Laars MagnaTherm HTD Series User manual

Installation and Operation Instructions Document 1422
H2397100-
FOR YOUR SAFETY: This product must be installed and serviced by a professional service technician,
qualied in hot water boiler and heater installation and maintenance. Improper installation and/or operation
could create carbon monoxide gas in ue gases which could cause serious injury, property damage, or
death. Improper installation and/or operation will void the warranty.
WARNING
If the information in this manual is not
followedexactly,areorexplosionmayresult
causing property damage, personal injury or
loss of life.
Do not store or use gasoline or other
ammable vapors and liquids in the vicinity of
this or any other unit.
WHAT TO DO IF YOU SMELL GAS
• Do not try to light any unit.
• 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 re department.
Installation and service must be performed by
a qualied installer, service agency, or gas supplier.
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 inammables 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 êtes.
• 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 service des incendies.
L’installation et l’entretien doivent être assurés par un
installateur ou un service d’entretien qualié ou par le
fournisseur de gaz.
Installation and Operation Instructions for
Boiler
with VARI-PRIME®
Model MGH1600
1,600 MBTU/h
Model MGH2000
1,999 MBTU/h
Model MGH2500
2,499 MBTU/h
Model MGH3000
3,000 MBTU/h
Model MGH3500
3,500 MBTU/h
Model MGH4000
4,000 MBTU/h
Water Heater
______________
Model MGV1600
1,600 MBTU/h
Model MGV2000
1,999 MBTU/h
Model MGV2500
2,499 MBTU/h
Model MGV3000
3,000 MBTU/h
Model MGV3500
3,500 MBTU/h
Model MGV4000
4,000 MBTU/h
HTD
20:1 Turndown. Laars Linc®
MODULATING AND CONDENSING

LAARS Heating Systems
i
TABLE OF CONTENTS
SECTION 1 General Information
1.A Introduction...........................................1
1.B Model Identication .............................1
1.C Warranty...............................................1
1.D Safety Notes.........................................2
1.E Unit Overview.......................................4
1.F Gas Train Components ........................5
1.G Venting Dimensions & Sizing ...............6
1.H Dimensions...........................................6
1.I Unpacking and the Install Kit................8
1.J Locating the Unit ..................................8
1.K Clearances...........................................9
SECTION 2 Venting and Combustion Air
2.A General Venting Information...............10
2.B Vent and Air Pipe Material..................10
2.B.1 Venting Reqs Unique to Canada........10
2.B.1.a Flue Gas Sampling Port -...................10
2.B.1.b Exhaust Vent Terminal - ..................... 11
2.C Vent and Air Pipe Sizing.....................12
2.C.1 Category lV Vent Sizes.......................13
2.C.2 Category II Vent Sizes........................13
2.C.3 Common Venting................................13
2.C.4 Common Vent Test.............................14
2.C.5 Combustion Air...................................15
2.C.5.a Combustion Air From Room...............15
2.C.5.b Ducted Combustion Air.......................16
2.D Locating the Vent
and Combustion Air Terminals............16
2.D.1 Side-wall Vent Terminal......................16
2.D.2 Side-wall Combustion Air Terminal.....18
2.D.3 Vertical Vent Terminal.........................18
2.D.4 Vertical Combustion Air Terminal........18
2.E Outdoor Installation............................19
2.F Installations in the
Commonwealth of Massachusetts .....19
SECTION 3 Gas supply and Piping
3.A Gas Supply and Piping.......................20
3.B Gas Pipe Sizing..................................21
SECTION 4 Water Flow & Headloss Data..
