Describe the boiler hot well and cascade tank. Why is it fitted and how would you trace an oil leak?
The boiler hot well is where the condensate drains return from the condenser. This condensate may be contaminated as some of the drains are from f.o.heating systems or tank heating system. Normally these drains will pass to the hot well via an observation tank, which permits inspection of drain and their discharge to an oily bilge if contaminated. The hot well tank is also arranged with internal baffles to bring about preliminary oil separation from any contaminated fuel or drains. The feed water is then passed through charcoal or cloth filters to complete the cleaning process. Any overflow from the hot well passes to the feed water tank which provides additional feed water to the system when required. Feed pumps take suction from the hot well to the boiler.
To trace an oil leak to the system, various heating coils to tanks would be shut off in turn until the leak stopped, thus indicating which heating coil was leaking.