FAQ Orals MEP (Auxiliary Boilers)

What Would You Do If You Had A High Chloride Level In The Boiler?
To Reduce The Chloride Level In The Boiler, The Boiler Would Be Blown Down, Thus Allowing Fresh Feed To The Boiler.

What Type Of Safety Valve Is Fitted To A Boiler And At What Pressure Does It Lift? 
The Type Of Safety Valves Fitted To Boilers Are High Lift Safety Valves And Are Designed To Operate At 10% Boiler Working Pressure And Must Also Be Capable Of Releasing All The Steam The Boiler Can Produce Without The Pressure Rising More Than 10% Over A Set Period:  15 Min For Tank Boilers And 7 Mins For Water Tube.  The Spring Pressure, Once Set, Is Fixed And Sealed By A Surveyor.
Note:  The Above Test Is Known As The Accumulation Of Pressure Test.

What Is The Purpose Of The Scum Valve On A Boiler?
The Scum Valve On A Boiler Is Connected To A Shallow Dish Positioned At The Normal Water Level Of The Boiler And Enables The Blowing Down Or Removal Of Scum And Impurities From The Water Surface.

What Type Of Water Tests Would You Do On A Low Pressure Auxiliary Boiler/Economiser?
Chlorides Test
PH-alkalinity Test
Total Dissolved Solids Test - Using Hydrometer
Phenolphthalein Alkalinity Test
Hardness Test
Phosphate Reserve.

How Would You Blow Down A Boiler Gauge Glass?
Close The Water And Steam Cocks On The Gauge Glass And Open The Drain.   
Then Open The Steam Cock - A Strong Jet Of Steam Should Be Seen From The Drain.
Close The Steam Cock.
Open The Water Cock - A Strong Jet Of Water Should Be Observed From The Drain.
Close The Water Cock And Then Close The Drain.
Then Open The Water Cock, The Water Will Rise In The Gauge, Above Normal Level.
Then Open The Steam Cock, The Water Should Then Settle Down, Finding Its Correct Level.

Why Purge A Boiler Furnace?
A Boiler Furnace Is Purged Before Burner Operations To Ensure That There Is No Unburned Fuel Or Gases In The Furnace, Which May Cause A Blowback.  Purging Should Be Carried Out For At Least Two Minutes.

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 Condensor.  This Condensate May Be Contaminated As Some Of The Drains Are From Fuel Oil Heating Systems Or Tank Heating Systems. Normally These Drains Will Pass To The Hot Well Via An Observation Tank, Which Permits Inspection Of Drains 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 Feedwater Tank, Which Provides Additional Feedwater 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.