4.A General Water Flow Information ........22
4.B Boiler Water Flow & Headloss Data...22
4.C Water Heater Water Flow
and Headloss Data.............................23
SECTION 5 Piping
5.A Boiler Water Piping.............................24
5.A.1 Boiler Water Connections...................24
5.A.2 Cold Water Make-Up..........................24
5.A.3 Freeze Protection...............................24
5.A.4 Suggested Boiler Piping Schematics .25
5.B Water Heaters ....................................29
5.B.1 Water Quality......................................29
5.B.2 Heater Water Connections.................29
5.B.3 Cold Water Make-Up..........................29
5.B.4 Freeze Protection...............................30
5.B.5 Suggested Piping Schematics............30
SECTION 6 Condensate Drain Trap.......32
6.A Condensate Trap Instructions ............33
SECTION 7 Electrical Connections
7.A Installation Warnings..........................34
7.B Main Power Connections ...................35
7.C Main Power Data................................36
7.D Control Panel Layout..........................36
7.E Field Connections...............................36
7.E.1 Power.................................................36
7.E.2 Dry Contacts.......................................36
7.E.3 Temperature Sensors.........................38
7.E.4 Heat Demands ...................................39
7.E.5 Analog In and Analog Out ..................39
7.E.6 Dry Contacts. Run & Alarm ................39
7.E.7 RS 485, Cascade...............................40
7.E.8 RS485 BMS........................................40
7.F Modbus to BACnet Memory Map.......41
7.G Wiring Diagrams.................................44
7.H High Voltage Wiring Diagrams ...........48
7.I Ladder Diagrams................................55
SECTION 8 Control Operation
8.A The Home Screen.............................62
8.A.1 Home Screen Active Icons.................62
8.A.2 Keypad Operations.............................63
8.B Login to Lock / Unlock the Display.64
8.C Quick Start ......................................65
8.C.1 Quick Start CH (Central Heat)............65
8.C.2.a Quick Start CH1 (Central Heat, One).66
8.C.2.b Quick Start CH2 (Central Heat, Two).66
8.C.2 Quick Start DHW (Dom Hot Water)....66
8.C.3 Outdoor Reset ...................................67
8.C.4 Warm Weather Shut Down ................67

HTD
ii
Section 8 (continued)
8.C.5 Anti-Short Cycle ................................68
8.C.6 Time & Date ......................................68
8.D Conguration ..............................69
8.D.1 CH (Central Heat)...............................70
8.D.1.a CH1 (Central Heat, One)....................70
8.D.1.a.3 PID Parameters................................71
8.D.1.b CH2 (Central Heat, Two)....................71
8.D.2 DHW (Domestic Hot Water) ..............71
8.D.3 Outdoor Reset ...................................72
8.D.4 Cascade (Lead / Lag) ..................73-77
8.D.4.a Cascade CH (Central Heat) ..............78
8.D.4.a.1 Cascade CH Lead Settings................79
8.D.4.a.1.A Cascade Base / Drop Load.............80
8.D.4.b Cascade DHW (Dom Hot Water) .......80
8.D.4.c Cascade Rotation ..............................81
8.D.4.c.1 Cascade Rotation Setup ...................81
8.D.4.d Cascade Redundancy........................82
8.D.5 Hybrid.................................................82
8.D.6 Pumps................................................83
8.D.6.a DHW Recirculation.............................84
8.D.6.b VARI-PRIME.......................................84
8.D.7 Manual Firing Rate ............................85
8.D.8 Temp Limits .......................................85
8.D.8.a Delta T Parameters............................86
8.D.8.b Flue Limitation Parameters ................86
8.D.8.c Outlet Limitation Parameters..............86
8.D.9 External .............................................87
8.D.9.a External – Remote Set Point..............88
8.D.9.b External Firing Rate............................89
8.D.10 Time & Date ......................................89
8.D.11 Miscellaneous Features ..................90
8.D.11.a Demand Priority ................................91
