Laars INDIRECT-FIRED User manual

238-43480-00E REV 01/08 Doc. 11045
INDIRECT-FIRED
WATER HEATER
A Spanish language version of these instructions is available by contacting
the manufacturer listed on the rating plate.
La version espanola de estas instruccions se puede obtener al escribirle a
la fábrica cuyo nombre aparece in la placa de especificaciones.
INSTALLATION/OPERATING MANUAL
WITH PARTS LISTING AND TROUBLESHOOTING GUIDE
For your family’s comfort, safety, and convenience, we
recommend this water heater be installed and serviced by a
plumbing professional.
WARNING
To avoid damage or injury, there
must be no materials stored
against the indirect water heater
and proper care shall be taken to
avoid unnecessary contact
(especially by children) with the
indirect water heater.
 Do not store or use
gasoline or other
flammable liquids in
the vicinity of this
water heater or any
other appliance.

2
CONGRATULATIONS!
You have just purchased one of the finest water heaters
on the market today!
This installation, operation, and instruction manual will
explain in detail the installation and maintenance of your
new Indirect water heater. We strongly recommend that
you contact a plumbing professional for the installation of
this water heater.
We require that you carefully read this manual, as well as
the enclosed warranty, and refer to it if questions arise.
If you have any specific questions concerning your
warranty, please consult the plumbing professional from
whom your water heater was purchased. For your
records we recommend that you write the model, serial
number and installation date of your water heater in the
back of this manual.
This manual should be kept with the water heater.
We’re committed to providing you with the finest water
heater made.

3
CAUTION
The maximum boiler water supply temperature to the indirect heat
exchanger must not exceed 240°F (115°C).
NOTICE
Insulation blankets are not required for this water heater. This
water heater meets or exceeds the ASHRAE/IES 90.1b standards with
respect to insulation and standby loss requirements.
TABLE OF CONTENTS
I- IMPORTANT INFORMATION…………….….. 4
II- SPECIFICATIONS………………………………. 8
III- GENERAL INFORMATION……………………. 12
IV- PRE-INSTALLATION…………………………… 15
V- WATER CONNECTIONS……………………….. 20
VI- ELECTRICAL CONNECTIONS……………….. 25
VII- OPERATING INSTRUCTIONS………………… 26
VIII- MAINTENANCE…………………………………. 29
IX- TROUBLESHOOTING GUIDE………………… 32
X- PARTS LIST………………………………………. 34
XI- NOTES…………………………………………….. 36

4
SECTION I
IMPORTANT INFORMATION
-READ CAREFULLY-
The equipment must be installed in accordance with those
installation regulations required in the area where the installation
is to be made. These regulations must be carefully followed in
all cases. Authorities having jurisdiction shall be consulted
before installations are made.
All wiring on water heaters installed in the USA must be in
accordance with the National Electrical Code and/or local
regulations; or in Canada, installed in accordance with the
Canadian Electrical Code and/or local regulations.
The following terms are used throughout this manual to bring
attention to the presence of hazards of various risk levels, or to
important information concerning product life.
DANGER
Indicates an imminently
hazardous situation, which,
if not avoided, will result in
death, serious injury, or
substantial property
damage.
WARNING
Indicates a potentially
hazardous situation, which,
if not avoided, could result
in death, serious injury, or
substantial property
damage.
CAUTION
Indicates a potentially
hazardous situation, which,
if not avoided, may result
in moderate, or minor
injury or property damage.
NOTICE
Indicates special
instructions on installation,
operation or maintenance,
which are important but
not related to personal
injury hazards.

