18
9.
Attach the micron gauge to the system on
the reheat line where it enters the air handler
unit. See Figure 3 below.
Figure 3 - AHU evacuation connections
10.
It is a good practice to replace the vacuum
pump oil after one hour of the evacuation
process. The oil can be broken down in the
pump in the initial first hour causing system
evacuation to take longer than it should.
11.
The minimum micron level required by
AAON is 350 microns for systems using POE
oils.
12.
The system must then be isolated and the
pump turned off to check for vacuum rise due
to leaks or moisture in the system. The
micron gauge
must not rise above
500 microns after 30 minutes of wait time.
Charging Refrigerant:
Charging a system in the field must be based on
determination
of
liquid
sub-cooling
and
evaporator superheat. On a system with a
thermostatic expansion valve liquid sub-cooling is
more representative of the charge than evaporator
superheat but both measurements must be taken.
Before Charging:
Refer to the Unit Nameplate to determine the
proper refrigerant to charge the system with.
The unit being charged must be at or near full load
conditions before adjusting the charge.
Units equipped with hot gas bypass must have the
hot gas bypass valve closed to get the proper
charge.
Units equipped with hot gas reheat must be
charged with the hot gas valve closed while the
unit is in cooling mode.
After adding or removing charge the system must
be allowed to stabilize, typically 10-15 minutes,
before making any other adjustments.
The type of unit and options determine the ranges
for liquid sub-cooling and evaporator superheat.
Refer to Table
when determining the proper sub-
cooling.
The vertical rise of the liquid line must be known
in order to adjust the sub-cooling range for proper
charge.
Units equipped with low ambient (0°F) option see
special charging instructions at the end of the
charging instructions.
CLEAN AIR ACT
The Clean Air Act of 1990 bans the
intentional venting of refrigerant as of July
1, 1992. Approved methods of recovery,
recycling, or reclaiming must be followed.
WARNING
Reheat Line on the
Outside of the Air
Handler
Содержание CL SERIES
Страница 1: ...CL SERIES Condensing Units Installation Operation Maintenance ...
Страница 25: ...25 Figure 6 Evaporative Condenser Section Water Treatment Components ...
Страница 56: ...NOTES ...
Страница 57: ...AAON E Coated Coil Maintenance Record ...
Страница 59: ......