HydroTherm MultiTemp MR Series Manual

®
MR SERIES
INSTALLATION
MANUAL AND
REPLACEMENT
PARTS LIST
Modular Gas-Fired Cast
Iron Water Heating Plants
360,000 to 2,400,000
Btuh Input
Applicable For Larger Heating
Plants Using Boiler Banks Of
8-Modules Or Less
NOTE: If shop drawings have not been provided, refer to the Appendices at the rear of this manual for sizing
(breeching, chimney & gas piping) and control system data.
IN UNITED STATES: 260 NORTH ELM ST • WESTFIELD, MA 01085 • [phone] • FAX [phone]
IN CANADA: 5211 CREEKBANK ROAD • MISSISSAUGA, ONT. L4W 1R3 • [phone] • FAX [phone]
SECTION 1: INTRODUCTION
Heating Plant Design............................................2
Code Compliance.................................................2
Heating Plant Shipment........................................2
Heating Plant Dimensions....................................3
SECTION 2: INSTALLING MODULES
Step 1: Planning Ahead........................................4
Step 2: Arranging Heating Plant...........................5
Step 3: Setting & Aligning Modules......................5
SECTION 3: INSTALLING WATER PIPING
Step 1: Planning Ahead........................................6
Step 2: MC Heat Exchangers...............................6
Step 3: Supply & Return Headers........................6
Step 4: Hydronic Components..............................7
Step 5 Hydrotesting The Systems........................8
Combination Heat/Cool Systems........................10
SECTION 4:VENTING THE HEATING PLANT
Step 1: Planning Ahead......................................11
Step 2: Drafthoods & Vent Dampers...................12
Step 3:Vent Connectors & Slip Joints................13
Step 4: Breeching Runs.......................................14
SECTION 5: INSTALLING JACKETS
Jacket Assembly..................................................15
SECTION 6: INSTALLING GAS PIPING
Step 1: Gas Main & Gas Headers.......................16
Step 2:Test Gas Piping.......................................16
SECTION 7:WIRING THE HEATING PLANT
Module Wiring......................................................17
SECTION 8: HEATING PLANT START-UP
Step 1: Planning Ahead......................................19
Step 2: Start-Up & Adjustments..........................19
Step 3: How To Change Orifices.........................21
APPENDICES
A: Breeching/Chimney Sizing..............................22
B: Gas Pipe Sizing..............................................24
C: Control Guidelines..........................................26
D: Field Installation of Vent Damper....................31
Replacement Parts List.......................................32
MRC2-1103
42-9154

HEATING PLANT DESIGN
Multi-Temp heating plants are comprised of individual
cast iron modules that are piped to common headers to
provide large hot water heating capacities. They are de-
signed and intended for use for a central space heating
system, for volume water heating, or for combination
space heating/volume water heating. Each module is
self-contained with its own set of controls and can oper-
ate independent of the other modules. Multi-Temp mod-
ules can be arranged to fit just about any available area.
Products of combustion are vented through each mod-
ule’s draft hood, connected to a manifold (breeching) for
joining individual draft hoods.The breeching is connect-
ed to a chimney which provides the necessary draft.
The objective of a Multi-Temp heating plant control sys-
tem is to relate plant output to the actual heating load by
automatic step-firing. This means that more or fewer
modules are operated in response to an increase or de-
crease in actual heating load. Hydrotherm has develop-
ed three basic methods (levels) of control which meet
most operating requirements encountered. Typical wi-
ring diagrams for these basic methods are provided in
the appendices at the rear of this manual.Special control
system designs can be developed through the Hy-
drotherm applications engineering group.
CODE COMPLIANCE
Installations must conform to requirements of the au-
thority having jurisdiction or, in the absence of such re-
quirements, to the National Fuel Gas Code ANSI Z223.1-
latest edition. Where required by the authority having
jurisdiction, the installation must also conform to
Standard for Controls and Safety Devices for
Automatically Fired Boilers, ANSI/ASME CSD-1.
All electrical wiring must be in accordance with the re-
quirements of authority having jurisdiction or, in absence
of such requirements, with National Electrical Code
NFPA-70- latest edition. If an external electrical source is
utilized, each installed module must be electrically
grounded in accordance with the requirements of the
authority having jurisdiction or, in the absence of such
requirements, with the National Electrical Code NFPA-
70- latest edition. UL listed power limited circuit cable is
almost universally approved for safety controls on heat-
ing equipment, either internally or externally, without pro-
tection of conduits or raceway.
For Canada, installations must be in accordance with
Standards CAN/CGA-B149 .1 or .2, Installation Codes
for Gas Burning Appliances and Equipment and with
Standard C.S.A.C22.1, Canadian Electrical Code, Part 1
and Part 2, and/or local codes.
HEATING PLANT SHIPMENT
Heating plant packing list (attached to one of the pack-
ages) clearly lists the number of packages and their con-
tents.Check this list against all material on the job site for
completeness.
Heating Modules: Each module is shipped unjacketed
in its own carton and weighs 525 lbs. (maximum for R-
300B module).
Drafthoods: One drafthood for each module is shipped
in a separate carton.
Optional Vent Dampers: When ordered, one vent dam-
per for each module is shipped in a carton enclosed with
the module carton.
Jackets: There are two jacket sizes- "A" jacket to en-
close two heating modules and "B" jacket to enclose
three heating modules. The correct combination of "A"
WARNING: Installers must follow local regulations
with respect to the installation of CO detectors and
follow the manufacturer’s stated maintenance
schedule for this boiler!
ATTENTION: Observer les réglements régional á
l’egard des détecteurs de monoxyde de carbone et
observer entretien de manufacturier pour cette
chaudiére!
The following terms are used throughout this manual to bring attention to the presence of potential hazards
or to important information concerning the product:
CAUTION: Indicates an imminently hazardous situ-
ation which, if not avoided, may result in minor
injury or property damage.
NOTE: Used to notify of special instructions on
installation, operation or maintenance which are
important to equipment but not related to personal
injury hazards.
2
SECTION 1: INTRODUCTION
DANGER: Indicates an imminently hazardous situ-
ation which, if not avoided, will result in death,
serious injury or substantial property damage.
WARNING: Indicates a imminently hazardous situ-
ation which, if not avoided could result in death,
serious injury or substantial property damage.

