United CoolAir AVW08, Installation, Operation And Maintenance Manual

Page: 35 / 41

Installation, Operation and Maintenance Manual
VariCool
®
VAV
35 Subject to change without notice. 10.20-IM (0818)
Start-Up Procedures
(R-410a Systems)
Continued:
22� Record the entering and leaving fluid temperatures.
b� Make sure the leaving fluid temperature is within the
proper limits:
i�
Minimum 60˚ F
ii� Maximum 115˚ F
23� Record the pressure drop of the water / fluid across the
unit
24� Verify that all valves on each fluid circuit function
properly
25�
Check the head pressure adjustment, DO NOT assume
that this has been set at the factory Typically this value
is to be 360 psi when 85˚ F water is supplied to the unit
at 3 GPM/Ton
26� Record the return air temperature to the evaporator coil
along with the supply air temperature (The unit should
have operated for at least 15 minutes before taking
these readings)
27� Record the suction line pressure and the suction line
temperature for each circuit near the compressor
28� Using an appropriate pressure / temperature chart for
R-410a refrigerant, look up and record the saturation
temperature corresponding to the suction pressure
29�
Calculate and record the suction superheat for each
circuit by taking the difference between the suction
line temperature and the saturation temperature
corresponding to the suction pressure
30� Record the liquid line pressure and the liquid line
temperature for each circuit near the condenser heat
exchanger outlet
31� Using an appropriate pressure / temperature chart for
R-410a refrigerant, look up and record the saturation
temperature corresponding to the liquid line pressure
32� Calculate and record the liquid sub-cooling for each
circuit by taking the difference between the liquid
line temperature and the saturation temperature
corresponding to the liquid line pressure
33�
Record the Amps for the evaporator blower motor and
each compressor If the system is single phase, use L1
and L2 only
a� Make sure the pressures on each compressor circuit
are within the proper limits:
i� 290 – 550 Discharge
ii�
100 – 140 psig Suction
b� Compressor Amperage is below the RLA Amps
listed on the unit data tag
i� The maximum compressor operating current
(amps) at start up depends a lot on the system
loading The lower the load, the less the current
The higher the load, the higher the current
c� The blower motor FLA value should never be
exceeded
i�
If the FLA value is exceeded, shut the unit off
and check the duct design, sheave turns open
or make sure there is no blockage / obstruction
in the duct or filters.
34� Document any additional information deemed
appropriate for the specific application or installation.
35� Shut the system down and remove all test instruments
and test sensors
36� Leave the system in the operating mode as appropriate
for the customer and the application
Optional Heating Start Up:
37� If the system has any optional heat, set the room
thermostat approximately 5 ° higher than the actual
room temperature Set the thermostat operating mode
to the HEAT position
38� Dependent upon the heating source the heating valve
or switch / contactor should be activated
39� After several minutes of operation, record the return air
temperature and the supply air temperature
40� Based on the heating source, document the
appropriate temperatures, pressures, voltage or amp
values