Lochinvar Harmony Installation And Operation Manual page 8

1 2 3 4 5 6
SYS A
N.O. contacts to activate a pump,
valve or other system component
8
WIRING THE SYSTEM OUTPUT
System Output Operation in Set Point Mode
• The SYS output relay will energize whenever there is a call for output
and the Shutdown feature is not active.
• Until the SYSTEM PROVE input is shorted, no Stages will be
activated. If a Prove is not required, the factory installed jumper
should remain.
7 8 9 10
• The SYS will remain energized while any Stage is active.
• When the last Stage relay turns off, the SYS output can remain
energized for the period of time set by the System Run-On (see pg.
19)
• A typical use of the SYS output is to activate a system pump starter.
B C
The pump can run whenever there is a call for heat. When heat is no
longer required, the pump will stay active for a few more minutes to
remove the residual heat from the boilers.
System Output Operation in Reset Mode
• The SYS output relay will energize whenever the outdoor tempera-
ture is below the Outdoor Cutoff.
• The SYS will remain constantly energized while the outdoor tempera-
ture is below the Outdoor Cutoff.
• When the outdoor temperature rises 2°F above the Outdoor Cutoff,
the SYS output will remain energized for the period of time set by the
System Run-On (see pg. 19).
Wiring the SYS Output
• The SYS output has one Normally Open (N.O.) relay contact.
• The N.O. contacts are dry contacts only. They do not source any
voltage.
• Class 1 voltages must enter the enclosure through a different
opening from any Class 2 voltage wiring.
• Each N.O. contact is capable of switching 6A resistive at 120VAC.
• Total output SYS and the OPERATING LIMIT OUTPUTS must not
exceed 15A.
WIRING THE STAGE OUTPUTS
Installing the Output Relays
• Each output stage (A through D) which is to be used must have a
relay installed in the socket.
The SYS relay is included with the Harmony.
• To install a relay, orient the pins and then press it gently into the
appropriate socket.
• Any stage output which does not have a relay must have its Mode
set to Off (see Stage Settings pg. 22).