and "B" jackets are furnished to form a complete enclo-
sure for the entire heating plant.
Optional Header Sets: When ordered, each header set
includes supply and return headers, pipe nipples, unions
and self-aligning couplings. There are two header set
sizes - "A" headers for joining two heating modules and
"B" headers for joining three heating modules. The cor-
rect combination of "A" and "B" headers is furnished to
manifold the complete heating plant.
Optional Heat Exchanger: When ordered, each heat
exchanger is shipped with the pipe and fittings required
for installation.There are three types of heat exchangers
for volume water heating - “MC2” for two heating mod-
ules;“MC3”for three heating modules; and “MC4”for four
heating modules.
Control Equipment: When ordered, controls such as
motorized valves, modulating aquastats, step controllers,
thermostats, etc., are furnished in separate cartons.
Pressure Drop: 1.1 ft. w.c.
at 24GPM (20F∆T)
E ectrica
Power
Requirements
:
120V/60Hz Side .2 amps
24V/60Hz Side 1.0 amps
Working Pressure: 100 psi ASME
Transformer Ratings:
MR/MR-P
120V/60Hz Side .3 amps
24V/60Hz Side 1.5 amps MR-PV
*
9-1/2"
9-1/2"
13"
SUPPLY CONNECTIONS FOR
MR-360C, 420C, 840C ONLY
ARE LOCATED ON THIS C/L
IN FRONT OF BOILER
21"
12"
9" 26" 7"
OPTIONAL
VENT
DAMPER
(MR-PV)
PRESS. RELIEF VALVES (LOCATED IN REAR ON
MR-360C, 420C & 840C)
2" SUPPLY
& RETURN
TAPPINGS
8" DIA. (7" ON MR-360C, 420C,
500C, 750C, 840C AND 1000C)
“A”
“HV”
(TYPICAL)
10-1/2" HI-LIMITS
“H”
46"
36-3/4"
TEMP./PRESS.
INDICATORS
“L”
GAS VALVES
DRAIN
VALVE 21"
Boiler
Model Length
“L”
Height
“H”
MR/MR-P “HV”
MR-PV
Vent
Damper
Height
“A”
MR-360C 3’6” 4’ 10”-1/2” 5’ 1/2” 25-1/2”
MR-420C 3’6” 5’2” 5’ 5-1/2” 28-3/4”
MR-500C 3’6” 5’ 5-1/2” 5’ 9-1/4” 32-1/2”
MR-600B 3’6” 5’6” 5’ 9-3/4” 33”
MR-750C 5’4” 5’ 5-1/2” 5’ 9-1/4” 32-1/2”
MR-840C 7’1” 5’2” 5’ 5-1/2” 28-3/4”
MR-900B 5’4” 5’6” 5’ 9-3/4” 33”
Boiler
Model Length
“L”
Height
“H”
MR/MR-P “HV”
MR-PV
Vent
Damper
Height
“A”
MR-1000C 7’1” 5’ 5”-1/2” 5’ 9-1/4” 32-1/2”
MR-1200B 7’1” 5’6” 5’ 9-3/4” 33”
MR-1500B 8’10” 5’6” 5’ 9-3/4” 33”
MR-1800B 10’7” 5’6” 5’ 9-3/4” 33”
MR-2100B 12’4” 5’6” 5’ 9-3/4” 33”
MR-2400B 14’1” 5’6” 5’ 9-3/4” 33”
3
MODEL MR HEATING PLANT DIMENSIONS
* OPTIONAL: FACTORY-SUPPLIED SUPPLY & RETURN HEADER

IMPORTANT TO NOTE
1. Observe minimum clearances to combustibles.
2. Observe proper combustion air requirements.
3. Provide a firm, level and fireproof foundation (mod
ules must be installed on non-combustible floor).
MINIMUM CLEARANCES TO COMBUSTIBLES: The
following clearances must be maintained: 24” from jack-
ets to front, rear and side walls; and 38” from jacket tops
to ceilings. Local requirements may specify greater
clearances and mst be adhered to.
COMBUSTION AIR REQUIREMENTS:
If the heating plant is installed in an unconfined
space, adequate air will be available via normal infiltra-
tion.
If the heating plant is installed in a confined space
having a volume of less than 50 cubic feet per 1000
Btu/hr of gas input for all fuel burning equipment within
the space, or building construction is unusually tight,
adequate air for combustion must be provided by two
openings: one located about 6” below the ceiling, the
other about 6” above the floor. Each opening must
have a minimum free area as follows:
1.One square inch per 4000 Btu/hr of has input when
communicating directly with the outside or through a
vertical duct.
2.One square inch per 2000 Btu/hr of gas input when
communicating through horizontal ducts to the out-
side.
3.One square inch per 1000 Btu/he of gas input when
ventilation air is provided by openings in doors, etc.to
adjoining spaces having adequate infiltration.
6"
4" HOLLOW CLAY TILE (TWO COURSES).
OPENINGS THRU BLOCKS IN TOP COURSE
TO BE AT 90 ANGLE TO OPENINGS THRU
BOTTOM COURSE
0
22 GAUGE
SHEET METAL
FLOOR
6" OVERHANG OF BLOCK AND
SHEET METAL ALL AROUND
SECTION 2: INSTALLING MODULES
NOTE: Modules employ atmospheric combustion.
Combustion air must not be contaminated with halo-
genated hydrocarbon vapors, cleaning fluid vapors,
aerosol propellants, freon or other corrosive chemi-
cals. Otherwise, module heat exchangers will be
subject to corrosion, reducing module life.
HEATING PLANT FOUNDATION: Concrete base pad is
preferred. Loading is 170 lbs. per square foot; special
material and where permitted by local codes, fabricate a
fireproof base as shown in Figure 2.1. Local codes may
require different construction.
WARNING: This heating plant must be supplied
with combustion air in accordance with Section 5.3,
Air for Combustion and ventilation, of the latest of
the National Fuel Gas Code, ANSI Z223.1, and all
applicable local building codes. Canadian installa-
tions must comply with CAN/CGA B149.1 or .2
Installation Code. Failure to provide adequate com-
bustion air to the heating plant can result in exces-
sive levels of carbon monoxide which can result in
severe personal injury or death!
WARNING: Never install this heating plant on car-
peting! Never install this heating plant on com-
bustible flooring without fireproof base depicted in
Figure 2.1 properly installed under boiler. Failure to
with this warning will result in a fire which will cause
extensive property damage, severe personal injury
or death!
FIGURE 2.1
4
STEP 1: PLANNING AHEAD

