System Volume; Boiler Sequence Of Operation - Dunkirk DCC-150 COMBI Manuel D'installation, D'utilisation Et D'entretien

2.8

SYSTEM VOLUME

When the boiler is operating at maximum operating temperature, providing heating with all heat emitters operating, the
pressure gauge should not indicate more than 26.11 psi / 1.80 bar. If the reading exceeds this figure a larger expansion tank is
required.
2.9

BOILER SEQUENCE OF OPERATION

• With a demand for heating, the pump circulates water through the primary circuit.
• The combustion fan will then come on and begin to run at ignition speed.
• Once the fan reaches ignition speed the control board will allow power to flow to the spark generator and gas valve
creating ignition in the combustion chamber. The flame sensor will acknowledge the presence of a flame in the
combustion chamber and send a signal to the control board.
• The temperature sensor will send a signal to the control board allowing the control board to increase / decrease the speed
of the fan. The combustion fan will in turn modulate the gas rate accordingly.
• Once the central heating loop temperature exceeds the central heating loop setpoint the unit will shutdown and go through
a 3 minute time delay (burner pause time) before another call for heat.
• During this time the pump will run for an additional three minutes to dissipate any residual heat.
9
240011373, Rev. G [03/31/2017]