CHAPTER 11 Book 1 Basic Boiler Operation

Question 1

Which controls need to be manually reset

Answer 1

If the boiler is shut down due to a flame failure it will not start again until the lock out rekey has been reset manually any other switch will auto reset once conditions return to normal

Question 2

Two conditions that may appear abnormal during boiler start up

Answer 2

Slight smoking-in a oil fired boiler is cold the furnace temp is not high enough to vaporize the the fuel completely and can result in white smoke from the stack. If this persist after warm up adjust the dampers to obtain proper air to fuel ratio
Condensation- when a cold gas fired boiler is started the condensation caused by the water water in the flue gases hitting the cold heating surface can condense enough to appear like the boiler is leaking. Once the boiler is full warmed up this should go away.

Question 3

Uneven expansion

Answer 3

When boilers are heated up and not allowed to circulate water the metal tube will heat up very quickly and can gain enough heat and expansion that they may damage the tube sheets they are fastened to.

Question 4

Thermal shock

Answer 4

Will cause strong internal stress in metal due to uneven expansion and contraction of the metals. The conditions is worsened by scale build up. Always warm the boiler up slow, keep the boiler free of scale build up, do not allow cold make up water

Question 5

Cutting in additional boilers (steam and water)

Answer 5

When cutting in either boiler ensure that the outlet and return is closed and bring the boiler up to temp or press slowly then slowly crack open the outlet valve to equal the pressure and then open the return once the supply valve is fully open. When the outlet is closed on a boiler the return line should be closed as well. Also if a common expansion tank is used ensure enough room is available to accommodate the extra water

Question 6

Pressure and temp checks and ranges for steam and hot water

Answer 6

Hot was should be kept below 121C and above 77C to avoid condensation the operating pressure varies a lot but should be kept 10 psi or 25% below the popping pressure of the relief valve. STEAM should be set at 2-3 psi below the popping press if the pop valve which should be set at 15 psi these pressure diffs allow for proper seating of the pop valve when they are needed.

Question 7

Diffs in steam and hot water boilers

Answer 7

Steam does not have a expansion tank and has the gauge glass on the water column of the boiler where water boilers have a expansion tank and the gauge glass is located on the expansion tank. How water boilers don’t generally need make up water or refilling and don’t need to be blown down or cleaned between the 2 year inspection. Steam should have a make up water line that flows into the condensate receiver to warm up and get rid of the oxygen in the make up water before it enters the boiler