LAARS Mighty Max VW User Manual
Installation, Operation and Maintenance Instructions Document 2064D
Installation,
Operation and
Maintenance
Instructions for
Mighty Max
Volume Water Heaters
Model VW
Sizes 320M - 400M
U.S. Reg. 1,901,192
Canada Reg. 433,882
OUT OF
FOR YOUR SAFETY: This product must be installed and serviced by a professional service technician,
qualified in hot water heater installation and maintenance. Improper installation and/or operation could
create carbon monoxide gas in flue gases which could cause serious injury, property damage, or death.
Improper installation and/or operation will void the warranty.
PRODUCTION
If the information in this manual is not
followed exactly, a fire or explosion may
result causing property damage, personal
injury or loss of life.
Do not store or use gasoline or other
flammable vapors and liquids in the vicinity
of this or any other appliance.
WHAT TO DO IF YOU SMELL GAS
• Do not try to light any appliance.
• Do not touch any electrical switch; do not
use any phone in your building.
• Immediately call your gas supplier from a
nearby phone. Follow the gas supplier's
instructions.
• If you cannot reach your gas supplier, call
the fire department.
Installation and service must be performed by
a qualified installer, service agency, or gas
supplier.
WARNING
Assurez-vous de bien suivres les instructions
données dans cette notice pour réduire au
minimum le risque d’incendie ou d’explosion ou
pour éviter tout dommage matériel, toute
blessure ou la mort.
Ne pas entreposer ni utiliser d’essence ni
d’autres vapeurs ou liquides inflammables dans
le voisinage de cet appareil ou de tout autre
appareil.
QUE FAIRE SI VOUS SENTEZ UNE ODEUR DE GAZ:
• Ne pas tenter d’allumer d’appareils.
• Ne touchez à aucun interrupteur. Ne pas vous
servir des téléphones dansle bâtiment où vous
vous trouvez.
• Appelez immédiatement votre fournisseur de
gaz depuis un voisin. Suivez les instructions
du fournisseur.
• Si vous ne pouvez rejoindre le fournisseur de
gaz, appelez le sservice des incendies.
L’installation et l’entretien doivent être assurés par
un installateur ou un service d’entretien qualifié ou
par le fournisseur de gaz.
AVERTISSEMENT
H0192500D
A subsidiary of BRADFORD WHITE Corporation
Page 2
LAARS Heating Systems
TABLE OF CONTENTS
SECTION 1.
General Information
1.1 Introduction................................................... 3
1.2 Warranty ....................................................... 3
1.3 Technical Assistance .................................... 3
SECTION 2.
Installation Instructions
2.1 General Information ...................................... 3
2.2 Heater Placement ......................................... 4
2.3 Installation of Outdoor Heaters ..................... 4
2.4 Freeze Protection ......................................... 4
2.5 Installation of Indoor Water Heaters ............. 4
2.6 Gas Supply and Piping ................................. 5
2.7 Water System Piping .................................... 6
2.7.1 Water Chemistry ........................................... 6
2.7.2 Water Piping ................................................. 6
2.7.3 Pressure Buildup in Water System ............... 7
2.7.4 Temperature and Pressure Relief Valve ...... 7
2.7.5 Pump Requirements ..................................... 7
2.7.6 Combined Space Heating/Potable
Water Heating Systems ................................ 8
2.8 Venting and Combustion Air Information ...... 9
2.9 Top-to-Rear Vent Collar Conversion ............ 9
2.10 Venting ......................................................... 9
2.10.1 Vertical Venting - Category I......................... 9
2.10.2 Vertical Venting - Non Category I ................. 9
2.10.3 Horizontal Venting - Non Category I ........... 10
2.10.4 Side Wall Vent Terminal ............................. 10
2.11 Air for Combustion and Ventilation ............. 13
2.11.1 Air From Room ........................................... 13
2.11.2 Ducted Combustion Air .............................. 14
2.11.3 Conversion for Ducted Combustion Air ...... 14
2.11.4 Combustion Air Piping ................................ 14
2.12 Electrical Wiring .......................................... 15
PRODUCTION
OUT OF
SECTION 3.
