Laars MINI-THERM JX Series Installation And Operation Instructions Manual
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Laars MINI-THERM JX Series Installation And Operation Instructions Manual

Laars MINI-THERM JX Series Installation And Operation Instructions Manual

Residential gas-fired hydronic boilers sizes 50-200 mbtu/h
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Installation and Operation Instructions
FOR YOUR SAFETY: This product must be installed and serviced by a professional service technician,
qualified in hot water boiler and 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.
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.
Installation and Operation Instructions for
WARNING
M
-T
INI
HERM
JX
Residential
Gas-Fired
Hydronic Boilers
Sizes 50-200 MBTU/h
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
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 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 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.
Document 1478
®
ou la mort.

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January 24, 2025

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Summary of Contents for Laars MINI-THERM JX Series

  • Page 1 Installation and Operation Instructions Document 1478 Installation and Operation Instructions for HERM ® Residential Gas-Fired Hydronic Boilers Sizes 50-200 MBTU/h FOR YOUR SAFETY: This product must be installed and serviced by a professional service technician, qualified in hot water boiler and 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.

  • Page 2: Table Of Contents

    LAARS Heating Systems TABLE OF CONTENTS SECTION 1 GENERAL INFORMATION Field Connections ......24 Safety Warnings ........4 7.D.1 TB1 (Term Block 1 -TT, DHW, OAS) . 24 Introduction ..........6 7.D.1.a TT (Central Heat)........24 Warranty ..........6 7.D.1.b DHW............ 24 Model Number and Nomenclature ..
  • Page 3 JX Residential Boilers INI- HERM ® 8.C.3 Manual Reset Low Water Cut-Off ..34 8.C.4 Low water Cut-Off ........ 34 8.C.5 High Limit Differential ......34 8.C.6 Restore Factory Default Settings ..34 TEST / SETTINGS Button ....35 Temperature and Pressure Gauge ..35 SECTION 9 INITIAL STARTUP Filling the System .........

  • Page 4: Section 1 General Information 1.A Safety Warnings

    Page 4 LAARS Heating Systems SECTION 1 GENERAL INFORMATION 1.A Safety Warnings Safety Warnings are used throughout this manual to bring attention to the presence of hazards with various risk levels and to off er important information concerning the life of this product. There are 3 basic types.
  • Page 5 JX Residential Boilers Page 5 INI- HERM ® WARNING WARNING The Repair Parts list designates parts that contain Electrical Shock Hazard refractory ceramic fi bers (RCF). RCF has been classifi ed Electrical shock can cause severe injury, death or as a possible human carcinogen. When exposed to property damage.

  • Page 6: B Introduction

    1.C Warranty (Low Loss Header & Pump Installed) P = 50-100 with Pump Kit The Laars Mini-Therm JX boilers are covered by a 8th Character (Altitude in Feet) limited warranty. The owner should complete the warranty registration online by going to www.Laars.

  • Page 7: E Model Overview

    JX Residential Boilers Page 7 INI- HERM ® 1.E Model Overview Low Loss Header. Models 125 - 200 only 200 MBH 50 MBH Rating Plate Figure 1. Largest and Smallest w/ Model Number and Nomenclature...
  • Page 8 Page 8 LAARS Heating Systems 1.E Model Overview (continued) Hydronic Return Hydronic Supply Low Loss Header (sizes 125 - 200) Temp and Pressure Gauges User Control Panel Lock Interface Drain Rating Plate Pressure Relief Valve ‘Knock-outs’ Gas Supply DHW Relay...

  • Page 9: F Dimensions

    JX Residential Boilers Page 9 INI- HERM ® Dimensions IN (Return) Dimensional 1-1/4” NPT Male IN (Return) Data 1-1/4” NPT Male OUT (Supply) Out Supply 1-1/4” NPT Male 7" OUT (Supply) In Return 18cm Out Supply 1-1/4” NPT Male 7" In Return 18cm Control Display...

  • Page 10: G The Installation Kit

    Page 10 LAARS Heating Systems 1.G The Installation Kit 1.H Accessory Kits Available See Section 12.C on page 50 for part numbers. This residential unit is shipped in a single crate with a boxed installation kit that contains these components.