21"
REAR
FRONT
CHALK LINE
IN-LINE GROUPING
36"
TO WALL
OR NEXT
BANK
8 MODS
36"
26"
48"
36"
TO WALL
OR NEXT
BANK
36"
5 MODS
8 MODS
FACE-TO-FACE GROUPING
36"
36"
26"
26"
48"
36"
48"
36"
36"
8 MODS
8 MODS
BACK-TO-BACK GROUPING
26"
29"
26"
48"
5
STEP 2: ARRANGING HEATING PLANT
1. Locate heating plant as close to the chimney as possi-
ble so breeching length to chimney is kept to a minimum.
Only 24” is required between the first module and the
chimney.
2. Modules employing MC heat exchangers (if any) must
be located closest to the chimney to assure adequate
draft for summertime operation.
3. Arrange heating plant in multiple banks of eight mod-
ules or less (unless otherwise specified on factory-
approved specially-designed venting systems). NO
MORETHAN EIGHT MODULES MAY BE CONNECTED
DIRECTLY WITH FACTORY-SUPPLIED HEADERS.
Several examples of typical arrangements are shown
here. Recommended clearances (which are more than
clearances to combustibles) allow for servicing, system
installation & connections.
4. Make sure that any connecting breeching runs will not
oppose or face each other, but rather mix together in the
same general direction, specifically “Y” together rather
than “tee” together.
1.Snap a chalk line on foundation where rear of modules
will be located. Modules must be spaced 21” center to
center.
2. Remove cartons from modules; move with skids to a
position alongside final module location. Rock module
off skid into proper location on foundation -rear of burner
base should rest on the chalk line and left of burner base
at the interval mark.
3.Ensure that supply and return tappings on rear of each
module are spaced at 21” intervals. If more than 1/8” of
vertical discrepancy exists, shim under module base to
bring the supply tappings in line.
4. Level each module front-to-rear and side-to-side by
shimming under base as necessary.
STEP 3: SETTING & ALIGNING MODULES
CAUTION: Do not loosen tie rods on module absorption unit.They accommodate thermal expansion. Loss of
module’s structural integrity & water leaks/damage may result.
FIG 2.2A
FIG 2.2B
FIG 2.3

RETURN HEADER
SUPPLY HEADER
SECTION 3: INSTALLING WATER PIPING
STEP 1: PLANNING AHEAD
6
IMPORTANT TO NOTE
1. Field-fabricated headers must have correct number of
tappings to accept all water piping accessories; locations
of tappings must be in accordance with guidelines pro-
vided in Step 4 in this section.
2. If system anti-freeze will be used, the system must be
designed to accommodate the necessary changes in
heat transfer, pump head, flow rate and expansion.
3. Water treatment is recommended in areas where
water quality is a problem; it must be used in hard water
areas and on very large volume heating systems.
FIELD-SUPPLIED COMPONENTS: Some of the follow-
ing components may not have been supplied by
Hydrotherm, depending on how the heating plant was
ordered, but are required for installation: air separator,
air eliminator, expansion tank, low water cut-off, manual
reset hi-limit, pressure reducing fill valve, pump(s), shut-
off valves, and motorized valve (for combination space/
volume water heating). Optional: flow check valve,
make-up water meter, strainer & backflow preventer.
FREEZE PROTECTION: Where it’s absolutely neces-
sary, system anti-freeze can be utilized, but it must be
compatible with hydronic heating systems. For more
information, consult The hydronics Institute Technical
Topics Number 2A publication.
NOTE: Never use an RV type anti-freeze protection
solution no an automotive type anti-freeze as dam-
age to modules and other system components may
result.
WATER TREATMENT: A local water treatment company
should be consulted t determine the requirements for
your particular system and locality through a thorough
chemical analysis of your system water.
CAUTION: Modules are not for use in systems where
water is replenished. Minerals in the water can build
up on heat transfer surfaces and cause overheating
and subsequent failure of the cast iron sections. If
piping exists where water leakage would not be visi-
ble, a water meter should be installed to record
introduction of boiler feed water.
STEP 2: MC HEAT EXCHANGERS
nal piping must be supported by hangers, not by the boil-
ers or their accessories.
For installation of factory-supplied MC/MCI heat
exchangers, refer to Hydrotherm MC & MCI Installation
Guide MC2 packaged with the heat exchanger. All exter-
STEP 3: SUPPLY & RETURN HEADERS
1. Whether installing factory-supplied headers or field-
fabricated headers, WATER PIPING MUST BE IN-
STALLED TO PROVIDE REVERSE RETURN FLOW
(see Figure 3.1). This piping arrangement ensures ad-
equate flow to every heating plant module.
2. For installation of factory-supplied supply and return
headers, refer to Hydrotherm Supply & Return Header
Installation Guide H2 package with the header sets. All
external piping must be supported by hangers, not by the
boilers or their accessories. NO MORE THAN EIGHT
MODULES MAY BE DIRECTLY CONNECTED WITH
FACTORY-SUPPLIED HEADERS. FIGURE 3.1

IN-LINE - 8 MODULES OR LESS BACK TO BACK
MORE THAN 8 MODULES
IN-LINE - MORE THAN 8 MODULES
SUPPLY
RETURN
SUPPLY
RETURN
SUPPLY
RETURN
RELIEF VALVE
DISCHARGE
PIPING
MUST
TERMINATE
6" ABOVE
FLOOR
SAME SIZE
OR LARGER
THAN OUTLET
NIPPLE
COUPLING
PRESSURE
RELIEF VALVE
(VERTICAL)
The diagrams in Figures 3.4 through 3.7 show typical
locations of various hydronic components required for
Multi-Temp heating plants. In all cases, installation
should be in accordance with component manufacturer’s
recommendations (literature, if applicable, is packaged
with component). In addition, the following guidelines
should be followed.
PRESSURE RELIEF VALVES: One supplied for each
module. Install relief valves with spindle in the vertical
position (i.e., valve discharge in horizontal) with coupling
and nipple in 3/4" tapping at top of modules. Install field-
supplied valve discharge piping (Figure 3.3).
CAUTION: Piping must be installed from the relief
valve discharge so there will be no danger of scald-
ing personnel.
TEMPERATURE/PRESSURE INDICATORS: One tem-
perature/pressure indicator supplied for each module.
INSTALL AFTER ASSEMBLING JACKET.
DRAIN VALVES: One supplied for each module. Install
below return connection.
PRESSURE REDUCING (FILL) VALVE: Follow manu-
facturer’s installation instructions.
AIR SEPARATOR(1):Locate in the supply line between
boiler and system pump (where it will protect all modules
under all operating conditions). Follow manufacturer’s
installation instructions.
AIR ELIMINATOR(1):Install on air separator (where it will
protect all modules under all operating conditions).
Follow manufacturer’s installation instructions.
EXPANSION TANK(1):Locate on suction side of pump
(where it will protect all modules under all operating con-
ditions). Follow manufacturer’s instructions.
WARNING: Never install any type of valve between
the pressure relief valve and the heating plant mod-
ules! Failure to comply with this warning can result
in a heating plant explosion causing extensive
property damage, severe personal injury, or death!
STEP 3: SUPPLY & RETURN HEADERS (CONTINUED)
STEP 4: HYDRONIC COMPONENTS
Examples of typical
supply & return water
piping for headers.
No more than eight
modules may be
directly connected!
FIGURE 3.3
FIG 3.2
7
(1) For heating plants providing volume water heating only (instantaneous recovery or with storage tank), see Figures 3.6 and
3.7 on page 10 for installation guidelines

