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SERVICING
CAUTION
Do not allow the sludge or oil to contact the skin.
Severe burns may result.
NOTE: The Flushing Method using R-11 refrigerant is no longer
approved by Daikin Heating-Cooling.
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 compo-
nents, causing a failure of the replacement compressor and/or
spread contaminants throughout the system, damaging addi-
tional components.
Install a field supplied suction line drier . This drier should be in-
stalled 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 immediate-
ly out of the compressor stub must be discarded due to burned
residue and contaminates.
1. Remove compressor discharge line strainer.
2. Remove the liquid line drier and expansion valve.
3 Purge all remaining components with dry nitrogen or carbon
dioxide until clean.
4. Install new components including liquid line drier.
5. Braze all joints, leak test, evacuate, and recharge system.
6. Start up the unit and record the pressure drop across the
drier.
7. Continue to run the system for a minimum of twelve (12)
hours and recheck the pressure drop across the drier. Pres-
sure drop should not exceed 6 PSIG.
8. 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.
9. 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-201 CLEANING ALUMINUM COILS
This unit is euqipped with an alumninum tube evaporator coil.
The safest way to clean the evaporator coil is to simply flush the
coil with water. This cleaning practice remains as the recom-
mended cleaning method for both copper tube and aluminum
tube residential cooling coils.
An alternate cleaning method is to use one of the products listed
in the technical publication TP-109 (shipped in the literature
bag with the unit) to clean the coils. The cleaners listed are the
only agents deemed safe and approved for use to clean round
tube alunumum coils. TP-109 is available on the web site in
Partner Link > Service Toolkit.
NOTE: Ensure coils are rinsed well after use of any chemical
cleaners.
S-202 DUCT STATIC PRESSURES AND/OR STATIC
PRESSURE DROP ACROSS COILS
This minimum and maximum allowable duct static pressure for
the indoor sections are found in the specifications section.
Tables are also provided for each coil, listing quantity of air
(CFM) versus static pressure drop across the coil.
Too great an external static pressure will result in insufficient
air that can cause icing of the coil. Too much air can cause poor
humidity control and condensate to be pulled off the evaporator
coil causing condensate leakage. Too much air can also cause
motor overloading and in many cases this constitutes a poorly
designed system.
S-203 SINGLE PIECE AIR HANDLER EXTERNAL STATIC
To determine proper airflow, proceed as follows:
1. Using a Inclined Manometer or Magnehelic gauge , measure
the static pressure of the return duct at the inlet of the air
handler, this will be a negative pressure (for example-.30"wc)
2. Measure the static pressure of the supply duct at the outlet
of the air handler, this should be a positive pressure (for
example .20"wc).
3. Add the two readings together (for example -.30"wc +
.20"wc = .50"wc total external static pressure.
NOTE: Both readings may be taken simultaneously and read
directly on the manometer if so desired.
4. Consult proper air handler airflow chart for quantity of air
(CFM) at the measured external static pressure.
76
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