Operation
3.1 Start Up Requirements ............................... 17
3.2 Hi-Limit Checkout ....................................... 18
3.3 Venturi and Gas Pressure
Regulator System ....................................... 18
3.3.1 Overall Operation ....................................... 18
3.4 To Start Up System .................................... 18
3.4.1 Setting Temperature Controls .................... 19
3.5 To Shut Down System ................................ 19
3.6 Venturi Adjustment - Natural Gas ............... 19
3.6.1 Pressure Measurement Port ...................... 19
3.6.2 Adjustment Procedure - Natural Gas.......... 19
3.6.3 Venturi Setup Procedure - Natural Gas ...... 21
3.7 Venturi Adjustment - Propane Gas ............. 21
SECTION 4.
Maintenance
4.1 General Instructions ................................... 22
4.2 Heater Exchanger ...................................... 22
4.2.1 Inspection of the Heat Exchanger .............. 23
4.2.1a External Heat Exchanger Inspection .......... 23
4.2.1b Internal Heat Exchanger Inspection ........... 23
4.2.1c Cleaning the Heat Exchanger - External .... 23
4.2.1d Cleaning the Heat Exchanger - Internal ..... 24
4.3 Gas and Electric Controls ........................... 24
4.4 Filter ........................................................... 24
4.4.1 Filter Function ............................................. 24
4.4.2 Filter Service .............................................. 24
SECTION 5.
Troubleshooting
5.1 Sequence of Operation .............................. 24
5.2 Venturi and Gas Pressure Regulator
System ....................................................... 26
5.3 Electrical Components ............................... 26
5.3.1 General Troubleshooting ............................ 26
5.3.2 Electrical Troubleshooting .......................... 27
SECTION 6.
Parts List for Mighty Max VW Heater
6.1 General Information .................................... 27
Mighty Max Volume Water Heater
Page 3
SECTION 1.
General Information
1.1 Introduction
This manual provides installation, operation, and
maintenance instructions for the Mighty Max Volume
Water Heater, Model VW, Sizes 320M and 400M.
Review all application and installation procedures
completely before proceeding with the installation.
Consult the local factory representative or Laars
factory with any questions regarding this equipment.
Experience has shown that most operating problems
are caused by improper installation. The VW heaters
are offered in an indoor version and an outdoor
version (see Figure 1). Table 1 lists the input/output
ratings for each heater size.
The indoor version is convertible for outdoor use
with the installation of a conversion kit (see Section 6,
Parts List, for part number).
1.2 Warranty
The Mighty Max VW heaters are sold with a
limited factory warranty. Details are specified on the
back cover of this manual.
Make all warranty claims to an authorized Laars
representative or directly to the factory. Claims must
include the heater serial number and model number
(this information can be found on the rating plate),
installation date, and name of the installer. Shipping
costs are not included in the warranty coverage.
packages. Inspect everything for damage immediately
upon delivery, and advise the transporter of any
shortages or damage. Any such claims should be filed
with the transporter. The transporter will not accept a
claim from the shipper, Laars.
PRODUCTION
Some accessory items are shipped in separate
OUT OF
The warranty does not cover damage caused by
improper installation, operation, or field modification.
1.3 Technical Assistance
Consult the local factory representative or Laars
factory with any questions regarding the specification,
installation, and operation of Laars equipment. An
experienced technical support staff is ready to assist in
assuring the proper performance and application of
Laars products.
Heater Input Output
Size BTU/h kW BTU/h kW
320M 320,000 94 272,000 80
400M 399,000 117 339,150 99
Table 1. Input/Output Ratings.
SECTION 2.
Installation Instructions
2.1 General Information
Install the Mighty Max VW heater in accordance
with the procedures in this manual (or the Laars
warranty may be voided), local codes, and ordinances.
In the absence of such codes, install the heaters in
accordance with the latest edition of the National Fuel
Gas Code, ANSI Z223.1/National Fire Protection
Association (NFPA) 54. In Canada, the installation
must be in accordance with CSA B149.1 and local
codes. The authority having jurisdiction may require
the installation be in accordance with the American
Society of Mechanical Engineers (ASME) Safety
Codes for Controls and Safety Devices for
INDOOR OUTDOOR
Front Side
(Water Connections)
Figure 1. Mighty Max VW Heater Configuration.
