Slant/Fin EM-10 Service Manual - Manual (Page 22)

22 EM-40-SM Service Manual
Applications
Mode 4 and 5 – Outdoor Reset and Setpoint Operation
Mode 4 – Outdoor Reset and Setpoint with Parallel
Piping
The control receives a heat demand provided from zone
valve end switches or a switching relay end switch. The
control turns on the boiler pump and operates the boiler to
maintain the outdoor reset boiler temperature at the boiler
outlet sensor. The control receives a setpoint demand from
a DHW aquastat. The control turns on the boiler pump and
operates the boiler to maintain the setpoint boiler target
temperature at the boiler outlet sensor whenever a setpoint
demand is present.
Note: An external relay is required to operate the DHW
pump and provide DHW priority if required by disabling
the boiler pump.
Mode 5 – Outdoor Reset and Setpoint with Primary
– Secondary Piping
The control receives a heat demand provided from zone
valve end switches or switching relay end switch. The
control turns on the boiler pump and operates the boiler to
maintain the outdoor reset target temperature at the boiler
supply sensor. The control receives a setpoint demand
from a DHW aquastat. The control turns on the boiler pump
and operates the boiler to maintain the setpoint boiler
target temperature at the boiler supply sensor whenever a
setpoint demand is present.
Note: An external relay is required to operate the DHW
pump and provide DHW priority if required by disabling the
system pump or zone pumps.
BTC
Mode 4
Relay
Outdoor
Sensor
Boiler Inlet Sensor (Included)
Factory
Installed
Boiler
Outlet
Sensor
BTC
Mode 5
Outdoor
Sensor
Relay
Factory
Installed
Boiler
Outlet
Sensor
Boiler Inlet Sensor (Optional)
Secondary
Piping
Sensor
(Included)