LAARS SC 12 - Install and Operating Manual - Manual (Page 25)

Page 25 Laars Sequencing Controls
DHW CALL
• When the DHW terminals are closed, the SC Set Point immediately changes to 200°F. This will happen regardless of outdoor DHW DHW
temperature, the status of the Setback/Shutdown inputs, or the External Set Point (if that function is being used).
• Typically, the DHW input is wired to an aquastat which monitors the domestic hot water temperature. When the aquastat calls DHW DHW
for heat, it will close the DHW input terminals. DHW DHW
• If the System Output is confi gured for Combustion Air Damper operation, the System relay output will be closed when any Stage
Output is activated to hold the 200°F set point.
• If the System Output is confi gured for System Pump operation without DHW priority (see pg. 22) then the System relay will be
closed whenever the outdoor temperature is below the Outdoor Cutoff, regardless of the DHW input status.
• If the System Output is confi gured for System Pump operation with DHW priority (see pg. 22) then:
- The System relay output will be open for the time set by the DHW Priority time dhP
- After the DHW priority time has elapsed, the System relay output will revert to its normal mode of operation (that is either
on or off depending on outdoor temperature.)
• For wiring the DHW input, see pg. 6.