SYSTEM COMMISSIONING
1. Although delivered static pressure is measured with the
integrated control board, it is important to verify an ac-
curate reading, and within acceptable limits (minimum
1.2" W.C., maximum 1.5" W.C.) by using the following
steps. You can use a U-tube manometer or calibrated
digital manometer to check the external static pressure
on the duct system.
1. Puncture a ¼" diameter hole in the plenum duct at
least 18" from the fan coil unit.
2. Insert the high-side manometer tube into the hole so
that the end is approximately flush with the inside wall
of the plenum, and perpendicular to the direction of airflow.
3. System static pressure should be between 1.2" and 1.5" WC.
a. If the pressure is higher than 1.2" provide additional
supply runs to increase airflow or lower the fan
speed by turning the fan speed adjustment for the
current mode of operation counter-clockwise to
reduce the static pressure.
b. If the pressure is lower than 1.2", look for leaks in
the supply plenum, restrictions in the return system
(including clogged filters) If more than the
recommended number of supply runs are installed,
you may install flow restrictors (orifices) in these
runs. If the number of runs is appropriate for the
load, increase the static pressure by turning fan
speed adjustment for the current mode of operation
clockwise to increase the static pressure.
2. Every "J" series unit has the ability to adjust fan speeds
through the control board. On the J+ integrated control,
the fan speed can be adjusted for each individual type
of thermostat call (Y1, G, W1 etc...) through the fan bal-
ancing menus. Refer to control menus portion of this
manual to access these menus. To properly ensure the
delivered airflow is adequate for the system, it is recom-
mended that the installer measure delivered CFM's at
each outlet and then add for total CFM's in the system.
Reference the total CFM in figure 3.1 and compare for
appropriate delivered CFM. Once the CFM has been es-
tablished (adjust the fan speed up or down accordingly)
then the installer can move on to properly charging the
system with refrigerant. If adjusting the fan speed will
not satisfy the CFM requirements, please refer to the
troubleshooting guide for "Improper airflow". Or reach
out to technicalservice@spacepak.com for toubleshoot-
ing help. DO NOT TRY TO CHARGE A SYSTEM WITH-
OUT PROPER AIRFLOW BEING ESTABLISHED. This
can severely affect the overall performance of the sys-
tem, indoors and outdoors.
3. Place the thermostat in COOL position, which will start the
outdoor unit. Let the system run the minimum amount of
time identified by the outdoor unit's instructions to stabilize
operating conditions.
4. For outdoor unit start-up, follow manufacturer’s in-
structions.
5. Check that temperature drop across evaporator coil
in the indoor unit is between 20°F to 30°F.
NOTICE: Do not introduce refrigerant liquid to system
through suction port. Liquid in the suction line may
damage the compressor.
NOTICE: Before adding refrigerant to system verify
Items #1-3 have has been performed.
6. Verify that system refrigerant is correct by measuring
subcooling at liquid service port at the outdoor unit.
Subcooling should be in accordance with outdoor unit
manufacturers recommendations.
7. Check the super heat leaving the evaporator coil
against the corresponding suction pressure from the
schrader fitting at the fan coil unit. Superheat value
should be between 9°F and 12°F.
8. If a sight glass has been installed on the liquid line at the
air handler check for the presence of flashing. If flashing
is occuring, check and adjust subcooling by adding
refrigerant.
CHARGING COOLING ONLY SYSTEMS
After start-up, allow the system to operate the minimum
suggested time per the outdoor unit manufactures
installation guidelines in order to establish stable
operating conditions. Check that the temperature drop
across the evaporator coil is 20°F to 30°F. Do not attempt
to adjust the charge at ambient temperatures below 65°F.
Verify and adjust refrigerant charge based upon outdoor
unit manufacturer’s published recommendations.
Releasing refrigerant gas into the atmo-
sphere is a criminal offense.
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