Temperature Control Units : MFC with G Series Instrument
Page: 46
Milacron Process Support Business
4165 Halfacre Road Batavia, Ohio 45103
Phone: 513-536-2584
www.milacron.com
b. High drain back pressure. Pressurized plant drain lines will prevent
ow to drain if the differential between the water supply pressure
and the drain line pressure is inadequate. The factory recommended
minimum differential is 20 psi. If the differential is less than the factory
recommendation, plant service personnel should take measures to
reduce drain line pressure.
4. Instrument defective. The instrument is designed and manufactured exclusively
for this unit. The instrument is life-tested and found to be eld reliable. However,
in the case where the instrument is determined to be defective, the operator must
remove the assembly according to instructions outlined in section 5.8 and return
the assembly to the factory. The instrument is not a eld serviceable component.
4.5 UNIT UNDERHEATS
A. This is evidence by operations with To Process temperatures consistently below the
selected setpoint temperature.
1. Process water leakage. When the instrument engages the heater to elevate
process temperature, the input of heat into the process can be offset by a
defective AVT
TM
valve. If the AVT
TM
valve is defective, it may pass a larger than
required stream to drain, thus providing unwanted cooling. A defective AVT
TM
valve should be repaired immediately.
2. Heater element failure. A failed heater element will not input adequate heat
into the process to elevate the process water temperature. The operator must
check the amps at the heater contactor with the contactor energized. Zero amps
at the contactor indicate a failed heater or burnt wire connections. The operator
should remove the failed heater and replace with a new heater according to the
procedure outlined in section 5.2.
3. Unit capacity too low. This occurs when the process requires more heat than
the unit is capable of producing. The only option in such cases is to install a unit
with an adequate heater KW rating for the load.
4. Instrument defective. The instrument is designed and manufactured exclusively
for this unit. The instrument is life-tested and found to be eld reliable. However,
in the case where the instrument is determined to be defective, the operator must
remove the assembly according to instructions outlined in section 5.8 and return
the assembly to the factory. The instrument is not a eld serviceable component.
4.6 PRESSURE RELIEF VALVE LEAKS
A. The unit has a 150 psi pressure relief valve mounted in the cooling cylinder. If the valve is
found to be leaking, the operator should check the following:
1. Water supply pressure exceeds 75 psi. The unit is designed to operate with
water supply NOT exceeding 75 psi. See section 2.3 paragraph B for specic
water supply pressure requirements at corresponding setpoint temperatures.
If the plant water supply pressure exceeds 75 psi, the pressure relief valve
may leak. Static water supply pressure can be determined at the unit’s location
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