Document BR7VyqJ52oRozEjXGgxx7vv3X

ofAmerican Society Heating and Ventilating Engineers Guide7i935 . 3. Connections to the chimney should .be cleaned and in case of small boilers the n' should be placed in a dry. place after cleaning. r pipe 4. If there is much moisture in the boiler-room, it is desirable to drain the boiler t prevent atmospheric condensation on the heating surfaces of. the.boiler when they aTM below the deW-poirit temperature. Due to the hazardof some one inadvertently buildm a fire in a dry boiler, however, it is safer tokeep the boiler filled with water. A hot water system usually is left filled to' the expansion tank. 5. The grates anti ashpit should be cleaned. 6. Clean find repack the gage glass if necessary. .7. Remove any rust or other deposit from exposed-surfaces by scraping with a wire briish or sandpaper. After boiler is thoroughly cleaned, apply a coat of preservative paint where required-to external parts-normally painted.1- -- ----- 1 ----- --- 8. Inspect all accessories of the boiler carefully to see that they are in gpod working order.,. In this.connection, oil all door hinges, damper bearings and regulator parti BOILER INSULATION -'Insulation for. cast>irqn- boilers is of two general;.types:, (l) .plastic material; or blocks wired on, .cemented and covered.with canyas-or. duck; and (2) blocks, sheets, or..:plastic; material. covered., with. a metal..jacket furnished by the boiler manufacturer,. Self-contained steel firebox boilers usually are. insulated. with -blocks, cement and canvas, or. rock wool blankets ; HRT boilers are brick set and.do not require insulation beyond that provided in the setting. It inessential that-the insulation on a boiler and adjacent.piping. be ofcnon-combustible material as even slow-burning insulation .constitutes- a dangerous, fire hazard in case of low water in the .boiler. -. -i: . .- , r.v' references ; : ,A.S.H:V.E. :Code of Minimum Requirements for the- Heating arid Ventilation of Buildings. ; . :; . ' ... - A.S.H.V.E: Standard and Short Form,Heat1 Balance Codes for:Testing Low-Pressure Steam.Heating-Solid Fuel Boilers (Godes-1 and 2). A.S^H.V.E. Performance Test Code for Steam Heatirig Solid Fuel Boilers (Code No.3). A.S.H.V.E. Standard Code for Rating Steam Heating Solid Fuel Hand^Fired Boilers. Heating, Ventilating and Air Conditioning,.by Harding,and.Willard, Revised Edition, 1932. 1 ..; ` , .' A.S.M.E. Boiler Construction Code for Low 'Pressure HeatingBoi|ers. Heating and. Piping Contractors National Association Standards (boiler selection tables).-' ' - ' " ' House-Heating,-published By American Gas Association.' Handbook of: Oil Burning, published by A merican Oil Burner Association. Heating and Ventilation, by Allen and Walker (3rd Edition). Selecting the Right Size Boiler, by Sabin Crocker (.Heating,. Piping and Air Con ditioning, February, March, April, 1932). PROBLEMS IN PRACTICE 1# What is,meant by. a low pressure heating boiler? A low pressure heating boiler is a boiler designed to be operated at less than 15 lb steam pressure or 30 lb water pressure as measured by a gage attached directly to the boiler. 420 .Chapter 25--Boilers j Itame the construction materials that distinguish two types of low pressure bating boilers. ,,. Cast-iron. b. Steel. jl ^pbat is the normal rating range of each type of boiler? Cast-iron boilers are rated at from 200 to 18,000 sq ft EDR. gteej boilers are rated at from 300 to 50,000 sq ft EDR. 4 a. What is meant by direct boiler heating surface? -- b. What is meant by indirect boiler heating slirface? " - --- ' ----- 1 ~ - i Direct boiler heatingsurface is that boiler surface upon which the fife shines, namely, - the walls of the firebox and the crown sheet. b Indirect boiler heating surface is that boiler surface not exposed to the direct rays of the fire and over, which heated gases pass after they have been.-in contact With :the direct surface. Indirect surface is generally known as-convective,surface. :. 5 What is the average heat transmission rate in heating boilers inBtiTper sq ft of heating surface per hour? S: 3500 for coal burning boilers; 4200 for oil burning boilers. / (What factors contribute to economical fuel operation in low pressure boilers burning coaLor oil?. . a: Proper furnace volume for complete comburtion. '.- , ^ 'Arrangement of hfetirig surfaces in series td'create a turbulent "and^ scrubbing contadt of gases against the'convective surfaces: ' . ,- c. Rapid internal water circulation which will remove steam bubbles from the water side of heating surfaces and allow other steam bubbles to be formed. ' Rapid-diseri- gagement of steam bubbles increases the steam generating efficiency:of each, unit area of heating surface, and thereby lowers flue gas ..temperatures: .. 7 What equipment is usually directly attached to a low pressure heating boiler? For coal burning steam boilers: water column, water gage, tri-cocks, steam gage lever pop safety valve, boiler damper regulator. : . -' - . .,--t . For coal burning hot water boilers: damper regulator, altitude gage, thermometer relief valve. .- . . ...... . ... ... ... ,, , ,y ... For oil burning boilers, the damper regulators are omitted and: the:following additional equipment is usually attached: automatic water.feeder,.low water cutout, a-.pressure control, and a water temperature cdntrol These are generally furnistied by the oil burner manufacturer and do not come with the boiler. . ,.r .... 8 What' general' precautions regarding tlie boiler should be taken to make sure a proposed heating installation will work properly? 0. Select the right size and type of boiler. ........ sure the combustion space is proper for the type of fuel burned. c. Allow sufficient space around the boiler for cleaning. 1. Secure proper height and area of chimney and connecting breeching. .* Slean the boiler thoroughly and provide surface blowoff connections and bottom oiowort connections for periodic cleaning after operation is begun. / See that the boiler heating surface is cleaned at regular periods. I- Check flue gas temperatures and make a flue gas analysis at least once a month. * Secure information and advice from boiler manufacturer.