  • Page 11: Section 3 Air And Venting 3.A Safety Warnings

    JX Residential Boilers Page 11 INI- HERM ® SECTION 3 Air and Venting 3.A Safety Warnings WARNING WARNING This boiler must be vented in accordance with Part For Category I, II and IV boilers, have horizontal runs sloping upwards not less than ¼ inch per foot (21 mm/m) 7, Venting of Equipment, of the latest edition of the from the boiler to the vent terminal.

  • Page 12: B Combustion Air Supply

    Page 12 LAARS Heating Systems 3.B Combustion Air Supply Boiler Size Outside Air Area Inside Air Area The boiler location must provide sufficient air sq. in sq. in. sq. cm sq. cm supply for proper combustion, and ventilation of the surrounding area as outlined in the latest edition of U.S.

  • Page 13: C Venting

    JX Residential Boilers Page 13 INI- HERM ® 10 (3.0) OR LESS MORE THAN 10 (3.0) 2 (0.6) MIN. 3 (0.9) 3 (0.9) MIN. MIN. WALL OR WALL OR PARAPET TERMINATION PARAPET CHIMNEY 10 FT. (3.0m) CHIMNEY OR LESS FROM RIDGE, NOTE: NO HEIGHT WALL OR PARAPET 10 (3.0)

  • Page 14: D Vertical Venting - Category I

    Page 14 LAARS Heating Systems 3.D Vertical Venting - Category I WARNING All venting must comply with fuel gas code and Do not store any chemical, cleaners, or other be installed by a licensed installer. corrosive material near combustion air openings or in the room.

  • Page 15: E Locations For Vent Pipe Terminator

    JX Residential Boilers Page 15 INI- HERM ® 3.E Locations for Vent Pipe Terminator Canadian Installations 1 U.S. Installations 2 A = Clearance above grade, veranda, porch, deck, or balcony B = Clearance to window or door that may be ●...

  • Page 16: F Venting With A Power Venter

    Page 16 LAARS Heating Systems Venting with a Power Venter 3.G Évent Commun This boiler is certified for use with the manufacturer's suggested Power Venter, which is supplied in a kit that AVERTISSEMENT includes Installation Instructions. See the accesories Lorsqu'une chaudière existante est retirée d'un list in the Parts Section of this manual.

  • Page 17: Section 4 Gas Connections 4.A Gas Supply And Piping

    JX Residential Boilers Page 17 INI- HERM ® SECTION 4 Gas Connections 4.A Gas Supply and Piping 1. Gas piping installation must be in accordance with the latest edition of ANSI Z223.1 and all local CAUTION codes. In Canada, the installation must be in accordance with CSA-B149.1 and all local codes Permanent damage to the gas valve will occur if the that apply.

  • Page 18: Blp Gas Conversion

    Page 18 LAARS Heating Systems NOTE: The boiler and all other gas WARNING appliances sharing the boiler gas supply line must be firing at maximum capacity to The boiler is designed for use with either natural properly measure the inlet supply pressure.

  • Page 19: Section 5 Pump Requirements

    1-1/4 29.3 24.9 36.6 31.1 1-1/4 1-1/4 44.0 37.2 JX Residential Boilers Page 19 INI- HERM ® 1-1/4 58.3 49.2 SECTION 5 PUMP REQUIREMENTS 5.A Pump Sizing Water Flow Requirements Temperature Rise 15°F 8°C 20°F 11°C 25°F 14°C Size Flow Rate Headloss Flow Rate Headloss...

  • Page 20: Section 6 Water Connections 6.A Water Piping

    Page 20 LAARS Heating Systems SECTION 6 WATER CONNECTIONS 6.A Water Piping The Low Loss Header is available for the model 50, NOTE: This boiler must be installed in a closed 75, and 100 as an option for smaller systems that pressure system with a minimum of 12 psi (82.7kPa)

  • Page 21: Typical Plumbing Diagrams

    JX Residential Boilers Page 21 INI- HERM ® Typical Plumbing Diagrams These diagrams are only meant as a guide. All components or piping required by local code must be installed. Check Check Valves Air Scoop Valves Air Scoop Air Scoop Check Valv Air Scoop...
  • Page 22 Page 22 LAARS Heating Systems Typical Plumbing Diagrams (continued) Check Air Scoop Valves Valves Zone Pumps (must be sized properly) Pump Valves Valves Check Valve Low Loss Header w/ Pump Indirect Tank Figure 13. Low Loss Header with Zone Pumps and DHW Low Loss Header is standard on models 125, 150, and 200 and Optional for models 50, 75, and 100.

