Refrigerant System; Condensate Drain Cleaning; Air Coil Cleaning; Condenser Cleaning - Carrier Aquazone 50RHE 006 Installation, Operation And Maintenance Instructions

9.4 - Refrigerant system

Verify air and water flow rates are at proper levels before
servicing. To maintain sealed circuitry integrity, do not install
service gauges unless unit operation appears abnormal.
Check to see that unit is within the superheat and subcooling
temperature ranges shown in Table 16. If the unit is not within
these ranges, recover and reweigh in refrigerant charge.

9.5 - Condensate drain cleaning

Clean the drain line and unit drain pan at the start of each cooling
season. Check flow by pouring water into drain. Be sure trap is
filled to maintain an air seal.

9.6 - Air coil cleaning

Remove dirt and debris from evaporator coil as required by
condition of the coil. Clean coil with a stiff brush, vacuum
cleaner, or compressed air. Use a fin comb of the correct tooth
spacing when straightening mashed or bent coil fins.

9.7 - Condenser cleaning

Water-cooled condensers may require cleaning of scale (water
deposits) due to improperly maintained closed-loop water
systems. Sludge build-up may need to be cleaned in an open
water tower system due to induced contaminants.
Local water conditions may cause excessive fouling or pitting
of tubes. Condenser tubes should therefore be cleaned at least
once a year, or more often if the water is contaminated.
Proper water treatment can minimise tube fouling and pitting. If
such conditions are anticipated, water treatment analysis is
recommended. Refer to the Carrier System Design Manual,
Part 5, for general water conditioning information.
CAUTION: Follow all safety codes. Wear safety glasses and
rubber gloves when using inhibited hydrochloric acid solution.
Observe and follow acid manufacturer's instructions.
Clean condensers with an inhibited hydrochloric acid solution.
The acid can stain hands and clothing, damage concrete, and,
without inhibitor, damage steel. Cover surroundings to guard
against splashing. Vapours from vent pipe are not harmful, but
take care to prevent liquid from being carried over by the gases.
Warm solution acts faster, but cold solution is just as effective if
applied for a longer period.
9.7.1 - Gravity flow method
Do not add solution faster than vent can exhaust the generated
gases.
When condenser is full, allow solution to remain overnight,
then drain condenser and flush with clean water. Follow acid
manufacturer's instructions (see Fig. 18).
9.7.2 - Forced circulation method
Fully open vent pipe when filling condenser. The vent may be
closed when condenser is full and pump is operating (see Fig. 19).
Regulate flow to condenser with a supply line valve. If pump is
a non-overloading type, the valve may be fully-closed while
pump is running.
For average scale deposit, allow solution to remain in condenser
overnight. For heavy scale deposit, allow 24 hours. Drain con-
denser and flush with clean water. Follow acid manufacturer's
instructions.
Fig. 18 - Gravity flow method
Fill condenser with cleaning
FILL CONDENSER WITH
solution. Do not add solution
CLEANING SOLUTION. DO
NOT ADD SOLUTION
more rapidly than vent can
MORE RAPIDLY THAN
exhaust gases caused by
VENT CAN EXHAUST
chemical action.
GASES CAUSED BY
CHEMICAL ACTION.
VENT
Vent pipe
PIPE
0.9 to 1.2 m
3' TO 4'
Pail
PAIL
Fig. 19 - Forced circulation method
Priming
Pump
connection
Suction
Pump
support
Tank
Fine mesh
screen

9.8 - Checking system charge

Units are shipped with full operating charge. If recharging is
necessary:
1. Insert thermometer bulb in insulating rubber sleeve on
liquid line near filter drier. Use a digital thermometer for
all temperature measurements. DO NOT use a mercury or
dial-type thermometer.
2. Connect pressure gauge to discharge line near compressor.
3. After unit conditions have stabilised, read head pressure
on discharge line gauge.
NOTE: Operate unit a minimum of 15 minutes before checking
charge.
4. From standard field-supplied pressure-temperature chart
for R-407C, find equivalent bubble point temperature.
5. Read liquid line temperature on thermometer; then
subtract from bubble point temperature. The difference
equals subcooling temperature.
Pail
PAIL
Funnel
FUNNEL
25 mm
1"
pipe
PIPE
1.5 m approx.
5' APPROX
Condenser
CONDENSER
Gas vent
Globe
valves
Supply
25 mm
pipe
Condenser
Remove water
regulating valve
Return
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