8.D.11.b Anti-Short Cycle .................................91
8.D.11.c Warm Weather ...................................92
8.D.11.d COM Port, BMS .................................93
8.D.11.e Temperature Conversion ...................94
8.D.11.f Anti-Frost ...........................................94
8.D.11.g Trim (O2Trim Enable / Disable) .......95
8.D.12 Login ..................................................95
8.E Service Screens..........................96
8.E.1 Burner.................................................96
8.E.2 Digital I/O ( Input / Output ) ...............97
8.E.3 Analog I/O ..........................................98
8.E.4 Screen Settings Timeout....................99
8.E.5 History................................................99
8.E.6 Restart Touchscreen & Recalibrate....99
8.E.7 Factory Reset...................................100
8.E.8 HMI Model OEM only. .....................100
8.E.9 BIC Model OEM only.......................100
8.E.10 Both Model. OEM only. ...................100
8.E.11 About About the Firmware version. 100
8.E.12 O2 (Trim Set Point) ..........................100
8.E.13 LMV..................................................100
8.F Messages and USB........................101
8.F.1 Messages.........................................101
8.F.2 USB Functionality.............................101
8.G Active Demands .............................102
SECTION 9 Parameter Tables...............103
SECTION 10 Initial startup Instructions
10.A Filling the Boiler System...................109
10.B Initial Operation................................ 110
10.B.1 Initial Burner Operation .................... 110
10.B.2 Combustion Setup Procedure
Hi Fire, Low Fire................................111
10.C Shutting Down the Unit..................... 113
10.D Restarting the Unit............................ 113
10.E Controllers........................................ 113
10.F Transmitters ..................................... 114
SECTION 11 Maintenance
11.A System Maintenance ....................... 115
11.B Maintenance Notes .......................... 115
11.B.1 Burner............................................... 115
11.B.2 Gas Train Components .................... 115
11.B.3 Controller.......................................... 116
11.B.4 Spark Ignition Electrodes ................. 116
11.B.5 Flame Sensor................................... 116
11.B.6 Blower Model 1600........................... 116
11.B.7 Blower Model 2000-4000 ................. 116
11.B.8 Heat Exchanger Tubes..................... 117
11.B.9 Gas Pressure Switches.................... 117
11.B.10 Pressure Transmitters...................... 118
11.B.11 Oxygen Sensor................................. 118
11.B.12 High Temperature Limits (optional) .. 118
SECTION 12 Troubleshooting
12.A Lockouts and Errors ........................ 119
12.B LMV Errors.......................................121
SECTION 13 Replacement Parts
13.A General Information..........................126
13.B Component Illustrations, Parts Lists,
and Part Numbers...................126 - 140

LAARS Heating Systems

Page 1
HTD
This manual includes information which will help you
to install, operate, and maintain the Laars Heating
Systems MagnaTherm HTD. Please read this manual
completely before proceeding with the installation.
If you have any questions regarding this equipment,
please contact Laars Heating Systems, or your local
Laars representative. Experience has shown that most
operating problems are caused by improper installation.
LAARS Heating Systems MagnaTherm HTD boilers and
volume water heaters are covered by a limited warranty.
The owner should complete the warranty registration at
http://www.LAARS.com
ALL WARRANTY CLAIMS must be made by an
authorized LAARS Heating Systems representative.
Claims must include the serial number and model (this
information can be found on the rating plate). All claims
must also include the installation date and name of the
installer. Shipping costs are not included in the warranty
coverage.
SECTION 1 General Information
Rating Plate
1.A Introduction
1.B ModelIdentication
Primary information regarding your unit can be found
on the Rating Plate on the outside face of the
right-side panel.
