单项选择题
A.treating with oxygen scavengers B.securing the boiler and giving it a blowing down C.increasing the pH D.reducing the phosphate level
Excessive alkalinity of the water in an auxiliary boile...
单项选择题Excessive alkalinity of the water in an auxiliary boiler can cause （）.
A.caustic embrittlement of the boiler metal B.acidic corrosion of the boiler metal C.hard scale deposits on the boiler tubes D.etching of the heat exchange surfaces
The purpose of the delivery check valve used in a diese...
单项选择题The purpose of the delivery check valve used in a diesel fuel injection jerk pump is to （）.
A.assist in a quick cutoff of fuel injection B.allow oil backflow from the injector to the helix C.reduce fuel oil pressure between injection strokes D.meter the quantity of fuel delivered
Before an auxiliary boiler is shutdown for an extended ...
单项选择题Before an auxiliary boiler is shutdown for an extended period of time, the water in the boiler should have a pH value of （）.
A.10 B.7 C.4 D.1
