Laars MIGHTY THERM2 MT2H Owner's manual

Installation and Operation Instructions Document 1231E
H2358000E
Installation and Operation
Instructions for
MIGHTY THERM2®
Hydronic Boiler
Model MT2H
Sizes 300, 400
Water Heater
Model MT2V
Sizes 200, 300, 400
WARNING
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.
FOR YOUR SAFETY: This product must be installed and serviced by a professional service technician,
qualified in hot water boiler 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. For indoor installations, as an
additional measure of safety, Laars strongly recommends installation of suitable Carbon Monoxide
detectors in the vicinity of this appliance and in any adjacent occupied spaces.
AVERTISSEMENT
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
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.

Page 2
TABLE OF CONTENTS
SECTION 1 General Information ...............3
1.A Introduction................................................ 3
1.B Model Identication.................................... 4
1.C Warranty .................................................... 4
1.D Dimensions................................................ 4
1.E Locating the Appliance............................... 4
1.F Locating Pump-Mounted Water Heater
with Respect to Storage Tank(s)................ 7
1.G Locating Pump-Mounted Boiler with
Respect to Return/Supply Header............. 7
1.H Locating Appliance for Correct Horizontal
Vent/Ducted Air Distance
From Outside Wall ..................................... 7
SECTION 2 Venting and Combustion Air .8
2.A Combustion Air .......................................... 8
2.A.1 Combustion Air From Room ...................... 8
2.A.2 Intake Combustion Air................................ 9
2.B Venting....................................................... 9
2.B.1 Vent Categories ......................................... 9
2.B.2 Category I Vent.......................................... 9
2.B.3 Common Venting Systems ........................ 9
2.B.4 Category III Vent...................................... 10
2.C Locating Vent & Combust Air Terminals... 10
2.C.1 Side Wall Vent Terminal........................... 10
2.C.2 Side Wall Combustion Air Terminal.......... 13
2.C.3 Vertical Vent Terminal .............................. 13
2.C.4 Vertical Combustion Air Terminal............. 13
2.D Common Vent Test — Boilers.................. 13
2.E Vent Terminals for Outdoor Units............. 14
SECTION 3 Gas Supply and Piping .......15
3.A Gas Supply and Piping ............................ 15
SECTION 4 Water Connections — .........16
4.A Boiler........................................................ 16
4.A.1 Heating System Piping:
Hot Supply Connections — Boiler ........... 16
4.A.2 Cold Water Make-Up — Boiler ................ 16
4.A.3 Water Flow Requirements — Boiler ........ 16
4.A.4 Freeze Protection — Boiler...................... 16
4.B Water Connections — Water Heater ....... 17
4.B.1 Water System Piping — Water Heater .... 17
---Suggested Piping Diagrams............17-19
4.B.2 Hot Water Supply Piping —Water Heater 20
4.B.3 Water Flow Requirements —.......................
Water Heater ........................................... 20
4.B.4 Combined Water Heating (potable)
and Space Heating — Water Heater ....... 20
4.B.5 Freeze Protection — Water Heater ......... 20
SECTION 5 Electrical Connections........24
5.A Main Power.............................................. 24
5.B Field Wiring.............................................. 24
5.C Low Water Cut-O󰀨 ................................... 24
5.C Logic Diagrams........................................ 25
5.C Wiring Diagrams ...................................... 26
SECTION 6 Operating Instructions ........28
6.A Filling the Boiler System .......................... 28
6.B Operating Temperature Control ............... 28
6.B.1 Temp Control on Boilers.......................... 29
6.B.2 Temp Control on Water Heaters.............. 30
6.C External Boiler Operations....................... 30
6.D Sequence of Operation............................ 31
6.E Ignition Control Reaction to Air Flow
/ Blocked Vent Pressure Switch............... 31
6.F Operating the Burner and Set-Up............ 31
6.F.1 Set-Up for 0 to 2500 Feet Altitude ........... 31
6.F.2 High Altitude Adjustment and Set-Up....... 32
6.G Shutting Down the Unit............................ 33
6.H To Restart the Unit................................... 33
SECTION 7 Maintenance.........................33
7.A System Maintenance ............................... 33
7.B Appliance Maintenance and Component
Description............................................... 33
7.B.1 Burners .................................................... 34
7.B.2 Filter......................................................... 34
7.B.3 Gas Valves............................................... 34
7.B.4 Manual Reset High Limit Control............. 34
7.B.5 Ignition Control......................................... 34
7.B.6 Ignitor....................................................... 34
7.B.7 Transformer ............................................. 35
7.B.8 Flow Switch.............................................. 35
7.B.9 Heat Exchanger Coil ............................... 35
SECTION 8 Trouble Shooting ..................36
8.A Resolving Lockouts.................................. 36
8.B Delayed Ignition — Possible Causes....... 36
8.C Short Cycling — Boiler............................. 36
8.D Short Cycling — Water Heater ................ 36
8.E High Gas Consumption............................ 36
SECTION 9 Replacement Parts ...............37
9.A General Information................................. 37
9.B Parts List.................................................. 37
LAARS Heating Systems