1.C Warranty
1 2 3 4 5 6 7 8 9 10 11 12 13
M G 3
M G 1 6 0 0
2000
2500
3000
3500
4000
X- std MGH, 75psi PRV, H-Stamp N- MGV w/ H-Stamp, 30psi PRV
W- std MGV, 125psi PRV, HLW-Stamp P- MGV w/ H-Stamp, 50psi PRV X- None H- Gateway LONworks
A- 30psi PRV R- MGV w/ H-Stamp, 60psi PRV A- Gateway, BACnet IP* & alarm bell
B- 50psi PRV S- MGV w/ H-Stamp, 75psi PRV B- Gateway, LONworks J- Gateway LONworks
C- 60psi PRV T- MGV w/ H-Stamp, 125psi PRV C- Alarm bell & high limits
D- MGV 75psi PRV U- MGV w/ H-Stamp, 150psi PRV D-
Auto & manual
K- Gateway LONworks
E- MGH 125psi PRV 2- Flange kit, MGV w/ H-Stamp, 30psi PRV high limits & alarm bell
F- 150psi PRV
3- Flange kit, MGV w/ H-Stamp, 50psi PRV E- Gateway BACnet IP* & high limits
G- Flange kit & 30psi PRV
4- Flange kit, MGV w/ H-Stamp, 60psi PRV & alarm bell L- Alarm & high limits
H- Flange kit & 50psi PRV
5- Flange kit, MGV w/ H-Stamp, 75psi PRV F- Gateway BACnet IP*
J- Flange kit & 60psi PRV 6- Flange kit, MGV w/ H-Stamp, 125psi PRV & high limits *BACnet Gateway is
K- Flange kit & 75psi PRV 7- Flange kit, MGV w/ H-Stamp, 150psi PRV G- Gateway BACnet IP* used for BACnet IP
L- Flange kit & 125psi PRV & alarm bell and Modbus TCP/ IP
M- Flange kit & 150psi PRV & high limits
Model Nomenclature
Series
Size / MBH
H- CSD-1
G- Standard
Construction
N- Nat
Fuel
V - Volume Water
Usage
H - Hydronic
B- 220/240V, single ph (1600-2000)
F- 208V, single ph (1600-2000)
A- 120V, single ph (1600-2000)
Electrical System
3- Third
Revision
Additional Options
Waterway Options
D- 480V, three ph (2000-4000)
E- 600V, three ph (2000-4000)
C- 208V, three ph (2000-4000)
MagnaTherm

LAARS Heating Systems
Page 2
WARNING
Carbon Monoxide Hazard
Improper adjustment of the burners may lead to poor
combustion quality, increasing the amount of carbon
monoxide produced. Excessive carbon monoxide
levels may lead to personal injury or death.
WARNING
This unit must be installed in accordance with the
procedures detailed in this manual, or the manufacturers
warranty will 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 CSAB149.1 Natural Gas and Propane Gas
Installation Code, and/or local codes. Where required
by the authority having jurisdiction, the installation of
these units must conform to the Standard for Controls
and Safety Devices forAutomatically Fired Boilers,
ANSI/ASME CSD-1. Any modi cations to the boiler, its
gas controls, or wiring may void the warranty. If  eld
conditions require modi cations, consult the factory
representative before initiating such modi cations.
WARNING
• Water temperature over 125°F (52°C) can cause
severe burns instantly or death from scalds.
• Children, disabled and
elderly are at highest
risk of being scalded.
• See instruction manual
before setting temperature
at the unit.
• Feel water before bathing
or showering.
• If this unit is used
to produce water that could scald if too hot, such
as domestic hot water use, adjust the outlet control
(limit) or use temperature limiting valves to obtain a
maximum water temperature of 125°F (52°C).
WARNING
The inlet gas pressure to the unit must not
exceed 13” W.C. (3.2kPa).
WARNING
Fire or Explosion Hazard
Improper con guration can cause fuel buildup and
explosion. Improper user operation may result in
property loss, severe physical injury, or death.
Any changes to safety-related con guration
parameters must only be done by experienced and/or
licensed burner/boiler operators and mechanics.
If any odor of gas is detected, or if the gas burner does
not appear to be functioning in a normal manner, close
the main gas shuto󰀨 valve. Do not shut o󰀨 the power
switch. Contact your heating contractor, gas company,
or factory representative.
NOTE: This unit is protected against hydronic
over-pressurization. A pressure relief valve is included
with each unit.
WARNING
Indicates an imminently hazardous situation which, if not
avoided, can or will result in death or serious injury and can
or will result in catastrophic property damage.
CAUTION
Indicates a potentially hazardous situation which, if not avoided,
may result in moderate injury and/or property damage.