5
Important Information continued-
DANGER
DO NOT store or use gasoline or other flammable, combustible, or
corrosive vapors and/or liquids in the vicinity of this or any other
appliance.
IF YOU SMELL GAS:
 DO NOT try to light any appliance.
 DO NOT touch any electric switch; do not use any
telephone in your building.
 Immediately call your gas supplier from a telephone in another
building. Follow the gas supplier’s instructions.
 If you cannot reach your gas supplier, call the fire department
DO NOT OPERATE THE APPLIANCE UNTIL THE LEAKAGE IS
CORRECTED!
Liquefied petroleum gas/propane gas is heavier than air and will
remain at floor level if there is a leak. Basements, crawl spaces,
closets, and areas below ground level will serve as pockets for
accumulation of leaking gas.
This water heater is supplied with an adjustable thermostat to control
water temperature. Hot water temperatures required for automatic
dishwasher and laundry use can cause scald burns resulting in serious
personal injury and/or death. The temperature at which injury
occurs varies with the person’s age and the time of exposure. The
slower response time of disabled persons increases the hazards to
them. NEVER allow small children to use a hot water tap or to draw
their own bath water. NEVER leave a child or disabled person
unattended in a bathtub or shower.

6
Important Information continued-
WARNING
Installation is not complete unless a pressure and temperature
relief valve is installed into the side of the water heater. See the
Water Connections section of this manual for details.
This water heater contains very hot water under high pressure.
Do not unscrew any pipe fittings or attempt to disconnect any
components of this water heater without positively assuring the
water is cool and has no pressure. Always wear protective
clothing and equipment when installing, starting up, or servicing
this water heater to prevent scald injuries. Do not rely on the
pressure and temperature gauges to determine the temperature
and pressure of the water heater. This water heater contains
components that become very hot. Do not touch any components
unless they are cool.
Improper installation, adjustments, alteration, service or
maintenance can cause property damage, personal injury or loss
of life. Failure to follow all instructions in the proper order can
cause personal injury or death. Read and understand all
instructions, including all those contained in component
manufacturer’s manuals, which are provided with the appliance
before installing, starting-up, operating, maintaining, or
servicing this appliance. Keep this manual and literature in
legible condition and posted near the appliance for reference by
owner and service technician.
This water heater requires regular maintenance and service to
operate safely. Follow the instructions contained in this manual.
Installation, maintenance, and service must be performed only
by an experienced, skilled, and knowledgeable installer or service
agency.
To comply with NSF requirements this water heater is to be:
a) Sealed to the floor with sealant, in a smooth and easily
cleanable way, or
b) Installed with an optional leg kit that includes legs and/or
extensions that provide a minimum clearance of 6”
beneath the water heater.

7
Important Information continued-
WARNING
It is the responsibility of the installing contractor to see that all
controls are correctly installed and are operating properly when
the installation is complete.
DO NOT operate the water heater with jumpered or absent
controls or safety devices.
DO NOT tamper with or alter the water heater and/or controls.
DO NOT operate the water heater if any external part has been
under water. Immediately call a qualified service technician to
inspect the appliance and to replace any part of the control
system that was under water.
This water heater is suitable for installation on combustible
flooring. DO NOT install this water heater on carpeting.
DO NOT operate this water heater without first being certain it
is filled with water.
Flammable items, pressurized containers, or any other potential
fire hazardous articles must never be placed on or adjacent to the
heater. Containers of flammable gases should not be stored or
used in the same room with this water heater.
Hydrogen gas can be produced in an operating water heater that
has not had water drawn from the tank for a long period of time
(generally two weeks or more). Hydrogen gas is extremely
flammable. To prevent the possibility of injury under these
conditions, we recommend that the water faucet be opened for
several minutes at the kitchen sink before you use any electrical
appliance that is connected to the hot water system. If hydrogen
is present, there will be unusual sounds such as air escaping
through the pipes as hot water begins to flow. Do not smoke or
have open flame near the faucet at the time it is open.

8
SECTION II
SPECIFICATIONS
Figure 1 – Tank Layout
Table 1: Water Heater Dimension (Inches)
MODEL A B C D E F
30-Gal. / Res. 22 33-5/8 28-1/4 34-3/8 5-3/8 27-1/2
40-Gal. / Res. 24 36 29-3/4 36-3/4 5-3/8 27-1/2
40-Gal. “R” / Res. 22 41-1/8 34-3/8 41-7/8 5-3/8 27-1/2
50-Gal. / Res. 26 36 29-3/4 36-3/4 5-3/8 27-1/2
50-Gal. “R” / Res. 22 46-1/4 40-1/8 47 5-3/8 27-1/2
65-Gal. / Res. 22 59-1/4 53-1/8 60 5-3/8 27-1/2
65-Gal. / Com. 22 59-1/4 53-1/8 60 5-3/8 47-3/4
80-Gal. / Res. 24 59 52-7/8 59-3/4 5-3/8 27-1/2
80-Gal. / Com. 24 59 52-7/8 59-3/4 5-3/8 47-3/4
120-Gal. / Com. 28-1/4 62-1/2 55-3/4 63-1/4 6-3/8 28-1/2
120-Gal. / Com. 28-1/4 62-1/2 55-3/4 63-1/4 6-3/8 48-3/4

