MGB
GAS FIRED BOILERS
FOR FORCED HOT WATER
Utica Boilers, • P.O. Box 4729 • Utica, NY 13504
Safety Symbols
The following defined symbols are used throughout this manual to notify the
reader of potential hazards of varying risk levels.
DANGER
DANGER - Indicates an imminently hazardous situation which, if not avoided, WILL
result in death or serious injury.
WARNING
WARNING - Indicates a potentially hazardous situation which, if not avoided, COULD
result in death or serious injury
CAUTION
CAUTION - Indicates a potential hazardous situation which, if not avoided, MAY result
in minor or moderate injury. It may also be used to alert against unsafe practices.
IMPORTANT! READ ALL INSTRUCTIONS BEFORE INSTALLING.
WARNING:
1. Keep boiler area clear and free from combustible materials, gasoline and other
flammable vapors and liquids.
2. DO NOT obstruct air openings to the boiler room.
3. Modification, substitution or elimination of factory equipped, supplied or specified
components may result in property damage, personal injury or the loss of life.
4. To the owner: Installation and service of this boiler must be performed by a qualified
installer.
5. To the installer: Leave all instructions with the boiler for future reference.
6. When this product is installed in the Commonwealth of Massachusetts the installation
must be performed by a Licensed Plumber or Licensed Gas Fitter.
WARNING: ALL INSTALLATIONS OF BOILERS AND
VENTING SHOULD BE DONE ONLY BY A QUALIFIED EXPERT AND
IN ACCORDANCE WITH THE APPROPRIATE UTICA BOILERS
MANUAL. INSTALLING OR VENTING A BOILER OR ANY OTHER
GAS APPLIANCE WITH IMPROPER METHODS OR MATERIALS MAY
RESULT IN SERIOUS INJURY OR DEATH DUE TO FIRE OR TO
ASPHYXIATION FROM POISONOUS GASES SUCH AS CARBON
MONOXIDE WHICH IS ODORLESS AND INVISIBLE.
PAGE2
INSTALLATION PROCEDURE
WARNING: Improperinstallation,adjustment,alteration,serviceormaintenance
can cause injury or property damage.
1.Theinstallationmustconformtotherequirementsoftheauthorityhavingjurisdictionor,
in the absence of such requirements, to the latest revision of the National Fuel Gas Code,
ANSI Z223. (Available from the American Gas Association, 8501 E. Pleasant Valley Road,
Cleveland, Ohio 44134). Reference should also be made to local gas utility regulations and
other codes in effect in the area in which the installation is to be made. When installed in
Canada: The latest revision of the CAN1-B149.1 and/or B149.2 Installation Codes for Gas-
Burning Equipment and/or local codes.
2. Where required by the authority having jurisdiction, the installation must conform to
AmericanSocietyofMechanicalEngineersSafetyCodeforControlsandSafetyDevicesFor
Automatically Fired Boilers, ANSI/ASME No.CSD-1.
3. This boiler series is classified as a Category 1 and the vent installation shall be in
accordance with Part 7 of the National Fuel Gas Code noted above when installed in the
United States. In Canada refer to the CAN1-B149.1 and or B149.2 Installation Codes for
Gas-Burning Equipment. Also refer to applicable provisions of the local building codes.
4. This boiler has met safe lighting and other performance criteria with the gas manifold
and control assembly on the boiler per the latest revision of ANSI Z21.13/CGA 4.9.
5.Theboilershallbeinstalledsuchthatthegasignitionsystemcomponentsareprotected
fromwater(dripping, spraying, rain, etc.)duringapplianceoperationandservice, (circulator
replacement, condensate trap, control replacement, etc.).
6. LOCATE BOILER on level, solid base as near the chimney as possible and centrally
located with respect to the heat distribution system as practical.
7. Allow 24 inches at the front and right side for servicing and cleaning.
8. When installed in a utility room, the door should be wide enough to allow the largest
boiler part to enter, or to permit replacement of another appliance such as a water heater.
9. FOR INSTALLATION ON NON-COMBUSTIBLE FLOORS ONLY . For installation
on combustible flooring special base part no. 325-2-8.00 must be used. The boiler can not
be installed on carpeting. Minimum clearances to combustible construction are:
TOP ........................................18 IN.
FRONT ...................................ALCOVE
FLUECONNECTOR ...............6 IN.
REAR......................................4 IN.
CONTROL SIDE.....................9 IN.
OTHERSIDE..........................3 IN.
NOTE: Greater clearances for access should supersede fire protection clearances.
PAGE3
VENTILATION & COMBUSTION AIR
WARNING: AIR OPENINGS TO COMBUSTION AREA MUST NOT BE
OBSTRUCTED. BY FOLLOWING THE INSTRUCTIONS BELOW, ADEQUATE
COMBUSTIONAIRCANBEMAINTAINED
COMBUSTION AIR REQUIREMENTS
(MINIMUMSQUAREINCHESOPENING)
*UNCONFINEDAREA
**CONFINED AREA
OUTSIDE
COMBUSTION COMBUSTION
AIR 1 SQ. IN AIR 1 SQ. IN.
/5000BTU/HR /1000BTU/HR
INSIDE
OUTSIDE COMBUSTION AIR
MODEL
NUMBER
MGB
VERTICAL
HORIZONTAL
DUCTS
DUCTS
1 SQ. IN.
1 SQ. IN.
(SEE FIG. 4)
(SEE FIG. 3)
/4000BTU/HR
/2000BTU/HR
MGB 38
MGB 50
MGB 75
8
100
100
100
100
125
150
175
200
10
13
19
25
32
38
44
50
57
69
75
19
25
38
50
63
75
88
100
113
138
150
10
15
20
25
30
35
40
45
55
60
MGB 100
MGB 125
MGB 150
MGB 175
MGB 200
MGB 225
MGB 275
MGB 300
225
275
300
* Unconfined area: A space whose volume is not less than 50 cubic feet per
1000 BTU per hour of all appliances installed in that space (cubic feet of space = height x
width x length).
** Confined area: A space whose volume is less than 50 cubic feet per 1000 BTU
per hour of all appliances installed in that space (cubic feet of space = height x width x
length).
