Boiler
1" Steam Equalizing Pipe
Pump and Low
Water Control
Normal Boiler
Water Level
Cutoff Level
is Arrow Mark
Blowdown
Valve
1" Water Equalizing Pipe
1-1/2"
18
1
2
8
7
3
4
6
5
1
6
5
4
3
2
5-3/4
REF.
4-1/2
REF.
FIG. 1
FIG. 2
MAINTENANCE
1
2
3
4
2-1/2
REF.
HEATER ELEMENT CONDITION PROBABLE CAUSE
1. Water leakage at heater flange
2. Water leakage at heater element
to flange junction.
3. Burned wiring connections
4. Heater element has open circuit.
(Element looks OK but Ohmmeter
check shows infinite resistance).
5. Heater element has developed a
ground fault. When this occurs, a
hole may be formed in the sheath
material, allowing water to enter the
element.
1.
Heater bolts improperly tightened. Refer to flange tightening instructions.
2.
Debris on heater flange or generator flange surface. Clean prior to installation.
3.
Heater bolts not retorqued after initial operation. Refer to flange tightening
instructions.
1.
Faulty weld or braze on element to flange connection or corrosion.
2.
Verify water is not exiting through heater terminal. Normally seen in condition #5.
1.
Loose wire connections. Tighten properly after inspection.
2.
High resistance in wire connection due to oxidation. Clean wires before
reconnecting to element. Replace if necessary.
1.
Element has open circuit due to normal wear and tear to end life.
2.
If generator is undersized for its application, heaters will be over worked and
reach end of life sooner.
3.
Element has been overheated due to excessive scale build up. The scale acts as an
insulator retarding heat transfer to the water. Short life will result. If significant
scale is observed on element, this would indicate need for more frequent blowdown
or descaling.
4.
Wrong voltage supplied to element.
5.
Element not totally immersed in water. This causes a localized hot spot which
melts the wire inside the element. Cause of problem is fault in water level control
system. Elements damaged in this manner may be distorted. Repair and verify oper-
ation of the level control prior to restarting the heater.
1.
Corrosion of heater element sheath-use of corrosive descaler compounds will etch
sheath. Use only approved descaler to remove scale.
2.
Element has overheated due to excessive scale build up. This can cause localized
hot spot which sometimes arcs thru insulation and the ground metal sheath. More
frequent blowdown and/or descaling is needed.
3.
Element not totally immersed in water. This causes a localized hot spot which pro-
duces a hole in sheath. Cause of problem is fault in water level control system.
Elements damaged in this manner may be distorted.
4.
Excess vibration. Vibration could cause rubbing of elements wearing a hole in the
sheath. Vibration could be caused by large machinery nearby.
5.
Wrong voltage supplied to element.
IMMERSION HEATER FAILURE CAUSES
FIG. 3