Trane CVGF-SVU02B-E4 Operation And Maintenance Manual page 84

Oil Sump Heaters
The CVGF uses two 500 watt
heaters to maintain the oil sump
temperature at 136°F (57.7°C).
These heaters are located in the
lower oil sump casting, one on
each side of the oil sump cover,
and can be serviced without
removing the refrigerant or oil,
since the heaters are not located
in the oil sump itself but in the
casting (See Figure 24).
The CH530 will not allow the
chiller to start unless the oil
sump temperature is at least
30°F (16°C) above saturated
evaporator temperature, or at
least 105°F (58°C), whichever is
higher. The oil sump comes
factory insulated and must
remain insulated to allow the oil
temperature to maintain 136°F
(57.7°C) while the unit is off.
The oil heaters are only
energized during the unit "off"
cycle to maintain oil
temperature for startup. During
the run cycle, the oil sump
heaters are de-energized and the
oil temperature may vary
depending on load and
operating conditions. The unit
will trip on a latching diagnostic
of high oil temperature if the oil
exceeds 165°F (74°C).
84
Periodic
Maintenance
Oil Pressure Protection
A differential oil pressure switch
provides protection for the CVGF
should the oil pressure fall
below safe operating levels for
any reason. This switch opens at
9 psid (62kPa) and closes at 12
psid (82 kPa). The oil pressure
regulator is factory set to
maintain oil pressure between
18 to 22 psid (124-151 kPa). The
unit will not start if the oil
pressure is below 12 psid (82
kPa).
Adjusting the Oil Pressure
Regulating Valve
The oil pressure regulator
should be calibrated to maintain
18 to 22 psid during
commissioning. In the event that
the oil pressure switch will not
close to allow unit
startup, the following diagnostic
procedure should be followed:
1. With the unit and the oil pump
off, connect a pressure gauge
to the service valve after the
oil filter and another gauge to
the Schrader valve located
next to the oil pressure switch
capillary on the oil sump. (An
optional method is to use a
differential pressure gauge
instead of two separate
gauges.)
2. On the DynaView ™ display,
select Settings, Mode
overrides and select Oil Pump.
Place oil pump in manual
mode. Check the oil pressure
gauge readings and calculate
the differential oil pressure by
subtracting the oil sump
pressure reading from the
discharge oil pressure
reading.
If the differential pressure is
between 18 to 22 psid (124-
151 kPa), the oil pressure
regulating valve should not be
adjusted. If the oil pressure
switch is not closed at
pressures above 12 psid
(82kPa), the switch is defective
and should be replaced. If the
switch is closed the unit will
not start due to a low oil
pressure diagnostic. If the
differential oil pressure cannot
be achieved, the oil pump
may be running backwards.
CVGF-SVU02B-E4