1. Ventilation of the boiler room must be adequate to provide sufficient air to properly
support combustion per the latest revision of the National Fuel Gas Code, ANSI Z223.1
section 5.3.
2.Whenaboilerislocatedinanunconfinedspaceinabuildingorconventionalconstruction
frame, masonry or metal building, infiltration normally is adequate to provide air for
combustionandventilation.However,iftheequipmentislocatedinabuildingofunusuallytight
construction (See the national Fuel Gas Code, Ansi Z223.1 section 1.7), the boiler area
shouldbeconsideredasaconfinedspace.Inthiscaseairforcombustionandventilationshall
be provided according to part 5 on page 5. If there is any doubt, install air supply provisions
in accordance with the latest revision of the National Fuel Gas Code.
3. When a boiler is installed in an unconfined space, in a building of unusually tight
PAGE4
construction, air for combustion and ventilation must be obtained from outdoors or from
spacesfreelycommunicatingwiththeoutdoors. Apermanentopeningoropeningshavinga
total free area of not less than 1 square inch per 5,000 BTU per hour of total input rating of
allappliancesshallbeprovided. Ductsmaybeusedtoconveymakeupairfromtheoutdoors
and shall have the same cross-sectional area of the openings to which they are connected.
4.Whenairforcombustionandventilationisfrominsidebuildings,theconfinedspaceshall
be provided with two permanent openings, one starting 12 inches from the top and one 12
inchesfromthebottomoftheenclosedspace.Eachopeningshallhaveaminimumfreearea
of1squareinchperonethousand(1000)BTUperhourofthetotalinputratingofallappliances
in the enclosed space, but must not be less than one hundred (100) square inches. These
openingsmustfreelycommunicatedirectlywithotherspacesofsufficientvolumesothatthe
combined volume of all spaces meets the criteria for an unconfined space.
5.Whentheboilerisinstalledinaconfinedspaceandallairisprovidedfromtheoutdoors
the confined space shall be provided with one or two permanent openings according to
methods A or B. When ducts are used, they shall be of the same cross sectional area as the
free area of the area of the openings to which they connect. The minimum dimension of
rectangular air ducts shall be not less than 3 x 3 inches or 9 square inches.
A. Wheninstallingtwoopenings,onemustcommencewithin12inchesfromthetopand
theotherwithin12inchesfromthebottomoftheenclosure.Theopeningsshallcommunicate
directly, orbyducts, withtheoutdoorsorspaces(crawlorattic)thatfreelycommunicatewith
the outdoors. One of the following methods must be used to provide adequate air for
ventilationandcombustion.
1. When directly communicating with the outdoors, each opening shall have a
minimum free area of 1 square inch per 4,000 BTU per hour of total input rating of all
equipment in the enclosure. See figure 2 below.
FIGURE1
FIGURE2
2. When communicating with the outdoors by means of vertical ducts, each
opening shall have a minimum free area 1 square inch per 4,000 BTU per hour of total input
rating of all appliances in the enclosed space. See figure 3 on page 6.
3. If horizontal ducts are used, each opening and duct shall have a minimum free
area1squareinchper2,000BTUperhouroftotalinputratingofallappliancesintheenclosed
space. See figure 4 on page 6.
B. Onepermanentopening,commencingwithin12inchesofthetopoftheenclosure,
PAGE5
FIGURE3
FIGURE4
shall be permitted where the equipment has clearances of at least 1 inch from the sides, 1
inch from the back, and 6 inches from the front of the boiler. The opening shall directly
communicatewiththeoutdoorsorshallcommunicatethroughaverticalorhorizontalductto
the outdoors or spaces (crawl or attic) that freely communicate with the outdoors. The
openings must have a minimum free area of 1 square inch per 3000 Btu per hour of the total
inputratingofallequipmentlocatedintheenclosure. Thefreeareamustbenolessthanthe
sum of the areas of all vent connectors in the confined space.
6.Incalculatingfreeareausinglouvers,grillesorscreensfortheabove,considerationshall
be given to their blocking effect. Screens used shall not be smaller than 1/4 inch mesh. If the
free area through a design of louver or grill is known, it should be used in calculating the size
opening required to provide the free area specified. If the design and free area is not known,
itmaybeassumedthatwoodlouverswillhave20-25%freeareaandmetallouversandgrilles
will have 60-75% free area. Louvers and grilles should be fixed in the open position or
interlocked with the boiler so they are opened automatically during the boiler operation.
CONNECTING SUPPLY AND RETURN PIPING
IMPORTANT: Circulators in the following illustrations are mounted on the system supply
side, but mounting on the system return side is also acceptable practice.
1. Connect supply and return piping as suggested in figure 5 on page 7, when the boiler
is used in connection with refrigerated systems.
A. The chilled medium MUST BE PIPED IN PARALLEL with the boiler.
B. Use appropriate valves to prevent the chilled medium from entering the
heating boiler.
a. During heating cycle open valves A and B, close valves C and D.
b. During cooling cycle, open valves C and D, close valves A and B.
C. Maintain a minimum clearance of one inch to hot water pipes.
2.Whentheboilerisconnectedtoheatingcoilslocatedinairhandlingunitswheretheymay
be exposed to refrigerated air circulation, the boiler piping system MUST BEsupplied with
flowcontrolvalvesorotherautomaticmeanstopreventgravitycirculationoftheboilerwater
duringthecoolingcycle.
PAGE6
BYPASSPIPING
FIGURE5
FIGURE6
3. Hotwaterboilersinstalledaboveradiationlevelmustbeprovidedwithalowwatercut-
off device.
4. Whenaboilerisconnectedtoaheatingsystemthatutilizesmultiplezonedcirculators,
eachcirculatormustbesuppliedwithaflowcontrolvalvetopreventgravitycirculation.
5. Hot water boilers and system must be filled with water and maintained to a minimum
pressure of 12 pounds per square inch.
6. Bypass piping is an option which gives the ability to adjust the supply boiler water
temperaturetofitthesystemortheconditionoftheinstallation.Thismethodofpiping,however,
is not typically required for baseboard heating systems. Typical installations where bypass
piping is used are as follows:
A. This method is used to protect
boilersfromcondensationformingduetolow
MIXINGVALVEPIPING
temperaturereturnwater.Generallynoticedin
largeconvertedgravitysystemsorotherlarge
water volume systems. See figure 6 above.