9
Specifications continued-
Table 2: Water Heater Capacities
MODEL
Tank
Capacity
(Gal)
Coil
Volume
(Gal)
Dry Weight
(Lbs) Wet Weight (Lbs)
30-Gal. / Res. 30 2.7 140 404
40-Gal. / Res. 40 2.7 172 500
40-Gal. “R” / Res. 38 2.7 172 486
50-Gal. / Res. 50 2.7 196 610
50-Gal. “R” / Res. 48 2.7 180 576
65-Gal. / Res. 60 2.7 196 704
65-Gal. / Com. 58 5.0 265 768
80-Gal. / Res. 75 2.7 224 861
80-Gal. / Com. 73 5.0 293 920
120-Gal. / Res. 116 2.7 355 1324
120-Gal. / Com. 114 5.0 415 1370
Table 3: Water Heater Ratings
MODEL
First Hour
Rating
(Gal/Hr)
Continuous
Draw Rating
(Gal/Hr)
Standby
Heat Loss
Rating
(°F/Hr)
Minimum Heat
Output Rate of
the Heat Source
(BTU/Hr)
Minimum
Heat Source
Flow Rate
(Gal/Min)
30-Gal. / Res. 255 235 1.2 157,000 13.7
40-Gal. / Res. 260 235 1.1 157,000 13.7
40-Gal. “R” / Res. 260 235 1.1 157,000 13.7
50-Gal. / Res. 265 235 0.9 157,000 13.7
50-Gal. “R” / Res. 265 235 0.9 157,000 13.7
65-Gal. / Res. 275 235 0.8 157,000 13.7
65-Gal. / Com. 405 370 0.8 245,000 14.0
80-Gal. / Res. 295 235 0.6 157,000 13.7
80-Gal. / Com. 415 370 0.6 245,000 14.0
120-Gal. / Res. 315 235 0.4 157,000 13.7
120-Gal. / Com. 445 370 0.4 245,000 14.0
NOTES: These ratings were obtained with a heat source output rate
and flow rate as specified in Table 3 and a 180°F boiler water supply
temperature. Other results will be obtained under different conditions.

10
Specifications continued-
Table 4: Water Heater Performance
MODEL
Maximum First
Hour Rating
(Gal/Hr) @
140 °F 115 °F
Continuous
Draw Rating
(Gal/Min) @
140 °F 115 °F
Approximate
Boiler Output
Needed For
Ratings
(BTU/hr)
30-Gal. / Res. 279 429 4.2 6.7 220,000
40-Gal. / Res. 288 438 4.2 6.7 220,000
40-Gal. “R” / Res. 288 438 4.2 6.7 220,000
50-Gal. / Res. 297 447 4.2 6.7 220,000
50-Gal. “R” / Res. 297 447 4.2 6.7 220,000
65-Gal. / Res. 306 456 4.2 6.7 220,000
65-Gal. / Com. 534 820 8.0 12.8 420,000
80-Gal. / Res. 321 470 4.2 6.7 220,000
80-Gal. / Com. 546 834 8.0 12.8 420,000
120-Gal. / Res. 357 507 4.2 6.7 220,000
120-Gal. / Com. 583 871 8.0 12.8 420,000
NOTES: Based on 200 °F boiler water temperature and 50 °F potable
water inlet temperature.
Table 5: Water Heater Performance
MODEL
Hot Water
Availability
(Minutes)
Coil Heat
Transfer Area
(Sq Ft)
Pressure Drop at
Rated Heat Source
Flow Rate
(Feet of Head)
30-Gal. / Res. 5.5 14.2 1.5
40-Gal. / Res. 7.5 14.2 1.5
40-Gal. “R” / Res. 7.5 14.2 1.5
50-Gal. / Res. 9.0 14.2 1.5
50-Gal. “R” / Res. 9.0 14.2 1.5
65-Gal. / Res. 11.0 14.2 1.5
65-Gal. / Com. 10.5 27.2 5.0
80-Gal. / Res. 13.5 14.2 1.5
80-Gal. / Com. 13.2 27.2 5.0
120-Gal. / Res. 20.8 14.2 1.5
120-Gal. / Com. 20.6 27.2 5.0