MANUAL RESET HI-LIMIT(1):Locate in supply piping
downstream of connection of the last module.
LOW WATER CUTOFF(1):(Electronic type or float type)
Locate in supply header. Follow manufacturer’s installa-
tion instructions. If heating plant is to be installed above
level of radiation, a low water cut-off must be installed to
protect plant from dry fire.
CAUTION: To prevent accidental dry fire, do not
install isolation valves between low water cutoff and
the module.
CAUTION: Do not install any low water cut-off in a
location where water will not freely drain away from
the float or probe (i.e., in a pipe tree or loop) should
a low water condition develop in the module.
For electronic probes, vertical installation (where all
water can freely drain away from probe) is preferred over
horizontal.Do not install in small diameter pipe nipples or
bushings, as insufficient clearance to probe may result in
corrosion and/or erroneous readings.
SYSTEM PUMP(1) Locate in the heating plant supply pip-
ing, downstream of the modules. Follow manufacturer's
installation instructions.
CAUTION: HEATING PLANTS MUST NOT BE USED
WITHOUT FORCED SYSTEM CIRCULATION, AS
OVERHEATING/FAILURE OF CAST IRON SECTIONS
MAY RESULT.
MOTORIZED VALVE: Commonly used on combination
space/volume water heating systems to ensure a priority
for domestic hot water over space heating. Use a 2"
globe valve with motor for MC2 heat exchanger and a 2-
2/2" butterfly valve with motor and linkage for MC-3 & 4
heat exchangers. See Figure 3.5 for location and follow
manufacturer’s instructions.
FLOW CHECK VALVE (Optional): Important to control
direction of flow and prevent gravity circulation. Locate
where it cannot cause isolation of any particular loop or
zone from the main system.Follow manufacturer’s instal-
lation instructions.
MAKE-UP WATER METER (Optional): Will help deter-
mine total system water volume for purposes of water
treatment, and aid in the identification of a system leak.
Follow manufacturer’s installation instructions.
STRAINER (Optional): For retrofit or steam conversion
systems, basket-type strainer will trap loose system
scale. Locate in return water line. Follow manufacturer’s
installation instructions.
BACKFLOW PREVENTER (Optional): Used as a
means of isolation (space heating system from main
water supply) to safeguard against potential hazard of fill
valve connection allowing migration of water treatment
chemicals into potable water supply. Follow manufactur-
er’s installation instructions.
OTHER COMPONENTS: Install all other waterside com-
ponents such as shut-off valves, mixing valves, ther-
mometers and supply water temperature sensors; install
sensors or probes in a location that will sense supply
water temperature from all modules. Follow manufactur-
er's installation instructions.
8
STEP 4: HYDRONIC COMPONENTS (CONTINUED)
(1) For heating plants providing volume water heating only (instantaneous recovery or with storage tank), see Figures 3.6 and
3.7 on page 10 for installation guidelines
STEP 5: HYDROTESTING THE SYSTEM
It is recommended that hydrotesting of the entire heating
system be performed before installing jackets and con-
trols or wiring the system. fill the entire system with
water. The assembled boiler shall be subjected to a
hydrostatic test pressure not less than 1-1/2 times the
maximum allowable working pressure. The required
test shall not exceed the test pressure by more than PSI.
All fittings and components should then be inspected for
visible signs of leakage. If no pressure drop is detected
for a two-hour period while the system is under pressure,
the heating system may be considered water tight.

LOW WATER
CUTOFF
BASKET TYPE
STRAINER
System
Return
MANUAL RESET
HI-LIMIT
SHUT-OFF
VALVE
RETURNHEADER
SUPPLY HEADER
AIR
SEPARATOR
CIRCULATOR
EXPANSION
TANK
PRESSURE
REDUCING
(FILL) VALVE
AIR ELIMINATOR
(AIR VENT)
FLOW CHECK
VALVE
BACKFLOW
PREVENTER
To Potable
Water
System
FILL
MAKE-UP
WATER METER
System
Supply
City
Water
Supply
RETURN
INLET MOUNT DRAIN VALVE BELOW
RETURN CONNECTION
FRONT OF BOILER
NOTE:WHEN A HOLBY MIXING VALVE IS USED
THERE MUST BE A 27" DROP BELOWTHE COIL
COLD WATER TERMINAL IN THE COLD WATER
LINE BEFORE ENTERING THE COIL
To Potable
Water
System
City
Water
Supply
MIXING
VALVE
LOW WATER
CUTOFF
HEAT EXCHANGER
MOTORIZED
VALVE
Service
Hot Water
Supply
Service
Recirculating
Hot Water
BRONZE
CIRCULATOR
*
*
BASKET TYPE
STRAINER
System
Return
SHUT-OFF
VALVE
MANUAL RESET HI-LIMIT
EXPANSION
TANK
AIR SEPARATOR
AIR ELIMINATOR (AIRVENT) CIRCULATOR
FLOW CHECK VALVE
Supply
FLOW CHECK VALVE
PRESSURE
REDUCING
(FILL) VALVE
RETURN
INLET MOUNT DRAIN VALVE BELOW
RETURN CONNECTION
FRONT OF BOILER
MAKE-UP
WATER METER
TYPICAL PIPING FOR SPACE HEATING SYSTEM
9
TYPICAL PIPING FOR COMBINATION SPACE/VOLUME WATER HEATING SYSTEM
FIG. 3.4
FIG. 3.5