B. Thesemethodsareusedtoprotect
systemsusingradiantpanelsandthematerial
they are encased in from high temperature
supply water from the boiler and protect the
boiler from condensation. See figure 7 at
right and 8 on page 8.
NOTE 1: When using bypass piping, adjust
valves A and B until desired system
temperature is obtained.
NOTE 2: Bypass loop must be same size
FIGURE7
piping as the supply and return piping.
PAGE7
PRIMARY SECONDARY PIPING WITH BY PASS
FIGURE8
7. Installation using circulators is shown in figure 9 below.
FIGURE9
8. Installation using zone valves is shown in figure 10 on page 9.
9. For further piping information refer to the I=B=R Installation and Piping Guide.
PAGE8
FIGURE10
WARNING: ALL INSTALLATIONS OF BOILERS AND
VENTING SHOULD BE DONE ONLY BY A QUALIFIED EXPERT AND
IN ACCORDANCE WITH THE APPROPRIATE UTICA BOILERS
MANUAL. INSTALLING OR VENTING A BOILER OR ANY OTHER
GAS APPLIANCE WITH IMPROPER METHODS OR MATERIALS MAY
RESULT IN SERIOUS INJURY OR DEATH DUE TO FIRE OR TO
ASPHYXIATION FROM POISONOUS GASES SUCH AS CARBON
MONOXIDE WHICH IS ODORLESS AND INVISIBLE.
VENT INSTALLATION
WARNING: This boiler shall not be connected to any portion of a mechanical
draft system operating under positive pressure.
1. The vent pipe must slope upward from the boiler not less then 1/4 inch for every 1 foot
to the vent terminal.
2. Horizontal portions of the venting system shall be supported rigidly every 5 feet and at
the elbows. No portion of the vent pipe should have any dips or sags.
3. This boiler series is classified as a Category 1 and the vent installation shall be in
accordance with chapter 7 and 10 of the National Fuel Gas Code noted above or applicable
provisions of the local building codes.
4. Inspect chimney to make certain it is constructed according to NFPA 211. The vent
or vent collector shall be Type B or metal pipe having resistance to heat and corrosion not
lessthanthatofgalvanizedsheetsteeloraluminumnotlessthan0.016inchthick(No.28Ga).
5. Connect flue pipe from draft hood to chimney. Bolt or screw joints together to avoid
sags.Fluepipeshouldnotextendbeyondinsidewallofchimney.Donotinstallmanualdamper
in flue pipe or reduce size of flue outlet except as provided by the latest revision of
ANSIZ223.1. Protect combustible ceiling and walls near flue pip with fireproof insulation.
Where two or more appliances vent into a common flue, the area of the common flue must
be at least equal to the area of the largest flue plus 50 percent of the area of each additional
flue.
PAGE9
VENT SYSTEM MODIFICATION
Whenanexistingboilerisremovedfromacommonventingsystem,thecommonventing
system is likely to be too large for the proper venting of the appliances remained connected
to it. If this situation occurs, the following test procedure must be followed:
REMOVAL OF BOILER FROM VENTING SYSTEM
Atthetimeofremovalofanexistingboiler,thefollowingstepsshallbefollowedwitheach
applianceremainingconnectedtothecommonventingsystemplacedinoperation,whilethe
other appliances remaining connected to the common venting system are not in operation.
A. Seal an unused opening in the common venting system.
B. Visuallyinspecttheventingsystemforpropersizeandhorizontalpitchanddetermine
there is no blockage or restriction, leakage, corrosion and other deficiencies which could
cause an unsafe condition.
C. Insofar as is practical, close all building doors and windows and all doors between the
space in which the appliances remaining connected to the common venting system are
locatedandotherspacesofthebuilding. Turnonclothesdryersandanyotherappliancenot
connected to the common venting system. Turn on any exhaust fans, such as range hoods
and bathroom exhausts, so they operate at maximum speed. Do not operate a summer
exhaust fan. Close fireplace dampers.
D.Placeinoperationtheappliancebeinginspected.Followthelightinginstructions.Adjust
thermostat so appliance will operate continuously.
E. Test for spillage at the draft hood relief opening after 5 minutes of main burner
operation. Use the flame of a match or candle, or smoke from a cigarette, cigar or pipe.
F. After it has been determined that each appliance remaining connected to a common
venting system properly vents when tested as outlined above, return doors, windows,
exhaust fans, fireplace dampers and any other gas burning appliances to their previous
condition of use.
G. Any improper operation of the common venting system should be corrected so the
installation conforms with the latest revision of the National Fuel Gas Code, ANSI Z223.1.
Whenresizinganyportionofthecommonventingsystem,thecommonventingsystemshould
be resized to approach the minimum size as determined using the appropriate tables in
appendix G in the latest revision of the National Fuel Gas Code, ANSI Z223.
PAGE10
VENT DAMPER INSTALLATION AND INSTRUCTIONS
INSTALLATION
NOTE: Refer to Figure 11for steps 1 - 7.
1. PlaceVentDamperonorasclosetoventoutletofboileraspossible.Seefigure12below.
2. Remove Vent Damper Motor cover.
3. Remove locknut from connector at the end of the Damper wire harness.
4. Feed Damper and Damper wire harness connectors through bracket hole on Damper
Motor frame.
5. Replace and tighten locknut onto Damper wire harness connector,
6. Plug Damper connector into socket on Damper Motor frame.
7. Replace Damper Motor cover.
8. Wire Damper in accordance with figure 11below.
FIGURE11
FIGURE12
INSTRUCTIONS
1. Ensure that only the boiler is serviced by the Vent Damper. See Figure 12, above.
2. Clearance of not less than 6 inches between Vent Damper and combustible material
must be maintained. Additional clearance should be allowed for service of Vent Damper.
3.VentDampermustbeintheopenpositionwhenappliancemainburnersareoperating.
4. The Vent Damper position indicator must be in a visible location following installation.
5. The thermostat's heat anticipator must be adjusted to match the total current draw of
all controls associated with the boiler during a heating cycle.