11
Specifications continued-
NOTICE
If the boiler takes longer to heat up from a cold start than the
water availability as noted above, hot water shortage may occur.
Hot water availability is based off drawing 80% of the heated
tank volume at 4 gallons per minute flow rate.
The maximum heat transfer through the coil (heat input) of the
water heater at 240°F boiler water supply temperature and 210°F
potable water temperature is 94,100 Btu/hr for residential models
and 180,300 Btu/hr for commercial models. Potable water
temperature is limited to below 210°F and nominal water-
containing capacity is below 120 gallons for all indirect-fired
models.
Accordingly, per Part HLW-101.2, Section IV of the ASME
Boiler and Pressure Vessel Code, all indirect-fired products
listed are exempted from compliance with the code.

12
SECTION III
GENERAL INFORMATION
FEATURES
This water heater contains the following features:
HEAT EXCHANGER -- The heat exchanger (coil) has 1” NPT female
fittings.
These water heaters with single-wall heat exchangers meets the
Uniform Plumbing Code for installation in all potable water systems
provided that:
• The boiler water (including additives) is practically non-toxic, having
toxicity rating of class of 1 as listed in Clinical Toxicology of
Commercial Products.
• The boiler water pressure is limited to maximum 30 psig by approved
relief valve.
• The heat transfer medium is potable water or contains only substances
that are recognized as safe by the U.S. Food and Drug Administration
(FDA).
• The pressure of the heat transfer medium is maintained less than the
normal minimum operating pressure of the potable water system.
• The equipment is permanently labeled to indicate that only additives
recognized as safe by the FDA shall be used in the heat transfer
medium.
ADJUSTABLE AQUASTAT – The temperature may be adjusted from
80°F to 160°F. The aquastat (thermostat) was adjusted to 120°F before the
heater was shipped from the factory. It is recommended that lower
temperatures be used to avoid the risk of scalding. Refer to the “Warnings”
and the section on SCALDING in “Section VII – Operating Instructions.”
It is further recommended, in all cases, that the water temperature be set for
the lowest temperature that satisfies your hot water needs. This will also
provide the most energy efficient operation of the water heater and
minimizes scale formation.
Setting the water heater temperature at 120°F will reduce the risk of scalds.
Some states require settings to specific lower temperatures.

13
General Information continued-
TEMPERATURE AND PRESSURE RELIEF VALVE
WARNING
Keep clear of the combination temperature and pressure relief valve
discharge line outlet. The discharge may be hot enough to cause scald
injury. The water is under pressure and may splash. For protection
against excessive temperatures and pressure, install temperature and
pressure protective equipment required by local codes, but not less than a
combination temperature and pressure relief valve certified by a
nationally recognized testing laboratory that maintains periodic inspection
of production of listed equipment or materials as meeting the
requirements of the Standard for Relief Valves and Automatic Gas Shutoff
Devices for Hot Water Supply Systems, ANSI Z21.22 and the Standard
CAN1-4.4 Temperature, Pressure, Temperature and Pressure Relief
Valves and Vacuum Relief Valves. The combination temperature and
pressure relief valve must be marked with a maximum set pressure not to
exceed the maximum working pressure of the water heater. The
combination temperature and pressure relief valve must also have an
hourly rated temperature steam BTU discharge capacity not less than the
hourly rating of the water heater. The supplied combination temperature
and pressure relief valve, when properly installed and unrestricted, will
discharge the maximum input produced by a 240°F (115°C) boiler supply
temperature. A lower boiler supply temperature will reduce the input
required to be discharged in the event of excessive potable water
temperatures.
Install the combination temperature and pressure relief valve into the
opening provided and marked for this purpose on the water heater.
Some models may already be equipped or supplied with a temperature
and pressure relief valve. Verify that the combination temperature and
pressure relief valve complies with local codes. If the temperature and
pressure relief valve does not comply with local codes, replace it with one
that does.