Rear Side
(Opposite Water
Connections)
Page 4
LAARS Heating Systems
Automatically Fired Heaters, CSD-1. In Canada, other
standards may apply. Any changes to the heater, its
gas controls, gas orifices, or wiring may void the
warranty. If field conditions require change, consult
the factory.
The Mighty Max VW heater is designedcertified for installation on a combustible floor, if a
non-combustible base is first placed under the heater.
Do not install the heater directly on carpeting
without placing a metal or wood panel between the
carpeting and the heater. The metal or wood panel
must extend beyond the full width and depth of the
heater by at least 3 inches (76.2mm) in all directions.
If the heater is installed in a carpeted alcove, the entire
floor of the alcove must be covered by the
metal or wood panel. The panel must be strong enough
to carry the total weight of the heater and all piping,
pumps, and any other equipment attached to the
heater.
Clearance Indoor Outdoor
From Combustibles Inches mm Inches mm
Top 18 457 Unobstructed
Water Conn. Side 12 305 12 305
Opposite side 6 152 6 152
Front Alcove Unobstructed
Rear 6 152 6 152
Vent *6
Flooring Combustible Combustible
Service clearance = 24 inches (610mm) at front of heater.
*1" (25mm) if double wall vent is used.
Table 2. Minimum Heater Clearances
PRODUCTION
From Combustible Surfaces.
OUT OF
* 152 —
2.2 Heater Placement
Locate the heater to provide adequate clearances
on all sides for maintenance and inspection. There
must also be minimum distances maintained from
combustible surfaces (see Table 2). The heater must be
isolated or otherwise protected from any source of
corrosive chemical fumes, such as trichlorethylene,
perchlorethylene, chlorine, etc. Install the heater so
that the gas ignition system components are protected
from water (drippings, spraying, rain, etc.) during
operation and service.
2.3 Installation of Outdoor Heaters
CAUTION
Outdoor installations are not recommended in
areas where the danger of snow blockage exists.
AVERTISSEMENT
L’eau chaude peut brûler ! L’eau chaude peut
causer des brûlures du troisième degré en 6
secondes à 60°C (140°F) et en 30 secondes à
54°C (130°F).
1. Locate the heater to provide at least the
minimum clearances as listed in Section 2.2,
“Heater Placement.” VW heaters require an
outdoor terminal kit when installed outdoors (see
Section 6, Parts List).
2. Do not locate the heater in an enclosure or throughwall recess. Avoid locations where wind deflection
off structures might cause down-draft. When such
wind conditions are possible, locate the heater at
least 3 feet (.9m) from structures.
3. Never install the heater under any kind of roof
overhang. Do not locate the heater below or
adjacent to any doors, windows, louvers, grills, etc.
which communicate in any way with an inhabited
area of a building, even though such
communication might be through another structure
such as a garage or utility room (see Figure 2).
Figure 2. Incorrect Installation of Boiler.
2.4 Freeze Protection
Although Mighty Max VW heaters are design-
certified for outdoor installations, such installations
are not recommended in areas subject to freezing
temperatures, unless proper precautions are taken.
Power outage, interruption of gas supply, failure
of system components, activation of safety devices,
etc., may prevent a heater from firing. Any time a
heater is subjected to freezing conditions, and the
heater is not able to fire, and/or the water is not
able to circulate, there is a risk of freezing in the
heater or in the pipes in the system. When water
freezes, it expands. This can result in bursting of pipes
in the system, or damage to the heater, which could
result in leaking or flooding conditions.
Contact the local factory representative or Laars
for additional information.
2.5 Installation of Indoor Water Heaters
Combustion Air Supply and Ventilation:
There are a variety of options available to the
installer when it comes to venting and combustion air;
venting can be vertical or horizontal, it can originate at
Mighty Max Volume Water Heater
Distance from Gas Meter or Last Stage Regulator
0-100 feet 100-200 feet 200-300 feet
0-30m 30-60m 60-90m
Natural Propane Natural Propane Natural Propane
Size in. mm in. mm in. mm in. mm in. mm in. mm
320M 1.25 32 1.25 32 1.50 38 1.25 32 1.50 38 1.50 38
400M 1.25 32 1.25 32 1.50 38 1.25 32 2.00 51 1.50 38
Notes: 1. These numbers are based on 1/2 inch (13mm) water column pressure drop.
