American Aldes DH-100V - Manual (Page 6)

The following procedure is effective only if the system is
monitored after replacing the compressor to insure that
the clean up was complete.
1.
This procedure assumes that the previously listed
compressor motor circuit tests revealed a shorted or
open winding. If so, cautiously smell the refrigerant
from the compressor service port for the acid odor
of a burn out.
WARNING: The gas could be toxic and highly
acidic. If no acid odor is present, skip down to the
section on changing a non-burn out compressor.
2.
Remove and properly dispose of the system
charge. DO NOT vent the refrigerant indoors or
allow it to contact your eyes or skin.
3.
Remove the burned out compressor. Use rubber
gloves if there is any possibility of contacting the oil
or sludge.
4.
To facilitate subsequent steps, determine the type
of burn out that occurred. If the discharge line
shows no evidence of sludge and the suction line is
also clean or perhaps has some light carbon
deposits, the burn out occurred while the
compressor was not rotating. Contaminants are
therefore largely confined to the compressor
housing. A single installation of liquid and suction
line filter/driers will probably clean up the system.
If sludge is evident in the discharge line, it will likely
be found in the suction line; this indicates the
compressor burned out will running. Sludge and
acid has been pumped throughout the system.
Several changes of the liquid and suction
filter/driers will probably be necessary to cleanse
the system.
5.
Correct the system fault that caused the burn out.
Consult the factory for advice.
6. Install the replacement compressor with a new ca-
pacitor and an oversized liquid line filter.
In a running burn out, install an oversized suction
line filter/drier between the accumulator and com-
pressor. Thoroughly flush the accumulator with re-
frigerant to remove all trapped sludge and to pre-
vent the oil hole from becoming plugged. A standing
burn out does not require a suction line filter/drier.
7.
Evacuate the system with a good vacuum pump
and accurate vacuum gauge. Leave the pump on
the system for at least an hour.
An alternate method of removing moisture and non-
condensibles from the system requires evacuation
to 29" Hg vacuum. Then break the vacuum with 35
to 50 PSIG refrigerant vapor charge. Leave the
vapor charge in the system for at least 5 minutes
before removing it. Repeat the vapor
charge/wait/remove sequence twice more and then
charge the system with the quantity and refrigerant
listed on the nameplate.
8.
Operate the system for a short period of time, moni-
toring the suction pressure to determine that the
suction filter is not becoming plugged. Replace the
suction filter/drier if pressure drop occurs. If a
severe running burn out has occurred, several fil-
ter/driers may have to be replaced to remove all of
the acid and moisture.
NOTE: NEVER use the compressor to evacuate
the system or any part of it.
5.6C Replacing a Compressor- Nonburn Out
Remove the refrigerant from the system. Replace the
compressor and liquid line filter/drier. Charge the system
to 50 PSIG and check for leaks. Remove the charge and
weigh in the refrigerant quantity listed on the nameplate.
Operate the system to verify performance.
5.7 Humidity Control
The humidity control is an adjustable switch that closes
when the relative humidity of the air in which it is located
rises to the dial set point. It opens when the RH drops 4
to 6% below the set point.
5.8 Defrost Thermostat
The defrost thermostat is attached to the refrigerant
suction tube between the accumulator and compressor.
It will automatically shut the compressor off if the low
side refrigerant temperature drops due to excessive frost
formation on the evaporator coil. The blower will
continue to run, causing air to flow through the
evaporator coil and melt the ice. When the ice has
melted, the evaporator temperature will rise and the
thermostat will restart the compressor.
5.9 Condensate Pump
Condensate is automatically pumped to a remote
location when the water level in the pump's reservoir
rises to close the float switch.
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