Laars NEOTHERM NTH Installation And Operation Instructions Manual
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Laars NEOTHERM NTH Installation And Operation Instructions Manual

Modulating boiler and water heater
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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.
WARNING
Installation and Operation
Instructions for
N
T
EO
HERM
Modulating Boiler
Model NTH
Sizes 080–850 MBTU/h
Water Heater
Model NTV
Sizes 150–850 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 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.
Document 1252B
®

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  • Page 1 Installation and Operation Instructions Document 1252B Installation and Operation Instructions for HERM ® Modulating Boiler Model NTH Sizes 080–850 MBTU/h Water Heater Model NTV Sizes 150–850 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.

  • Page 2: Table Of Contents

    LAARS Heating Systems Table of Contents Section 1 - Section 6B - General Information Water Connections - NTV Water Heater Introduction ............1 6B.1 NTV Water Quality .......... 26 1.2 Model Identification ........... 1 6B.2 Piping Requirements ........26 1.3 Appliance Overview .......... 2 6B.3 Cold Water Make-Up ........
  • Page 3 Boilers and Water Heaters HERM Section 9 - Section 12 - First Start-Up and Adjustment Instructions Replacement Parts 9.1 Filling the Boiler System ......... 50 13.1 General Information ........60 9.2 First Operation ..........50 13.2 Parts List ............60 9.3 Adjusting the Differential and Manifold Pressure ........... 51 Appendices - 9.4 Shutting Down the NeoTherm Unit ....
  • Page 4 LAARS Heating Systems...

  • Page 5: General Information

    Consult 6 0 0 = 600,000 BTU/hr input 7 5 0 = 750,000 BTU/hr input the LAARS Heating Systems factory, or local factory 8 5 0 = 850,000 BTU/hr input representative, with any problems or questions regarding Fuel this equipment.

  • Page 6: Appliance Overview

    Page 2 LAARS Heating Systems 1.3 Appliance Overview - See Figures 1 through 7. PRESSURE RELIEF VALVE EXHAUST VENT CONNECTION WATER INLET GAS CONNECTION WATER OUTLET AIR INLET CONNECTION USER CONTROL INTERFACE ON / OFF SWITCH HEAT EXCHANGER DRAIN VALVE GAS VALVE...
  • Page 7 Page 3 Boilers and Water heaters herm EXHAUST VENT CONNECTION WATER INLET AIR INLET CONNECTION WATER OUTLET GAS CONNECTION PRESSURE RELIEF VALVE USER CONTROL AIR PRESSURE SWITCH INTERFACE ON / OFF SWITCH HEAT EXCHANGER DRAIN VALVE CONDENSATE TRAP VENTURI GAS VALVE AIR TRANSITION AIR/ GAS BLOWER...
  • Page 8 Page 4 LAARS Heating Systems EXHAUST VENT CONNECTION WATER INLET PRESSURE RELIEF VALVE WATER OUTLET AIR PRESSURE SWITCH AIR INLET CONNECTION GAS CONNECTION AIR PRESSURE SWITCH USER CONTROL ON / OFF SWITCH INTERFACE DRAIN VALVE CONDENSATE TRAP HEAT EXCHANGER AIR/ GAS BLOWER...
  • Page 9 Page 5 Boilers and Water heaters herm WATER INLET GAS CONNECTION EXHAUST VENT PRESSURE RELIEF CONNECTION VALVE AIR INLET WATER OUTLET USER CONTROL INTERFACE ON / OFF SWITCH GAS VALVE VENTURI DRAIN VALVE AIR/ GAS BLOWER MANUAL SHUTOFF GAS VALVE HEAT EXCHANGER CONDENSATE TRAP Figure 7 - Location of Components, Sizes 750 and 850...

  • Page 10: Warranty

    LAARS Heating Systems’ NeoTherm appliances are covered by a limited warranty. The owner should complete the warranty registration at www.Laars.com. All warranty claims must also be made at www.Laars.com. or to an authorized LAARS Heating Systems representative. Claims must include the serial number and model (this information can be found on the rating plate), installation date, and name of the installer.
  • Page 11 Page 7 Boilers and Water heaters herm AIR INLET VENT SIzE 25 64 19½ 49 38¼ 97 2 5.1 2 5.1 25 64 19½ 49 38¼ 97 2 5.1 2 5.1 25 64 19½ 49 38¼ 97 3 7.6 3 7.6 199/210 25 64 26¾...