PAGE11
CONNECTING GAS SERVICE
1. Connect gas service from meter to control assembly in accordance with ANSI Z223.1
and local codes or utility. A ground joint union should be installed for easy removal of gas
control for servicing. A drip leg or trap must be installed at the bottom of a vertical section
ofpipingattheinlettotheboiler.Apipecompoundresistanttotheactionofliquifiedpetroleum
gasesmustbeusedonallthreadedpipeconnections. Checkwiththelocalutilityforlocation
of manual shutoff valve if required. See figure 13 below.
2. The gas line should be of adequate size to prevent undue pressure drop and never
smaller than the pipe size of the main gas control valve. See chart below.
3. To check for leaks in gas piping, use a soap and water solution or other approved
method.
WARNING: DO NOT USE AN OPEN FLAME.
4. Disconnect the boiler from the gas supply piping system during any pressure testing
of the gas piping. After reconnecting, leak test the gas connection and boiler piping before
placing the boiler back into operation.
Maximum Capacity of Pipe in
Cubic Feet of Gas Per Hour
(Gas pressure = 0.5 psig or less, pressure drop =
.5 in.w/c)
Nominal
Iron Pipe
Size
Length of Pipe (Feet)
10' 20' 30' 40' 60' 80' 100'
1/2"
3/4"
1"
175 120 97 82 66 57
50
360 250 200 170 138 118 103
680 465 375 320 260 220 195
1.1/4" 1400 950 770 660 530 460 400
For additional information refer to “Table C” of the
NationalFuelGasCodeHandbook.
FIGURE13
PAGE12
ELECTRICAL WIRING
SEE ADDENDUM " A" FOR WIRING DIAGRAMS
AND COMPONENT CODING.
ElectricalwiringmustconformwiththeNationalElectricalCode,ANSI/NFPANo.70-1990
when installed in the United states, the CSA C22.1 Canadian Electrical Code, Part 1, when
installed in Canada, and/or the local authority having jurisdiction.
WARNING: 1.Whenanexternalelectricalsourceisutilized,theboiler,when
installed MUST BE electrically grounded in accordance with these requirements.
2. Install a fused disconnect switch between boiler and meter at a convenient location.
THERMOSTAT INSTALLATION
1. Thermostat should be installed on an inside wall about four feet above the floor.
2. NEVER install a thermostat on an outside wall.
3. Do not install a thermostat where it will be affected by:
A. Drafts
B. Hot or Cold Pipes
C. Sun Light
D. Lighting Fixture
E.Television
F. A Fireplace or Chimney
4. Check thermostat operation by raising and lowering thermostat setting as required to
start and stop the burners.
5.Instructionsforthefinaladjustmentofthethermostatarepackagedwiththethermostat
(adjusting heating anticipator, calibration, etc.)
LIGHTING INSTRUCTIONS
WARNING: IFYOUDONOTFOLLOWTHESEINSTRUCTIONSEXACTLY,
A FIRE OR EXPLOSION MAY RESULT CAUSING PROPERTY DAMAGE, PERSONAL
INJURY OR LOSS OF LIFE.
Before any procedures are attempted on this appliance, it is necessary to
determine if the ignition system is electric or standing pilot. If you are un-certain,
contact the manufacturer before proceeding.
CAUTION: Before lighting any type of pilot burner (standing or
intermittent), make certain the hot water boiler and system are full of water to
minimumpressureof12lbs.persquareinchinthesystem,andalsomakecertainthat
the system is vented of air. Set the operating control of thermostat to a “below”
normal setting. Refer to the following appropriate lighting instruction.
PAGE13
LIGHTING PROCEDURE FOR BOILER WITH
INTERMITTENT PILOT SYSTEMS.
FOR YOUR SAFETY READ BEFORE OPERATING.
A. This appliance is equipped with an ignition device which automatically lights the pilot.
Do not try to light the appliance by hand.
B. Before operating, smell all around the appliance area for gas. Be sure to smell next
to the floor because some gas is heavier than air and will settle on the floor.
CAUTION: WHAT TO DO IF YOU SMELL GAS
* Do not try to light any appliance.
* Do not touch any electrical switches; do not use any phones in your building.
* Immediately call your gas supplier from a neighbor’s phone. Follow the gas supplier's
instructions.
* If you cannot reach your gas supplier, call the fire department.
C. Useonlyyourhandtopushinorturnthegascontrolknob. Neverusetools. Iftheknob
will not push in or turn by hand, don’t try to repair it. Call a qualified service technician. Force
or attempted repair may result in a fire or explosion.
D.Donotusethisapplianceifanyparthasbeenunderwater.Immediatelycallaqualified
service technician to inspect the appliance and to replace any part of the control system and
any gas control which has been under water.
OPERATING INSTRUCTIONS FOR
INTERMITTENT PILOT SYSTEMS
1. STOP! Read the safety information in the User’s Information Manual.
2. Set the thermostat to lowest setting.
3. Turn off all electric power to the appliance.
4. This appliance is equipped with an ignition device which automatically lights the pilot.
Do not try to light the pilot by hand. See figure 14 below.
5. Remove access panel.
6. Turn gas control knob clockwise
7. Wait (5) minutes to clear out any gas.
If you then smell gas, STOP!Follow “What
To Do If You Smell Gas” in the safety
informationabove.Ifyoudon’tsmellgas,go
on to the next step.
to “OFF”.
8.Turngascontrolknobcounterclockwise
to “ON”.
9. Replace access panel.
10. Turn on all electric power to the
appliance.
11. Set thermostat to desired setting.
12. If the appliance will not operate,
follow the instructions “To turn off gas to
appliance”, on page 16, and call a qualified
service technician or your gas supplier.
FIGURE14
PAGE14
LIGHTING PROCEDURE FOR BOILER
WITH CONTINUOUS PILOT
FOR YOUR SAFETY READ BEFORE LIGHTING
A. Read the warning at the beginning of the LIGHTING INSTRUCTIONS. (Page 13)
B.Thisappliancehasapilotwhichmustbelightedbyhand.Whenlightingthepilot,follow
these instructions exactly.