Page 3
SECTION 1 General Information
1.A Introduction
All installations must be made in accordance with:
1) In the U.S., the " National Fuel Gas Code "ANSI
Z223.1/NFPA54, Latest Edition and all applicable local
codes as required by the Authorities Having Jurisdiction
(AHJ), or
2) In Canada, the "Natural Gas and Propane Installation
Code", CSA B149.1, latest edition and all applicable local
codes as required by the AHJ.
All electrical wiring is to be done in accordance with:
1). In the U.S., the "National Electrical Code" (NEC),
ANSI/NFPA 70, latest Edition and all applicable local
codes as required by the AHJ, or
2). In Canada, the “Canadian Electrical Code - Part 1”,
CSA STD. C22.1 and all applicable local codes as required
by the AHJ.
This appliance must be electrically grounded in accordance
with the applicable codes and standards referenced above.
WARNING
To minimize the risk of electric shock, fire or
other hazards which could result in property
damage, injury, or death. The hydronic, boiler or
water heater must be installed in accordance
with the procedures detailed in this manual, or
the warranty may be voided. The installation
must conform to the requirements of the local
jurisdiction having authority, and, in the United
States, to the latest edition of the National Fuel
Gas Code, ANSI Z223.1/NFPA54. In Canada,
the installation must conform to the latest edition
of the Natural Gas and Propane Installation
Code, CSA B149.1 and/or applicable local
codes. Where required by the authority having
jurisdiction, the installation of unit, which must
conform to the Standard for Controls and Safety
Devices for Automatically Fired Boilers, ANSI/
ASME CSD-1. Any modifications to the boiler,
its gas controls, or wiring may void the warranty.
If field conditions require modifications, consult
the factory representative before initiating such
modifications.
AVERTISSEMENT
Afin de minimiser les risques d'électrocution,
d'incendie ou d'autres dangers qui pourraient
entraîner des dommages aux biens, des
blessures ou la mort. Le hydronique, une
chaudière ou un chauffe-eau doit être installé
conformément aux procédures détaillées dans
ce manuel, ou le chauffage garantie peut être
annulée. L'installation doit être conforme aux
exigences de la juridiction locale ayant l'autorité,
et, aux ÉTATS-UNIS , à la dernière édition du
National gaz combustible Code, ANSI Z223.1/
NFPA54. Au Canada, l'installation doit être
conforme à la dernière édition du gaz naturel
et propane Code d'Installation, CSA B149.1 et/
ou codes locaux. Lorsque requis par l'autorité
ayant juridiction, installation de l'unité, qui doit
être conforme à la norme pour les contrôles
et les dispositifs de sécurité automatiquement
pour chaudières, ANSI/ASME LA CDD-1. Toute
modification apportée à la chaudière, de ses
commandes de gaz, ou le câblage peut annuler
la garantie.
Mighty Therm2(200, 300, 400) Install & Operating
USING THIS MANUAL – Because the Mighty
Therm2 Boilers and Mighty Therm2 Water Heaters
are identical appliances, with the exception of
materials of manufacture, labels and ultimate use
application, this manual provides information
for the proper installation, operation and
maintenance of both products. Where dierences
exist between the application of the appliances and
their operation, the sections pertinent to only one
appliance or the other will be so identied.
In the Commonwealth of Massachusetts, this
appliance must be installed by a licensed plumber or
gas tter.
This manual provides information necessary
for the installation, operation, and maintenance of
Laars Heating Systems’ Mighty Therm2 copper tube
appliances, sizes 200-400 MBTU/hr (larger models are
covered in a separate manual). Read it carefully before
installation.
All application and installation procedures
should be reviewed completely before proceeding with
the installation. Consult the Laars Heating Systems
factory, or local factory representative, with any issues
or questions regarding this equipment. Experience
has shown that most operating issues are caused by
improper installation.
The Mighty Therm2 appliance is protected
against over pressurization. A pressure relief valve
is tted to all appliances. It is installed on the outlet
header, at the water outlet of the appliance.

