Specifications

86
JOHNSON CONTROLS
Form 201.28-NM1.EN.PED/CE (0211)
MAINTENANCE
REFRIGERANT REMOVAL, EVACUATION AND
CHARGING
Refrigerant Removal
The YVAA utilizes a flooded evaporator. Extreme care
must be taken when removing refrigerant to prevent
damage to the evaporator and the chiller. Carefully
review the following caution below before proceeding
with the recommended process.
Incorrect removal of refrigerant will
result in catastrophic freeze damage to
the evaporator and possible additional
damage to other chiller components.
Whenever there is water in the evaporator,
the chilled liquid pumps must be ON and
circulating liquid through the evaporator
above minimum recommended fl ow rates.
When liquid refrigerant is being removed,
monitor the pressure and do not allow the
pressure to drop below the freeze point
of the chilled liquid fl owing through the
evaporator until all liquid refrigerant has
been removed from the evaporator and
only gas remains. Once all liquid has been
removed, the remaining refrigerant vapor
can be removed while allowing the pressure
to drop below the freeze point with the pump
circulating liquid through the evaporator.
To remove refrigerant from the evaporator, follow the
procedure below:
1. Turn the chilled liquid pump ON and assure the
fl ow is above the minimum recommended fl ow.
2. Assure all manual valves in the system are open.
Open Condenser Drain and Economizer Feed
valves to 100% in the service mode.
3. Connect the recovery unit and a manifold gauge to
the liquid line feeding the eductor. There may be a
valve in the line or a fi tting on the eductor fi lter for
this purpose.
4. Connect the recovery unit to a recovery cylinder sit-
ting on a reliable scale.
5. Turn the recovery unit ON and observe the liquid
refrigerant fl owing from the line into the cylinder.
The fl ow of liquid should be obvious.
6. Monitor the pressure gauge to assure that the pres-
sure does not drop below the freeze point of the
chilled liquid. Throttle the fl ow as needed with the
manifold gauge valves to prevent pressures from
dropping below the freeze point.
7. Continue to remove the liquid refrigerant while ob-
serving the fl ow and the pressure. Note the charge
in the system based on the nameplate data to deter-
mine when the charge removal is nearly complete.
Monitor the weight of the recovery cylinder to de-
termine when the cylinder is full. Change the cyl-
inder as needed.
8. Continue removing refrigerant until liquid is no lon-
ger observed fl owing in the manifold hoses.
9. Once the liquid is removed and no longer visible in
the hose, the remaining gas can be pumped out with
the recovery unit while the pressure is allowed to
drop to 0 barg (0 PSIG).
10. Servicing may now be performed on the system as
needed.
Evacuating a System
To evacuate a system, follow the procedure below:
1. Turn the chilled liquid pump ON and assure the
fl ow is above the minimum recommended fl ow.
2. Assure all manual values are open. Open the Con-
denser Drain (Flash Tank Feed) and Economizer
Valves in the Service Mode to 100 %
3. Connect vacuum hoses to as many points as possi-
ble. Be sure that at least one connection is made on
both the high and low side of the piping. A connec-
tion to the evacuation fi tting on the compressor is
also recommended. Evacuate the system to a mini-
mum of 500 microns. Close the valves at the evacu-
ation points and assure the pressure in the chiller
does not rise more than 50 microns in 10 minutes.
Check for leaks if the pressure rises.