C. Before lighting, smell all around the appliance area for gas. Be sure to smell next to
the floor because some gas is heavier than air and will settle on the floor. See page 14 for
WHAT TO DO IF YOU SMELL GAS.
D.Useonlyyourhandtopushinorturngascontrolknoborresetbutton.Neverusetools.
If the knob or reset button will not push in or turn by hand, don’t try to repair it, call a qualified
service technician. Force or attempted repair may result in a fire or explosion.
E.Donotusethisapplianceifanyparthasbeenunderwater.Immediatelycallaqualified
service techniciantoinspecttheapplianceandtoreplaceanypartofthecontrolsystemand
any gas control which has been under water.
LIGHTING INSTRUCTIONS FOR
CONTINUOUS PILOT
1. STOP! Read the safety information at the beginning of these instructions.
2. Set the thermostat to the lowest setting.
3. Turn off all electric power to the appliance.
4. Remove access panel and burner door.
5. Turn gas control knob clockwise
to "OFF". See figure's 15 & 16 below.
NOTE #1: Some gas control knobs cannot be turned from "PILOT" to "OFF" unless
knob is pushed in slightly. DO NOT FORCE.
FIGURE15
FIGURE16
6. Wait (5) minutes to clear out any gas. If you then smell gas, STOP! Follow “What To
Do If You Smell Gas”, on page 14. If you don't smell gas, go to the next step.
7. Find pilot. Follow metal tube from gas control. Depending on the model of the boiler,
pilot is either mounted on the base or on one of the burner tubes.
8. Turn gas control knob counterclockwise
to "PILOT".
PAGE15
9. Push in gas control knob or reset button if so equipped, all the way in and hold.
Immediatelylightthepilotwithamatch. Continuetoholdthegascontrolknoborresetbutton
in for about 1 minute after the pilot is lit. Release knob or button, and it will pop up back up.
Pilot should remain lit. If it goes out, repeat steps 5 through 9.
*Ifknoborbuttondoesnotpopupwhenreleased,stopandimmediatelycallaqualified
service technician or your gas supplier.
* If the pilot will not stay lit after several tries, turn the gas control knob clockwise
to "OFF". (See note #1), and call a qualified service technician or your gas supplier.
10. Replace burner door.
11. Turn gas control knob counterclockwise
12. Replace access panel.
to "ON".
13. Turn on all electric power to the appliance.
14. Set thermostat to desired setting.
TO TURN OFF GAS TO APPLIANCE
1. Set the thermostat to lowest setting.
2. Turn off all electric power to the appliance if service is to be performed.
3. Push in gas control knob slightly and turn clockwise
NOT FORCE.
to "OFF", DO
5. Call a qualified service technician.
NORMAL SEQUENCE OF OPERATION
On a call for heat, the thermostat will actuate, completing the circuit to the aquastat. The
completed circuit to the aquastat will first activate the circulator and damper which will close
an end switch inside the damper. This action will complete the circuit to the ignition system
and ignition will take place.
In the event the boiler water temperature exceeds the high limit setting on the boiler
mounted aquastat, power will be interrupted between the aquastat and the ignition system.
Thepowerwillremainoffuntiltheboilerwatertemperaturedropsbelowthehighlimitsetting.
The circulator will continue to operate under this condition until the thermostat is satisfied.
In the event the flow of combustion products through the boiler venting system becomes
blocked, theblockedventsafetyswitchwillshutthemainburnergasoff. Seefigure18, page
17. Similarly, if the boiler flueway becomes blocked, a flame rollout safety switch will shut
the main burner gas off. See figuer 18, page 17. If either of these conditions occur, do not
attempt to place the boiler back into operation. Contact a qualified service agency.
PAGE16
GENERAL INSTRUCTIONS
Beforeseasonalstart-up,haveacompetentserviceagencychecktheboilerforsootand
scale in the flues, clean the burners and check the gas input rate to maintain high operating
efficiency.
CAUTION: Label all wires prior to disconnection when servicing controls.
Wiring errors can cause improper and dangerous operation.
Verify proper operation after service.
The service agency or owner should make certain the system is filled with water to
minimum pressure and open air vents, if used, to expel any air that may have accumulated
in the system. Check the entire piping system and if any leaks appear, have them repaired.
Many circulators like the one pictured in figure 17 below, require periodic servicing. The
motorusuallyhasopeningsateachendtolubricatethebearings.Putaboutonehalfteaspoon
of SAE 20 or 30 non-detergent motor oil in each opening twice a year.
CAUTION: DO NOT OVER OIL.
FIGURE17
FIGURE18
Manycirculatorshaveanoilopeningfortheshaftbearing.Thisshouldbeoiledatthesame
time for quiet operation. Follow the manufacturer's instructions for oiling the shaft bearing.
The venting system should be inspected at the start of each heating season. Check the
vent pipe from the boiler to the chimney for signs of deterioration by rust or sagging joints.
Repair if necessary. Remove the vent pipe at the base of the chimney or flue and using a
mirror, check vent for obstruction and make certain the vent is in good working order.
Theboilerfluegaspassagewaysmaybeinspectedbyalightandmirror. Removetheburner
door,figure18.Placeatroublelampinthefluecollectorthroughthedraftreliefopening.With
PAGE17
the mirror positioned above the burners, the flue gas passageways can be checked for soot
or scale.
The following procedure should be followed to clean the flue gas passageways:
1. Remove the burners from the combustion chamber by raising the burners up from the
manifold orifices and pulling toward the front of the boiler. See figure 18 on page 17.
2. Disconnect the vent pipe from the draft hood.
3. Remove the top jacket panel.
4. Remove the combination flue collector and draft hood from the boiler castings by
loosening the nuts on the hold down bolts located on each side of the collector. See figure
18 on page 17.
5. Place a sheet of heavy paper or similar material over the bottom of the base and brush
down the flue passageways. The soot and scale will collect on the paper and is easily
removed with the paper.
With the paper still in place in the base, clean the top of the boiler castings of the boiler
puttyorsiliconeusedtosealbetweenthecastingsandfluecollector.Makecertainthatchips
are not lodged in the flue passageways.
