Temptek G-500 Series, Instruction Manual

Page: 37 / 64

Temperature Control Unit : VTO Series with G500 Series Instrument
Page: 37
TEMPTEK, INC.
525 East Stop 18 Road Greenwood, Indiana 46142
317-887-6352 Fax: 317-881-1277
Email: service@Temptek.com
2. Motor overload switch opened. The display shows a Fault : System Safety
screen. The electric motor is protected from overload conditions by a set of
thermal overload relays. These relays will open (trip). If the overload relay is
open, it must be reset before operation can continue. An excessive flow condition
must be isolated and corrected immediately.
3. High temperature limit switch open. The display
shows a Fault : System Safety screen. The unit is
prevented from operations at temperatures exceeding
515°F by a “high temperature limit switch”. If this switch
is open (due to a high temperature condition), the unit
cannot be started and must “cool down” before the
“high temperature limit switch” will automatically reset.
4.4 UNIT OVERHEATS
A. This is evidenced by To Process temperatures consistently above the selected setpoint
temperature.
B. On units equipped with the cooling heat exchanger, check for :
1. Inadequate water supply pressure. The unit must be supplied with adequate
water flow to provide cooling when required. The minimum pressure differential
between the water supply and water drain to achieve full cooling capacity is 20
PSI. The minimum water supply pressure is 20 PSI.
2. Cooling valve defective. On units with the cooling heat exchanger, the
instrument opens and closes the cooling valve as prescribed by the current
process load. If the valve becomes clogged with process water debris or scaled
with mineral deposits, its operation is hindered or fully prevented and adequate
process water discharge to drain is prevented. The operator must service the
cooling valve and remove any loose debris. Massive debris or scale deposits
may necessitate replacement of the internal valve.
3. Heat exchanger is fouled or undersized for duty. Clean or replace heat
exchanger.
C. On all units, check for :
1. Water drain line obstruction. The operator must determine if the water drain
line is obstructed by the following conditions. Section 2.4 outlines the parameters
of correct drain line installation.
a. Closed drain line valve. An installed but partially or fully closed valve
in the drain line prevents full discharge to drain and contributes to an
overheating condition. The operator should determine the drain line is
open.
b. High drain back pressure. Pressurized plant drain lines will prevent
flow 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
High Temp Limit Fault
Screen.