  • Page 12: Locating The Appliance

    Page 8 LAARS Heating Systems Section 2 - LOCATING THE APPLIANCE 2.1 General Information APPLIANCE SUGGESTED SERVICE ACCESS CLEARANCE SURFACE INCHES The NeoTherm unit is designed for indoor installations Left Side only. Right Side The appliance should be located to provide clearances on all sides for maintenance and inspection.

  • Page 13: Venting And Combustion Air

    Page 9 Boilers and Water heaters herm Section 3 - Method 1: Two permanent openings, one commencing within 12” (300mm) of the top and one commencing within 12” VENTING AND COMBUSTION AIR (300mm) of the bottom, of the enclosure shall be provided. The openings shall communicate directly, or by ducts, with the outdoors or spaces that freely communicate with the 3.1 Combustion Air...

  • Page 14: Venting

    When taken from the wall, it must be taken from Class IIB or higher venting material is recommended. out-of-doors by means of the LAARS horizontal wall The NeoTherm is a Category IV appliance and may be terminal, shown in Table 3a and 3b. See Table 2 to select the installed with PVC and CPVC that complies with ANSI/ appropriate diameter air pipe.
  • Page 15 However, if one is not available with pressures. Do not common vent NeoTherm units the certified vent system, Laars suggests using a tee with the unless the vent system meets this requirement. branch connection sized to allow for insertion of a flue gas NeoTherm units are never permitted to share a vent analyzer probe.

  • Page 16: Locating Vent & Combustion Air Terminals

    1 foot (0.3m) above the Side Wall Vent Terminal combustion air terminal. The appropriate Laars side wall vent terminal must be used. For concentric vent, follow instructions included The terminal must be located in accordance with ANSI with vent kit.
  • Page 17 Page 13 Boilers and Water heaters herm U.S. Installations (see note 1) Canadian Installations (see note 2) A= Clearance above grade, veranda, porch, 12 inches (30 cm) 12 inches (30 cm) deck, or balcony See note 6 See note 6 B= Clearance to window or door that may be Direct vent only: 12 inches (30cm);...
  • Page 18 Page 14 LAARS Heating Systems a. In the event that the side-wall horizontally vented gas fueled equipment is installed in a crawl space or an attic, the hard-wired carbon monoxide with alarm and battery back-up may be installed on the next adjacent floor level.

  • Page 19: Common Vent Test

    Page 15 Boilers and Water heaters herm Section 4 - 3.4 Common Vent Test GAS SUPPLY AND PIPING NOTE: This section does not describe a method for common venting NeoTherm units. It describes what must be done when a unit is removed from a common Gas piping should be supported by suitable hangers or floor vent system.

  • Page 20: Pump Requirements

    Page 16 LAARS Heating Systems Section 5 - NEOTHERM NATURAL GAS PUMP REQUIREMENTS REQUIRED CU FT TO SIzE PIPING: SIZE / HR. Measure linear distance from meter outlet to last boiler. Add total input of all boilers and divide 5.1 NeoTherm Boiler Flow and Head by 1000 to obtain cu ft / hr required.

  • Page 21: Section 6A

    “volume water” without a pump included. domestic hot water applications. Refer to the NeoTherm NTH models 80-500 can also be ordered with or proper section for instructions on installing without a pump included. and piping your product. Refer to Table 9 for NeoTherm with a pump MUST be piped in a primary- the connection pipe sizes required.

  • Page 22: Condensate Drain

    LAARS Heating Systems temperature rise through the boiler. 6A.3 Condensate Drain NOTE: Laars supplied pumps are not all capable of maintaining the reduced temperature rise required A condensate drain trap is built into the NeoTherm unit. with glycol concentrations greater than 35%. If glycol Connect a 3/4”...
  • Page 23 Page 19 Boilers and Water heaters herm Figure 15 - Hydronic Piping — Single Boiler, Zoning with Circulators...
  • Page 24 Page 20 LAARS Heating Systems Figure 16 - Hydronic Piping — Single Boiler, Low Temp Radiant Space Heating Using Low Loss Header and Zone Valves...
  • Page 25 Page 21 Boilers and Water heaters herm Figure 17 - Hydronic Piping — Multiple Boilers, Zoning with Circulators...
  • Page 26 Page 22 LAARS Heating Systems Figure 18 - Hydronic Piping — Multiple Boilers with Indirect DHW Tank Piped from System Loop...
  • Page 27 Page 23 Boilers and Water heaters herm Figure 19 - Hydronic Piping — Multiple Boilers, Reverse Return, Multi-Temp Zones, Zoning with Circulators...
  • Page 28 Page 24 LAARS Heating Systems Figure 20 - Hydronic Piping — Heating Zones with Indirect DHW Tank Piped with Zone Pumps The indirect DHW tank is piped directly off of the boiler. The boiler pump must shut down during DHW operation.
  • Page 29 Page 25 Boilers and Water heaters herm Figure 21 - Hydronic Piping, Multiple Boilers with Indirect DHW Off of One Boiler The boiler pump must shut down during DHW operation.

