Chapter 12 Book 1 Routine Boiler Maintenance

Question 1

Two methods of laying up a boiler

Answer 1

Dry method- cool and drain boiler then clean Fire and Water side dry boiler out and place a tray of absorbing material that is to be changed out regularly make sure everything is closed up tight including dampers swab fire side with a mineral oil to prevent rusting
Wet method- still drain and clean boiler but fill it back up and bring it to temp to drive off oxygen then treat water and put a small drum of treated water connected to the air vent to allow for some expansion and contraction during down time. This can’t be used if freezing is possible

Question 2

Boiler repairs

Answer 2

Repairs in the pressure parts can only be made after consult with the authorized inspector. When a welder is needed the must have pressure ticket and valid performance qualification card

Question 3

Common reasons for fire tubes to mess up

Answer 3

• overheating of the tube due to excessive firing rate, poor water circ, heavy scale forming, failure of low water cut off
• corrosion due to lack of water treat or corrosive combustible gases
• cracked tube ends due to uneven expansion from thermal shock

Question 4

Two methods of finding cracks on tube ends and tube sheets

Answer 4

Dye penetrants method- a penetrant is applied by either brushing or spraying and once it has had time to soak in the excess is removed and a developer is sprayed on which will bring and penetrant that is trapped in a crack to the surface.
Black light- pretty much the same but once the penetrant is wiped off a black light ks used to highlight the cracks they soaked into.

Both require to tubes to be cleaned well first