When the cleaning process is complete, restore the boiler components to their original
position. Use boiler putty or IS-808 GE silicone, available from a Utica Boilers distributor, to
seal around the flue collector and boiler castings.
FIGURE19
FIGURE20
A visual check of the main burner and pilot flames should be made at the start of the
heatingseasonandagaininmid-season. Themainburnerflameshouldhaveawelldefined
innerbluemantelwithalighterblueoutermantel.Checktheburnerthroatsandburnerorifices
for lint or dust obstruction. See figures 19 and 20 above.
Thepilotflameshouldenvelop3/8to1/2inchofthetipofthepilotthermocouple, ignition/
sensing electrode or mercury sensor. See figure 21 on page 19. To adjust the pilot flame,
remove the pilot adjustment cover screw (figures 14, 15, & 16 on pages 14 & 15), and turn
the inner adjustment screw counterclockwise
to increase or clockwise
to decrease pilot flame. Be sure to replace cover screw after adjustment to prevent possible
gas leakage.
PAGE18
The burners and pilot should be checked for signs of corrosion, rust or scale buildup.
The area around the boiler must be kept clear and free of combustible materials, gasoline
and other flammable vapors and liquids.
The free flow of combustion and ventilating air to the boiler and boiler room must not be
restricted or blocked.
It is recommended that a qualified service agency be employed to make an annual
inspectionoftheboilerandheatingsystem.Theyareexperiencedinmakingtheinspections
outlined above, and, in the event repairs or corrections are necessary, trained technicians
can make the proper changes for safe operation of the boiler.
FIGURE21
FIGURE22
CHECKING GAS INPUT RATE TO BOILER
Gas input to the boiler can be adjusted by removing the protective cap on the pressure
regulator, (See figures 14, 15, & 16 on pages 14 & 15), and turning the screw clockwise
to increase input and counterclockwise
to decrease input. Natural gas
manifold pressure should be set at approximately 3.5 inches water column. Propane gas
manifoldpressureshouldbesetatapproximately11.0incheswatercolumn.Thesemanifold
pressures are taken at the outlet side of the gas valve. See figures15 & 17 on pages14 &
15. To check for proper flow of natural gas to the boiler, divide the input rate shown on the
rating plate by the heating value of the gas obtained from the local gas company. This will
determine the number of cubic feet of gas required per hour. With all other gas appliances
off, determine the flow of gas through the meter for two minutes and multiply by 30 to get
the hourly rate. Make minor adjustments to the gas input as described above.
Burner orifices should be changed if the final manifold pressure varies more than plus or
minus 0.3 inches water column from the specified pressure.
Primaryairadjustmentisnotnecessary, thereforeairshuttersarenotfurnishedasstandard
equipment. Air shutters can be furnished on request where required by local codes or
conditions.
PAGE19
CHECKSAFETYCONTROLCIRCUIT, afterburneradjustmentsaremade,forsatisfactory
operation.
1. Pilot: With main burner operating, turn the pilot gas adjusting screw clockwise
until pilot gas is turned off. See figures 14, 15, & 16 on pages 14 & 15. Within 90 seconds
the main gas control should close, shutting off the gas to the main burner.
2. High limit control (figure 22 on page 19). Remove cover and note temperature setting.
Decrease this setting to minimum and operate boiler. When the boiler water temperature
exceeds the control temperature setting, the control will open the circuit, closing the
automatic main gas valve.
MGB SERIES REPLACEMENT PARTS
ROLLOUT & SPILL SWITCH
ITEM
NO.
PART
NO.
DESCRIPTION
OTY.
1
2
3262001
AQ02101
TEMP. SENSOR BRACKET
CONTROL-FIXEDTEMPERATURE
THERMO (ROLLOUT SWITCH)
SCREW - #6 X1/4 HEX HD
1
1
3
HW06501
2
THE ROLLOUT SWITCH IS LOCATED ON THE BASE AND FLUE COLLECTOR
NOTE: THE QUANTITIES ABOVE ARE FOR EACH SWITCH.
FIGURE23
PAGE20
MGB SERIES REPLACEMENT PARTS - PILOTS
ITEM
#
PART
NUMBER
ITEM
#
PART
NUMBER
DESCRIPTION
OTY.
DESCRIPTION
OTY.
1
4
32622001
PILOT BRACKET ASSY 24V
1
2
3
1520001
THERMOCOUPLEQ309A
1
4
1
(THIS INCLUDES #5 & 2 SCREWS)
PILOTSHIELD
HW-009.01 SCREW#8-18X1/2
PB-011.03 PILOTSTDGQ380NAT
PB-011.04 PILOT STDG Q380 LP
5
6
3261401
1
1
MS-003.03 PILOTTUBE1/4"X20.1/2"AL.
FIGURE24
ITEM
#
PART
NUMBER
ITEM
#
PART
NUMBER
DESCRIPTION
OTY.
DESCRIPTION
OTY.
3
4
5
HW-009.01 SCREWS#8-18X1/2
2
1
1
1
2
32623601
PILOTBRACKETASSYSPARK 1
PB00702
PILOTIGNITIONCABLE30"
PB-011.01 PILOTSPARKQ381NAT
PB-011.02 PILOT SPARK Q381 LP
1
MS-003.03 PILOTTUBE1/4"X20.1/2"AL.
FIGURE25
PAGE21
MGB SERIES REPLACEMENT PARTS - BASE
ITEM PART
NUMBER
ITEM PART
NUMBER
#
DESCRIPTION
OTY.
#
DESCRIPTION
OTY.