NOTE: WHEN A HOLBY MIXING VALVE IS USED THERE MUST BE A 27" DROP BELOW THE COIL COLD WATER TERMINAL IN THE COLD WATER
LINE BEFORE ENTERING THE COIL
*
SHUT-OFF VALVE
City
Water
Supply
Service Hot
Water Supply
Service
Recirculating
Hot Water
BRONZE CIRCULATOR FLOW CHECK VALVE
EXPANSION
TANK
AIR ELIMINATOR (AIR VENT)
BACKFLOW PREVENTER
MAKE-UP
WATER METER
MIXING VALVE
*
PRESSURE
REDUCING
(FILL) VALVE
LOW WATER
CUTOFF
MANUAL RESET
HI-LIMIT
THERMOMETER
City
Water
Supply
Service
Recirculating
Hot Water
Service
Hot Water
Supply
PRESSURE
REDUCING
(FILL) VALVE
BACKFLOW PREVENTER
MAKE-UP
WATER METER
BRONZE CIRCULATOR
FLOW CHECK VALVE
SHUT-OFF VALVE
PRESS RELIEF VALVE
STORAGE TANK
AIR ELIMINATOR (AIR VENT)
LOW WATER
CUTOFF
MANUAL RESET HI-LIMIT
EXPANSION
TANK
NOTE: VALVES "H" OPENED ON HEATING WITH "C" VALVES
CLOSED REVERSE PROCEDURE ON COOLING.
EXP. TANK VENT ROOM
UNIT
DRAIN CHILLER
BOILER
H
C
PUMP
RELIEF
VALVE
FILL
VALVE
DRAIN
C
H
BOILER
TYPICAL PIPING FOR VOLUME WATER HEATING ONLY
(INSTANTANEOUS RECOVERY)
10
TYPICAL PIPING FOR VOLUME WATER HEATING ONLY
(WITH STORAGE TANK)
FIG. 3.6
FIG. 3.7
FIG. 3.8
COMBINATION HEATING
& COOLING INSTALLATIONS
If hot water module is installed in connection with water
chiller, chilled water must be piped in parallel with module
using appropriate valves to prevent chilled medium from
entering module.When modules are connected to heating
coils in air handling units, where they may be exposed to
refrigerated air circulation, module piping system shall be
equipped with flow-control valves or other automatic
means to prevent gravity circulation of module water dur-
ing cooling cycle.

BREECHING CONSTRUCTION REQUIREMENTS:
Round breeching is preferred to maximize flue gas flow.
Rectangular breeching is the only acceptable alterna-
tive; the larger dimension of the rectangle must be in
the vertical. Breeching should be constructed of sheet
metal with smooth interior surfaces. Figure 4.2 provides
minimum sheet metal gauges (adhere to local require-
ments for sheet metal thickness). All joints must be
rolled or welded with sufficient overlap to provide a gas
tight joint.
CHIMNEY REQUIREMENTS: Lined masonry chimneys
or Type B metal vent systems, constructed in accor-
dance with the National Fuel Gas Code, are suitable.
Chimney construction materials must be compatible with
the fuel being used.
Chimney condition is of paramount importance for a
safe/efficient installation. For existing chimneys, all
installations must include a chimney inspection by quali-
fied individual or agency. Particular attention should be
paid on oil-to-gas conversions. Soot may have accumu-
lated in the chimney and/or degraded the chimney liner.
Most utilities require installation of a new liner, safety spill
switches or other chimney upgrades. Check local utility
for the required safety precautions.
MECHANICAL DRAFT REQUIREMENTS: When proper
venting of the Multi-Temp heating plant cannot be
accomplished by natural means, mechanical draft induc-
ers or power venters may be used. All mechanical draft
equipment must be properly sized and properly installed
by following the recommendations of their manufactur-
ers. A fan prove switch must be used in the control sys-
tem and wired such that the heating plant will not fire
(prevent flow of fuel) until inducer or power venter fan
operation is proved.
GAS HEATING PLANT
DRAFT
HOODS
VENT
DAMPERS
C
H
I
M
N
E
Y
VENT
CONNECTORS
BREECHING
MINIMUM SHEET METAL GAUGE
FOR ROUND AND RECTANGULAR BREECHING
SHEET
METAL
GAUGE
24
22
20
16
DIAMETER
IN INCHES
6 TO 10
10 TO 12
14 TO 16
OVER 16
ROUND GREATER
DIMENSION
IN INCHES
10 TO 13
14 TO 18
19 TO 20
OVER 20
RECTANGULAR
STEP 1: PLANNING AHEAD
SECTION 4:VENTING THE HEATING PLANT
IMPORTANT TO NOTE:
1. Breeching runs must be as short as possible.
2. No more than eight modules may be served by one
breeching run to assure adequate draft (unless otherwise
specified on factory-approved specially-designed venting
systems).
3. Observe breeching construction requirements.
4. Observe proper chimney requirements.
5. Flues from other fuel-burning appliances must not be
connected into heating plant breeching; otherwise, inad-
equate draft may result.
6. Natural draft equipment (heating plants without
mechanical draft components) must not be connected
into any portion of a mechanical draft or power vent sys-
tem operating under positive pressure, including the
chimney.
7. If shop drawings with approved breeching and chim-
ney sizes are not available, you can use sizing guidelines
recommended in Appendix A at the rear of this manual.
MULTI-TEMP HEATING PLANT VENTING SYSTEM:
Consists of drafthoods, vent dampers (when ordered)
vent connectors, breeching and chimney or vent pipe
(see Figure 4.1). Drafthoods are installed between each
modules’s flue outlet and vent connector. Breeching is
the horizontal manifold for connecting each module’s
vent connector to the chimney. When specified, vent
dampers are installed between the top of each module’s
drafthood and vent connector.
Venting system components must be installed in accor-
dance with requirements of the local authority having
jurisdiction or, in the absence of such requirements, to
the National Fuel Gas Code ANSI Z223.1-latest edition
and chimney manufacturer’s guidelines. DANGER: A chimney which does not meet modern
safety standards will result in a fire or deadly carbon
monoxide poisoning of the building residents.
FIGURE 4.1
FIGURE 4.2
11

