Maintenance Procedures
RTHD-SVX02H-EN 107
when charging a system with oil. The diagnostic “Loss of
oil at the compressor stopped” will be generated if the
oil lines are not full on start-up.
To properly charge the system with oil, follow the steps
below:
1. Locate the 1/4” schrader valve between the ball valve
and oil filter (or the ball valve and oil cooler, if so
equipped).
2. Loosely connect oil pump to schrader valve called
out in step 1.
3. Operate oil charging pump until oil appears at the
charging valve connection; then tighten the connec-
tion.
Note: To keep air from entering the oil, the charging
valve connection must be air- tight.
4. Close the ball valve just upstream of the schrader
valve connected to the oil pump. This will allow the
oil to travel through the oil lines to the compressor
first rather than directly to the oil sump.
5. Energize the master oil solenoid.
6. This will allow the oil to travel from the schrader to
the compressor. It takes approximately 2 gallons of
oil to fill the lines.
7. After charging the first 2 gallons, de-energize the
master solenoid.
8. Open the ball valve just upstream of the schrader
connected to the oil pump. This will allow the remain-
der of the charge to flow to the oil sump.
9. Monitor the “Oil Loss Level Sensor Status in TechView
under the Status view. This display shows whether
the optical sensor is seeing oil (wet) or if it is not (dry).
Note: The remainder of the oil charge can be charged
into the 1/4” service valve located at the bottom
of the sump if a larger connection is preferred.
Replacing the Main Oil Filter (Hot
Filter)
The filter element should be changed if the oil flow is
sufficiently obstructed. Two things can happen: first, the
chiller may shut down on a “Low Oil Flow” diagnostic,
or secondly, the compressor may shut down on a “Loss
of Oil at Compressor (Running) diagnostic. If either of
these diagnostics occurs, it is possible the oil filter needs
replacement. The oil filter is not usually the cause of a
Loss of oil at Compressor diagnostic.
Specifically, the filter must be changed if the pressure
drop between the two service valves in the lubrication
circuit exceeds the maximum level as given in Figure 73.
This chart shows the relationship between the pressure
drop measured in the lubrication circuit as compared
with operating pressure differential of the chiller (as
measured by pressures in the condenser and evapora-
tor).
Normal pressure drops between the service valves of the
lubrication circuit are shown by the lower curve. The up-
per curve represents the maximum allowable pressure
drop and indicates when the oil filter must be changed.
Pressure drops that lie between the lower and upper
curves are considered acceptable.
For a chiller equipped with an oil cooler, add 5 psid to
the values shown in Figure 73. For example, if the sys-
tem pressure differential was 80 psid, then the clean
filter pressure drop would be approximately 15 psid (up
from 10 psid). For a chiller with an oil cooler and operat-
ing with a dirty oil filter, the maximum allowable pres-
sure drop would be 28 psid (up from 23 psid).
Under normal operating conditions the element should
be replaced after the first year of operation and then as
needed thereafter.
Refer to Table 4 - Table 7 and Unit nameplate for Oil
charge information.
1. Isolate the oil filter by closing the two ball valves
located before and after the filter.
2. Relieve the pressure from the hydraulic line through
the 1/4” schrader valve located between the ball
valve and the oil filter (or the ball valve and oil cool-
er, if so equipped).
3. Use a strap wrench to break loose the nut that se-
cures the oil filter element to the filter manifold.
4. Turn the nut clockwise until the filter element detach-
es from the manifold.
5. Remove the filter element and measure the exact
amount of oil contained in the filter bowl and ele-
ment.
6. Place the cartridge in the nut after filling the bowl
with the proper amount of refrigerant oil (see Step
5). Turn the new nut assembly counterclockwise and
tighten securely.
7. Connect manifold gauge set at oil charging valve and
evacuate the filter to 500 microns.
8. Charge the oil line back with the amount of oil re-
moved. Open the isolation valves to the oil supply
system.
Replacing the Gas Pump Oil Filter
The filter element in the gas pump circuit may need to
be changed if the gas pump is unable to return the oil to
the compressor.
An evaporator logged with oil will have a high liquid
level when referring to the liquid level sensor, low suc-
tion pressures, and higher than normal approach on the
evaporator.
Refer to Figure 73 to determine if the pressure drop
across the filter is above the normal range at full load
conditions. Once the oil is logged in the evaporator, it
may be necessary to manually move the oil from the
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