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No.
System
High CO at low fire (con't)
9
Gas combustion noise
(rumbling)
10
Oil combustion smoking
11
Fuel-Air-Ratios are
not consistent
12
Fuel-Air-Ratios have changed
over time
12
Cannot obtain capacity on
gas
13
Cannot obtain rated input on
oil firing (pressure atomized)
oil f
14
Cannot obtain NOx levels on
gas
15
High NOx during normal oper.
SC Manual
Cause
High stack draft (especially at low fire)
Fluctuating gas pressure (regulator not holding pressure)
Input too low for burner components
Improper excess air
Fluctuating gas pressure (regulator not holding pressure)
High stack draft (especially at low fire)
Flame instability
Oil nozzle dirty or plugged
Improper excess air
Input too low for burner components
High stack draft (especially at low fire)
Incorrect nozzle position
Fluctuating oil pressures (regulator not holding)
Poor air flow distribution (off center flame)
Fuel line plugged
Fuel supply pressure changing
Combustion air temperature changed
Draft condition changed
Gas control valve - low fire stop not set (if used)
No back pressure
Air damper seal worn
Fuel lines plugged
Fuel control valve worn
Gas orifices or gas manifold plugged
Combustion air temperature changed
Draft condition changed
Vessel plugged
Wrong spring range in regulator
Too many elbows before control valve
Gas line too small, high pressure drop
Supply pressure lower then stated
Supply pressure drops too low at high fire
Regulator too small for flow and pressure
Oil nozzles plugged
By-pass seal on nozzle leaking
Operating on propane, not natural gas
Loose diffuser plate
Gasket burned up
Page 27
Correction
Stabilize draft
Check regulator pressure, sensing line
and supply pressure: sized properly
Check input, compare to rating label
Readjust excess air
Check regulator pressure and supply
Stabilize draft
Add primary fuel
Clean oil nozzle
Redajust excess air
Check input, compare to rating label
Stabilize draft
Adjust the nozzle to diffuser position
Check regulator pressure and oil supply
Adjust air straightener blade
Check and clean lines, strainers & filter
Check and/or replace pressure regulator
Retune burner
Check draft and outlet damper
Adjust low fire stop
Decrease the stack exhaust area (close
the stack)
Replace air damper seals
Check and clean lines, strainers & filters
Replace fuel control valve
Clean and/or replace
Retune burner
Check draft and outlet damper
Clean vessel
Install higher spring range
Rework piping to reduce elbows
Use larger pipe size
Increase supply pressure
Use larger gas line sizes / orifice in
service regulator
Change regulator
Replace nozzles
Replace nozzles
Tighten diffuser plate
Replace gasket
Toubleshooting
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