1. Install drafthood on each module’s flue outlet.
2. If ordered with heating plant, mount each module’s
vent damper directly on top of the drafthoods with the
vent damper motor on the right side (see Figure 4.3).
The flow arrow imprinted on the vent damper must point
upward.
NOTE: The vent damper must accessible for servic-
ing and checking the position indicator.
3. Position the vent damper motor cable (see Figure 4.3)
so it does not touch the metal surface of the drafthood.
Where necessary, turn the angle connector on the vent
damper upward until the cable clears; tighten the locknut
to secure.
Secure vent damper housing to drafthood outlet as
shown in Figure 4.4
ANGLE
CONNECTOR
VENT
DAMPER
CABLE
DRAFT
HOOD
PLUG INTO MOLEX
RECEPTACLE ON FRONT
OF BOILER
PLUG INTO MOLEX
RECEPTACLE INSIDE
DAMPER MOTOR VENT
DAMPER
WIRE
HARNESS
TOP VIEW
ATTACH LOWER
PORTION OF VENT
DAMPER TO DRAFTHOOD
WITH 1/2" OR SHORTER
SCREWS OR POP RIVETS
BOILER FRONT
12
FIG. 4.3
FIG. 4.4
FIG. 4.5
STEP 2: DRAFTHOODS & VENT DAMPERS
DANGER: Drafthood, flue outlet and vent damper as
supplied must not be altered in any way as proper
module operation would be jeopardized. Flame roll-
out, fire or carbon monoxide poisoning will result.
DANGER: Only one module may be served by one
vent damper. Do not vent more than one module
through a vent damper. In addition, a minimum
clearance distance of 6”must be maintained
between vent system components and all com-
bustible construction. Failure to comply with this
warning can result in carbon monoxide poisoning or
a fire which will cause extensive property damage,
severe personal injury or death!

SLIP JOINT
OR DRAW
BAND
BREECHING
VENT
CONNECTOR
SLIP JOINT
OR DRAW
BAND
VENT
DAMPER
BREECHING
1-FT. MINIMUM RISE
3-FT. OR MORE
RISE PREFERRED
FLOW
45°
ELBOW
1-FT. MINIMUM RISE
3-FT. OR MORE
RISE PREFERRED
BREECHING
45°VENT
CONNECTOR
ROUNDED
45°ELBOW
INEFFECTIVE
BREECHING
AREA
STEP 3:VENT CONNECTORS & SLIP JOINTS
13
FIG. 4.6
FIG. 4.7
1. Install a vent connector between each module’s draft-
hood (or vent damper) outlet and the breeching. Vent
connector diameter should be the same as drafthood (or
vent damper) outlet; IT MUST NEVER BE SMALLER.
2. Where possible, vent connector height should use all
available head room. Minimum vertical height of vent
connector is 1-foot; a 3-foot rise is preferred.
3.Vent connector should connect to the breeching with a
straight 90° connection. For improved flue gas flow, vent
connectors may be installed with a 45° rounded type
elbow; angled toward the chimney (as shown on the far
right).
4. For ease of servicing, install a slip joint or a draw
band between the drafthood (or the vent damper) outlet
and the vent connector.
5. Where it may be necessary to vent two banks of boil-
ers into a common breeching, the vent connectors must
be angled at 45°s and they must enter the breeching at
the lowest point possible to minimize the ineffective area
of the breeching. The 45° elbows must be the rounded
type, and the 1-foot minimum height; 3-foot or more pre-
ferred height must be maintained.
This arrangement applies for a maximum of four boilers
per bank, unless otherwise specified on factory-approved
specially-designed venting systems. For larger banks
of boilers, use individual breeching for each bank.

TAPERED INCREASER
TAPERED
PITCH 1/4" PER RUNNING FOOT
UPWARD TOWARD CHIMNEY
C
H
I
M
N
E
Y
C
H
I
M
N
E
Y
FULL SIZE
PITCH 1/4" PER RUNNING FOOT
UPWARD TOWARD CHIMNEY
PREFERRED
DOUBLE "Y" FITTING "Y" FITTING
45 ELBOW
0
ACCEPTABLE
CHIMNEY
BREECHING
RUN
BREECHING
RUN
STEP 4: BREECHING RUNS
14
FIG. 4.8 FIG. 4.9
1. Breeching can be full size for an entire bank of boilers
(Figure 4.8 left) or may be tapered (Figure 4.9 right).
using one tapered division within a bank of eight mod-
ules.
2. For tapered breeching, the smallest sized breeching
division is always the furthest from the chimney with
transition to the larger division leading toward the chim-
ney (see Figure 4.9 right). All increaser fittings must be
tapered to assure proper flue gas flow.
3. Remember, for rectangular breeching, the larger di-
mension of the rectangle must be in the vertical position,
4. ALL BREECHING RUNS MUST BE PITCHED 1/4”
PER FOOT OF LENGTH UPWARDS TOWARD THE
CHIMNEY.
5. Where one breeching run connects into another
breeching run, they must be connected so the flow-
streams from each breeching run do not face or oppose
each other. They must flow in the same general direction
(see Figure 4.10). Construction involves using “Y”-fittings
and rounded 45° elbows angled towards the chimney to
assure proper flue gas flow, specifically “Y” together
rather than “tee” together.
FIGURE 4.10
FIGURE 4.11
6. Where two or more breeching runs connect into the
same chimney, make sure the openings into the chimney
do not directly face or oppose each other.
7. At the breeching-chimney connection, breeching must
be flush with the inside of the chimney liner and sealed.
8. Always use “Y” fittings rather than “tee” fittings when
connecting breeching together.

HI-LIMIT K.O.'s
FOR R-300B MODULES
A
B
A
B
HI-LIMIT K.O.'s
FOR R-180C, 210C & 250C
MODULES
ELECTRICAL SUBCHASSIS
TEMPERATURE/PRESSURE
INDICATORS
(FOR EACH MODULE)
CENTER TOP PANEL
LEFT TOP PANEL
SIDE PANEL STIFFENING CHANNEL
FRONT PANEL
SIDE PANEL
RIGHT TOP PANEL
FRONT PANEL
SIDE PANEL
FRONT PANEL
REAR PANEL
15
SECTION 5: INSTALLING JACKETS
NOTE: Remember, “A”jacket sets are for enclosing
two modules and “B”jacket sets are for enclosing
three modules.
1. Place front and rear panels along heating plant, and
attach side panel on the right with screws provided.
2. Any number of “A” or “B” jackets may be joined to-
gether to form one continuous jacket by omitting one left
side panel in between jacket sets. Fasten front and rear
panels to remaining side panel(s) with screws provided.
When assembling the jacket, overlap bends as shown.
3. Install top panels starting with left top panel. Lock
each panel into the preceding panel and secure with the
screws provided.
4. Snap stiffening channels across elongated slot in rear
panel beneath each return water piping connection.
5. Attach rating plate, lighting instructions label and liter-
ature pack where indicated by stencils.
FIGURE 5.2
6. Temperature/Pressure indica-
tors: Install in top holes of front
panels; one per module
7. Hi-Limits: Install through
appropriate knockouts as shown;
one per module. (Well is factory
installed.)
8. Electrical Subchassis: For all
modules equipped with electronic
ignition (does not apply for standing
pilot mods); mount on front panels.
FIGURE 5.3 FIGURE 5.4
FIGURE 5.1

