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A discharge temperature control is mandatory to stop the compressor when the maximum
discharge temperature is exceeded
protection".
Additional warning notices shall be af fixed to any system equipped with shut -off valves. The
warnings must contain instructions to open the shut-off valves completely af ter each repair or
maintenance work. The compressors may only be energized when the saf ety measures (high-
and low-pressure cut-outs and discharge temperature cut-out) have been checked and verified
to be operational.
NOTE: All of the above points must be fulfilled. If any of them cannot be met, the compressors
shall not be operated below atmospheric pressure.
3.6
Crankcase heating function
WARNING
Ignition source in a potentially flammable atmosphere! Fire hazard! In
case a crankcase heater is used, it is not an ignition source during normal
operation but could become one if not installed properly according to
installation instructions. Ensure correct electrical and mechanical installation.
CAUTION
Motor overheating and burnout! Compressor damage! The crankcase
heating f unction must not be energized when the system is in a vacuum or if
there is no ref rigerant charge in the system. The system low-pressure cut-out
control can be used as an indicator of the presence of refrigerant charge.
IMPORTANT
Oil dilution! Bearing malfunction! Follow the off-cycle migration statement
described below f or long-term reliability and to minimize nuisance associated
with f looded start conditions. Turn the crankcase heating function on 12 hours
bef ore starting the compressor.
Contrary to the standard f ixed-speed Copeland scroll compressors, the YHV*RG/RT models do not
require any optional external crankcase heater to be mounted on the compressor.
Instead, the ED3 and EV3 drives have a programmable feature that will utilize the motor windings to
provide up to 50 Watts DC of heating to serve as a crankcase heater.
The crankcase heating f unction activation is recommended when the system charge exceeds the
ref rigerant charge limits indicated in Table 8 below.
When the crankcase heating f unction is required, the power has to be determined by tests across
the envelope for winter and summer situations.
Compressor
YHV029RG & YHV046RG
YHV072RG
YHV029RT & YHV046RT
YHV072RT
Table 8: Refrigerant charge limits
NOTE: At first start, the crankcase heating function must be energizeda minimum of 12 hours
prior to starting the compressor.
3.7
Discharge gas temperature protection
CAUTION
Inadequate lubrication! Scroll set damage! All YHV*RG/RT compressors
must be equipped with an external discharge gas temperature protection.
A good system control shall prevent the system from operating outside the published operating
envelope and acceptable superheat range, whatever the climatic conditions and the capacity
demand. However, under some extreme operating conditions such as loss o f charge or improper
control operation, the internal discharge gas temperature reached can cause compressor damage.
16
see section 3.7 "Discharge gas temperature
Refrigerant
Refrigerant charge limit
R290
R454C
1.2 kg
2.3 kg
2.4 kg
4.5 kg
AGL_HP_VS_YHV_RG_RT_EN_Rev00
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