  • Page 30: Section 6B

    Page 26 LAARS Heating Systems Section 6B - WATER CONNECTIONS - NTV WATER HEATER 6B.2 Piping Requirements Section 6 is divided into two parts. Section 6A covers NTH units designed for hydronic Water piping should be supported by suitable hangers and heating. Section 6B covers NTV models, which floor stands.

  • Page 31: Cold Water Make-Up

    Page 27 Boilers and Water heaters herm 6B.3 Cold Water Make-Up 6B.5 Freeze Protection The cold water make-up may be connected to the tank or to NeoTherm heaters are not certified for outdoor installation, the inlet of the boiler as shown in Figures 22-25.
  • Page 32 Page 28 LAARS Heating Systems NOTES: 1. Optional CWMU & Recirc. line location. 2. Locate NTV DHW sensor or remote aquastat well in lower 1/3 of tank. 3. Back flow preventer may be required - check local codes. 4. Thermal expansion tank may be required - check local codes.
  • Page 33 Page 29 Boilers and Water heaters herm NOTES: 1. Optional CWMU & Recirc. line location. 2. Locate NTV DHW sensor or remote aquastat well in lower 1/3 of tank. 3. Back flow preventer may be required - check local codes. 4.

  • Page 34: The User Interface

    Page 30 LAARS Heating Systems Section 7 - The Neotherm ‘User Interface’ was updated for the 2013 THE USER INTERFACE model year to the User Interface shown in this manual. For older NeoTherms, you will need to download the 1218G-NH.pdf from the ‘Discontinued Documents’ on 7.1 About the User Interface...

  • Page 35: Navigating Through The User Interface

    Page 31 Boilers and Water heaters herm • Press “I” Info/Install button 7.2 Navigating the User Interface • Scroll to highlight “Display Setup”, press OK • Highlight the line you would like to change,(example Navigating into the Display area menus is as easy as it looks. ”Line 2 Operating Temp”), press OK The Info/Install button will be the primary button that you will use to start, and the OK button is what you press to select...
  • Page 36 Page 32 LAARS Heating Systems quick Start This menu gives you an easy way to check or change the most common set- tings on the unit: • CH setpoint • DHW setpoint • Outdoor reset • Low water temperature • Maximum outdoor temperature •...
  • Page 37 Page 33 Boilers and Water heaters herm • You can change the numbers in the other boxes in the same way. • When the new setting is correct, press the round OK button. Entering a Password or Name The system uses a different type of screen to enter a password or name.
  • Page 38 “lnt” (lower case “LNT”). OEM Level Some of the settings can only be changed at the Laars factory. Once you enter a password, the password access remains valid until you exit to the normal no-password state. If you do not make any edits for 10 minutes, the password access will be cancelled.

  • Page 39: Section 8A

    Page 35 Boilers and Water heaters herm Section 8A - QUICK START MENU Section 8 is divided into three parts. Section 8A includes instructions for using the Quick Start menu. Section 8B covers basic installation and wiring. Section 8c includes more detailed setup instructions and wiring diagrams.

  • Page 40: Section 8B

    Page 36 LAARS Heating Systems Section 8B - BASIC INSTALLATION AND WIRING Section 8 is divided into three parts. Section 8A includes instructions for using the Quick Start menu. Section 8B covers basic installation and wiring. Section 8c includes more detailed setup instructions and wiring diagrams.

  • Page 41: Main Power Connections

    Page 37 Boilers and Water heaters herm 8B.3 Pump Connections and Operation Caution The controller in the NeoTherm energizes the pump contacts The supply voltage to the NeoTherm unit must not when it receives a call for heat. Once the call for heat is be disconnected, except for service or isolation, or satisfied, the pump will remain on for the defined pump unless otherwise instructed by procedures outlined...

