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SERVICING
40
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 com-
pressor 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 imme-
diately 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 deter-
mined 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 Specifications 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).
2. Measure the static pressure of the supply duct, (Positive
Pressure).
3. Add the two readings together.
NOTE:
Both readings may be taken simultaneously and read
directly on the manometer if so desired.
4. Consult proper table for quantity of air.
If the external static pressure exceeds the minimum or maxi-
mum allowable statics, check for closed dampers, dirty filters,
undersized or poorly laid out ductwork.
S-201 CHECKING TEMPERATURE RISE
Temperature rise is related to the BTUH output of the unit and
the amount of air (CFM) circulated over the heat exchanger.
All units are designed for a given range of temperature
increase. This is the temperature of the air leaving the unit
minus the temperature of the air entering the unit.
The more air (CFM) being delivered through a given unit the
less the rise will be; so the less air (CFM) being delivered,
the greater the rise. The temperature rise should be adjusted
in accordance to a given unit specifications and its external
static pressure.
1. Check BTUH input to unit do not exceed input rating
stamped on rating plate.
2. Take entering and leaving air temperatures.
Summary of Contents for DBG Series
Page 51: ...51 ACCESSORIES GAS ELECTRIC...
Page 52: ...ACCESSORIES 52 GAS ELECTRIC...
Page 53: ...53 ACCESSORIES...
Page 54: ...ACCESSORIES 54...
Page 95: ...95 DBC COMMERCIAL 15 25 Ton Packaged Air Conditioner Unit WIRING DIAGRAMS...
Page 100: ...100 DBG COMMERCIAL 15 25 Ton Packaged Gas Electric Unit WIRING DIAGRAMS...