2. Check supply pressure and local code requirements before proceeding with work.
3. Pipe fittings must be considered when determining gas pipe sizing.
Table 3. Natural Gas and Propane, Pipe Size Requirements.
Page 5
the top of the heater or the back, and combustion air
can be obtained from the room where the heater is
installed or ducted directly to the heater from outdoors
(see Sections 2.8 through 2.11 for details).
Air Shutter
Enclosure
Filter
Housing
Automatic,
Regulator
and
Redundant
PRODUCTION
Gas Valve
Venturi
Mixture
Plenum
NOTE: The above diagram is a representation, actual venturi
assembly may vary depending upon heater size.
OUT OF
Blower
Motor
SIZES:
320M, 400M
with CSA B149.1 and all local codes that apply
(see Figure 3 for heater gas valve arrangement).
2. Check the rating plate to make sure the heater is
fitted for the type of gas being used. Laars
heaters are normally equipped to operate below a
2000 foot (610m) altitude. Heaters equipped to
operate at high altitudes have appropriate
stickers or tags attached.
3. The figures in Table 3 should be used to size the
gas piping from the gas meter to the heater.
Check local codes for BTU/h capacity required.
4. Install a sediment trap (drip leg) ahead of the gas
controls (see Figure 4). Fit the trap with a
threaded cap which can be removed for cleaning.
5. When required by code, install a second manual
gas shutoff valve. Do not remove manual shutoff
valve supplied with the heater.
6. Disconnect the heater and its individual shutoff
valve from the gas supply piping system during
pressure testing of the system at pressures higher
than 1/2 psi (3.5 kPa). Isolate the heater from the
gas supply piping system by closing its
individual manual gas shutoff valve during any
pressure testing of the gas supply piping system
at test pressures equal to or less than 1/2 psi
(3.5 kPa).
7. Gas supply pressures to the heater are listed in
Table 4.
Figure 3. Heater Gas Valve Arrangement.
2.6 Gas Supply and Piping
Review the following instructions before
continuing the installation.
1. Gas piping installation must be in accordance
with the latest edition of ANSI Z223.1/NFPA 54.
In Canada, the installation must be in accordance
Supply Pressure Natural Gas Propane Gas
Water Column
Minimum 5 127 9 229
Maximum 9 229 14 356
Table 4. Gas Supply Pressure Requirements.
in. mm in. mm
Page 6
LAARS Heating Systems
NOTE: The heater and all other gas appliances
sharing the heater gas supply line must be firing at
maximum capacity to properly measure the inlet
supply pressure. Low gas pressure could be an
indication of an undersize gas meter and/or
obstructed gas supply line.
8. Do not exceed the maximum inlet gas pressures
specified. Excessive pressure will result in
damage to the heater's gas controls. The
minimum pressures specified are for gas input
adjustment.
9. The correct differential gas pressure is stamped
on the rating plate. The regulator is preset at the
factory, but may need adjustment for altitude per
Section 3.
10. Before operating the heater, test the complete gas
supply system and all connections for leaks using
a soap solution.
CAUTION
Since some leak test solutions (including soap and
water) may cause corrosion or stress cracking,
rinse the piping with water after testing.
ATTENTION
La commande d’allumage fonctionne sur un
courant de 120V. Pensez-y lorsque vous travaillez
sur le chauffe-eau et prenez soin d’éviter tout
contact avec des pièces branchées sur le courant
qui causeraient une électrocution, conduisant à des
dégâts matériels, aux blessures voire à la mort.
OUT OF
PRODUCTION
Gas Supply
Inlet
Te e
Fitting
3 in.
(76mm) Min.
Figure 4. T-Fitting Sediment Trap Installation.
up a heat exchanger tube-cleaning maintenance
schedule to prevent heat exchanger tube cracking and
wear. Not fixing the condition may cause serious
damage to the heater and the water system.
