Bryant 189BNV EVOLUTION Service Manual page 37

The service valve- -stem cap is tightened to 20  2 ft/lb torque and
the service- -port caps to 9  2 ft/lb torque. The seating surface of
the valve stem has a knife- -set edge against which the caps are
tightened to attain a metal- -to- -metal seal.
The service valve cannot be field repaired; therefore, only a
complete valve or valve stem and service- -port caps are available
for replacement.
If the service valve is to be replaced, a metal barrier must be
inserted between the valve and the unit to prevent damaging the
unit exterior from the heat of the brazing operations.
CAUTION
!
PERSONAL INJURY HAZARD
Failure to follow this caution may result in personal injury.
Wear safety glasses, protective clothing, and gloves when
handling refrigerant.
Pumpdown & Evacuation
CAUTION
!
ENVIRONMENTAL HAZARD
Failure to follow this caution may result in environmental
damage.
Federal regulations require that you do not vent refrigerant to
the atmosphere. Recover during system repair or final unit
disposal.
If this system requires either a Pump Down or Evacuation for any
reason, the procedures below must be followed:
Pump Down - - Evolution Communicating - - 288BNV
Because this system is inverter controlled, compressor, suction
pressure transducer and EXV, conventional procedure cannot be
used to "pump down" and isolate the refrigerant into the outdoor
unit. The UI (User Interface) has provisions to assist in performing
this function.
1. Connect gauges to 288BNV liquid and vapor service valve
ports to monitor operating pressures during and at comple-
tion of the procedure.
2. In the advanced menu of the UI, go to Checkout > Heat
Pump> Pumpdown
3. Select mode to pump down in (COOL or HEAT), COOL
mode allows refrigerant to be isolated in outdoor unit.
HEAT mode allows the refrigerant to be isolated in indoor
coil and lineset. Set desired time period. Default time peri-
od for the procedure is 120 minutes.
4. Select Start on UI to begin the pump- -down process. Unit
will begin running in selected mode after a brief delay.
5. Close the liquid service valve.
6. The unit will run in selected mode with the low pressure
protection set to indicate pump- -down is complete when the
suction pressure drops below 10 psig. Compressor protec-
tions are still active to prevent damage to the compressor or
inverter (high pressure, high current, high torque, etc.) .
7. Once system indicates pump- -down complete or failure to
complete shutdown, close vapor service valve.
8. A small quantity of charge will remain in isolated section of
system dependent on ambient temperature and overall sys-
tem charge. This charge must be manually recovered. A
recovery system will be required to remove final quantity of
refrigerant from indoor coil and line set.
9. Remove power from indoor and heat pump unit prior to ser-
vicing unit.
Pump Down - - Evolution Communicating - - 189BNV
Because this system is inverter controlled, compressor, suction
pressure transducer, conventional procedure cannot be used to
"pump down" and isolate the refrigerant into the outdoor unit. The
UI (User Interface) has provisions to assist in performing this
function.
1. Connect gauges to 189BNV liquid and vapor service valve
ports to monitor operating pressures during and at comple-
tion of the procedure.
2. In the advanced menu of the UI, go to Checkout > Pump-
down
3. Select mode to pump down in (COOL). Set desired time
period. Default time period for the procedure is 120 min-
utes.
4. Select Start on UI to begin the pump- -down process. Unit
will begin running in selected mode after a brief delay.
5. Close the liquid service valve.
6. The unit will run in selected mode with the low pressure
protection set to indicate pump- -down is complete when the
suction pressure drops below 10 psig. Compressor protec-
tions are still active to prevent damage to the compressor or
inverter (high pressure, high current, high torque, etc.) .
7. Once system indicates pump- -down complete or failure to
complete shutdown, close vapor service valve.
8. A small quantity of charge will remain in isolated section of
system dependent on ambient temperature and overall sys-
tem charge. This charge must be manually recovered. A
recovery system will be required to remove final quantity of
refrigerant from indoor coil and line set.
9. Remove power from indoor and outdoor unit prior to ser-
vicing unit.
Pump Down – Using 2- - stg HP Tstat - - 288BNV
(Non- - Communicating)
Because this system has an inverter controlled compressor, suction
pressure transducer and EXV, conventional procedure cannot be
used to "pump down" and isolate the refrigerant into the outdoor
unit.
1. Connect gauges to 288BNV liquid and vapor service valve
ports to monitor operating pressures during and at
completion of the procedure.
2. Force system to operate in high stage by creating a large
differential between room temperature and set point on
thermostat. Use multi- -meter to verify that 24 VAC is
present between C and Y1 and Y2 terminals at outdoor unit.
3. Close the liquid service valve.
4. The unit will continue to run until high or low pressure
switches open. Close vapor service valve once compressor
shuts down.
5. Remove power from indoor and heat pump unit prior to
servicing unit.
6. A quantity of charge will remain in isolated section of
system dependent on ambient temperature and overall
system charge. This charge must be manually recovered. A
recovery system will be required to remove final quantity of
refrigerant from indoor coil and line set.
Pump Down – Using 2- - stg Tstat - - 189BNV
(Non- - Communicating)
Because this system has an inverter controlled compressor, suction
pressure transducer, conventional procedure cannot be used to
"pump down" and isolate the refrigerant into the outdoor unit.
1. Connect gauges to 189BNV liquid and vapor service valve
ports to monitor operating pressures during and at
completion of the procedure.
2. Force system to operate in high stage by creating a large
differential between room temperature and set point on
thermostat. Use multi- -meter to verify that 24 VAC is
present between C and Y1 and Y2 terminals at outdoor unit.
37