Sterlco SEU Series Economical Water TCU - Manual (Page 20)

WTR1-600 Chapter 3: Installation 20 of 42
If a non-relieving device such as a regulator, ball valve,
or check valve is installed on the WATER IN line,
you MUST install an expansion tank
of at least ½ gallon (about 2 liters) capacity.
Failure to do so can result in system overpressure from thermal expansion.
Install the tank configured as shown below:
Royal Series
unit
Expansion
tank
Non-relieving
device
Check the expansion tank frequently to make sure it is not flooded.
Water Out
Size Depends on Solenoid Used
The cooling water outlet leading back to the cooling tower, chiller, or drain.
Net supply pressure must be between 25 psig and 55 psig (172.38 kPa/1.72 bars and 379.2
kPa/3.79 bars). Net supply below 15 psig (103.43 kPa/1.03 bars) may allow water to flash to
steam, cavitate the impeller, and damage the pump, which prevents the unit from cooling
properly. Operation above 55 psig (379.2 kPa/3.79 bars) may cause premature opening of the
relief valve from pump pressure and pressure surges.
Pressure Relief — ¾”
The pressure relief valve, located at the back of the unit, is pre-piped to approximately four inches
(4” or 10 cm) above the floor. This piping reduces the chance of scalding nearby personnel if the
relief valve should trip.
3-9 Making System Purge Connections
Economical Series systems equipped with the System Purge option have a compressed air inlet
marked MOLD PURGE. Connect to a clean, dry 100 psig (689.50 kPa/6.90 bars) air line. Install
your own shutoff valve to prevent process liquid from backing up into the plant air piping if the
compressed air is turned off and the check valve fails. Don’t depend on the solenoid valve to
hold water pressure in the temperature control unit.