Bryan Boilers Forced Draft Steam Boilers Service Manual Download Page 8

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FIG. 1.8.1: VENT DESIGN INSTRUCTION -

REFERENCES

TABLE 1.8.1A: ESTIMATING FLUE GAS VOLUMETRIC FLOW RATE

Approximate Flue Gas VOLUMETRIC FLOW RATE

(Per 1000 Btu/hr Input)

(Multiply factor listed times boiler input in MBH)

BOILER TYPE

SCFM Per

1000 Btu/hr

INPUT

ACFM Per

1000 Btu/hr

INPUT

APPROXIMATE

FLUE GAS

TEMPERATURE

Water & 15# Steam

Gas Fired

Oil Fired

0.230

0.402

450 F

150# Steam

Gas Fired

Oil Fired

0.230

0.425

500 F

TABLE 1.8.1B: STACK EXIT VELOCITY

Estimated STACK EXIT VELOCITY Calculation

(Multiply total ACFM times the velocity factor below velocity in feet per second)

STACK INSIDE

DIAMETER (Inches)

VELOCITY

FACTOR

STACK INSIDE

DIAMETER (Inches)

VELOCITY

FACTOR

STACK INSIDE

DIAMETER (Inches)

VELOCITY

FACTOR

6
7
8

10
12
14
16

0.0849
0.0624
0.0477
0.0306
0.0212
0.0156
0.0119

18
20
22
24
26
28
32

0.00943
0.00764
0.00631
0.00531
0.00390
0.00340
0.00298

34
36
38
40
48
60

0.00264
0.00236
0.00212
0.00191
0.00133
0.00085

Summary of Contents for Forced Draft Steam Boilers

Page 1: ...on Operation Service Manual for Forced Draft Steam Boilers E Mail bryanboilers iquest net Internet www bryanboilers com BRYAN BOILERS 783 N CHILI AVENUE PERU INDIANA 46970 Telephone 765 473 6651 Fax 765 473 3074 ...

Page 2: ...uild up an insulating floor under the boiler using high temperature mineral fiber board at least 1 1 2 thick 1 2 CLEARANCES See Table 1 for minimum clearances to wall ceilings or obstructions The clearances in Table 1 are intended as a general recommendation only Local codes must be applied to specific installations and the minimum clearances established accordingly Provisions must also be made fo...

Page 3: ...ER 50 WATER STEAM TO 50 STEAM OVER 50 A 18 36 18 48 24 24 18 36 24 24 B 24 24 48 96 48 36 48 24 48 48 CV CH 18 36 18 36 24 24 24 24 24 24 D 48 96 18 36 24 24 24 24 24 24 EL ER 24 24 18 36 24 24 24 24 32 32 1 F Series boilers are approved for installation on combustible flooring Do not install on carpeting A Clearance above boiler B Front of boiler CV Clearance from gas vent measured vertically abo...

Page 4: ...he feed pump and the boiler It is also recommended to install a globe valve between the feed pump and the receiver tank This valve can then be adjusted to bypass excess pump capacity to better control the boiler feed rate 1 4 4 SAFETY RELIEF VALVE S A connection is provided in the top of the boiler for the relief valve The relief valve discharge piping must be the same size as the relief valve dis...

Page 5: ... as large as the gas train connection at the boiler This connection should be made with a union so that the boiler gas train components and burner may be easily removed if necessary for service 1 5 2 GAS PIPING LEAK TEST After completion of the gas piping hookup the installation must be checked for leaks using a soap and water solution Disconnect the boiler and gas train from the gas supply piping...

Page 6: ...ric gas fired boilers which are equipped with either draft diverters or barometric dampers Combustion air openings for boilers which are equipped with forced draft burners may be reduced to 70 of that required for atmospheric gas fired boilers This is because the forced draft boiler is not equipped with a draft control device so no air is required for draft control COMBUSTION AIR OPENINGS AREA REQ...