  • Page 23: And Safety Warnings

    Input Nat Gas Conn. Conn. Size MBTU/h MBTU/h JX Residential Boilers Page 23 1-1/4 INI- HERM 14.7 12.6 ® 1-1/4 22.0 18.8 1-1/4 29.3 24.9 SECTION 7 ELECTRICAL AND WIRING DIAGRAMS 1-1/4 36.6 31.1 7.A Safety Warnings 44.0 37.2 1-1/4 58.3 49.2 1-1/4...

  • Page 24: D Field Connections

    Page 24 LAARS Heating Systems 7.D Field Connections This boiler has three Field Connection Terminals. TB1, TB2 and TB3 (TB3 is for optional equipment). TB1 -TT, DHW, OAS Open TB2 -Pumps and Aux Power Closed TB3 -DHW Relay Connections (optional) Figure 16.

  • Page 25: Tb2 (For Pumps And Aux Power)

    JX Residential Boilers Page 25 INI- HERM ® 7.D.2 TB2 (for pumps and aux power) 7.D.2.a Boiler Pump This terminal and the 120V(N) terminal will provide power to the boiler pump whenever the boiler is running. Use this to power the Low Loss Header (LLH) pump. If not using a LLH then this terminal can run power for a single zone or a zone valve system pump.

  • Page 26: E Wiring Connects, Power Vent And Air

    Figure 18. - Combustion Air System wiring example Combustion Air System Example: Laars Power Vent Kit and Fields Controls CAS-4 Wiring to JX Combustion Air System Example: Laars Power Vent Kit and Fields Controls CAS-4 Wiring to JX Example: Laars Power Vent Kit and Fields Controls CAS-4 Wiring to JX...
  • Page 27 JX Residential Boilers Page 27 INI- HERM ® Laars Power Vent Kit Example: Typical Zone Pump Control Wiring to JX for Anti-condensing protection NOTE: Must have a dedicated boiler pump (such as LLH) when using this method. Figure 20. - Typical Zone Pump Control Wiring for Anti-condensing protection Example: Typical Zone Valve Control Wiring to JX for Anti-condensing protection.

  • Page 28: F Wiring Diagram

    Page 28 LAARS Heating Systems Wiring Diagram CUSTOMER POWER CONNECTION 120VAC TRANSFORMER 24VAC DAMPER CONNECTOR Boiler Controller BLOCKED VENT ROLL OUT SWITCH SWITCH PILOT VALVE 24V (L) GAS VALVE MAIN VALVE 24V (N) 24V (L) 120VAC FACTORY INSTALLED JUMPERS: Figure 22. - Wiring Diagram...

  • Page 29: G Logic Diagram

    JX Residential Boilers Page 29 INI- HERM ® 7.G Logic Diagram 120VAC (1PH/60Hz) 10K OHM L1 N SENSOR INPUTS WWSD FIELD 24V (N) PV2 INPUTS Field AUX POWER TB2:5A TB2:3A Interlock 120VAC OPTIONAL P1:1 P1:2 HEAT DHW PUMP RELAY DEMANDS P1:3 BOILER/HEATER 120VAC CONTROL INPUT...

  • Page 30: Section 8 The Digital Dashboard

    Page 30 LAARS Heating Systems SECTION 8 THE DIGITAL DASHBOARD The Current Status of the boiler is displayed by the This boiler is ready to go ‘Out of the Box’ and into a typical single loop installation with a preset outlet water various indicators along the top of the Dashboard temperature of 190°F.

  • Page 31: Control Leds

    Decimal lights on a call for heat. JX Residential Boilers Page 31 INI- HERM ® Indicator Light (OFF or LO, 1, 2, 3, 4, 5, HI) (announces heat call) Factory: 1 L E D s Control, Digital and Ignition *Model specific differential en the econ- d off.

