Glow-worm SwiftFlow 125 Instructions For Use Manual page 23

11.3 Preparation for Lighting
Isolate the boiler from the mains electrical supply at the external
isolator.
Test for soundness and purge air from the gas supply in accordance
with the rules in force in the countries of destination. Turn on the gas
service cock, slot in line with the length of the cock.
Remove the burner pressure test point screw and connect a
suitable pressure gauge, see diagram 11.2.
Remove the combustion chamber negative pressure test point
screw and connect to the pressure gauge as above, see diagram
11.1.
Note: The resultant readings given are differential pressures
11.4 Burner Pressure - Hot Water
The burner pressure will always require checking and in the
majority of installations will require adjustment. Provision for this is
made in the form of a potentiometer on the main P.C.B.
Note: All adjustments to be made while the appliance
The pressures are to be measured as a
It is therefore essential that one side of the manometer is connected
to the valve test point, and the other side is connected to the
negative pressure test point, see diagrams 11.1 and 11.2.
Connect the electrical supply, the pump will operate for about 30
seconds, then the pump stops.
Fully open the largest hot water draw off tap whereby the main
burner will light, the flames gradually increasing to maximum.
Check the soundness of the boiler gas joints, with the main burner
on, using leak detection fluid. Take care not to splash any of the
electrical components.
Fully open the hot water throttle, (clockwise), see diagram 11.4.
Check that the water flow rate is not less than 14Litre/min (3.1gall/
min) to prevent any modulation of the gas pressure. This is
equivalent to 4.3 seconds to fill a 1Litre container (2.4 seconds for
1pint).
To achieve this flow rate a water pressure of at least 0.8bar is
required during commissioning, although subsequently the appliance
will work at a minimum pressure of 0.5bar.
This flow rate should prevent any modulation of the gas pressure.
Check the burner pressure is within +/-0.2mbar of 16.8mbar, the hot
water burner pressure. If this is incorrect, the burner pressure may
be adjusted to the correct setting by turning the hot water gas
pressure adjuster (potentiometer), using an insulated screwdriver,
see section 11.5.
NOTE: If any adjustments have to be made, set the minimum
pressure first.
Close the hot water draw off.
11.5 Gas Rate Modulation
ALWAYS CHECK HOT WATER BURNER PRESSURE FIRST -
REFER TO SECTION 11.4.
Note: All adjustments to be made while the appliance is hot.
Check the minimum gas pressure.
First, make sure that the boiler is isolated from the electrical supply
at the external isolator. Remove the jumper, see diagram 11.3,
taking care not to mislay it
Note: This will lock the appliance at minimum gas rate
Switch on the electrical supply.
Supplied By www.heating spares.co Tel. 0161 620 6677
11 Commissioning
Half open a hot water draw off tap and the main burner will light at
minimum gas rate.
Check that the burner pressure is 1.2mbar +/-0.2mbar. If this is
incorrect, it may be adjusted by turning the minimum pressure
potentiometer with a insulated screwdriver
decrease pressure), see diagram 11.3.
Disconnect the electrical supply, and replace the jumper.
Switch on the electrical supply.
If the above adjustment was necessary, it will be essential to check
that the maximum pressure can still be obtained.
is hot.
p (differential pressure).
23
SWITCH 'ON'
SWITCH 'OFF'
CENTRAL HEATING
SELECTOR SWITCH 'C'
NEGATIVE
PRESSURE
TEST POINT
PRESSURE
GAUGE 'A'
To measure gas pressure as
is located in the bottom of the combustion chamber.
(anticlockwise to
NEON
RESET
BUTTON
Diagram 11.1
TEST
POINT
p a second test point
Diagram 11.2
221474C