  • Page 42: Section 8C

    Page 38 LAARS Heating Systems Section 8C - DETAILED SETUP INSTRUCTIONS and DIAGRAMS Section 8 is divided into three parts. Section 8A includes instructions for using the Quick Start menu. Section 8B covers basic installation and wiring. Section 8c includes more detailed setup instructions and wiring diagrams.
  • Page 43 Page 39 Boilers and Water heaters herm • As the temperature begins to rise above 32°F, the Outdoor go to “Info/ Install.” Choose “Advanced Setup,” then go Reset function causes the setpoint to be lowered. At these to “Lead/ Lag Configuration.” Select “Lead/ Lag Outdoor warmer temperatures, the heating load on the system is Reset.”...

  • Page 44: Warm Weather Shutdown

    Page 40 LAARS Heating Systems then go to “CH Configuration.” Select “Outdoor Reset “CH Configuration.” Select “Warm Weather Shutdown.” Configuration.” Set the value on the line for “Min. Boiler On the line for “Warm Weather Shutdown,” select Water Temp.” “Immediately.”...
  • Page 45 Page 41 Boilers and Water heaters herm DHW Temperature Setting - Hydronic Heating Using Local Lead-Lag/Cascading Feature with Indirect Hot Water - Regardless of the type of DHW setup, the setpoint adjustment is made the same way. (For a complete explanation of the Lead/Lag system, see Section 8C.8.) How to get there: From the “Home”...

  • Page 46: Cascading Lead/Lag Operation

    Page 42 LAARS Heating Systems Boiler Pump Interrupt Function - 3. Set the DHW priority time. If the DHW function has the The Boiler pump interrupt feature is used in some applications priority, the priority will continue during the priority time.
  • Page 47 Page 43 Boilers and Water heaters herm Boiler 1 Boiler 2 Boiler 3 Boiler 4 Display Controller Burner Fig. 38 – “Lead/Lag” Operation in a System with Four Boilers. Note - the Displays on Boilers 2 thru 4 will display information pertaining only to that specific boiler. Number of boilers Base load value Notice that, when a boiler is operating as part of a Lead/Lag installed system, it does not use the normal CH setpoint –...
  • Page 48 Page 44 LAARS Heating Systems Low demand - Low demand - The first boiler in The first boiler in sequence fires at sequence fires at less than 35% less than 50% First Third Fourth First Third boiler boiler boiler boiler...

  • Page 49: Hydronic Heating Using External Modulation Control

    4-20mA signal supplied by an external 1. On the Lead/Lag Master, set the setpoint used by the Lead/ control. (This can also be 0-10Vdc using a converter - Laars Lag system. part number CA006100.) When setting up a system using an How to get there: From the “Home”...

  • Page 50: 10 Optional Field Connections

    Modbus ports. The Modbus wiring should be completed according to the diagrams shown below. If alternate communication protocols are desired, Laars offers “gateways” to allow BACnet, LON, and other communications protocols. For additional information on Fig. 41 - BAS Connections to a Single Boiler setting up Modbus and other communication protocols, contact the factory.

  • Page 51: 12 Ladder And Wiring Diagrams

    Page 47 Boilers and Water heaters herm 8C.12 Ladder and Wiring Diagrams (See Figures 43 through 45.) WARNING When servicing the controls, label all wires prior to disconnection. Wiring errors can cause improper and dangerous operation. Verify proper operation after servicing. Figure 43 - Ladder Diagram...
  • Page 52 Page 48 LAARS Heating Systems R/BLK DKB/Y DKB/Y TRANSFORMER 110VAC INPUT 24VAC OUTPUT GY/WH Figure 44 - Wiring Diagram, All Sizes (with standard EMEA display) H2354300B...
  • Page 53 Page 49 Boilers and Water heaters herm R/BLK DKB/Y DKB/Y TRANSFORMER 110VAC INPUT 24VAC OUTPUT GY/WH Figure 45 - Wiring Diagram, All Sizes - with Optional Full-Color Touchscreen H2355400B...

  • Page 54: First Start-Up And Adjustment Instructions

    Then run the system and appliance pumps Do not use this appliance if any part has been under for a minimum of 30 minutes with the gas shut off. water. Laars Heating Systems requires boilers and water heaters to be replaced, not repaired, if they WARNING have been partially or completely submerged.

