Sterlco SEU Series Economical Water TCU - Manual (Page 25)

WTR1-600 Chapter 4: Controls 25 of 42
Chapter 4: Controls
4-1 Identifying Mechanical Controls and Features
To Process Thermocouple
A type K ungrounded thermocouple with a 304SS probe is downstream from the heater to sense
process temperature.
Safety Thermostat
The safety thermostat mounted on the side of the heater tank protects against thermal runaway.
The thermostat guards against the unlikely event of “runaway” heating. If overheating occurs, the
safety thermostat shuts down heater outputs. The unit continues to pump water through the
system to prevent heater damage. We recommend that you install an audible or visual alarm to
the terminals provided. Factory installed alarms are available; see the electrical schematics for
more information.
Pressure Relief Valve
If the combined pressure of the cooling supply water and pump discharge exceeds 150 psig
(1,034.25 kPa/10.34 bars), the pressure relief valve opens and relieves the pressure. This is a non-
adjustable ASME construction valve with a stainless steel spring.
Important!
Route a pipe from the pressure relief valve
to a suitable drain to reduce potential scalding hazard.
The drain line must not have any restrictions or back pressure.
Low Pressure Cutout Switch
This switch, set at 16 psig with a 2 psig differential (110.3 kPa/ 1.10 bars with a 13.79 kPa/0.14
bars differential) shuts down the unit if the COOLING WATER IN water pressure drops below
16 psig (110.3 kPa/1.10 bars). For the 300 °F (148.9 °C) option, this switch is set at 55 psig with
a 2 psig differential (379.2 kPa/ 3.79 bars).
Pumps
Pumps range in power from ¾ hp to 7.5 hp (0.56 kW to 5.59 kW) and are equipped with 3-phase
ODP motors and seal flush lines as standard.
The pump is a bronze-fitted close-coupled centrifugal type. It features a split case design to
facilitate replacement of the seal. It has a high output capacity with excellent discharge pressure
helping it facilitate turbulence to maximize heat transfer, and is well suited for the conditions
under which it was designed to operate.