FROM
METER
LUBRICATED
PLUG VALVE
GAS HEADER
GROUND JOINT UNION
SUPPORT
GAS MAIN
SEDIMENT
TRAP
SUPPORT
For any pressure testing in excess of 1/2 psi, the module
and its individual shutoff valve must be isolated from the
piping system by disconnecting them and capping the
outlet(s). For any pressure testing equal to or less than
1/2 psi, module must be isolated from the piping system
by closing its manual shutoff valve.
Minimum pressure required at the gas valve inlet is 5"
W.C., 5.5” W.C. on R300 modules (natural gas) and 11"
W.C.(propane). Maximum pressure allowable at the gas
valve inlet is 12" W.C. If the gas pressure is above these
limits, a pressure regulator must be installed. If the gas
pressure is below these limits, contact the local utility.
FIGURE 6.1
SECTION 6: INSTALLING GAS PIPING
16
STEP 1: GAS MAIN & GAS HEADERS
STEP 2:TEST GAS PIPING
1.Gas pipe (gas main and gas headers) must be sized to
provide a total maximum pressure drop of 0.3”W.C. (nat-
ural gas) or 0.5” W.C. (propane) between gas meter and
each module’s gas valve.If shop drawings with approved
pipe sizes are not available, use sizing guidelines rec-
ommended in Appendix B at the rear of this manual.
2. Gas main (from meter to gas headers) must have a
non-restrictive lubricated plug valve installed close to the
modules as well as a full-sized sediment trap at the
lowest point in the gas main. The vertical rise of sedi-
ment trap must be a minimum of three times gas main
pipe diameter.
3.The gas header is the manifold t which each module’s
gas valve is connected; the connection at each gas valve
inlet requires a ground joint union. If total equivalent pipe
length (straight pipe plus fittings) from gas valve inlet to
header is 5-feet or less, use a pipe diameter that match-
es gas valve inlet; over 5-feet, calculate pipe diameter.
4. All piping must be supported with floor supports or by
hangers, not by the boilers or accessories. Always follow
good piping practices. Pipe joint compound must be
compatible with gas being used. Check local codes and
utilities for any special requirements.
DANGER: Before placing gas piping into service, carefully test it to assure every joint is gas tight.
Bubble test all joints with soap solution. NEVER TEST WITH AN OPEN FLAME AS FIRE
OR EXPLOSION WILL RESULT.
WHEN PRESSURE TESTING IS COMPLETED, CLOSE MAIN GAS SHUT-OFF VALVE & SET
BOILER COMBINATION GAS VALVES IN “OFF”POSITION

For Vent Damper-equipped modules: Attach damper
cables to cable clamps on module front panels and join
the molex connectors.
CAUTION: Label all wires prior to disconnection
when servicing controls. Wiring errors can cause
improper and dangerous operation
Verify proper operation after servicing.
If shop drawings with approved control selection and
wiring diagrams are not available, you can use the con-
trol and wiring guidelines recommended in Appendix C at
the rear of this manual. For individual module wiring refer
to wiring diagrams in Figures 7.1 thru 7.3.
All electrical wiring must be in accordance with require-
ments of the authority having jurisdiction or, in absence
of such requirements, with National Electrical Code
NFPA-70- latest edition. If an external electrical source is
utilized, module must be electrically grounded in accor-
dance with requirements of the authority having jurisdic-
tion or, in the absence of such requirements, with the
National Electrical Code NFPA-70- latest edition. UL list-
ed power limited circuit cable is almost universally
approved for safety controls on heating equipment, either
internally or externally, without protection of conduits or
raceway.
For Canada, installations must be in accordance with
Standard C.S.A. C22.1 Canadian Electrical Code, Part 1
and Part 2, and/or local codes.
Safety devices (such as low water cut-offs and manual
reset high limits) must be wired so they shut down all
modules protected by those devices. Switch ratings on
safety or control devices must not be exceeded; this may
require the use of relays for larger heating plants.
Air and water temperature sensor wiring must not be run
in the same conduit as power wiring; use shielded wiring
in runs over 25 feet long.
NOTE: If any of the original wire supplied with mod-
ule must be replaced, use similar wire of 105 C rat-
ing. Otherwise, insulation may melt or degrade,
exposing bare wire.
NOTE: Module transformers must not be used to
power external accessories (i.e. zone valves, relays,
etc.) Otherwise, transformers will be overloaded and
burn out.
17
DANGER:Turn off electrical power supply before
servicing. Contact with live electric components
can cause shock or death.
FIGURE 7.1 WIRING DIAGRAM & OPERATION
SEQUENCE FOR BOILERS EQUIPPED WITH
STANDING PILOT
SECTION 7:WIRING THE HEATING PLANT
POWER REQUIREMENTS PER MODULE
MR: .2 amps 115V/60Hz Side
1.0 amps 24V/60Hz Side
MR-P: .2 amps 120V/60Hz Side
1.0 amps 24V/60Hz Side
MR-PV: .3 amps 120V/60Hz Side
1.5 amps 24V/60Hz Side

18
FIGURE 7.3 WIRING DIAGRAM & OPERATION
SEQUENCE FOR BOILERS EQUIPPED WITH
INTERMITTENT PILOT & VENT DAMPER
FIGURE 7.2 WIRING DIAGRAM & OPERATION
SEQUENCE FOR BOILERS EQUIPPED WITH
INTERMITTENT PILOT