Scaling is a layer on the inner surface of the heat
exchanger tubes which restricts the flow of water.
Scale can be any color or texture, smooth or rough,
granular or amorphous. Erosion is usually identified
by pitting, cavitation, ridges and “islands” on the inner
surfaces of the heat exchanger tubes. If this is caused
by extremely soft water, or a water softener in the
system, the internal copper surfaces will be very
shiny. Other chemicals, such as chlorine or chlorides
in the water, will cause dark patches of erosion.
NOTE: Laars does not warrant heat exchangers
damaged by scaling, corrosion, or erosion.
Nipple
Cap
To Equipment
Inlet
2.7 Water System Piping
2.7.1 Water Chemistry
Laars equipment is designed to be used in a
variety of water conditions. The water velocity in the
heat exchanger tubes is kept high enough to prevent
scaling from hard water, yet low enough to avoid
erosion by soft water. The water in 95 percent of the
urban centers in the United States is compatible with
this equipment, but in some areas a water supply will
contain a large quantity of scaling chemicals or the
water may be extremely soft or erosive. In rare
situations the water will contain both scaling
chemicals and erosive chemicals such as calcium or
sodium chloride. These conditions may be caused by
well water or a nearby pumping station, and the
particular condition may not be characteristic of the
entire city water system.
NOTE: It is possible to have hard and soft water in
the same city. Check with the local water company.
If an installer sees damage to any water handling
equipment at the installation site, it should be repaired
as soon as possible to help reduce maintenance costs.
If there is erosion, resize the pump to reduce water
velocity before the tube ruptures. If scaling is bad, set
2.7.2 Water Piping
Minimum inlet water temperature is 120°F
(49°C).
VW heaters are intended for heating large
volumes of water at constant flow rates, usually for
storage in a tank. Heaters in this type of application
are sometimes called circulating water heaters.
Figure 5 shows the VW heater with tank and two
pumps. One pump (recirculation) only circulates the
hot water through the building plumbing. The other
pump (heater) circulates water between the tank and
the heater. This heater circulating pump is essential for
proper operation of the heater (see Section 2.7.5).
The heater circulating pump must be sized to
provide enough flow to prevent damage to the heat
exchanger, and must handle the hardness or softness
of the water being heated. Generally, hard water must
be pumped at higher velocity; however, soft water will
erode holes in the heat exchanger tubing if pumped
too fast.
The Mighty Max VW heater comes standard
with copper tubes, but in areas where the water supply
is soft or corrosive, the heat exchanger should be
factory ordered with cupronickel tubes. Consult the
Mighty Max Volume Water Heater
Page 7
local factory representative or Laars factory for
additional information.
2.7.3 Pressure Buildup in Water System
The water utility supply meter may contain a
check valve, back flow preventer, or water pressure
reducing valve. This will create a closed water supply
system. Contact the water supplier or local plumbing
inspector on how to control this situation.
During the heating cycle of the heater, the water
expands creating a pressure buildup in the water
system. The pressure and temperature relief valve may
discharge hot water under these conditions, causing a
loss/waste of energy and a buildup of lime on the
relief valve seat.
NOTE: Do not plug the relief valve.
There are two methods to prevent the water
heater pressure relief valve from discharging hot water
in a closed water system:
1. Install a pressure relief valve on the cold water
supply line. Make sure that the discharge of this
valve is directed to an open drain and protected
from freezing.
2. Install a properly sized thermal expansion tank
on the cold water supply line.
2.7.4 Temperature and Pressure Relief
Valve
For protection against excessive pressure, the
water heater is equipped with a pressure relief valve.
storage vessel, a temperature and pressure relief valve
must be installed on the storage vessel. The
temperature and pressure relief valve must be designcertified by a nationally recognized testing laboratory
that maintains periodic inspection of listed equipment
or materials, in accordance with the requirements of
the standard for Relief Valves for Hot Water Supply
Systems, ANSI Z21.22 / CSA 4.4.
have a BTU/h (kW) capacity rating that is greater than
the BTU/h (kW) input of the water heater. The
temperature and pressure relief valve must be marked
with a maximum working pressure not to exceed the
maximum working pressure shown on the rating plate
of the water heater, or the maximum working pressure
of the separate storage vessel, whichever is the lower
pressure. The temperature and pressure relief valve
must have a maximum working temperature not to
exceed 210°F (99°C).
temperature and pressure relief valve and the storage
vessel.
quantities should circumstances demand.