1
6
VG-003.05 GASVALVEVR8200H
MGB50-15024VNAT
1
3352401
BURNERTUBE1.3/4"
MGB50(1)
MGB125(3)
MGB200(4)
5611601
5611602
5611603
5611604
5611605
5611606
3261201
3262701
3262801
32621001
32621002
32621003
MGB75(2)
MGB150(3)
MGB250(5)
MGB100(2)
MGB175(4)
MGB300(6)
VG00307
VG01101
VG01103
VG01104
VG01201
VG01202
GASVALVEVR8200H
MGB50-30024VLP
GASVALVEVR8204H
MGB50-150SPARKNAT
GASVALVEVR8304H4
MGB175-300SPARKNAT
GASVALVEVR8304
MGB50-300SPARKLP
GASVALVEVR8300H4
MGB250&30024VNAT
GASVALVEVR8300H4
MGB175&20024VNAT
2
BASEW/INSULMGB50
1
1
1
4
BASEW/INSULMGB75&100
BASEW/INSULMGB125&150
BASEW/INSULMGB175&200
BASEW/INSULMGB225&250
BASEW/INSULMGB275&300
BURNERDOORMGB50
BURNERDOORMGB75&100
BURNERDOORMGB125&150
BURNERDOORMGB175&200
BURNERDOORMGB250
BURNERDOORMGB300
3
4
5
7
355-1-5.01 ORIFICE #30 NAT
MGB50, 100, 150, 200, 250, & 300
1
355-1-5.02 ORIFICE #31 NAT
MGB125&175
355-1-5.03 ORIFICE #33 NAT MGB75
355-1-5.04 ORIFICE#47LP
MGB50, 100, 150, 200, 250, & 300
355-1-5.06 ORIFICE#49LPMGB125&175
355-1-5.07 ORIFICE#50LPMGB75
356-2-1.01 MANIFOLDMGB50
356-2-1.02 MANIFOLDMGB75&100
356-2-1.03 MANIFOLDMGB125&150
356-2-1.04 MANIFOLDMGB175&200
356-2-1.05 MANIFOLDMGB225&250
356-2-1.0\6 MANIFOLDMGB275&300
HW-005.01 SCREW 1/4-20X1/2 SELF TAP
FIGURE26
PAGE22
MGB SERIES REPLACEMENT PARTS - JACKETS
ITEM
#
PART
NUMBER
ITEM
#
PART
NUMBER
DESCRIPTION
OTY.
1
DESCRIPTION
OTY.
6
7
3162705
PANEL-RIGHTMGB50-200
PANEL-RIGHTMGB225-300
PANEL-REARMGB50
PANEL - REAR MGB75 & 100
PANEL - REAR MGB125 & 150
PANEL - REAR MGB175 & 200
PANEL - REAR MGB225 & 250
PANEL - REAR MGB275 & 300
FLUECOLMGB50
FLUECOLMGB100
FLUECOLMGB150
FLUECOLMGB200
FLUE COL MGB225 & 250
FLUE COL MGB275 & 300
FLUECOLMGB125
FLUECOLMGB75
FLUECOLMGB175
1
1
1
31621501
31621502
31621503
31621504
31621505
31621506
31621507
3162704
3162706
3162707
3162708
PANEL-TOPMGB50
PANEL - TOP MGB75 & 100
PANEL-TOPMGB125
3162703
3162601
3162602
3162603
3162604
3162605
3162606
3462101
3462102
3462103
3462104
3462105
3462106
3462107
3462108
3462109
1182004
1182005
1182006
1182007
1182008
1182009
PANEL-TOPMGB150
PANEL - TOP MGB175 & 200
PANEL - TOP MGB225 & 250
PANEL - TOP MGB275 & 300
PANEL-LEFTMGB225-300
PANEL-LEFTMGB(L)50-200
PANEL-LEFTMGB(L)225-300
PANEL-LEFTMGB50-200
2
3
1
1
8
1
3162501 DRAFTDEFLECTORMGB50
3162502 DRAFTDEFLECTORMGB75/100
3162503 DRAFTDEFLECTORMGB125/150
3162504 DRAFTDEFLECTORMGB175/200
3162505 DRAFTDEFLECTORMGB225/250
3162506 DRAFTDEFLECTORMGB275/300
9
DAMPER4"MGB50
DAMPER5"MGB75
1
4
5
3161101
3161102
3161103
3161104
3161105
3161106
3161201
3161202
3161203
3161204
3161205
3161206
PNL LWR ACCES MGB50
1
1
PNLLWRACCESMGB75/100
PNLLWRACCESMGB125/150
PNLLWRACCESMGB175/200
PNLLWRACCESMGB225/250
PNLLWRACCESMGB275/300
PANEL-BASEMGB50
PANEL - BASE MGB75 & 100
PANEL - BASE MGB125 & 150
PANEL-MGB175&200
DAMPER6"MGB100&125
DAMPER7"MGB150&175
DAMPER 8" MGB200, 225, &250
DAMPER 9" MGB 275 & 300
PNL-UPPERACCESSMGB50
PNL-UPPERACCESSMGB75&100
PNL-UPPERACCESSMGB125
PNL-UPPERACCESSMGB150
PNL-UPPERACCESSMGB175&200
PNL-UPPERACCESSMGB225&250
PNL-UPPERACCESSMGB275&300
10 31621201
31621202
31621203
31621204
31621205
31621206
31621207
1
PANEL-BASEMGB225&250
PANEL - BASE MGB275 & 300
FIGURE27
PAGE23
MGB SERIES REPLACEMENT PARTS
HEAT EXCHANGER
ITEMNO
P/N
DESCRIPTION
QTY.
1
1
2
100-2-2.01
100-2-1.01
B-LEFTHANDSECTION
B-CENTERSECTION
MGB50 (0)
MGB150(2)
MGB250(4)
MGB75 (1)
MGB175(3)
MGB275(5)
MGB100(1)
MGB125(2)
MGB225(4)
MGB200(3)
MGB300(5)
3
4
100-2-3.01
HW-011.01
HW-011.03
HW-011.05
HW-011.07
HW-011.09
HW06901
B-RIGHTSECTION
1
2
TIEROD1/4X11.1/2MGB75&100
TIEROD1/4X15.1/2MGB125&150
TIEROD1/4X19.1/2MGB175&200
TIE ROD 1/4X23 MGB225 & 250
TIE ROD 1/4X27 MGB275 & 300
NUT5/16-18WISLOCK
5
6
6
43300976
PUSHNIPPLE2"MACH.