  • Page 55: Manifold Pressure

    Page 51 Boilers and Water heaters herm Observe all warnings on the Operating Instructions NeoTherm can be forced to low fire to allow for easier label and turn on the gas and electrical power to the setup. appliance. How to get there: From the “Home” screen, press The NeoTherm unit will begin the start sequence.
  • Page 56 Page 52 LAARS Heating Systems 80–285 Inlet gas pressure High re CO adjustment (under cap) pressure Low re CO adjustment Outlet gas pressure Outlet Gas Inlet gas Low re CO Pressure pressure adjustment (manifold pressure) High re CO adjustment (under cap)

  • Page 57: Shutting Down The Neotherm Unit

    Page 53 Boilers and Water heaters herm 9.4 Shutting Down the NeoTherm Unit Turn off the main electrical disconnect switch. Close all manual gas valves. If you think the NeoTherm unit might freeze, drain it. All water must be removed from the heat exchanger, or damage from freezing may occur.

  • Page 58: Maintenance

    Component Description instructions in Section 9. Once the boiler is operating. check for leaks again and confirm that all fasteners are tight. Use only genuine LAARS replacement parts. Check the appliance setup according to Section 9. Caution Label all wires prior to disconnection when servicing Appliance Control controls.
  • Page 59 Page 55 Boilers and Water heaters herm the control. If control replacement is required, turn off all two bolts connecting the ignitor assembly to the burner door. power to the appliance and shut off all manual gas valves If the old ignitor assembly is determined to be defective, to the appliance.
  • Page 60 Page 56 LAARS Heating Systems Transformer with Integral Circuit Breaker WARNING The appliance has a 24Vac transformer with integral 4 amp Black carbon soot buildup on a dirty heat exchanger circuit breaker installed to supply the control voltage required can be ignited by a random spark or flame. To prevent for the appliance.

  • Page 61: Gas Conversion

    CA006206 gas valve adjustment. Other units require no additional parts CA006206 - only proper gas valve adjustment. Please contact the Laars CA006206 factory for specific information regarding the gas conversion of a particular appliance. If a gas conversion is performed,...

  • Page 62: Operating Details And Troubleshooting

    Page 58 LAARS Heating Systems Section 11 - There is a pre-ignition time of two seconds to check the flame sensor operation and status. During this period an OPERATING DETAILS AND intermittent spark can be seen. TROUBLESHOOTING Next there is a trial for ignition period of four seconds.

  • Page 63: Anti-Short-Cycle

    Page 59 Boilers and Water heaters herm 11.5 Anti-Short-Cycle (ASC) 11.7 Diagnostics Because the NeoTherm unit is a modulating boiler, and its Use the Diagnostics to check the status of the sensors and the input will decrease when there is a reduction in the heating digital inputs and outputs.

  • Page 64: Replacement Parts 13.1 General Information

    Page 60 LAARS Heating Systems...
  • Page 65 Page 61 Boilers and Water heaters herm...
  • Page 66 Page 62 LAARS Heating Systems...
  • Page 67 Page 63 Boilers and Water heaters herm...
  • Page 68 Page 64 LAARS Heating Systems Figure 50 - Jacket Components Optional Touchscreen User Interface Kit (KM50D7130)
  • Page 69 Page 65 Boilers and Water heaters herm Figure 51a - Internal Components, Sizes 80–210 Figure 51b - Internal Components, Sizes 285–600...
  • Page 70 Page 66 LAARS Heating Systems Figure 51c - Internal Components, Sizes 750-850...
  • Page 71 Page 67 Boilers and Water heaters herm Figure 52a - Gas Train Components, Sizes 80-500...
  • Page 72 Page 68 LAARS Heating Systems Figure 52b - Gas Train Components, Sizes 600-850...
  • Page 73 Page 69 Boilers and Water heaters herm Figure 53 - Heat Exchanger Components...
  • Page 74 Page 70 LAARS Heating Systems Figure 54 - Electrical Components...

  • Page 75: Appendix A - Software Control Functions

    Page 71 Boilers and Water heaters herm Appendix A - SOFTWARE CONTROL FUNCTIONS This table includes a listing of all of the control functions that can be used by the operator or installer. Functions that require a password are indicated in the second column. Name Function How to get there...
  • Page 76 Info/ Display Setup of the Home display, and to set the brightness of the display. General configuration Used by the Laars factory. Info/ Advanced Setup/ System Config./ System Config. I gain (CH) This gain is applied to the Integral term of the PID Info/ Advanced Setup/ CH equation for the CH loop.
  • Page 77 Page 73 Boilers and Water heaters herm Name Function How to get there Max. outdoor temp. (CH) - Used with Outdoor Reset – quick Start This is the maximum outdoor temperature at which Info/ Advanced Setup/ CH the Outdoor Reset feature will be active. Above Configuration/ Outdoor Reset Config.
  • Page 78 Page 74 LAARS Heating Systems Name Function How to get there Off hysteresis (DHW) When producing Domestic Hot Water – Info/ Advanced Setup/ DHW Configuration The control system will not shut off the boiler until the temperature at the System sensor rises to the DHW setpoint plus a hysteresis value (normally about 10°F).
  • Page 79 Page 75 Boilers and Water heaters herm Name Function How to get there Pump exercise interval The system can be set to exercise the pumps at Info/ Advanced Setup/ System set intervals. Enter a non-zero value to turn on the Config./ Pump Config.

