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2 Important recommendations for connecting the boiler to the heating circuit
Installation must be carried out in accordance with the prevailing
regulations, the codes of practice and the recommendations in these
instructions.
Minimum safety valve flowrate as a function of maximum boiler nominal output :
Minimum relieving capacity
Maximum gross boiler output
The water flow in the boiler when the burner is operating must
correspond with the following formulae:
- Nominal water flow Qn = 0.86 Pn/20
- Minimum flow Qmin = 0.86 Pn/45 (this flow also corresponds with
the minimum recycle flow in the boiler)
After stopping the burner:
- Timeout required before the order to close a butterfly valve: 3 min
- Switch a possible shunt pump (located between the boiler and a
butterfly valve) off via the end of run contact of the butterfly valve
- The water temperature in the boiler is maintained at 50°C or more ;
the first stage must be set to a minimum of 30% of the nominal
stage
- Operation at modulated low temperature (minimum outlet
temperature: 30°C) ; the first stage must be set to a minimum of
50% of the nominal stage
3 Refilling the installation
Filling shall be performed with a low flow rate from a low point in the
boiler room in order to ensure that all the air in the boiler is bled from
14
Example
Maximum boiler nominal output is 200 kW.
Minimum safety valve flowrate must be 1500 Kg/h
Water flow in the boiler :
- Maximum water flow Qmax = 0.86 Pn/5
Qn = flow in m
Pn = Nominal output (full boiler output) in kW.
Operation in cascade
Operation with 2-stage burner
- Operation with modulating burner
- The water temperature in the boiler is maintained at 50°C or more:
the burner can modulate down to 30% of the nominal stage
- Operation at modulated low temperature (minimum outlet
temperature: 30°C) ; the burner can modulate down to 50% of the
nominal stage
the high point of the system.
Always stop the pump before filling.
GT 330
3
/h
10/04/06 - 300007650-001-A
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