NOTE:
Indicates instructions that are important to that topic but not
related to personal injury or property damage.
Safety Notes are used thoughout this manual to bring attention to the presence of hazards with various risk
levels and to o󰀨 er important information concering the life of this product. There are 3 basic types.
WARNING
CANCER AND REPRODUCTIVE HARM.
WWW.P65WARNINGS.CA.GOV.
AS REQUIRED BY THE STATE OF
CALIFORNIA PROPOSITION 65.
1
2
3
1.D Safety Notes

Page 3
HTD
WARNING
Electrical Shock Hazard
Electrical shock can cause severe injury, death or
property damage. Disconnect the power supply before
beginning installation or changing the wiring to prevent
electrical shock or damage to the equipment. It may be
necessary to turn o󰀨 more than one power supply
to disconnect.
All electrical wiring is to be done in accordance with
local codes, or in the absence of local codes, with: 1)
The National Electrical CodeANSI/NFPANo. 70 - latest
Edition, or 2) CSASTD. C22.1 “Canadian Electrical Code
- Part 1.” This appliance must be electrically grounded in
accordance with these codes.
WARNING
The Repair Parts list designates parts that contain
refractory ceramic  bers (RCF). RCF has been classi ed
as a possible human carcinogen. When exposed to
temperatures above 180ºF, such as during direct  ame
contact, RCF changes into crystalline silica, a known
carcinogen. When disturbed as a result of servicing or
repair, these substances become airborne and, if inhaled,
may be hazardous to your health.
Do not remove or replace RCF parts or attempt any
service or repair work involving RCF without wearing
the following protective gear:
1. ANational Institute for Occupational Safety and
Health (NIOSH) approved respirator.
2. Long sleeved, loose  tting clothing.
3. Gloves.
4. Eye Protection.
NOTE: All installations must be made in accordance with
1)American National Standard Z223.1/NFPA54-Latest
Edition “National Fuel Gas Code” or
2) CSAB149.1 “Natural Gas and Propane Installation
Code” or in Canada reference the B149.1 latest
edition and with the requirement of the local utility or
other authorities having jurisdiction. Such applicable
requirements take precedence over the general
instructions contained herein.All electrical wiring is to
be done in accordance with the local codes, or in the
absence of local codes, with: 1) The National Electrical
CodeANSI/NFPANo. 70-latest Edition, or
2) CSASTD. C22.1 “Canadian Electrical Code - Part
1”. This appliance must be electrically grounded in
accordance with these codes.
CAUTION
The supply voltage to this unit must not be
disengaged, except for service or isolation, or
unless otherwise instructed by procedures outlined
in this manual. To signal a call for heat, use the
correct terminals as instructed in the Electrical
Connections, Field Wiring 7.E on page 36 of this
manual.

LAARS Heating Systems
Page 4
Shown with front doors
and side panels removed.
Spark
Generator
Control Panel
Heat Exchanger
Air Intake
and Filter
Water Outlet
Water Inlet
Vent
Power Pack Drain
Condensate
Trap
O2 Sensor
Gas Supply
Valve
Main Power
Connections
Field
Electrical
Connections
Blower
Pressure
Transmitters
On all models, the Control Panel hinges forward for
easy access to wiring and to the heat exchanger.
1.E Unit Overview

Page 5
HTD
Manual
Gas Valve
Manual
Gas Valve
Pilot
Gas Valve
Gas Inlet Gas
Valve
Gas Inlet
Air / Fuel Mixer
Gas Solenoid
Low Gas Pressure Switch
(Press to Re-Set)
Low Gas Pressure
Switch
(Press to Re-Set)
High Gas Pressure
Switch
(Press to Re-Set)
High Gas Pressure
Switch
(Press to Re-Set)
Fuel Damper
Air Damper
Pressure Regulator
& Shut-o󰀨
The Gas Train for all sizes has the same layout. These two views of the gas train show the linear path
of the gas around the front of the unit to the Air Mixing Valve and then into the blower.