14
General Information continued-
SACRIFICIAL ANODES—Three sacrificial anode rods have been
installed in the tank head to extend tank life. The anode rods should be
inspected annually to determine the amount of sacrificial decay and replaced
when necessary to prolong tank life. Water conditions in your area will
influence the time interval for inspection and replacement of the anode rod.
The use of a water softener may increase the speed of anode consumption.
More frequent inspection of the anode is needed when using softened (or
phosphate treated) water. Contact the plumbing professional who installed
the water heater or the manufacturer, listed on the rating plate, for anode
replacement information.
WARNING
Install a discharge line so that water discharged from the temperature
and pressure relief valve will exit within six (6) inches above, or any
distance below, the structural floor and cannot contact any live electrical
part. The discharge line is to be installed to allow for complete drainage
of both the temperature and pressure relief valve and the discharge line.
The discharge opening must not be subjected to blockage or freezing.
DO NOT thread, plug, or cap the discharge line. It is recommended
that a minimum clearance of four (4) inches be provided on the side of
the water heater for servicing and maintenance of the combination
temperature and pressure relief valve
Do not place a valve between the combination temperature and
pressure relief valve and the tank!

15
SECTION IV
PRE-INSTALLATION
UNPACKING
INSPECT SHIPMENT carefully for any signs of damage. If
damage is noted, do not install the product. Contact the shipper or
manufacturer. All equipment is carefully manufactured, inspected,
and packed. Our responsibility ceases upon delivery of the packaged
heater to the carrier in good condition.
NOTE: Any claims for damage or shortage in shipment must be filed
immediately against the carrier by the consignee.
IMPORTANT DECISIONS REQUIRED BEFORE
INSTALLATION
SIZING
1. Boiler DOE Heating Capacity – The indirect-fired water heater will
provide the rated performance only if used in conjunction with a heat
source with a DOE heating capacity (Boiler Output) at least as much
as the minimum noted in Table 3. If the heat source has less capacity,
the output of the tank will be reduced. To determine the approximate
reduction in output from the tank use the following formula:
New Rating = (maximum continuous draw rating) x
Actual Boiler Output Capacity
Minimum Boiler Output Capacity
For example, what would the continuous draw rating be if a 50-gallon
indirect-fired heater were installed with a heat source having a DOE
heating capacity of 125,000 BTU/h?
Answer:
New Rating
= 235 gal/hr x (125,000 BTU/h)/(157,000 BTU/h)
= 235 gal/hr x 0.796 = 187 gal/hr

16
Pre-installation continued-
NOTICE
Increasing the boiler DOE heating capacity above the values listed
in Table 3 will not increase the rating of the water heater.
2. Circulator Sizing – Refer to Table 5 for the corresponding
pressure drop through the coil for the given model. Calculate the
pressure drop of all straight pipe and fittings on the supply and
return of the water heater at the selected flow rate. Add the
piping/fitting pressure drop to the pressure drop through the water
heater coil.
Select a circulator that will provide an appropriate flow rate at the
combined pressure drop.
SYSTEM ZONE CONTROL
The indirect-fired water heater must be installed as a zone separate
from the space heating system. The domestic hot water zone’s piping
and circulator must be sized for a minimum flow rate with all zones
in use and a maximum flow rate with only the water heater in use.
For this reason, the preferred method of zone control is with
circulators.
1. Circulators – With space heating zones using circulators, the
indirect-fired heater should be added as an additional zone with a
circulator.
2. Zone Valves – Select a valve with a low-pressure drop to assure
adequate flow through the water heater.
3. Hybrid – The space heating zone can be zoned using zone valves
and the indirect-fired heater zoned with a circulator.

