1.3
Operating of a modulating boiler compared with that of
an "on/off" boiler
On/off boiler
Modulating boiler
•
The graph shows how a modulating boiler works. The boiler burns for longer on a
lower heat output. This enables temperatures to remain more uniform.
A non-modulating boiler (on/off) simply burns at full heat output and then switches
off again. This means that the temperature fluctuates more.
•
A modulating boiler also ensures that the radiators do not get too hot — even
when the temperature on the thermostat is increased. The radiators remain at a
more constant temperature, which can be gradually increased or decreased.
•
After increasing the temperature on the modulating thermostat, the boiler will not
fire up immediately as with an on/off thermostat. This takes around a minute.
Remeha Celcia 20
16
Time
fig. 15 115817LTGBCEL015