View 1
View 2
1.F Gas Train Components

LAARS Heating Systems
Page 6
Model A B C D E
1600
29.3 (
75
)79.8 (
203
)38.0 (
96
)57.5 (
147
)49.8 (
126
)
2000
29.3 (75)79.8 (203)38.0 (96)57.5 (147)49.8 (126)
2500
30.8 (78)87.0 (221)41.5 (105)60.5 (154)60.8 (154)
3000
30.8 (78)87.0 (221)41.5 (105)60.5 (154)60.8 (154)
3500
34.5 (
88
)97.5 (
248
)52.0 (
133
)70.0 (
178
)60.8 (
154
)
4000
34.5 (
88
)97.5 (
248
)52.0 (
133
)70.0 (
178
)60.8 (
154
)
inches (cm)
Model G H J K N P
1600
60.8 (
154
)2.6 (
7
)8.4 (
21
)67.4 (
171)
30.4 (
77
)16.0 (
41
)
2000
60.8 (154)2.6 (7)8.4 (21)67.4 (171) 30.4 (77)16.0 (41)
2500
71.0 (180)4.0 (10)9.8 (25)76.4 (194)34.5 (88)17.7 (45)
3000
71.0 (180)4.0 (10)9.8 (25)76.8 (195)34.5 (88)17.7 (45)
3500
81.3 (
207
)7.0 (
18
)8.3 (
21
)86.4 (
219
)40.0 (
102
)21.6 (
55
)
4000
81.3 (207)7.0 (18)8.3 (21)86.4 (219)40.0 (102)21.6 (55)
inches (cm)
Model Q R S T U
1600
23.0 (58)10.2 (26)14.0 (36)13.0 (33)6.3 (16)
2000
23.0 (58)10.2 (26)14.0 (36)13.0 (33)6.3 (16)
2500
27.2 (69)11.8 (30)18.3 (46)14.8 (38)6.0 (15)
3000
27.2 (
69
)11.8 (
30
)18.3 (
46
)14.8 (
38
)6.0 (
15
)
3500
30.7 (78)13.0 (33)16.0 (41)17.4 (44)6.7 (17)
4000
30.7 (78)13.0 (33)16.0 (41)17.4 (44)6.7 (17)
inches (cm)
1.G Venting Dimensions & Sizing
1.H Dimensions
Venting
Information
inches cm inches cm ft** minches cm ft** minches cm
615 50 15.2 14 36
8* 20* 100 30.5 14 36
2000 820 820 100 30.5 820 100 30.5 14 36
820 50 15.2 18 46
10* 25* 100 30.5 18 46
3000 10 25 10 25 100 30.5 10 25 100 30.5 18 46
10 25 50 15.2 22 56
12* 30* 100 30.5 22 56
4000 12 30 12 30 100 30.5 12 30 100 30.5 22 56
*A vent increaser at the boiler outlet is required
**Equivalent Feet: To calculate maximum equivalent length, measure the linear feet of the pipe
and add 5 feet (1.5m) for each elbow used.
***Category II: Category II pipe size may vary. Draft must remain between -0.01 and -0.001" w.c..
Notes:
1. Installations in the U.S. require exhaust vent pipe that is CPVC complying with ANSI/ASTM D1785 F441,
stainless steel complying with UL1735, or polypropylene complying with ULC S636.
2. Installations in Canada require exhaust vent pipe that is certified to ULC S636.
3. Intake (air) pipe must be PVC or CPVC that complies with ANSI/ASTM D1785 F441, ABS that complies with
ANSI/ASTM D1527, stainless steel, or galvanized material.
10 25 100 30.5
615
820 100 30.5
100 30.51600
2500
3500
Vent / Air
Connector Size
Model
615
8
10
20
25
Maximum
Ducted Air Pipe
Length
Air Pipe Size Typical
Category II Vent
Pipe Size***
Maximum
Category IV
Vent Pipe
Length
Category IV
Vent Pipe Size