Hydraulic Connection Of The Heating Circuit - DeDietrich GT 430 Installation And Service Manual

4.5.3

Hydraulic connection of the heating circuit

Water flow in the boiler
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).
- Maximum water flow Qmax = 0.86 Pn/5.
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Qn = flow in m /h.
Pn = Nominal output (full boiler output) in kW.
Operation in cascade
After stopping the burner:
- Timeout required before the order to close a 2 way 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.
Operation with 2-stage burner
- 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: 40°C); The first stage must be set to a minimum of
50% of the nominal stage.
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: 40°C); The burner can modulate down to 50% of the
nominal stage.
05/03/2013 - 300011893-001-02 GT 430
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