MGB100(4)
MGB50 (2)
MGB150(6)
MGB250(10)
MGB75 (4)
MGB175(8)
MGB275(12)
MGB125(6)
MGB225(10)
MGB200(8)
MGB300(12)
7
3461601
BAFFLE (USED ON MGB75 & MGB175 ONLY)
MGB175(4)1perflueway
MGB75(4)2perflueway
HW-008.01
8
9
WASH-5/16FLATSTLZP
NUT-1/4-20HEX-STLZP
4
2
HW-003.02
FULLY ASSEMBLED HEAT EXCHANGERS
100-2-7.01
100-2-7.02
100-2-7.03
100-2-7.04
100-2-7.05
100-2-7.06
HEATEXCHANGER3SECTION
HEATEXCHANGER4SECTION
HEATEXCHANGER5SECTION
HEATEXCHANGER6SECTION
HEATEXCHANGER7SECTION
HEATEXCHANGER2SECTION
FIGURE28
PAGE24
MGB SERIES REPLACEMENT PARTS
PIPING & CONTROLS
ITEMNO
P/N
DESCRIPTION
QTY.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
37513301
37413602
PB00702
PF-006.07
HW-016.03
PF-008.03
PF-006.01
375-1-14.01
37519501
1010002
VR-001.01
AQ-020.01
GA-001.00
PF-005.11
PF-002.04
EF03601
WIREROLLOUT/SPILL28"
HARNESS IGN TO G/V 18"
PILOTIGNITIONCABLE30"
PIPE - NPL 1.1/4X4.1/2 NPT
DRAIN-SHORT
PIPE - TEE 1.1/4X3/4X1.1/4
PIPE - 1.1/4" CLOSE NPL
WIRELOWVOLTAGE/DAMPER
HARNESSCIRCULATOR72"
CONTROLL8148E1257(AQUASTAT)
RELIEF VALVE 30#
WELL 3/4"X3"
GAUGE-THERALTIMETER
PIPE - NPL 3/4"X4"
PIPE - ELBOW 3/4" 90°
CLAMP #3600 WHITE
PLT SPARK CTRL S8600
2
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
1
PB00604
FIGURE29
PAGE25
RATINGS AND D
A
T
A
OPANE GAS
NATURAL GAS AND PR
†
§
§
§ **
∆
Natural Propane
Boiler
No.
A.G.A. Heating
I=B=R
NetRating
No.
Recommended
Gas
Orifice
Drill Size
30
Orifice Water
Input Capacity NetOutput Sq. Ft. HW
of
Air Cushion
Drill
Size
47
Content
(Gals.)
2.4
Btu/Hr. Btu/Hr.
50,000 42,000
75,000 63,000
Btu/Hr
37,000
55,000
72,000
90,000
@ 170o
Burners
Tank
15
15
30
30
30
30
30
30
60
MGB50
MGB75
243
1
2
2
3
3
4
4
5
6
365
33
50
4.0
MGB100 100,000 83,000
MGB125 125,000 104,000
481
30
47
4.0
603
31
49
5.6
MGB150 150,000 124,000 108,000
MGB175 175,000 143,000 124,000
MGB200 200,000 165,000 143,000
MGB250 250,000 205,000 178,000
MGB300 299,999 243,000 214,000
719
30
47
5.6
829
31
49
7.2
957
30
47
7.2
1189
1368
30
47
8.8
30
47
10.4
STANDARDEQUIPMENT:BoilerJacket,CastIronBoilerBattery,CombinationAquastatRelay,Theraltimeter
Gauge,Circulatorwithreturnpipingtoboiler,MainGasBurners,Combination24VoltGasControl(includes
automaticgasvalve,gaspressureregulator,automaticpilot,safetyshutoff,pilotflowadjustment,pilotfilter),
A.S.M.E. Relief Valve, Drain Cock, Spill Switch, Rollout Switch, Automatic Vent damper. Not shown are
a wiring harness, thermocouple, and non-linting safety pilot.
OPTIONAL EQUIPMENT: Intermittent Electric Ignition Pilot System.
EXPLANATORYNOTES
--All boilers are design certified for installation on noncombustible floor.
--For installation on combustible floors use combustible floor kit.
--Recommended chimney height 20 feet. In special cases where conditions permit, chimney height may
be reduced to 10 feet. Refer to the latest revision of NFGC part 11.
--Electric service to be 120 Volts, 15 Amps, 60 Hz.
--The MEA number for the MGB series boiler is 19-79 Vol. II
§
For elevations above 2000 feet, ratings should be reduced at a rate of 4% for each 1000 feet above sea
level.
∆ Tank sized for non-ferrous baseboard or radiant panel systems. Increase size for cast iron baseboard
and radiation.
Base on 170' temperature in radiators.
†
--Net I=B=R ratings include 15% allowance for normal piping and pick-up load. Manufacturer should be
consulted on installations having otherthan normal piping and pick-up requirements.
**For equivalent square feet of radiation, divide I=B=R output by 150.
PAGE26
MGB SERIES
ATURAL GAS AND PR
OPANE GAS
DIMENSIONS FOR N
Pumpsize
Supply &
Return
*
Boiler
No.
Natural
Gas
Inlet
1/2"
1/2"
1/2"
1/2"
1/2"
1/2"
1/2"
3/4"
3/4"
Dimensions
A
B
C
D
E
F
Tappings
1.1/4"
1.1/4"
1.1/4"
1.1/4"
1.1/4"
1.1/4"
1.1/4"
1.1/4"
1.1/4"
MGB 50
11.1/8"
15
5.1/2"
7.1/2"
7.1/2"
9.1/2"
9.1/2"
4"
5"
6"
6"
7"
7"
8"
8"
9"
30.3/4" 36.1/4"
30.3/4" 37.3/4"
6"
6"
MGB 75
MGB 100
MGB 125
MGB 150
MGB 175
MGB 200
MGB 250
MGB 300
15
30.3/4" 37.1/4" 6.1/2"
30.3/4" 37.1/4" 6.1/2"
18.7/8"
18.7/8"
30.3/4" 37.3/4"
30.3/4" 38.3/4"
30.3/4" 38.3/4"
32.3/4" 40.3/4"
32.3/4" 42.3/4"
7"
7"
22.3/4" 11.3/8"
22.3/4" 11.3/8"
265.8" 13.1/4"
30.1/2" 15.1/4"
8"
8"
10"
Propane gas inlet, all units, 1/2"
*
Solutions you can be comfortable with.
37611601
PAGE 27
REV 14.1, May 2004
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