19
7.
MALFUNCTIONS
Troubleshooting may only be performed by suitably trained and qualified personnel
Ø
Observe all applicable safety instructions of this manual!
Ø
Immediately repair or correct each malfunction, defect or fault that may generate a hazard.
Refer to section 6 for instructions concerning inspection and repairs.
Malfunction
Possible cause
Excessive vibrations and abnormal
noise
―
air trapped in the box cooler. Open the vent and bleed until all air is out of the system
―
pressure fluctuations in circulating medium, defective or incorrect pump
―
vibrations or resonance transmitted to the box cooler from attached piping (see
section 4.1.2)
Box cooler is leaking
―
leakage at the nozzle to water cover joints. Too high nozzle loads, thermal expansion or
vibrating piping. Contact Duramax Marine®.
―
defective tube. Seal the defective tube at both ends with tube plugs
(see section 6.2).
―
defective tube – tube sheet connection. Contact Duramax Marine®.
―
leakage between pipe flanges. Re-‐tighten the bolts. Check the gasket faces for damage
(see section 4.4.4).
―
leakage between tube sheet and mounting frame. Bolts insufficiently tightened. Re-‐
tighten the bolts.
―
leakage between tube sheet and mounting frame. Mating flanges not flat or face
surfaces damaged (see section 4.2). Re-‐tighten the bolts (see section 4.4.4). Contact
Duramax Marine® if this does not succeed.
―
pressure and/or temperature too high (see section 5.2)
―
internal corrosion (contact Duramax Marine®)
―
wrong gaskets used (see sections 4.3 and 4.4)
―
abrasive or corrosive (cleaning) medium used
―
frost damage (see section 5.3)
After carrying out the corrective measures, pressure test the box cooler to make sure it is
leak free, see section 6.3.7.
Insufficient capacity
(can be determined by checking the
temperatures of the medium and
the air)
―
insufficient or incorrectly sized slot openings (see section 4.1)
―
air trapped in the sea chest
―
wave hollow occurring in the sea chest (see section 4.1)
―
sea chest (slots) too close to ship’s propeller
―
box cooler too close to the walls of the sea chest (contact Duramax Marine®)
―
water cover mounted in the wrong way (see section 4.3.4)
―
medium inlet temperature or flow higher than specified
―
air trapped in the box cooler. Open the vent and bleed until all air is out of the system.
―
box cooler tubes are fouled, damaged or blocked (see section 6.2 and 6.3)
―
excessive marine growth on the tube bundle (see section 6.3.2)
Corrosion
―
coatings damaged (on tube bundle and/or on sea chest)
―
sacrificial anode depleted or not installed. Contact Duramax Marine® for advice.
―
stray currents. Install sacrificial anodes and/or contact Duramax Marine®.