Page 7: ...onal Fuel Gas Code NFPA 54 for sizing and design of flue gas venting systems For additional reference to good practice in vent design refer to the Chimney Gas Vent and Fireplace Design chapter of the ASHRAE Equipment Handbook OUTSIDE VENTS AND CHIMNEYS Outside uninsulated single wall pipe is not recommended for use in cold climates for venting gas fired appliances since temperature differentials m...

Page 8: ... F 450 F 150 Steam Gas Fired Oil Fired 0 230 0 230 0 425 0 425 500 F 500 F TABLE 1 8 1B STACK EXIT VELOCITY Estimated STACK EXIT VELOCITY Calculation Multiply total ACFM times the velocity factor below velocity in feet per second STACK INSIDE DIAMETER Inches VELOCITY FACTOR STACK INSIDE DIAMETER Inches VELOCITY FACTOR STACK INSIDE DIAMETER Inches VELOCITY FACTOR 6 7 8 10 12 14 16 0 0849 0 0624 0 0...

Page 9: ...oom must be supplied with adequate air for combustion and for proper operation of draft control devices barometric dampers or draft diverters as outlined in Combustion Air Supply Section 1 7 of this manual WARNING THE BOILER ROOM MUST BE MAINTAINED AT A POSITIVE OR NEUTRAL PRESSURE RELATIVE TO OUTDOORS AT ALL TIMES EXHAUST FANS OR CONNECTIONS FROM THE BOILER ROOM TO ZONES OF NEGATIVE PRESSURE AIR ...

Page 10: ...nt manufacturer s instructions and with adherence to the codes and clearances as outlined herein Masonry or metal chimneys must be built and installed in accordance with nationally recognized building codes or standards MASONRY CHIMNEYS FOR RESIDENTIAL APPLICATIONS MUST BE LINED WITH FIRE CLAY FLUE LINING KX C315 OR THE EQUIVALENT WITH THICKNESS NOT LESS THAN 5 16 INCH OR WITH A LINER OF OTHER APP...

Page 11: ...hysical damage and separation of joints and to prevent sagging of the vent connector Supports should usually be overhead hangers of load bearing capacity appropriate for the weight involved LOCATION When the vent connector used for an appliance having a draft hood must be located in or pass through a crawl space or other area difficult to access or which may be cold that portion of the vent connec...

Page 12: ...t less than 18 above and 6 below the roof with the annular space open at the bottom and closed at the top may be used INSPECTIONS OF CHIMNEYS Before connection of a vent connector to a chimney the chimney passageway must be examined to ascertain that it is clear and free of obstructions Cleanouts must be constructed such that they will remain tightly closed when not in use Tee fittings used as cle...

Page 13: ...D LOW PRESSURE STEAM BOILERS No less than 3 feet above the roof and no less than 2 feet above any parapet or obstacle closer than 10 feet from the vent outlet HIGH PRESSURE OVER 15 PSIG STEAM BOILERS No less than 10 feet higher than any portion of any building within a distance of 25 feet from the vent MINIMUM HEIGHT ABOVE DRAFT CONTROL Chimneys and gas vents must extend at least 5 feet above the ...

Page 14: ...nt Single wall vents must terminate in an approved cap which does not obstruct the exit The preferred type of cap for natural draft vented atmospheric boilers is the Briedert Cap This is because of the protection this cap provides against wind generated downdrafts Where there is no concern of high winds or turbulence at the vent exit a low resistance conical cap may be used See Fig 1 8 12B for typ...

Page 15: ...as factory built orifices must be replaced to properly adjust the gas input Consult the factory or the local Bryan Representative for the proper parts For the purpose of vent system sizing assume full input and determine sizing as if at sea level The derate factor of 4 per 1000 feet above sea level accounts for the increased volume per Btu hr of flue products at high altitude INDUCED DRAFT FANS Oc...

Page 16: ...e of such compliance is that of the system designer and or the system installer All sizing and installation must be checked against such local requirements RECTANGULAR VENTS Vent systems may be rectangular as well as circular Table 1 8 15F has been provided to give the circular equivalent of rectangular duct These equivalent values account for the higher pressure drop per cross section area for re...

