7.3.6 Run Mode
During run mode the combustion rates are pre-set for the 5 different power levels.
On entering this phase the system starts at Power Level 1 and after a 20
second intervals increases a Power Level each time until Power 5 is
reached.
The boiler will continue to run at Power 5 until the water temperature
reaches within 5 C of the set point.
The ignition element is off during this phase.
The auger ON/OFF values are pre-set for each of the power levels.
During commissioning the combustion fan and exhaust fan speeds are
fan are set to maintain the correct CO2 (Carbon Dioxide) and CO (Carbon
Monoxide) levels for clean efficient combustion.
The circulation pump is activated by the controller once the water in the
boiler reaches 55 C. The pump will turn off once the temperature drops to
52 C.
If the unlikely event that light diminishes below a pre-set low value for a
period of time then Er13 will appear to indicate that the light has gone out.
This may be due to a lack of pellets entering the combustion tube due to
dust or poor quality pellets.
7.3.7 Modulation Mode
The modulation range has been pre-set so that the system starts reducing to a lower
power level when the water temperature comes within 5 C of the set point.
Example : Water temperature on the controller has been set to 70 C.
When the water temperature in the boiler reaches 65 C the system
enters Modulation Mode. When the water temperature reaches 66 C the
power level drops to Power 4, 67 C – Power 3, 68 C – Power 2, 69 C –
Power 1 and 70 C – Standby / Extinguishing.
During Modulation each power level has it own pre-set parameters for
fan speeds and auger ON/OFF values.
Power Level 5 is the full rated output of the boiler.
Power Level 1 is 30% of the rated output of the boiler.
Depending on the heat loss from the heating system the boiler may
settle at a power level to match the heat loss from the system and may
increase power levels again to match a drop in water temperature.
The Modulation band may be set wider (up to a max of 15 C) by the
Commissioning Engineer if it is deemed necessary
47
To Next Page
Loading...
