World Leaders in Ultra-Pure Heating
Revision 10
www.heateflex.com
01/17/13
405 E. Santa Clara St.
Arcadia, CA 91006-7218
Tel: (626) 599-8566 Fax: (626) 599-9567
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3.4 Input/Output Functions
Standard on all units is a contact strip in the electrical enclosure, labeled “Customer Interface
Signals”, which provides for inputs and outputs. The outputs consist of four, 4-20 mA signals
for D.I. water process temperature, D.I. water flow rate, D.I. water supply pressure, and steam
temperature. The other type of output is a relay is used to signal that an alarm condition exists
in the unit. The two contacts on the terminal strip will be a “make” under normal conditions
and open under alarm conditions.
On the same contact strip there are also three sets of 24 VDC contacts, which must be a
“make” to enable the unit. Two of these act as the remote shutdown and isolation input from
your equipment or control room - if you open the contacts labeled “Remote Auto Shut Down”,
the unit shuts down or closes the steam inlet valve. If you open the contacts labeled “Remote
Auto Isolation”, the unit closes the inlet and outlet D.I. water valves and a cold bypass line
automatically opens so that there is always a flow of water to the tools, hot or cold. The Auto-
Shutdown will also initiate causing the steam inlet valve to also shut down when the Auto-
Isolation is initiated. If you subsequently make these circuits, the equipment must still be
restarted at the main unit. These contacts can be left jumpered as shipped from the factory, if
you do not desire to use them. The other dry contact is reserved for the remote EMO
(Emergency Off). The unit can be completely shutdown from a remote location if the contact
labeled “Remote EMO” is opened.
There is also a set of dry contacts on the contact strip in the main unit. The contacts will open
depending on the alarm condition present from the unit. One dry contact indicates a Vessel
Flooding alarm while the other dry contact indicates a Global Alarm for any of the following
alarm conditions: D.I. Pressure Relief Venting, Hot Valve Over Temperature, Low Flow Rate,
Low Process Pressure, Low Process Temperature, Process Over Temperature, Shellside Over
Temperature, Steam Pressure Relief Venting, Vessel Flooding, and Water Leak. All but the
Process Low Temperature, Vessel Flooding and Water Leak will shut down the unit when the
alarm condition exists. The Process Low Temperature, Vessel Flooding
and Water Weak are
considered non-critical alarms and warn of the alarm condition but does not affect the
operation of the unit.
