Carrier 50PEC09-18 - Manual (Page 27)

27
PRE-START-UP
System Cleaning and Flushing — Cleaning and
flushing the unit and system is the single most important step to
ensure proper start-up and continued efficient operation of the
system.
Follow the instructions below to properly clean and flush
the system:
1. Verify that electrical power to the units is disconnected,
and that the circulation pump is deenergized.
2. Connect the supply hose directly to the return riser valve.
Use a single length of flexible hose, as shown in Fig. 29.
NOTE: If the length of hose is too short (i.e., the resulting con-
nection would exceed the minimum bend radius of the hose),
substitute two lengths of flexible hose joined together with a
field-supplied, standard NPT coupling and the flare-fitting-to-
pipe adapters provided with the hose kit (Fig. 29).
3. Open all air vents. Fill the system with water. Do not al-
low system to overflow. Bleed all air from the system.
Check the system for leaks and repair appropriately.
4. Check and adjust the water and air level in the expansion
tank.
5. Verify all strainers are in place. Start the pumps, and sys-
tematically check each vent to ensure all air is bled from
the system.
6. Verify make-up water is available. Adjust make-up water
appropriately to replace the air that was bled from the
system. Pressure test and inspect the system for leaks and
make any necessary repairs. Check and adjust the water
and air level in the expansion tank.
7. Open a drain at the lowest point in the system. Adjust the
make-up water replacement rate to equal the rate of bleed.
Continue to bleed the system until the water appears
clean or for at least three hours, whichever is longest;
then, completely drain the system.
8. Refill the system with clean, chemically treated water.
Since water varies for each locality, contact a local water
treatment company for the correct treatment chemicals to
use in the area. Set the boiler to raise the loop temperature
to approximately 29.4 C.
.
Circulate the solution for a minimum of 8 to 24 hours. At
the end of this period, shut off the circulating pump and
drain the solution. Repeat system cleaning as necessary.
9. When the cleaning process is complete, remove the short-
circuited hoses. Connect the hoses to the proper supply
and return connections on each unit. Refill the system and
bleed off all air.
10. Test the system pH with litmus paper. The system water
should be slightly alkaline (pH 7.0 to 8.5). Add chemi-
cals, as appropriate, to maintain acidity levels.
11. When the system is successfully cleaned, flushed, refilled
and bled, check the main system panels, safety cutouts
and alarms. Set the controls to properly maintain loop
temperatures.
System Checkout — When the installation is complete
and the system is cleaned and flushed, follow the system
checkout procedure outlined below.
1. Voltage: Ensure voltage is within the utilization range
specifications of the unit compressor and fan motor.
2. System Water Temperature: Ensure temperature is within
an acceptable range shown in Table 4. (When conducting
this check, also verify proper heating and cooling set
points.)
WARNING
To prevent injury or death due to electrical shock or contact
with moving parts, open unit disconnect before servicing
unit.
CAUTION
Do not flush system through the unit. Damage to unit could
result.
CAUTION
To avoid possible damage to piping systems constructed of
plastic piping DO NOT allow loop temperature to exceed
43.3 C.
CAUTION
DO NOT use “Stop-Leak” or any similar chemical agent in
this system. Addition of these chemicals to the loop water
will foul the system and will inhibit unit operation.
1/2” Flexible Hose
Brass Adapter
(1/2” MPT x 1/2”
Male Flare)
Supply Valve
Floor Line
Return Valve
Fig. 29 — Temporary Connection for Flushing System Piping
NOTE: Use standard coupling (field-supplied)
and hose adapters to join 2 hoses.