Carlin G3B - Manual (Page 20)

Model G3B Gas burner — Instruction manual
Carlin part number MNG3B Gas Rev. 03/17/09
20
7. Troubleshooting
(continued)
Problem Possible
cause Corrective action
WARNING
These procedures must only be performed by a qualifi ed service
technician. Use care when performing tests on electrically or
mechanically live parts. Disconnect power to burner/appliance and close
main manual gas valve when removing components for service. Failure
to comply could result in severe personal injury, death or substantial
property damage.
Burner pre-
purges for 34
seconds but
does not light
(continued) Bad primary
control Check for 24 V on valve lead on control during TFI.
Check for 120 V on HSI lead on control during pre-purge.
Replace primary control if either above tests show negative.
Burner lights but
primary control
locks out after TFI Incorrect air
setting For initial light-off, set air throttle according to desired input.
Wrong orifi ce
size Check orifi ce drill size.
Manifold
pressure Adjust regulator to 3.5 W.C. for natural gas or propane.
Inadequate gas
supply Line pressure requirements are: 5.0 W.C. for both natural and propane
fuels.
Line pressure in excess of 14.0 W.C. could damage combination gas
valve.
Watch line pressure gauge during TFI. If pressure drops below minimum
required when gas valve is energized look for partially closed gas cocks
in line, other appliances using the same supply or improperly adjusted
intermediate regulators.
If other appliances are on the same supply line and piping will not
sustain adequate pressure for all units on that piping, then it is
undersized. Check with gas utility.
Insuffi cient fl ame
signal Check fl ame signal. Minimum signal 0.8 DC microamps.
Improper draft Improperly adjusted air throttle setting for the fuel input.
Over-fi re draft is normally -0.01 W.C. Refer to boiler/furnace
manufacturer’s recommendations for specially packaged units.
Polarity Check 120 V at L1 on terminal strip.