Unigas R91, Installation Manual

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PART I: SPECIFICATIONS
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1.9 Combustion head gas pressure curves depending on the flow rate
The curves referred to the gas pressure in the combustion head, depending on the gas flow rate, are referred to the burner properly
adjusted (percentage of residual O
2
in the flues as shown in the “Recommended combustion values” table and CO in the standard
limits). During this stage, the combustion head, the gas butterfly valve and the actuator are at the maximum opening. Refer to Fig. 4,
showing the correct way to measure the gas pressure, considering the values of pressure in combustion chamber, surveyed by means
of the pressure gauge or taken from the boiler’s Technical specifications.
Fig. 4
Note: the figure is indicative only.
Key
1 Generator
2 Pressure outlet on the combustion chamber
3 Gas pressure outlet on the butterfly valve
4 Differential pressure gauge
1.10 Measuring the gas pressure in the combustion head
In order to measure the pressure in the combustion head, insert the pressure gauge probes: one into the combustion chamber’s
pressure outlet to get the pressure in the combustion chamber and the other one into the butterfly valve’s pressure outlet of the burner.
On the basis of the measured differential pressure, it is possible to get the maximum flow rate: in the pressure - rate curves (showed on
the next paragraph), it is easy to find out the burner’s output in Stm
3
/h (quoted on the x axis) from the pressure measured in the
combustion head (quoted on the y axis). The data obtained must be considered when adjusting the gas flow rate.
ATTENTION: THE BURNED GAS RATE MUST BE READ AT THE GAS FLOW METER. WHEN IT IS NOT POSSIBLE,
THE USER CAN REFERS TO THE PRESSURE-RATE CURVES AS GENERAL INFORMATION ONLY.
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