Page 17: ...y a trial diameter Proceed to Step 4 to calculate the system k factor to determine the actual stack diameter required STEP 4 CALCULATE SYSTEM K FACTOR The system k factor accounts for the pressure drop through fittings and vent piping It is calculated by adding up the individual k factors for each of the fittings plus the k factor for the vent pipe s From Table 1 8 15D find the k factors for each ...

Page 18: ...sing this adjusted equivalent input check the stack diameter by following Steps 2 thru 3 again If the stack diameter remains the same the sizing is complete If not redo Steps 4 thru 5 etc until an acceptable result is achieved Table 1 8 15E K Factor Equivalent Input Correction Factor F3 K Factor F3 K Factor F3 K Factor F3 K Factor F3 K Factor F3 1 00 0 37 1 50 0 45 2 00 0 52 2 50 0 58 3 00 0 63 3 ...

Page 19: ... 5160 5650 6110 6530 6920 7300 8160 8940 10330 26 1910 2260 2710 2960 3320 3830 4280 4690 5070 5420 5750 6060 6640 7170 7660 8130 8570 9580 10490 12120 28 2220 2630 3140 3440 3850 4440 4970 5440 5880 6280 6660 7030 7700 8310 8890 9430 9940 11110 12170 14060 30 2550 3010 3600 3950 4420 5100 5700 6250 6750 7210 7650 8070 8840 9540 10200 10820 11410 12760 13970 16140 32 2900 3430 4100 4490 5020 5800 ...

Page 20: ... 54 17 21 23 26 29 31 33 35 39 39 40 42 44 48 52 56 59 62 60 18 21 24 27 30 32 34 37 39 40 42 44 46 50 55 59 62 66 1 8 16 SPECIAL APPLICATIONS FLUE GAS ECONOMIZERS When applying flue gas economizers care must be taken to assure that 1 Proper draft must be maintained This requires that the gas side pressure drop be considered and that the economizer exchanger must be designed so as to allow cleanin...

Page 21: ...tems tend to have fewer problems with air entrainment in the oil Air in the oil will cause nuisance problems and delayed ignition 1 10 PROCEDURES TO BE FOLLOWED BEFORE PLACING BOILER IN OPERATION 1 10 1 HYDROSTATIC TEST OF BOILERS AND SYSTEM After completing the boiler and burner installation the boiler connections fittings attachments and adjacent piping must be inspected for leaks by filling the...

Page 22: ...he boiler manual for the proper adjustment of the pilot burner This is absolutely essential before attempting to adjust the main burner 2 1 3 ADJUST BOILER INPUT S The boiler input must be adjusted for both maximum and minimum input values which are listed on the boiler nameplate First adjust the maximum input rating using the method described in Lighting Instructions in the Boiler Manual Refer to...

Page 23: ...h both valves achieving full input 2 2 FIRING RATE ADJUSTMENT GAS METER READINGS 2 2 1 CHECKING BURNER INPUT The burner input rate can be checked by taking readings from the gas meter Please note checking the rate with a meter is the only way to be sure of input Manifold readings are only an approximate value and may vary from unit to unit In order to obtain accurate data there must be no other ap...

Page 24: ...ol is provided as the high limit control It is set at a pressure above the operator to act as a back up should the operator fail The high limit control must be operationally tested With the boiler operating decrease the pressure setting of the limit control below the current pressure of the boiler The boiler should cycle off Restore the high limit control setting to normal pushing rest button if i...

Page 25: ...tener and chemical treatment system Chemically test the feedwater to be certain it complies with the recommendations of the chemical treatment consultant 2 5 RECOMMENDED DRAFT AND COMBUSTION READINGS ATMOSPHERIC GAS FIRED BOILERS BOILER SERIES DRAFT AT BOILER OUTLET i w c CO2 HIGH FIRE O2 HIGH FIRE CO ppm SMOKE NO F 0 01 TO 0 04 7 5 TO 8 5 5 0 TO 7 5 400 0 CL 0 02 TO 0 04 7 5 TO 9 0 4 8 TO 7 5 400...

