10
IO-123114 Effective 12-04-2014
1.
Bring airflow up to the maximum CFM possible according to Table
11A-1.
2.
Evacuate refrigeration system to micron level required by outdoor
unit manufacturer.
14. System Charging
An improperly charged system may cause
degradation in system performance and
damage the compressor. After installation
of the coil, refer to the outdoor unit manufacturer for charging
techniques and amount of charge. If outdoor unit manufacturers
charging instructions are unavailable, then refer to instructions
below to charge the system.
CAUTION
!
16. Start-Up
14B . Expansion Valve Coils
Add refrigerant until the subcooling measured at the outdoor unit
liquid line matches the subcooling recommendation of the outdoor
manufacturer (typically 7º – 10º F). If chart is unavailable refer to
Table 14B-1.
Table 14B-1.
After all connections are made, start-up and checkout must be per-
formed before proper evaluation of the entire system can be made.
Make sure that heat anticipator is properly set as noted on thermo-
stat instructions. Load requirements can vary in each residence and
it may be necessary for the installer or homeowner to make slight ad-
justments to the heat anticipator setting for longer or shorter cycles.
It is recommended to change the setting no more than plus or minus
0.05 amps at a time. Greater changes can cause the unit to rapid
cycle or remain on excessively.
15. Adjustment Of Heat Anticipator
14A . Flowrator Coils
Add refrigerant until the superheat measured at the outdoor unit suc-
tion/vapor line matches the superheat listed in Table 14B-1.
To properly check the unit’s operation, the installer should have an
electrical current measuring device (0-10 amp Amprobe, Fluke), air
pressure measuring device (0-1.0 in slope gauge), and a tempera-
ture-measuring device (0-200ºF thermometer).
3.
Release system charge from outdoor unit and call for cooling.
4.
Use outdoor unit equipment manufacturer specific charging charts
if available and make proper charge adjustment based upon outdoor
unit instructions.
5.
If outdoor unit instructions and charts are not available, use Aspen
provided charts. Make certain indoor air temperature is near comfort
level setpoint of 75°F prior to establishing superheat and subcooling
levels.
Install the Amprobe to measure blower current, the slope gauge to
measure static air pressure at the units and the temperature device
to measure unit supply and return air temperature. Before taking
measurements, be sure that all registers, grilles and dampers are
open or set to their proper positions. Be sure that clean filters are
in place. Temperature measuring device must be installed to obtain
average temperature at both inlet and outlet. For outlet, measure
temperature of each main trunk at a location far enough away to
avoid heater radiation and read the average temperatures. Table
11A-1 shows the CFM that should be achieved at various external
static pressures
Turn on power supply. Set thermostat fan switch to on. Set the cool-
ing indicator to maximum, heating to minimum. System switch may
be on heat or cool. Check slope gauge measurement against appro-
priate air flow chart. Make damper, register and motor speed adjust
-
ments to obtain required airflow.
Set thermostat fan switch to auto, system to heat and thermostat
heating indicator to maximum heat. Blower should start and all heat
be energized.
Check air flow using temperature rise method.
17. Checking Air Flow/Temperature Rise Method
CFM OUTPUT BTUH
TEMP RISE
=
•
(
)
.
.
1 08
NOTE:
BTUH output should be computed by VOLT x AMPS x 3.4 =
BTUH OUTPUT. Since line volt can vary, do not use nameplate rat
-
ing to determine output.
