General Maintenance - Carrier 38XTZ 007-024 Installation, Operation And Maintenance Instructions

- Fan high pressure switch (38XTZ 014).
- Low pressurestat: This protects the 40ABZ/ALZ units
against excessive low pressure in the evaporator or in the
refrigerant lines.
The low pressurestat has factory fixed non-adjustable
settings. To check, see section Initial checks.
CAUTION: When any of these cuts out, the unit stops and
will not re-start until the contacts have been reclosed after
rectification of the fault.
Table 13 - Pressure switch settings
38XTZ 007, 008, 011, 016, 020 and 024
Cut-out
High pressurestat *2844 kPa
Low pressurestat *265 kPa
* Factory-calibrated
38XTZ 014
Cut-out
High pressurestat *2844 kPa
Low pressurestat *265 kPa
High pressurestat, fan *2354 kPa
* Factory-calibrated
WARNING: Alteration of factory settings other than the
design set-point, without manufacturer's authorisation, may
void the warranty.
Table 14 - Operating limits
Zone
Cooling operation:
Indoor
Maximum
Minimum
Outdoor
Maximum
Minimum
Indoor air flow
Maximum
Minimum
Hot water coil (accessory/option)
Maximum water temperature
* Sizes 007, 011, 014, 020 and 024: 40°C
Sizes 008 and 016: 44°C
** With optional/accessory head pressure control, the unit will operate at
temperatures below 19°C.
ATTENTION: Operation of the units at temperatures, air
flows, etc. outside the limits indicated in the table above can
cause serious damage to the units and will void the Carrier
warranty.
36
Cut-in Reset
*1863 kPa Manual
*363 kPa Automatic
Cut-in Reset
*1863 kPa- Manual
*363 kPa Automatic
*1863 kPa Automatic
Air temperature °C
Min. Max.
+35 +21
+19 +14
+40/44* -
19** -
+20% of nominal value
-20% of nominal value
80°C

GENERAL MAINTENANCE

ATTENTION: Before starting any servicing or maintenance
operation on the unit, make sure that the power supply has
been disconnected. A current discharge could cause personal
injury.
In order to obtain maximum performance from the unit special
attention should be paid to the following points:
- Electrical connections: The supply voltage should be
within the limits permitted by the compressor and the unit.
Ensure that no faulty contacts exist in the terminal blocks,
contactor boards, etc. Make sure that all the electrical
connections are properly tightened, and that all the
electrical components (contactors, relays, etc) are firmly
secured to the corresponding rails.
Pay special attention to the condition of the connecting
cables between the control elements and the electrical box,
and to that of the unit power supply cable. They should not
be twisted and there should be no slits or notches in the
insulation. Check the starting and running consumptions
are within the limits specified in the corresponding
technical information.
- Drainage: Frequently check that the drain is not obstructed,
and that the condensate pan is clean and level. Ensure that
the condensate drain pan of the 40ABZ/ALZ unit is
perfectly clean and does not contain sludge or other
foreign substances, corrosion, etc. and is level.
- Inlet filter: This should be cleaned periodically. The
frequency depends on the purity of the entering air. The
filter may be cleaned with a household vacuum cleaner, or
by immersing it in water.
- Refrigerant circuit: Ensure that there is no leakage of
refrigerant or oil from the compressor. Check that the high
and low side operating pressures are normal. Make sure
that the coils are not dirty, if necessary clean with water
and air. Straighten bent aluminium fins with a suitable fin
comb. Check for unusual compressor noise.
- Controls: Check the operation of all electric controls, high
and low pressurestats, etc.
- Fans: The fan of the 38XTZ unit must rotate freely. There
must not be any foreign elements in the fans of the
40ABZ/ALZ indoor units. Please check:
a) the condition of the pulleys
b) the condition of the belts
c) the belt tension.
Periodically check the condition of the belts and pulleys and
ensure that they are correctly aligned. Also ensure that the
belt tension is correct. At the first start-up, and after a longer
shut-down period, recheck the belt tension after a few hours
of operation.