: Never operate the unit without a suitable air filter

in the return--air duct system. Always replace the filter with the
same dimensional size and type as originally installed. See Table 1
for recommended filter sizes.
Inspect air filter(s) at least once each month and replace

(throwaway--type) or clean (cleanable--type) at least twice during
each cooling season and twice during the heating season, or

whenever the filter becomes clogged with dust and lint.

INDOOR BLOWER AND MOTOR

NOTE

: All motors are pre--lubricated. Do not attempt to lubricate

these motors.
For longer life, operating economy, and continuing efficiency,

clean accumulated dirt and grease from the blower wheel and

motor annually.

ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal

injury or death.
Disconnect and tag electrical power to the unit before

cleaning the blower motor and wheel.