AEC TCU Series Open Reservoir Water Temperature Control Units - Manual (Page 47)

Page 48 Open Resevoir Water Temperature Control Units
Condition Possible cause Solution
Temperature fluctuations/rapid
cycling from hot to cold.
Undersized connectors/water
lines. Increase size of connectors/
water lines.
Long connecting lines between
unit and mold. Move the unit closer to the mold
and shorten connecting lines.
Serpentine flow through mold.
Connect lines for parallel flow
instead of series flow.
Blocked water line in mold.
Check mold for metal chips or
lime buildup. Clean mold.
Quick disconnect fitting with
check valve. Remove and replace fitting or
valve.
Lime buildup in unit piping. Clean or replace.
Faulty TCU.
Check unit by connecting ¾” line
directly from delivery to return
line. Run unit to determine if
TCU controls set point
temperature.
Unit overheats or does not cool.
Drain is plugged or excessive
back pressure is in drain line. Clear drain line or eliminate
back pressure condition.
Faulty solenoid valve.
Test solenoid valve by pressing
VENT button and listen for valve
operation. Replace if faulty.
Controller Cool output relay
open.
Replace output relay.
Solenoid valve is not operating,
but COOL LED is on.
Set process temperature to
minimum and check for mag-
netism on solenoid coil top.
Solenoid coil circuit is open.
Check coil resistance. If MΩ
range, replace solenoid coil.
Modulating valve is not
operating, but OUT2 LED is on.
Set process temperature to
minimum and check for
complete travel of valve; .
Insufficient pressure differential
between cooling WATER IN and
OUT lines. Find a means to get less back
pressure in the WATER OUT
line.
Cooling valve is undersize.
Replace cooling valve with a
larger valve.
Heater contactor(s) welded
closed.
Replace Contactors.
Relief valve leaks.
Foreign material under valve
seat. Manually open valve to clear
seat of material.
High system pressure.
Reduce WATER IN or MAKEUP
water pressure.
Unit runs continuously cooling or
heating, and cannot attain set
point.
Unit under-sized for application. Call sales representative.