PRODUCTION
When the water heater is connected to a separate
The temperature and pressure relief valve must
Do not place any shutoff valves between the
The relief valves discharge water in large
OUT OF
The discharge pipe:
1. Must not be connected directly to a drain. The
Discharge pipe must terminate 6 inches (152mm)
above a floor drain or external to the building. If
the discharge pipe is not directed to a drain or
other suitable means, the water flow may cause
property damage.
2. Must not be smaller than the pipe size of the
relief valve.
3. Must be of material capable of withstanding
210°F (99°C) without distortion.
4. Must be installed to allow complete drainage of
both the relief valve and discharge pipe.
5. Must not have any valve between the relief valve
and the end of the discharge pipe.
Do not thread, cap, plug, or block the end of the
discharge pipe. Do not install a reducing coupling or
other restrictions in the discharge pipe.
WARNING
Hot water can scald! Hot water can produce third
degree burns in 6 seconds at 140°F (60°C) and in
30 seconds at 130°F (54°C).
ATTENTION
Au moment de l’entretien des commandes, mettez
des étiquettes sur tous les fils avant de les
débrancher. Des erreurs de câblage peuvent
causer un fonctionnement inadéquat et dangereux.
Vérifier que tout fonctionne bien après votre
entretien.
Manually operate the relief valves at least once a
year. To prevent water damage, discharge pipe must
terminate at an adequate drain. Standing clear of the
outlet (discharge water may be hot), lift and release
the lever handle on the relief valve to make the valve
operate freely.
2.7.5 Pump Requirements
Table 5 specifies water flow rates for the
Mighty Max VW heaters, and the pumping head
required for typical piping configurations. Table 5
allows for 30 feet (9.1m) of piping and typical
fittings (see Figure 5). Piping with a shorter length or
larger diameter may reduce the head requirement and
pump power consumption. Contact a Laars
representative for assistance.
The correct flow rate can be verified by checking
the temperature rise of water as it passes through the
heater. To check the temperature rise, measure the
difference in water temperature between the heater
inlet and outlet to determine flow. For example: If a
Size 320M VW heater is installed and normal water is
used; the inlet water temperature is 160°F (71°C); the
outlet water temperature is 171°F (77°C). Then there
is a 11°F (6°C) degree temperature rise. Per Table 3,
Page 8
LAARS Heating Systems
Hot Water
To Bldg.
To Drain
Mighty Max
VW Heater
Thermal
Expansion
Tank
Cold
Water
Hot Water
Return From
Bldg.
NOTE: Intermittent pump must be used with EM2 and remote temperature control.
Figure 5. Water Piping Diagram.
this is essentially correct for normal water. If a higher
temperature rise is measured, flow must be increased
by changing the piping or pump.
2.7.6 Combined Space Heating/Potable
When using the Mighty Max VW heater as a
source of heat for a combined space heating/potable
water heating system, be sure to follow the
instructions of the space heating system.
Do not use water piping, fittings, valves, pumps,
and any other components which are not compatible
with potable water.
Do not connect the heater, which will be used to
supply potable water, to any heating system or
components previously used with a nonpotable water
heating system.
Do not add boiler treatment or any chemicals to
the heating system piping, since the piping contains
water for potable use.
Do not use solder containing lead in the potable
water lines.
If the space heating system requires water
temperatures greater than the water temperature for
potable hot water use, a tempering valve (see Figure 6)
PRODUCTION
Water Heating Systems
OUT OF
Conventional
Tank
Service
Valve
To Drain
Mixing Valve
Hot Water
From Water Heater
or Storage Tank
Figure 6. Installation of Tempering Valve.
or other means should be installed in the potable hot
water supply line to limit the risk of scald injury.
Some jurisdictions may require a backflow
preventer in the cold water line. In such cases, the
temperature and pressure relief valve may discharge
water due to expansion. An expansion tank approved
for potable water will eliminate this condition. Follow
the manufacturer's instructions for installation of the
expansion tank.
