Beckett CG10 Manuel D’Utilisation

High limit – To check the High Limit, raise the 
temperature or pressure of the operating control to 
a higher level and lower the limit to a setting less 
than the operating control. Run the burner until the 
high limit opens and shuts the burner off. Adjust the 
controls back to the desired settings.
Operating control – Run the burner until the 
operating control shuts it off. If necessary, make 
adjustments to ensure the control cycles the burner 
in the desired temperature or pressure range. 

 

 

 

 

 

 

 

Operating controls should be 
set to minimize the number of 

fi ring cycles that the burner runs.  High cycling rates 
increase the possibility of light-off lock outs.
Low water cutoff (LWCO) – With the burner fi ring, 
open the blow down valve on the low water cutoff, 
if applicable. As the water level drops, the LWCO 
switch contacts open and shut the burner off. When 
the water level rises, the LWCO contacts close 
and restart the burner. Monitor the LWCO switch 
operation in relation to the water level in the sight-
glass for synchronization.

The testing of operation and safety controls requires 
technical training and experience with commercial 
gas burning systems.
Carefully follow the manufacturer’s instructions 
supplied with the controls.
Verify the correct function of all operation and safety 
controls used in the installation.
If instructions are not available, use the following 
recommended procedures and record all results in a 
start-up log.
Refer to Figure 7 and Figure 10 for typical test 
points and component locations.

y

y

y

y

y

Airfl ow proving switch – With the burner fi ring at 
its lowest rate, loosen the tubing connection to the 
airfl ow proving switch. A loss in air pressure at the 
tubing should immediately cause the diaphragm 
in the switch to open and recycle or lockout the 
safeguard control.
Low gas pressure switch – With the burner fi ring 
and a manometer attached to a test port near 
the low pressure switch, gradually close the main 
leak test cock to shut off the gas supply. Note the 
pressure at which the low gas pressure switch 
opens and shuts the burner off. Manually reset the 
switch. The low gas pressure switch should be set 
at half of the normal supply pressure in the line.
High gas pressure switch – With the burner fi ring 
and a manometer attached to the test port nearest 
the high pressure switch, gradually increase the 
gas pressure until the high pressure switch opens 
and shuts the burner off. Note the pressure and 
manually reset the switch. The high gas pressure 
switch should be set at one and one half times the 
high fi re manifold pressure (see nameplate data in 
Figure 1 or set switch as determined by testing).
Leak-test valve – With the burner fi ring and 
manometer attached to the leak-test valve port, turn 
the burner electrical switch off and observe that 
the gas pressure does not increase after several 
minutes. This proves total closure of the main gas 
valve.
Flame safeguard safety lockout – Simulate a 
fl ame failure by turning the main gas supply off. The 
control should shut the burner off on safety within 
the safety lockout time.  
Flame sensor circuit (fl ame rod) – With the 
burner power switch turned off, refer to the wiring 
diagram supplied with the control and locate the 
sensor connection terminals. Place DC voltmeter 
probes in the fl ame amplifi er test jacks.  With the 
burner fi ring, the fl ame signal should be steady and 
at least 1.25 VDC.
Flame sensor circuit (UV scanner) – With the 
burner power switch turned off, refer to the wiring 
diagram supplied with the control and locate the 
sensor connection terminals. Place DC voltmeter 
probes in the fl ame amplifi er test jacks.  With the 
burner fi ring, the fl ame signal should be steady and 
at least 1.25 VDC.