58
10.3 Improper Combustion
Cause
Steps to be Taken
Fuel flow rate is excessively high or low
Adjust fuel control valve and air damper opening
Check and adjust fuel supply pressure
Gas supply pressure fluctuates
(for gas-fired unit)
Adjust gas supply pressure
Air-fuel ratio is improper
Check fuel and air ratio
Adjust fuel control valve and air damper opening
Pressure loss of smoke duct is
excessively high
Measure the draft force and modify the shape and size
of the smoke duct
Pressure loss of smoke duct is
excessively low (excessive draft force)
Measure the draft force and install a damper in the
smoke duct
Note: Only skilled service engineers are allowed to do above mentioned adjustment works for safety.
10.4 Actuation of Protective Devices
Protective Devices
Cause
Steps to be Taken
Chilled water flow rate differential
pressure switch (U3)
Reduction of chilled water flow
rate
Check chilled water pump
Chilled/hot water system
Chilled water
Temperature low switch (U6)
Chilled water load is too small
Chilled water temperature is too
low
Check the setting point of chilled
water thermostat and chilled
water controller
Check the chilled water flow rate
High pressure generator pressure
switch (U7)
High
pressure
generator
temperature switch (u8)
High pressure generator level
Switch (low) (U9)
Drop of degree of vacuum
Rise of cooling water inlet
temperature
Shortage of cooling water flow
rate
Dirty cooling water tubes
Shortage of solution circulating
flow rate
Operation error of electrodes
As mentioned before
Adjust solution circulating flow
rate
Replace with new electrodes
Exhaust gas temperature switch
(Y2)
Too much flow rate of fuel
Dirty heat transfer tubes
Set fuel flow rate to the rating
Check fuel supply pressure
Clean heat transfer tubes
Adjust air-fuel ratio
Gas pressure switch (Y1)
(applied for gas fired type)
Gas pressure drop of the forced
fan
( Failed governor
( Check the forced fan
( Check air inlet
(Check duct leakage and repair it
Over-current relay for
Canned pump motor
( Over load of motor
( Crystallization
( Check and replace with new
igniter transformer
( De-crystallize (See 5.8)
Summary of Contents for HDFN-80-1400
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Page 66: ...66 Fig 8 Lithium Bromide Temperature Specific Gravity Concentration Curve...
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