S-113 Overcharge Of Refrigerant; S-114 Non-Condensables; S-115 Compressor Burnout - Daikin DP14UM Service Instructions Manual

SERVICING
If a restriction should become evident, proceed as follows:
1. Recover refrigerant charge.
2. Remove the orifice or tube strainer assembly and
replace.
3. Replace liquid line drier, evacuate and recharge.
Checking Equalization Time
During the "OFF" cycle, the high side pressure bleeds to
the low side through the fixed orifice restriction device.
Check equalization time as follows:
1. Attach a gauge manifold to the suction and liquid line
dill valves.
2. Start the system and allow the pressures to stabilize.
3. Stop the system and check the time it takes for the
high and low pressure gauge readings to equalize.
If it takes more than seven (7) minutes to equalize, the
restrictor device is inoperative. Replace, install a liquid line
drier, evacuate and recharge.
S-112 Checking Restricted Liquid Line
When the system is operating, the liquid line is warm
to the touch. If the liquid line is restricted, a definite
temperature drop will be noticed at the point of
restriction. In severe cases, frost will form at the
restriction and extend down the line in the direction of the
flow.
Discharge and suction pressures will be low, giving the
appearance of an undercharged unit. However, the unit
will have normal to high subcooling.
Locate the restriction, replace the restricted part, replace
drier, evacuate and recharge.

S-113 Overcharge Of Refrigerant

An overcharge of refrigerant is normally indicated by an
excessively high head pressure.
An evaporator coil, using an expansion valve metering
device, will basically modulate and control a flooded
evaporator and prevent liquid refrigerant return to the
compressor.
An evaporator coil, using a fixed orifice restrictor device
(flowrator) metering device, could allow liquid refrigerant
to return to the compressor under extreme overcharge
conditions.
Also with a fixed orifice restrictor device (flowrator)
metering device, extreme cases of insufficient indoor air
can cause icing of the indoor coil and liquid refrigerant
return to the compressor, but the head pressure would be
lower.
There are other causes for high head pressure.
If other causes check out normal, an overcharge or a
system containing non-condensables would be indicated.
If this system is observed:
1. Start the system.
2. Remove and capture small quantities of refrigerant
as from the suction line access fitting until the head
pressure is reduced to normal.
3. Observe the system while running a cooling
performance test. If a shortage of refrigerant
is indicated, then the system contains non-
condensables.

S-114 Non-Condensables

If non-condensables are suspected, shut down the system
and allow the pressures to equalize Wait at least 15
minutes. Compare the pressure to the temperature of
the coldest coil since this is where most of the refrigerant
will be. If the pressure indicates a higher temperature
than that of the coil temperature, non-condensables are
present.
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.
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.
NOTICE
25