Page 26: ...f the draft hood relief opening or barometric If the venting system is operating correctly the match flame will be drawn toward the draft hood relief opening Otherwise the products of combustion will tend to push the flame and extinguish it CAUTION IF THE PRODUCTS OF COMBUSTION ARE BEING EMITTED INTO THE ROOM VENTING SYSTEM NOT OPERATING CORRECTLY THE BOILER MUST NOT BE OPERATED UNTIL PROPER ADJUS...

Page 27: ...he boiler must familiarize himself with this manual and the burner manual for forced draft boilers to be sure he is prepared to operate and maintain the boiler properly READ THE MANUAL BEFORE ATTEMPTING A START UP 2 7 MAINTENANCE SCHEDULE 2 7 1 POSTING SCHEDULE Post a maintenance schedule in accordance with the recommendations in this manual A copy of a typical schedule is included in this manual ...

Page 28: ...nowledge of burner boiler operation 2 Possession and understanding of boiler burner operating instruction manual 3 Assurance that the boiler is fed with only treated water at all times and that chemical treatment and blowdown procedures are always followed 4 Notification to the manufacturer or manufacturer s agent to provide start up services if the boiler was purchased with start up by a factory ...

Page 29: ... piping to and from the system must be closed to prevent the chemical solution from getting into the system 5 Gauge glasses must be protected from contact with the boil out chemicals 6 Fill the boiler with clean softened water until the water level reaches the upper header Then add the cleaning solution into the upper header Add more clean water until the boiler is completely filled The water used...

Page 30: ...eed pump on a boiler feed system It will be necessary to supply such a system if not already installed OR by an automatic water feeder mounted on the boiler This is used only on systems requiring 100 make up such as humidification steam process etc NOTE It is not recommended to provide the make up for a closed steam heating system to the boiler by means of a water feeder It is preferred that syste...

Page 31: ...ve The heating surface of a boiler must be kept free from soot accumulation to keep the boiler operating at its highest efficiency and to avoid damage from corrosion SOOT REMOVAL If the yearly inspection of the boiler tube surfaces reveals a build up of either soot or rust usually due to condensation the tubes should be thoroughly brushed Tube cleaning brushes are available from Bryan Steam To ins...

Page 32: ...ed in manufacturer s manual 7 Check float low water cutoff as described above MONTHLY 1 Make visual inspection of linkage and proper operation of flue vent stack or outlet dampers Check draft as specified in Section 2 of this manual 2 Check float low water cutoff as described above 3 For those units equipped with a power burner check low draft fan air pressure and damper position interlocks as spe...

Page 33: ...running and well lubricated preferably with a graphite type lubricant Washers under nuts and bolt heads are desirable DO NOT tighten while equipment is in operation MAINTENANCE Inspect the gauge glass regularly for any signs of clouding or scratching In new processes the gauge glass should be inspected daily until the need for replacement becomes apparent This will help establish the routine inspe...

Page 34: ......

Page 35: ...ven days prior to shutdown manual blowdown frequency should be increased During this period the lower conductivity limit should be below 3500 micro mohs per centimeter The feed of internal treatment must be increased to maintain a specific residual concentration Continuous blowdown when used should be kept to a minimum so the reduction of solids is achieved by the increased manual blowdown WASHDOW...

Page 36: ...prevent leakage and resultant dilution of the lay up solution ALTERNATE METHOD An alternate wet lay up method is to pipe clean continuous blowdown water from a properly treated boiler into any convenient bottom connection on the idle boiler allowing the water to flow through the boiler and out the top through any convenient top opening to the sewer This method will insure a continuous complete fil...

Page 37: ... After wet lay up To start an idle boiler after wet lay up use the following procedure 1 If the boiler was pressurized with nitrogen disconnect the nitrogen supply source and vent the boiler 2 Using the blowdown valve drain the boiler partially and make up with feedwater so as to dilute the chemical residuals to operating concentration levels 3 After the boiler water concentrations and the water l...

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