18 About the Boiler
Exhaust
Gas
Blow Fan
Air In
Air In
Ignitor
Gas
Valve
Gas
Inlet
DHW Out
Cold
Water In
Three
-way
Valve
DHW Heat
Exchanger
Circulation
Piump
Heat
Exchanger
1.6.3 Operating in DHW Mode
To operate DHW mode, press the DHW button on the front panel
and select a DHW temperature setpoint higher than current
DHW temperature.
1. When a hot water tap is turned on in the home, the boiler
flow meter detects DHW demand, the 3-way valve goes
to DHW mode and the circulation pump starts up, which
makes the water in the boiler primary circuit flow through
the DHW heat exchanger, producing instant hot water.
2. The electronic control modulates the burner output in
order to constantly produce hot water at the temperature
required.
3. When there is no further DHW demand, the burner switches
off and the 3-way valve remains in DHW mode position
during a wait time (5 minutes by default), so that it can work
more efficiently and provide more flexibility if the taps are
continuously turned on and off.
4. When the wait time has elapsed, the 3-way valve returns to
the Heating mode position and the boiler is ready to provide
heating.
Note
●
DHW priority: Whenever a hot water tap is turned
on in the home, the boiler begins to run in DHW
mode and the heating function is deactivated until
all the taps are turned off again.
●
When the boiler water pressure drops below 0.4 bar
the automatic fill function is activated.