  • Page 32: A.6.D Flame

    Page 32 LAARS Heating Systems Ignition LED's (continued) The control’s Outdoor Reset feature uses a reset ratio 8.A.6.d FLAME method to control the boiler temperature. The reset ratio Illuminates when the pilot flame is lit. If pilot flame is determines how much the boiler temperature is adjusted not sensed within 75 seconds or if flame is lost the for changes in outdoor temperature.

  • Page 33: C.1.D Thermal Boost

    JX Residential Boilers Page 33 INI- HERM ® 8.C.1.c Thermal Boost To ensure that the heating system always satisfies a call for heat, the control is equipped with a thermal boost feature. If the thermostat is not satisfied thirty minutes after the boiler reaches the reset temperature, the control will boost the reset temperature by 10 degrees.

  • Page 34: Degrees Fahrenheit Or Celsius

    Page 34 LAARS Heating Systems 8.C.2 Degrees Fahrenheit or Celsius 8.C.4 Low water Cut-Off To turn off Low Water Cut-Off. The control has the ability to operate in degrees Fahrenheit or Celsius. When operating in Celsius, a 1. Turn the LO TEMP dial to access the Program Mode c will appear in the display next to the temperature –...

  • Page 35: Test/Settings Button

    Dial Default Feature Options Description Setting Setting JX Residential Boilers Page 35 INI- HERM ® Degrees Fahrenheit Fahrenheit or Celsius OPTIONAL FEATURES continued Degrees Celsius LWCO Manual or Automatic Reset Automatic Reset Dial Default Manual Reset Feature Options Description Setting Setting Not available on this control...

  • Page 36: Section 9 Initial Startup

    Page 36 LAARS Heating Systems SECTION 9 INITIAL STARTUP WARNING Carbon monoxide hazard. The vent damper must be 9.A Filling the System fully open and the flue must be clear before the main burner fires. If the burner fires when the vent damper...
  • Page 37 JX Residential Boilers Page 37 INI- HERM ® 6. When pilot flame is sensed the green “flame” LED will turn on. If flame is not sensed in 75 seconds the pilot valve will de-energize, the spark will terminate, and the green “flame” LED will blink. After a 5 minute delay the sequence will retry at step 5.

  • Page 38: C Proper Pilot Flame

    Page 38 LAARS Heating Systems 9.C Proper Pilot Flame To view the pilot flame, the cover must be unlocked Open and removed. A properly adjusted pilot should have a blue, steady flame with an inner cone that engulfs 3/8” - 1/2” of the pilot ignitor sensor. The pilot ignitor sensor should glow bright orange from the heat and the flame current should be 1.0 μA to 1.8 μA.

  • Page 39: D Lighting Instructions Decal

    JX Residential Boilers Page 39 INI- HERM ® 9.D Lighting Instructions FOR YOUR SAFETY READ BEFORE OPERATING Decal WARNING: If you do not follow these instructions exactly, a fire or explosion may result causing property damage, personal injury or loss of life. Lighting instructions are located on A.

  • Page 40: E System Shutdown

    Page 40 LAARS Heating Systems 9.E System Shutdown Turn off the main electrical disconnect switch. Close all manual gas valves. If you think the unit might freeze, drain it. All water must be removed from the heat exchanger, or damage from freezing may occur.

  • Page 41: Side Panel Removal

    JX Residential Boilers Page 41 INI- HERM ® 10.A.3 Side Panel Removal Remove the front access and the top as described previously. Drain the boiler and remove the drain valve and/or the PRV and associated fittings depending on the panel being removed.

  • Page 42: B Maintenance

    Page 42 LAARS Heating Systems 10.B Maintenance 1. Lubricate any motor bearings that are not sealed is cleaned of exterior residue periodically based on system conditions) bearings per the instructions. e. Mechanical flue damper operation. 2. If a strainer is employed in a pressure reducing valve f.

  • Page 43: Operating Details And Troubleshooting

    JX Residential Boilers Page 43 INI- HERM ® SECTION 11 Operating Details and Troubleshooting 11.A Operating Details CAUTION When power is turned on, the digital display will indicate Label all wires prior to disconnection when the Boiler Outlet Temperature. If a demand for heat is servicing controls.