Pump
KEY
Valve
Check Valve
Gauge
Out Mixed Water
For Potable Use
Cold Water
Supply
Mighty Max Volume Water Heater
Page 9
2.8 Venting and Combustion Air
Information
Provisions for venting and supply of air for
venting and combustion must be done in accordance
with these instructions and applicable requirements of
the latest edition of ANSI Z223.1/NFPA 54. In
Canada, installation must be in accordance with CSA
B149.1, and applicable local codes.
There are a variety of ways to provide venting
and combustion air for the VW heater (see Figure 7).
The Mighty Max VW heater is certified as a true
direct vent unit when installed according to the
instructions for horizontal venting and ducted
combustion air. This can be done even if the runs are
vertical.
2.9 Top-to-Rear Vent Collar Conversion
The Mighty Max VW heater is shipped with the
vent collar on top of the heater. Follow this procedure
to convert it for rear connection (see Figure 8).
1. Remove the adapter plate from the top panel.
2. On the heater jacket, remove the top panel and
ease its lip from under the edge of the bonnet to
gain access to the flue collector.
3. Remove the vent collar/stack from the flue
collector. Do not damage the vent collar/stack
during removal.
4. Remove the blank plate from the rear of the
heater jacket.
5. Remove the blank plate from the rear section of
the flue collector. Be careful not to lose the
PRODUCTION
insulation attached to the plate.
6. Apply high temperature sealant and install the
blank plate (previously removed from the rear
section of the flue collector) on top of the flue
collector.
7. Install the blank plate (previously removed from
the rear of the boiler jacket) over the stack
opening on the top panel of the boiler.
OUT OF
8. Apply high temperature sealant (see Table 6) to
vent/collar stack and install on the rear of the
flue collector.
9. Slip the adapter plate over the vent collar/stack
and install it onto the rear heater jacket (see
Figure 8).
2.10 Venting
Venting must be in accordance with these
instructions and applicable requirements of the latest
edition of ANSI Z223.1/NFPA 54. In Canada,
installation must be in accordance with the latest
edition of CSA B149.1, and applicable local codes.
2.10.1 Vertical Venting - Category I
The Mighty Max VW heater has a “fan-assisted”
combustion system, so vertical vents must be installed
in accordance with the special code requirements for
Category I - Fan-Assisted Appliances. These
requirements can be found in the latest edition of
ANSI Z223.1/NFPA 54; Chapters 10 & 13 may be
referenced. In Canada, CSA B149.1 should be used
for guidance. These codes permit installation as a
single appliance or in combination with other
Category I appliances. However, there are very
important requirements for minimum and maximum
vent diameter and length. Make sure vertically-vented
installations comply with these codes.
NOTE: If a vent cannot be installed in accordance with
the requirements of these codes, it must be installed
as a horizontal vent, even if it is mainly vertical.
2.10.2 Vertical Venting - Non-Category I
When venting does not meet the code
requirements for Category I - Fan-Assisted Vertical
Vents, it can develop positive pressure. Such venting
must be installed in accordance with this section or
Section 2.10.3.
Soft or Normal Water Hard Water
Pipe Size Flow Headloss Temp, Rise Flow Headloss Temp. Rise
Model in. mm gpm L/m ft. m °F °C gpm L/m ft. m °F °C
0320M 1.5 38 51 193 25.9 8 10.5 6 68 257 46.0 14 7.9 4
2.0 51 51 193 13.9 4 10.5 6 68 257 24.7 8 7.9 4
0400M 1.5 38 51 193 26.0 8 13.1 7 68 257 46.3 14 9.8 5
2.0 51 51 193 14.1 4 13.1 7 68 257 25.0 8 9.8 5
Notes: 1. Pressure dop includes allowance for 30 feet 9.1m of piping and normal fittings. If piping is shorter or of larger
diameter, pump power may be reduced substantially. Contact Laars Representative for assistance.
2. Heaters for soft water application should be equipped with cupronickel heat exchangers.
Soft Water: 0 to 7.5 Grains/gallon
Normal Water: 7.5 to 17 Grains/gallon
Hard Water: More than 17 Grains/gallon
3. The temperature rise across the heater should never exceed 20°F (11°C). Minimum inlet water temperature is
120°F (49°C).
