Reading Gas (Methane) Meter - Air Pressure Switch - baltur COMIST 180 Manual De Instrucciones

READING GAS (METHANE) METER
When the burner is operating at maximum output, check that the quantity of gas delivered is necessary for the boiler's
needs. The low calorific value for methane gas is about 8550 kcal/m
To find out the low calorific values of other types of gas, contact the Gas Distributing Company.
Delivery per hour should be taken at the meter. When checking delivery make sure that gas is not being consumed by
other users.
If the gas delivery pressure at the meter is not above 400 mm.W.C., take into consideration the value indicated by the
meter without correcting it.
For a first indication, turn on the burner and when it arrives at nominal delivery, measure the gas output in one minute
exactly (the difference between the two readings should be one minute exactly from one to the other.
Multiply this value by 60 in order to obtain the output for 60 minutes (one hour).
The output measured is considered the actual value if the meter reads a pressure below 400 mm.W.C.
If the pressure is more than 400 mm.W.C., the value read must be multiplied by a correction coefficient, as previously
described.
Subsequently, multiply the delivery per hour (m
this should correspond or be very near to that requested for the boiler (low calorific value for methane gas = 8550 kcal/m
Do not allow the burner to operate for a long time (only a few minutes) if the output exceeds the maximum
allowed for the boiler, to avoid possible damage to it; it would be timely to stop the burner immediately after
having taken the two meter readings.
Correcting the value indicated by the meter
If the meter measurer the gas delivery at a pressure above 400 mm.W.C., it is necessary to multiply the value by a
correction coefficient.
As an indication, the correction coefficient values to be adopted in function with the gas pressure existing at the meter,
can be determined in the following way:
Add to number 1 (one) the number which expresses the gas pressure value in bar, existing at the meter.
Example n° 1
Gas pressure at the meter = 2 bar, the multiplication coefficient is 1 + 2 = 3.
Therefore, if the meter reads a delivery of 100 m
3
m /h.
Example n° 2
Gas pressure at the meter = 1,2 bar, the multiplication coefficient is 1 + 1,2 = 2,2.
Therefore, if the meter reads a delivery of 100 m
3
= 220 m /h.
Example n° 3
Gas pressure at the meter = o,3 bar (3000 mm.W.C.), the multiplication coefficient is 1 + 0,3 = 1,3.
Therefore, if the meter reads a delivery of 100 m
Example n° 4
Gas pressure at the meter = 0,06 bar (600 mm.W.C.), the multiplication coefficient is1 + 0,06 = 1,06.
Therefore, if the meter reads a delivery of 100 m
m 3 /h x 1,06 = 106 m 3 /h.
AIR PRESSURE SWITCH
The purpose of the air pressure switch is to prevent fuel (natural gas or light oil) valves opening if air pressure
is not as planned. The pressure switch must therefore be set to close the contact (closed during operation)
when air pressure in the burner is sufficient. The pressure switch connection circuit is self controlling.
Therefore, the contact which is meant to be closed in non operating state (fan stopped and thus no air
pressure in burner), should in fact be in this state, otherwise the command/control equipment will not be
switched on (burner remains inoperative). Please note that if the contact meant to be closed during operation
does not close, the equipment carries out its cycle but the ignition transformer is not switched on and the fuel
valves do not open. As a result, the burner stops in "blocked" state.
To verify that air pressure switch is operating correctly, while the burner is ignited on first flame only, increase
adjustment value until the switch triggers instant "blocked" stoppage of the burner.
Release the burner by pushing the appropriate button and readjust the pressure switch until preventilation air
pressure can be detected.
3
3
/h) by the gas calorific value to obtain the potentiality delivered in Kcal/h;
3
/h, multiply it by 3 to obtain the actual output which is 100 m
3 /h, multiply it by 2,2 to obtain the actual output which is 100 m
3
/h, multiply it by 1,3 to obtain the actual output which is 130 m
3
/h, multiply it by 1,06 to obtain the actual output which is 100
48
.
3 ).
3
/h x 3 = 300
3 /h x 2,2
3
/h.