  • Page 44: C Troubleshooting Table

    Page 44 LAARS Heating Systems 11.C Troubleshooting Table Symptom Cause Remedy Boiler Pump not No power ..Check circuit breakers and power source. Replace. Recheck wiring Pump defective ..diagrams (System pump will not work if below 160ºF or if DHW call) operating Incorrectly wired .

  • Page 45: Troubleshooting Flow Chart 1 (Burners Off)

    JX Residential Boilers Page 45 INI- HERM ® 11.C.1 Troubleshooting Flow Chart 1 (burners off) Is the The Temp Active LED will be on at all times when the control is Green LED The Control is powered. (TEMP ACTIVE) Not Powered. Check for 120 VAC on the control input.

  • Page 46: Troubleshooting Flow Chart 2 (Burners On)

    Page 46 LAARS Heating Systems Troubleshooting Flow Chart 2 – Burner Will Not Shut Down 11.C.2 Troubleshooting Flow Chart 2 (burners on) Is the The Control is Red LED Sensing (LOW WATER) Low Water. WARNING! WARNING TURN OFF POWER TO BURNER IMMEDIATELY! CAUTION –...

  • Page 47: A Parts Illustrations

    JX Residential Boilers Page 47 INI- HERM ® SECTION 12 REPLACEMENT PARTS 12.A Parts Illustrations Reference to 12.B Parts List starting on next page.
  • Page 48 F0024300 F2032800 1-106 E2403300 E2402100 F0035900 H2410700 H2410600 REVISIONS THIS DOCUMENT AND THE INFORMATION CONTAINED HEREIN ARE PROPRIETARY TO LAARS HEATING SYSTEMS REV. DRAFT CHECK E0101800 ENGR APP AND SHALL NOT BE REPRODUCED, TRANSFERED 20-026N-01 JM 6JUL20 CF 6JUL20 KAG 6JUL...

  • Page 49: B Parts List

    JX Residential Boilers Page 49 INI- HERM ® Jacket Components Panel, Top, Front R5X3032 R7X3032 R10X3032 R12X3032 R15X3032 R20X3032 Panel, Left Side R5X3043 R5X3043 R5X3043 R5X3043 R5X3043 R5X3043 Jacket Components Panel, Front 5X3038 7X3038 10X3038 12X3038 15X3038 20X3038 Panel, Top, Front R5X3032 R7X3032 R10X3032 R12X3032 R15X3032 R20X3032 12.B Parts List Front Cover R5X3045 R7X3045...

  • Page 50: C Accessories List

    7X3031 10X3031 12X3031 15X3031 20X3031   Main Gas Orifice (not shown)  Note: For complete conversion kits (LP or Nat all altitudes available) see accessory section.  Panel, Rear 5X3037 7X3037 10X3037 12X3037 15X3037 20X3037 Page 50         Natural Gas     0‐2000' L0032200 L0032200 L0032200 LAARS Heating Systems L0032200 L0032200 L0032200 Gas System Panel, Right Side R5X3044 R5X3044 R5X3044 R5X3044 R5X3044 R5X3044                                      2001'‐5000' L0050700 L0050700 L0050700 L0050700 L0050700 L0050700 Pilots Base Assy (includes A12,A13 and A14)

  • Page 51: D Glossary Of Terms

    JX Residential Boilers Page 51 INI- HERM ® 12.D Glossary of Terms Air Vent Reverse-Return Piping A device used to purge air from the Circuit. Should Balanced, equal flow (first in, last out) piping. Utilized be located at the highest point in the Circuit. with multiple boilers and/or radiation.
  • Page 52 Customer Service and Product Support: Industrial Way, Rochester, NH, USA 03867 • 603.335.6300 • Fax 603.335.3355 Headquarters: 9 Brigden Gate, Halton Hills, Ontario, Canada L7G 0A3 • 905.203.0600 • Fax 905.636.0666 www.Laars.com Litho in U.S.A. © Laars Heating Systems 21-01 Document 1478...

This manual is also suitable for:

Mini-therm jx-50 seriesMini-therm jx-75 seriesMini-therm jx-100 seriesMini-therm jx-125 seriesMini-therm jx-150 seriesMini-therm jx-200 series

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