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SERVICING
Non-condensables are removed from the system by first
removing the refrigerant charge, replacing and/or installing
liquid line drier, evacuating and recharging.
S-115 Compressor Burnout
When a compressor burns out, high temperature develops
causing the refrigerant, oil and motor insulation to
decompose forming acids and sludge.
If a compressor is suspected of being burned-out, attach
a refrigerant hose to the liquid line dill valve and properly
remove and dispose of the refrigerant.
NOTICE
Violation of EPA regulations may result in fines
or other penalties.
Now determine if a burn out has actually occurred.
Confirm by analyzing an oil sample using a Sporlan Acid
Test Kit, AK-3 or its equivalent.
Remove the compressor and obtain an oil sample from
the suction stub. If the oil is not acidic, either a burnout
has not occurred or the burnout is so mild that a complete
clean-up is not necessary.
If acid level is unacceptable, the system must be cleaned
by using the clean-up drier method.
CAUTION
Do not allow the sludge or oil to contact the skin.
Severe burns may result.
NOTE: Daikin does NOT approve the flushing method
using R-11 refrigerant.
Suction Line Drier Clean-Up Method
The POE oils used with R410A refrigerant is an excellent
solvent. In the case of a burnout, the POE oils will remove
any burnout residue left in the system. If not captured by
the refrigerant filter, they will collect in the compressor
or other system components, causing a failure of the
replacement compressor and/or spread contaminants
throughout the system, damaging additional components.
The suction line filter drier should be installed as close to
the compressor suction fitting as possible. The filter must
be accessible and be rechecked for a pressure drop after
the system has operated for a time. It may be necessary to
use new tubing and form as required.
NOTE: At least twelve (12) inches of the suction line
immediately out of the compressor stub must be
discarded due to burned residue and contaminates.
1. Remove the liquid line drier and expansion valve.
2. Purge all remaining components with dry nitrogen or
carbon dioxide until clean.
3. Install new components including liquid line drier.
4. Braze all joints, leak test, evacuate, and recharge
system.
5. Start up the unit and record the pressure drop across
the drier.
6. Continue to run the system for a minimum of twelve
(12) hours and recheck the pressure drop across the
drier. Pressure drop should not exceed 6 PSIG.
7. Continue to run the system for several days,
repeatedly checking pressure drop across the suction
line drier. If the pressure drop never exceeds the
6 PSIG, the drier has trapped the contaminants.
Remove the suction line drier from the system.
8. If the pressure drop becomes greater, then it must be
replaced and steps 5 through 9 repeated until it does
not exceed 6 PSIG.
NOTICE: Regardless, the cause for burnout must be
determined and corrected before the new compressor is
started.
S-200 Checking External Static Pressure
The minimum and maximum allowable duct static pressure
is found in the Spec Sheet Manual.
Too great of an external static pressure will result in
insufficient air that can cause icing of the coil, whereas too
much air can cause poor humidity control, and condensate
to be pulled off the evaporator coil causing condensate
leakage. Too much air can cause motor overloading and in
many cases this constitutes a poorly designed system. To
determine proper air movement, proceed as follows:
1. Using a draft gauge (inclined manometer) measure
the static pressure of the return duct at the inlet of
the unit, (Negative Pressure).
65
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