2200LZJE-HO-C6-N_2013.12.
Chapter 6 Troubleshooting
Compound 2-stage Screw Compressor 2016**C
6-10
Symptom
Direct cause
Root cause
Action
12
Compressor
generates
abnormal
vibration
and/or
sound.
Liquid flow-back
during operation
* Notable frosting
on the suction
side.
* In many cases,
flow-back of mist
(steam) rather
than liquid occurs.
* Sometimes,
gas-liquid
separator
(accumulator) is
attached to
prevent this
symptom.
* See also the
causes in item 02,
"Insufficient
refrigerant flow".
Aperture of liquid
supply expansion
valve is large.
In case of electronic expansion
valve, check devices attached on
the expansion valve aperture
control mechanism (circuit) such as
temperature sensor, converter,
controller (overheating regulator). If
any of them is found defective,
replace it.
In the same way as with
temperature-type expansion valve,
if orifice gets unsuitable due to the
change in operating conditions,
replace the orifice.
Rapid change from
no-load operation to
full-load operation
Set control parameters so as to
prevent rapid changes.
Otherwise, make adjustment by
throttling the aperture of the
capacity control increase-side oil
quantity adjusting valve.
Expansion valve
aperture control
cannot keep up with
rapid change in
heat load on the
load side.
Avoid rapid change in heat load that
exceeds the set value of follow-up
range of "heat exchanger on load
side (evaporator)" and "expansion
valve".
For details, refer to the instruction
manuals related to devices/control
on load side.
Heat exchange
failure in heat
exchanger on load
side
・
Related to
defrosting
In case of frosting (icing), conduct
manual defrosting.
Set defrosting interval shorter.
If a device which is specific to the
defrosting type fails, remove the
cause(s) and replace the device(s).
If a piping route which is specific to
the defrosting type gets blocked,
remove the cause(s) and take
necessary actions.
* Especially when handling hot gas
defrosting systems, thoroughly
read and understand the contents
of the instruction manuals for the
units associated with
devices/control on the load side.
Heat exchange
failure in heat
exchanger on load
side
・
Load side
conditions
If ventilation around the heat
exchanger is obstructed for any
reason such as piled up load,
improve the conditions.
* Ensure the flow of heating medium
through the heat exchanger on the
load side.
Heat exchange
failure in heat
exchanger on load
side
・
Heat exchanger
conditions
Check for any blocked heat
transmission tubes or fan motor(s)
failure. If any problem is found, take
necessary actions.