heat-timer Mini-MOD-CNC Installation And Operation Manual page 16

WIRING THE DOMESTIC HOT WATER CALL DHW
• DHW can be used to raise system Set Point to the DHW Set Point as well as manage the System
Pump according to the DHW Priority setting. One of the DHW options must be selected from the
PROVE/DHW Sharing Startup menu. See "PROVE/DOMESTIC HOT WATER (DHW) PRIORITY"
on page 24.
• Wire an aquastat or a control to provide dry-contact closure on the DHW Call terminals.
• Remove the jumper on the DHW terminals for proper operation.
• DHW Call terminals can accept dry contact signals only. No voltage can be placed across
these terminals.
WIRING THE SYSTEM OUTPUT
• The SYS output relay will energize whenever the outdoor temperature is below the
Outdoor Cutoff.
• The SYS relay will remain constantly energized while the outdoor temperature 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 set by the System Run-On. See "RUN-ON" on page 33.
• In addition, the System output will energize during summer DHW calls when DHW No Priority
is selected. See "PROVE/DOMESTIC HOT WATER (DHW) PRIORITY" on page 24.
• The SYS output has one Normally Open (N.O.) relay contact rated for (⅛ HP).
• 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.
WIRING THE BOILERS
When wiring condensing and non-condensing boilers make sure that condensing boilers utilize the
first stages and non-condensing boilers will utilize the following stages. That is, if the installation had
two condensing modulating boilers and two non-condensing staging On/Off boilers, Stage A and B
will be used by the condensing boilers while C and D will be used by the non-condensing boilers.
WIRING ON/OFF BOILER OUTPUTS
(B TERMINALS 7, 8),...
• Each boiler output (A through D) has one Normally Open (N.O.) relay contact.
• The N.O. contacts are dry contacts only. They do not source any voltage.
• Wire the N.O. relay contacts in series with the unit's limit circuit.
• Class 1 voltages must enter the enclosure through a different opening from any
Class 2 voltage wiring.
• Note that some modulating boilers may not require the use of these outputs.
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16 HEAT-TIMER CORP.
(TERMINALS 29, 30)
(TERMINALS 3, 4)
(A TERMINALS 5, 6),
DHW SIGNAL
L
N
System Pump or
Pump Starter
BOILER
BOILER ENABLE
OUTPUT
059102-00 REV. C
09 WIRING