17
Pre-installation continued-
DOMESTIC HOT WATER PRIORITY
Two options are available, Priority and Non-Priority.
1. Priority – Demand for space heating is interrupted or postponed
until the domestic hot water demand is satisfied. This option
provides maximum delivery of domestic hot water. Priority is
recommended when:
a) Boiler net output is 100,000 Btu per hour or less, or
b) When boiler output required to satisfy domestic hot water
demand is at least 50% of the boiler output required to satisfy
space heating demand, or
c) When an interruption in space heating can be tolerated during a
long domestic hot water draw.
2. Non-Priority – Boiler output is divided between space heating
and domestic hot water heating. Delivery of domestic hot water
can be reduced during simultaneous space and domestic hot water
heating operations, depending on such factors as boiler output,
boiler over-sizing, number of space heating zones calling for heat,
and the ratio of domestic hot water load to space heating load.

18
Pre-installation continued-
Component Location
Clearance from Combustible Materials
Top Sides Front Rear
0” 0” 0” 0”
Table 6 – Combustible Material Clearances
Recommended Service Clearances
Non-Piping
Side Front (Aquastat) Rear T & P Relief Valve Side
4” 16” 0” 4”
Table 7 – Service Clearances
CAUTION
This water heater must be located in an area where leakage of the tank,
water line connections, or the temperature and pressure relief valve
will not result in damage to the area adjacent to the water heater or to
lower floors of the structure. When such locations cannot be avoided,
a suitable drain pan must be installed under the water heater. The
drain pan depth must be suitable for draining and collecting water, and
have a minimum length and width of at least four (4) inches measured
from the jacket of the water heater. The drain pan, as described above,
can be purchased from your plumbing professional. The drain pan
must be piped to an adequate drain. The piping must be at least ¾ inch
in diameter and pitched for proper drainage.
CAUTION
Do not drop water heater. Do not bump water heater jacket against
floor.

19
Pre-installation continued-
Appliance Location
1. Boiler Location – Locate the indirect-fired water heater as close
to the boiler as practical.
2. Fixture Locations – For fastest delivery of hot water, place the
indirect-fired water heater close to points of use.
Additional Recommended Components
1. Shut-off Valves – Allows isolation of water heater from
domestic water system and/or boiler system during service.
2. Unions – Allows water heater movement during service if
adequate clearance cannot be provided.
3. Thermal Expansion Tank – If the water heater is installed in a
closed water supply system, such as one having a back-flow
preventer in the cold water line, provide thermal expansion
control. Contact the water supplier or local plumbing inspector
for additional information.
MOVE THE WATER HEATER TO A PERMANENT
POSITION BY SLIDING OR WALKING.
WARNING
Do not plug the inlet and outlet tappings of tankless heater left
installed in the boiler.
NOTICE
For California installation this water heater must be braced, anchored,
or strapped to avoid falling or moving during an earthquake. See
instructions for correct installation procedures. Instructions may be
obtained from California Office of the State Architect, 400 P Street,
Sacramento, CA 95814.

20
SECTION V
WATER CONNECTIONS
WARNING
FAILURE TO INSTALL AND MAINTAIN A NEW, LISTED
TEMPERATURE AND PRESSURE RELIEF VALVE WILL
RELEASE THE MANUFACTURER FROM ANY CLAIM WHICH
MIGHT RESULT FROM EXCESSIVE TEMPERATURE AND
PRESSURES.
Hydrogen gas can be produced in an operating water heater that has
not had water drawn from the tank for a long period of time.
HYDROGEN GAS IS EXTREMELY FLAMMABLE. To prevent
the possibility of injury under these conditions, we recommend the
hot water faucet be opened for several minutes at the kitchen sink
before you use any electrical appliance that is connected to the hot
water system. If hydrogen is present, there will be an unusual sound
such as air escaping through the pipes as hot water begins to flow.
Do not smoke or have open flame near the faucet at the time it is
open.
Keep clear of the temperature and pressure relief valve discharge line
outlet. The discharge may be hot enough to cause scald injury. The
water is under pressure and may splash.
CAUTION
If sweat fittings are to be used, DO NOT apply heat to the nipples on
top of the water heater. Sweat the tubing to the adapter before fitting
the adapter to the water connections. It is imperative that heat is not
applied to the nipples containing a plastic liner.