  • Page 80: Appendix B - Error Messages

    Page 76 LAARS Heating Systems Appendix B - ERROR MESSAGES This table includes a listing of the faults that might be generated by the controller, and displayed on the Operator Interface. Some of these can be corrected by an installer changing a parameter, while other conditions are more complicated, and will require a service technician.
  • Page 81 Page 77 Boilers and Water heaters herm Code Description L or H Procedure Internal fault: Internal fault Safety relay drive cap short 1. Reset module 2. If fault repeats, replace module. Internal fault: H or L Internal fault PII (Pre-Ignition Interlock) 1.
  • Page 82 Page 78 LAARS Heating Systems Code Description L or H Procedure Internal fault: Internal fault Flame rod shorted to ground 1. Reset module detected 2. If fault repeats, replace module. Internal fault: Internal fault A/D linearity test fails 1. Reset module 2.
  • Page 83 Page 79 Boilers and Water heaters herm Code Description L or H Procedure LCI (Limit Control Input) OFF 1. Check wiring and correct any faults. (Safety Chain Open) 2. Check Interlocks connected to the LCI to assure proper function. 3. Reset and sequence the module; monitor the LCI status. 4.
  • Page 84 Page 80 LAARS Heating Systems Code Description L or H Procedure Header sensor fault 1. Check wiring and correct any possible errors. 2. Replace the header sensor. 3. If previous steps are correct and fault persists, replace the module. Stack sensor fault 1.
  • Page 85 Page 81 Boilers and Water heaters herm Code Description L or H Procedure Flame lost in run 1. Check main valve wiring and operation - correct any errors. 2. Check the fuel supply. 3. Check fuel pressure and repeat turndown tests. 4.
  • Page 86 Page 82 LAARS Heating Systems Code Description L or H Procedure Fan speed failed during run 1. Check wiring and correct any potential wiring errors. 2. Check the VFDs (Variable-speed Fan Drive) ability to change speeds. 3. Change the VFD 4.
  • Page 87 Page 83 Boilers and Water heaters herm Code Description L or H Procedure Main valve Off 1. Check the main valve terminal wiring and correct any errors. 2. Reset and sequence the module. If fault persists, replace the module. Ignition On 1.
  • Page 88 Page 84 LAARS Heating Systems Code Description L or H Procedure Invalid DHW (Domestic Hot 1. Recheck selected parameters, reverify and reset module. Water) high limit enable setting 2. If fault repeats, verify electrical grounding. 3. If fault repeats, replace module.
  • Page 89 Page 85 Boilers and Water heaters herm Code Description L or H Procedure Invalid NTC sensor type setting 1. Recheck selected parameters, reverify and reset module. 2. If fault repeats, verify electrical grounding. 3. If fault repeats, replace module. Invalid Outlet high limit response 1.
  • Page 90 Page 86 LAARS Heating Systems Code Description L or H Procedure Unconfigured Outlet high limit 1. Recheck selected parameters, reverify and reset module. setpoint setting 2. If fault repeats, verify electrical grounding. 3. If fault repeats, replace module. Unconfigured Stack limit setpoint 1.
  • Page 91 Page 87 Boilers and Water heaters herm Code Description L or H Procedure Invalid DHW (Domestic Hot 1. Recheck selected parameters, reverify and reset module. Water) connector type setting 2. If fault repeats, verify electrical grounding. 3. If fault repeats, replace module. Invalid Stack connector type 1.
  • Page 92 (customer Service and Product Support) 20 Industrial Way, Rochester, NH 03867 • 603.335.6300 • Fax 603.335.3355 1869 Sismet Road, Mississauga, Ontario, Canada L4W 1W8 • 905.238.0100 • Fax 905.366.0130 www.Laars.com Printed in U.S.A. © Laars Heating Systems 1310 Document 1252B...

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