Safe lighting and other performance criteria were met
with the gas manifold and control assembly provided on
the module when module underwent tests specified in
ANSI Z21.13b-1994.
NOTE: Do not draw water from heating system for
cleaning. Minerals in the water can build up on heat
transfer surface and cause overheating and subse-
quent failure of the cast iron sections.
1. Thoroughly purge the heating system following stan-
dard purging practices.Remember, every loop in the sys-
tem must be properly purged.
2. Check air elimination equipment for proper operation
to ensure that there is no air in the heating system.
3. With the gas valve OFF, turn on power to modules.
Open all zones individually and let system pump(s) run
until all air is purged from each zone (sound of air bub-
bles flowing in piping has been eliminated).
4.Operate system pump(s) with all zones open; continue
for the minimum time required to pass entire system vol-
ume through separation point until sound of air bubbles
flowing in piping has been eliminated.
5. For vent damper-equipped modules, set operating
control(s) to call for heat. Observe that vent damper posi-
tion indicator has rotated to the open position (see Figure
8.1). Damper must be in the open position when
appliance main burner is operating.
a. After damper opens, spark should appear at pilot
ignition electrode.
b. Set operating control(s) to no longer call for heat.
Spark should stop. Observe that damper position
indicator rotates to the closed position.
6. Open the main manual gas valve, allowing gas to flow
through gas piping system. Open each module's gas valve.
7. Set operating control(s) to call for heat. Follow direc-
tions in lighting instruction labels on front of module jack-
ets and light the boiler modules.
8. Allow system water temperature to rise slowly to a-
bout 30°F above fill temperature; shut down modules but
allow system pump(s) to run continuously. When all
sounds of air bubbles are eliminated, increase system
temperature another 30°F. Repeat procedure until maxi-
mum system design temperature is reached.
9. Observe pilot and main burner flame (see Figure 8.2).
All burner ports should be ignited and burn with a steady
blue flame.
OPEN
CLOSED
DAMPER
POSITION
INDICATOR
FLOW
DIRECTION
ARROW
WARNING:Never store combustible materials,gaso-
line or any product containing flammable vapors or
liquids in the vicinity of the heating plant! Do not
allow lint,paper, rags or other combustibles to accu-
mulate around the heating plant! Never place cloth-
ing, rags or other combustible materials on the heat-
ing plant. Failure to comply with this warning can
result in a fire which will cause extensive property
damage, severe personal injury or death!
19
SECTION 8: HEATING PLANT START-UP
STEP 1: PLANNING AHEAD
1. Check that flow direction arrows imprinted on water
system components are pointing in the proper direction.
2. If system was not previously hydrotested, fill system.
Check all temperature/pressure indicators to assure
there is at least the desired cold fill pressure in the sys-
tem.
3. Check all fittings and components for visible signs of
leakage, including each module’s (and header’s) supply
and return water connections.
4. Check that system pump(s) are interlocked with the
heating plant’s operating controls so modules cannot
fire without pump(s) running.
STEP 2: START-UP & ADJUSTMENTS
FIGURE 8.1

CAUTION: Never leave the job with yellow burning
flames. This condition indicates poor combustion
and will quickly carbonize the module, reducing effi-
ciency and module life. It may also be an indication
of improper venting or combustion air supply. If
unable to adjust flame properly, consult your local
utility.
10. Modules are shipped from factory with primary air
shutters on main burner wide open. These air shutters
should be left in the wide open position unless there is
lifting of the flame above the burner ports. If there is lift-
ing, the air shutters should be gradually closed until lift-
ing is eliminated. It may also be necessary to adjust the
primary air shutters if the input rate is reduced by a
change in the orifices.
11. After burners have fired for about 15 minutes check
gas input rate to each module as follows:
a. Make sure all other appliances served by the gas
meter are turned off during timing of gas input rate.
b. Measure the number of seconds it takes for each
module to use 10 cubic feet of gas.Divide 36,000 by
the number of seconds; this is the number of cubic
feet of gas used per hour. Multiply this figure by the
heating value of the gas (obtained from your local
utility) to obtain Btu input per hour.
Example: R-300B module takes 2 minutes to use 10
cubic feet of natural gas. Utility indicated gas heating
value is 1000 Btu/cu ft.Therefore:
(2X60) = 120 seconds
36,000 X 1000 = 300,000 Btu/hr
120
Therefore, the module input is correct.
12. If module input needs to be corrected, adjust combi-
nation gas valve pressure regulator. (Regulator is factory
set at 3-1/2" W.C. for natural gas and 10" W.C. for
propane.)Turn adjusting screw clockwise to increase gas
flow (increase input).Turn adjusting screw counterclock-
wise to decrease gas flow (decrease input). In no case
should final manifold pressure setting vary more than +
.3” W.C. from factory-set pressures. If rated input cannot
be obtained with regulator adjustment, gas supply pres-
sure or orifice size may be the cause. Consult your local
utility and Hydrotherm.
13.Gas burner orifices supplied with modules have been
carefully designed to provide the correct gas input rate
for most gas conditions typically found in the U.S.
Occasionally, however, the local gas characteristics may
not allow the module to be properly adjusted for input. If
this is the case, the local utility or Hydrotherm may rec-
ommend orifices be changed. When changing orifices,
follow procedures in Step 3.
14. Start and stop burners several times by raising and
lowering the control settings. Observe light-off, flame
configuration and color.
15. Check all safety and operating controls to be sure
they are operating in accordance with manufacturer's
recommendations.
a. Hi-Limit Aquastat: Mounted on each module, it cuts
off gas supply to module when module water tem-
perature exceeds setting. Check high limit is set at
220°F. To verify aquastat operation, with a small
screwdriver, reduce high limit setting to 100°F. Fire
module until water temperature reaches or exceeds
100°F, at which time the burner should shut off.If for
any reason burner does not shut off, or allows the
water temperature to exceed 120°F, replace aquas-
tat. If no replacement is necessary, return setting to
220°F.
b. Manual Reset High Limit: Mounted in supply head-
er, it shuts off all module burners if system operat-
ing water temperature exceeds setting. Check that
setting is 250°F. To verify operation, with a small
screwdriver, reduce setting while heating plant is
c. firing. All module burners should shut off when the
Q345ALB
INTERMITTENT
IGNITION PILOT
MODELS NORMAL
PILOT
FLAME
A
A
Q314ALB
STANDING PILOT
MODELS
NORMAL
(HARD FLAME) LIFTING
(TOO MUCH AIR) YELLOW TIPPING
(MARGINAL) YELLOW FLAME (TOO LITTLE AIR)
MAIN BURNER FLAMES
STEP 2: START-UP & ADJUSTMENTS (CONTINUED)
FIGURE 8.2
20