53
TIGHTENING COOLER HEAD BOLTS (Fig. 28-32)
Gasket Preparation — When reassembling cooler heads, al-
ways use new gaskets. Gaskets are neoprene-based and are
brushed with a light film of compressor oil.
Do not soak gasket
or gasket deterioration will result
. Use new gaskets within
30 minutes to prevent deterioration. Reassemble cooler nozzle
end or plain end cover of the cooler with the gaskets. Torque all
cooler bolts to the following specification and sequence:
5
/
8
-in. Diameter Perimeter Bolts (Grade 5). . . . 150 to 170 ft-lb
(201 to 228 N-m)
1
/
2
-in. Diameter Flange Bolts (Grade 5) . . . . . . . . 70 to 90 ft-lb
(94 to 121 N-m)
1
/
2
-in. Diameter Center Stud (Grade 5). . . . . . . . . 70 to 90 ft-lb
(94 to 121 N-m)
1. Install all bolts finger tight, except for the suction flange
bolts. Installing these flanges will interfere with tighten-
ing the center stud nuts.
2. Bolt tightening sequence is outlined in Fig. 27-31. Follow
the numbering or lettering sequence so that pressure is
evenly applied to gasket.
3. Apply torque in one-third steps until required torque is
reached. Load
all
bolts to each one-third step before pro-
ceeding to next one-third step.
4. No less than one hour later, retighten all bolts to required
torque values.
5. After refrigerant is restored to system, check for refriger-
ant leaks using recommended industry practices.
6. Replace cooler insulation.
CHILLED WATER FLOW SWITCH — A factory-installed
flow switch is installed in the cooler nozzle for all machines.
This is a thermal-dispersion flow switch with no field adjust-
ments. The switch is set for approximately 0.5 ft/sec flow. See
Table 39 for unit flow rate information.
Table 39 — Unit Flow Rates
The sensor tip houses two thermistors and a heater element.
One thermistor is located in the sensor tip, closest to the flow-
ing fluid. This thermistor is used to detect changes in the flow
velocity of the liquid. The second thermistor is bonded to the
cylindrical wall and is affected only by changes in the tempera-
ture of the liquid. The thermistors are positioned to be in close
contact with the wall of the sensor probe and, at the same time,
to be kept separated from each other within the confines of the
probe.
In order to sense flow, it is necessary to heat one of the
thermistors in the probe. When power is applied, the tip of the
probe is heated. As the fluid starts to flow, heat will be carried
away from the sensor tip. Cooling of the first thermistor is a
function of how fast heat is conducted away by the flowing liq-
uid. The difference in temperature between the two thermistors
provides a measurement of fluid velocity past the sensor probe.
When fluid velocity is high, more heat will be carried away
from the heated thermistor and the temperature differential will
be small. As fluid velocity decreases, less heat will be taken
from the heated thermistor and there will be an increase in tem-
perature differential.
When unit flow rate is above the minimum flow rate, then
the output is switched on, sending 24 vac through a 560 ohm
dropping resistor. This provides 12 vac to the MBB to prove
flow has been established.
For recommended maintenance, check the sensor tip for
build-up every 6 months. Clean the tip with a soft cloth. If nec-
essary, build-up (e.g., lime) can be removed with a common
vinegar cleansing agent.
RTPF (Round Tube Plate Fin) Condenser Coil
Maintenance and Cleaning Recommenda-
tions —
Routine cleaning of coil surfaces is essential to
maintain proper operation of the unit. Elimination of contami-
nation and removal of harmful residues will greatly increase
the life of the coil and extend the life of the unit. The following
maintenance and cleaning procedures are recommended as part
of the routine maintenance activities to extend the life of the
coil.
REMOVE SURFACE LOADED FIBERS — Surface load-
ed fibers or dirt should be removed with a vacuum cleaner. If a
vacuum cleaner is not available, a soft non-metallic bristle
brush may be used. In either case, the tool should be applied in
the direction of the fins. Coil surfaces can be easily damaged
(fin edges can be easily bent over and damage to the coating of
a protected coil) if the tool is applied across the fins.
NOTE: Use of a water stream, such as a garden hose, against a
surface loaded coil will drive the fibers and dirt into the coil.
This will make cleaning efforts more difficult. Surface loaded
fibers must be completely removed prior to using low velocity
clean water rinse.
PERIODIC CLEAN WATER RINSE — A periodic clean
water rinse is very beneficial for coils that are applied in coastal
or industrial environments. However, it is very important that
the water rinse is made with very low velocity water stream to
avoid damaging the fin edges. Monthly cleaning as described
below is recommended.
ROUTINE CLEANING OF COIL SURFACES — Month-
ly cleaning with Totaline
®
environmentally sound coil cleaner
is essential to extend the life of coils. This cleaner is available
from Carrier Replacement parts division as part number
P902-0301 for a one gallon container, and part number
P902-0305 for a 5 gallon container. It is recommended that all
coils, including the standard copper tube aluminum fin, pre-
coated fin, copper fin, or E-coated coils be cleaned with the To-
taline environmentally sound coil cleaner as described below.
Coil cleaning should be part of the unit’s regularly scheduled
maintenance procedures to ensure long life of the coil. Failure
to clean the coils may result in reduced durability in the envi-
ronment.
Avoid the use of:
• coil brighteners
• acid cleaning prior to painting
• high pressure washers
• poor quality water for cleaning
Totaline environmentally sound coil cleaner is non-flamma-
ble, hypoallergenic, nonbacterial, and a USDA accepted biode-
gradable agent that will not harm the coil or surrounding
components such as electrical wiring, painted metal surfaces,
or insulation. Use of non-recommended coil cleaners is strong-
ly discouraged since coil and unit durability could be affected.
UNIT SIZE
30RB
COOLER
CONNECTION
SIZE (in.)
MINIMUM
FLOW - WATER
(GPM)
MINIMUM
FLOW - 40% EG
(GPM)
060-100
4
20
53
110-300
6
44
117
315-390
6
44 (per module)
117 (per module)
Summary of Contents for AQUASNAP 30RBA315
Page 77: ...77 Fig 37 Control Schematic 30RB060 080 a30 4619...
Page 78: ...78 Fig 38 Control Schematic 30RB090 150 a30 4620...
Page 79: ...79 Fig 39 Control Schematic 30RB160 190 a30 4622...
Page 80: ...80 Fig 40 Control Schematic 30RB210 300 a30 4622...
Page 81: ...81 Fig 41 Heat Reclaim Control Schematic a30 4622...