15
When There is No Gas Flow
To The Pilot Head
This is the trouble-shooting procedure for the gas supply:
Check if all gas connections are sealed by using strong
soapy water (avoid synthetic soaps). Be certain all valves
from the gas tank/cylinder are fully open.
When the pilot is to be lit for the first time with a new
installation, after a scheduled disconnection or after the
propane tank has been refilled, there will often be air in
the gas tube leading up to the appliance. The tube system
must be cleared of air before the pilot burner can be lit.
The recommended method for clearing air out of the tube
system, is to push in the gas control knob and turn anti-
clockwise to “PILOT”. Then push in the gas control knob for
5 seconds and push the control knob on the spark igniter
to the bottom several times. Repeat the procedure until
the pilot is lit.
If the pilot does not light after attempts to clear the
tube system of air, it indicates a problem with the gas
tank/cylinder or a leak in the gas tube. Check the gas
pressure as instructed in the section Gas Installation on
page 10 and determine if the fault/leak is before or after
the valve on the appliance. If the gas pressure at outlet D
(fig. 21) is too low or there is no gas pressure at all, the
fault or leak must be located before the valve on the
appliance. If the gas pressure is OK at outlet (D), but too
low at outlet (E), then the fault or leak must be located
after the valve.
Note! SIT valves are always equipped with a fine filter
at the inlet to avoid dirt from entering into the valve.
Consequently, dirt in the valve is not a common occur-
rence. If gas tubes are dismantled, all gas tubes must be
reinstalled and checked for gas leaks prior to operating
the appliance.
When the Pilot Goes Out - Problems
With the Gas Supply
This is the trouble-shooting procedure for the gas supply:
Remember to push in the gas control knob for at least 30
seconds. Make sure the flame is centred at the thermo-
couple. Make sure the thermocouple is enveloped by the
flame up to at least 3 mm (1/8") from the tip (fig. 18).
If the flame is abnormally large or small, check the gas
pressure first. See section about gas pressure, page 10.
Then check for errors, dirt or corrosion on the pilot burner
(fig.18), the pilot orifice and the gas supply to the pilot
burner.
Note! There could be a leak after the valve even if the
pressure is OK at outlet E. You should therefore always
check for leakage.
Thermocouple (Fig.24) and Thermopile
(Fig. 25)
A thermocouple is in principle a thermal generator and
consists of a copper wire (copper-nickel alloy) and an iron
wire twisted together. These wires will create friction and
generate 25 millivolt when exposed to a temperature
difference of 200°C. This voltage is sufficient to make the
gas valve function. In order to produce higher voltage a
thermopile is used, which is based on the same principle as
the thermocouple, but with more copper and iron wires.
The thermopile produces approx. 500-700 millivolts.
This only amounts to 1/3 of the voltage in a flashlight
battery. It is important to understand that even minor
resistance (ohm) will have great impact on such a small
voltage. If resistance is too great, the gas valve may not
receive enough voltage to operate. If there is too much
resistance, the cause may be that the copper wire con-
ducting the voltage is too long, or there are too many
connections. If the copper wire comes in contact with
metal, it may increase resistance and consequently reduce
the voltage.
When the Pilot Goes Out, But the Gas
Supply is OK.
This is the trouble-shooting procedure for the thermo-
couple, fig. 24,B: Check the copper wire (F) of the thermo-
couple for cracks or damage.
Check the gasket (C) at the valve by loosening the nut
that holds the copper wire. Look for signs of damage, if the
nut has been tightened too hard. A damaged gasket
results in resistance at contact with metal and conse-
quently the voltage to the valve will be too small.
Make sure the flame is centred at the thermocouple.
Make sure the thermocouple is enveloped by the flame up
to at least 3 mm from the tip (see fig.21). Check the voltage
generated by the thermocouple. Connect the multimeter
(fig.24-E) with plus to the ball point (D) at the end of the
copper wire. Connect minus to the copper wire. Light the
pilot (A) and hold in the control knob to prevent the flame
on the pilot burner from going out. At this point the
multimeter should show 14-28 mV. the thermocouple. Note
that there are 2 threaded holes that can be used when
installing a new thermocouple. Make sure the blue wire (A)
is fastened at the same threaded hole. The nut on the
thermocouple must not be tightened too much, just a 1/2
turn. If the gas pressure is correct and the possible faults
above have been checked, the pilot flame can be adjusted
with the adjusting screw. The gas volume is increased
when the screw is turned anti-clockwise.