Page 4
1.B Model Identication
Consult the rating plate on the unit. The
following information describes the model number
structure.
1.C Warranty
1.D Dimensions
See Figure 1 and Figure 2
1.E Locating the Appliance
The appliance should be located to provide
clearances on all sides for maintenance and inspection.
It should not be located in an area where leakage of
any connections will result in damage to the area
adjacent to the appliance or to lower oors of the
structure.
When such a location is not available, it is
recommended that a suitable drain pan, adequately
drained, be installed under the appliance.
The appliance is design certied by CSA-
International for installation on combustible ooring;
in basements; in closets, utility rooms or alcoves.
These Boilers or Water Heaters must never be
installed on carpeting. The location for the appliance
should be chosen with regard to the vent pipe lengths
and external plumbing. The unit shall be installed
such that the gas ignition system components are
protected from water (dripping, spraying, rain, etc.)
*
Outdoor installation of volume water heaters is not
permitted in Canada.
LAARS Heating Systems
Laars Heating Systems’ Mighty Therm2 boilers
and water heaters are covered by a limited warranty.
The owner should ll out the warranty registration
card and return it to Laars Heating Systems.
All warranty claims must be made to an
authorized Laars Heating Systems representative or
directly to the factory. Claims must include the serial
number and model (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.
Some accessory items are shipped in separate
packages. Verify receipt of all packages listed on
the packing slip. Inspect everything for damage
immediately upon delivery, and advise the carrier of
any shortages or damage. Any such claims should be
led with the carrier. The carrier, not the shipper, is
responsible for shortages and damage to the shipment
whether visible or concealed.
Model Character Designation
1-3 Model Series Designation
M T 2 = Mighty Therm2
4 Usage
H = Hydronic
V = Volume Water
5-8 Size
0 2 0 0 = 199,900 BTU/h input (MT2V only)
0 3 0 0 = 300,000 BTU/h input
0 4 0 0 = 399,900 BTU/h input
9 Fuel
N = Natural Gas
P = Propane
10 Altitude
A = 0-10,000 feet
11 Location
C = Indoor and Outdoor*
12 Firing Mode
C = On-O󰀨 (standard)
K = Two-stage (optional)
13 Revision
2 = Revision Level 2 (MT2H only)
3 = Revision Level 3 (MT2V only)
14 Heat Exchanger
B = Glass-lined CI / copper / brz trim (std. MT2V)
C = Glass-lined cast iron / copper (std. MT2H)
N = Glass-lined cast iron / cu-nickel
P = Glass-lined cast iron / cu-nickel / brz trim
2 = Glass-lined cast iron / copper, brz trim, HLW
5 = Glass-lined cast iron / cu-nickel / brz, HLW
15 Options Code
X = Standard unit
L = Low temperature control (std. MT2V)
16 Pump Options
X = No Pump
N = Pump mounted, normal water, Taco
S = Pump mounted, soft water pump (MT2V
only), Taco
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
M T 2 A C
SERIES
M T 2
USAGE
H
V
SIZE
0 2 0 0
0 3 0 0
0 4 0 0
FUEL
N
P
ALTITUDE
A
FIRING
MODE
C
K
LOCATION
C
REVISION
2
3
HEAT
EXCHANGER
B
C
N
P
2
5
OPTIONS
CODE
X
L
PUMP
OPTIONS
X
N
S

Page 5
Figure 1. Dimensional Data - Non Pump Mounted.
*Air and vent connections may be on the top or back of this appliance, and are eld convertible.
Model A Combustion Air Connection
B*
Vent Connection
C*
Horizontal
(Cat III)
Vent Pipe Size
in. cm in. cm in. cm in. cm
200 20.5 52 410 513 410
300 26.5 67 410 615 513
400 33.6 85 615 718 615
Dimensions shown in inches, cm.
Mighty Therm2(200, 300, 400) Install & Operating