Carrier 69NT40-489-100 Series, Руководство по эксплуатации и обслуживанию

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68 T-305
Centrifugal pump
30 GPM at 35’ head
Pump
Suction
Pump
support
Tank
Fine mesh
screen
Return
Remove water
regulating valve
Condenser
Globe
valves
Vent
Close vent pipe
valve when pump
is running.
Priming
connection
Figure 38. Water-Cooled Condenser Cleaning --
Forced Circulation
7 The time required for de-scaling will vary, depending
upon the extent of the deposits. One way to deter-
mine when de-scaling has been completed is to
titrate the solution periodically, using titrating equip-
ment provided free by the Oakite Technical Service
representative. As scale is being dissolved, titrate
readings will indicate that the Oakite No. 32 solution
is losing strength. When the reading remains
constant for a reasonable time, this is an indication
that scale has been dissolved.
8 When de-scaling is complete, drain the solution and
flush thoroughly with water.
9 Following the water flush, circulate a 56.7 gram (2
ounce) per 3.785 liter (1 U.S. gallon) solution of
Oakite Aluminum Cleaner 164 thru the tubes to
neutralize. Drain this solution.
10 Flush the tubes thoroughly with fresh water.
NOTE
If the condenser cooling water is not being used
as drinking water or is not re-circulated in a
closed or tower system, neutralizing is not nec-
essary.
11 Put the unit back in service and operate under nor-
mal load. Check the head pressure. If normal, a thor-
ough de-scaling has been achieved.
What You Can Do For Further Help:
Contact the Engineering and Service Department of the
OAKITE PRODUCTS CO., 675 Central Avenue, New
Providence, NJ 07974 U.S.A. (or visit www.oakite.com)
for the name and address of the service representative
in your area.
Fill condenser with clean-
ing solution. Do not add
solution more rapidly than
vent can exhaust gases
caused by chemical
action.
Condenser
Vent
pipe
1” Pipe
5’ Approximate
3’ to 4’
Figure 39. Water Cooled Condenser Cleaning -
Gravity Circulation
6.13 FILTER-DRIER
On units equipped with a water-cooled condenser, if the
sight glass appears to be flashing or bubbles are
constantly moving through the sight glass when the
suction modulation valve is fully open, the unit may have
a low refrigerant charge or the filter-drier could be
partially plugged.
a. To Check Filter-Drier
1. Test for a restricted or plugged filter-drier by feeling
the liquid line inlet and outlet connections of the drier
cartridge. If the outlet side feels cooler than the inlet
side, then the filter-drier should be changed.
2. Check the moisture-liquid indicator if the indicator
shows a high level of moisture, the filter-drier should
be replaced.
b. To Replace Filter-Drier
1. Pump down the unit (refer to section 6.4, page 59)
and replace filter-drier.
2. Evacuate the low side in accordance with section
6.6, page 59.
3. After unit is in operation, inspect for moisture in sys-
tem and check charge.
6.14 THERMOSTATIC EXPANSION VALVE
The thermal expansion valve (see Figure 2, page 6) is
an automatic device which maintains constant
superheat of the refrigerant gas leaving the evaporator,
regardless of suction pressure.
The valve functions are:
1. Automatic control of the refrigerant flow to match the
evaporator load.
2. Prevention of liquid refrigerant entering the com-
pressor.