Table 5. Pump Requirements for Mighty Max VW Heaters.
Page 10
Term Description
Pipe Must comply with UL Standard 1738
such as type 29-4C stainless steel
Joint Sealing Follow vent manufacturer's
instructions
Insulation Recommended, but not required,
minimum R5 with protective cover
Table 6. Required Horizontal Venting Material.
The following requirements must be used for
Non-Category I venting:
1. Laars specified vent pipe material (Table 6) and
sizes (Table 7).
2. Pipe insulation and sealing tape.
3. Routing vent pipe through spaces which, except
for the terminal, remain above 60°F (16°C)
during heater operation.
OUT OF
2.10.3 Horizontal Venting - Non-Category I
When venting is horizontal, or cannot meet the
code requirements for Category I - Blower-Assisted
Vertical Vents, it can develop positive pressure and
must be installed in accordance with this section.
The following requirements must be used for
Horizontal Venting - Non-Category I:
1. Laars specified vent piping materials
(Table 6) and sizes (Table 7).
2. Laars side wall vent hood.
3. Pipe insulation and sealing tape.
4. Routing vent pipe through spaces which, except
for the terminal, remain above 60°F (16°C)
during heater operation.
2.10.4 Side Wall Vent Terminal
The side wall vent hood must be used when the
heater is vented through a side wall. It provides a
means of installing vent piping through the building
wall, and must be located in accordance with ANSI
Z223.1/NFPA 54 and applicable local codes. In
Canada the installation must be in accordance with
CSA B149.1 and local applicable codes (see Figure 9).
Consider the following when installing the terminal:
1. Locate the vent terminal so that it will not be
damaged by pedestrians and other traffic, and so
the discharge is not objectionable. The National
Fuel Gas Code requires a through-wall vent
terminal be at least 7 feet (2.1m) above grade if
located at a public walkway.
2. Locate the vent terminal so that vent gases
cannot be drawn into air conditioning system
inlets. The National Fuel Gas Code requires that
PRODUCTION
LAARS Heating Systems
it be at least 6 feet (1.8m) above any such inlet
that is within 10 feet (3m).
3. Locate the vent terminal so that vent gases
cannot enter the building through doors,
windows, gravity inlets or other openings. The
National Fuel Gas Code requires that it be
located at least 4 feet (1.2m) below, 4 feet (1.2m)
horizontally from, or 3 feet (0.9m) above such
openings.
4. Locate the vent terminal so that it cannot be
blocked by snow. The National Fuel Gas code
requires that it be at least 12 inches (305mm)
above grade, but the installer may determine it
should be higher depending on local conditions.
5. Locate the terminal so the vent exhaust does not
settle on building surfaces and other nearby
objects. Vent products may damage such
surfaces or objects. But the actual construction of
the vent terminal and the flow of vent products
must not be altered.
6. Locate the terminal at least 6 feet (1.8m)
horizontally from any gas or electric metering,
regulating, or relief equipment, or building
opening.
Mighty Max units are Category I fan-assisted
when vented vertically and adhering to all applicable
codes. Mighty Max units are not allowed to be vented
into a common horizontal vent system, unless a
properly-sized vent fan is used, and the common vent
system is properly designed by the vent fan
manufacturer or a qualified engineer.
When common venting Mighty Max fan-assisted
heaters with other appliances through one shared
vertical duct called a “common vent”, special care
must be taken by the installer to ensure safe operation.
In the event that the common vent is blocked, it is
possible, especially for fan-assisted devices, to vent
backwards through non-operating appliances sharing
the vent, allowing combustion products to infiltrate
occupied spaces. If the appliances are allowed to
operate in this condition, serious injury or death may
occur.
WARNING
Operation of appliances with a blocked common
vent may lead to serious injury or death. Safety
devices must be implemented to prevent blocked
common vent operation. If safe operation of all
appliances connected to a common vent cannot be
assured, including prevention of spillage of flue
gasses into living spaces, common venting should
not be applied, and appliances should each be
vented separately.
Loading...