Laars U.H.E. - Service Manual User Manual

Service Manual Document 11019AService Manual for U.H.E.Ultra High Efciency Water HeatersThese instructions are to be stored next to the boiler for

LAARS Heating SystemsPage 10Refer to ignition module illustration, is there 120VAC between P1(1) and P1(3)?Is front panel power switch light on,indi

U.H.E Service ManualPage 11Determine failure mode by observing flashing LED status on ignition module.LED status and probable cause shown below.* Deno

LAARS Heating SystemsPage 12Refer to ignition module illustration, Is there 24VAC between P3(7) and P3(8)?YOK, thermostat is calling for heat.Turn o

U.H.E Service ManualPage 13°F012345678 940 26109 25400 24712 24045 23399 22771 22163 21573 21000 2044550 19906 19383 18876 18383 17905 17440 16990 165

LAARS Heating SystemsPage 14Refer to ignition module illustration, Is there 120VAC between P1(1) and P1(3)?Refer to ignition module illustration, Is

U.H.E Service ManualPage 15Step 5. Carefully disconnect all wires from thermostatboard.Note: it may be necessary to identify wiresfor proper re-conne

LAARS Heating SystemsPage 16Thermostat Potentiometer Replacement ProcedureStep 4. Loosen set screw of adjustingknob (small blade screw driver)and re

U.H.E Service ManualPage 17Thermostat Sensor (Thermistor) Replacement ProcedureStep 5. Fold back insulation just in front of burner to expose temperat

LAARS Heating SystemsPage 18Does inlet gas pressure drop more than 2" W.C. during burner ignition?Adjust gassupply regulatorInadequately sized

U.H.E Service ManualPage 19Refer to ignition module illustration below,is there 24VAC between P3(2) and P3(5) (blue and brown wires) during the flame

LAARS Heating SystemsPage 2Table of Contents2Page U.H.E.TMService ProcedureIntroduction 3 - - -How to use this manual 4 - - -Tool required for servi

LAARS Heating SystemsPage 20Step 1. Position main power switch to “OFF”.Step 2. Disconnect (unplug) water heater from120 volt power source.Step 3. T

U.H.E Service ManualPage 21Combustion System Replacement ProcedureStep 1. Fully inspect burner mounting insert gasket for the following:a) Tears d) Di

LAARS Heating SystemsPage 22Step 1. Position main power switch to “OFF”.Step 2. Disconnect (unplug) water heater from120 volt power source.Step 3. T

U.H.E Service ManualPage 23Burner Tube InspectionStep 1. Inspect burner tube as follows (BSI ceramic fiber mesh burner, water heaters prior toserial n

LAARS Heating SystemsPage 24Gas Valve Replacement ProcedureStep 6. Remove the 2 gas valve mounting screws (Torx bit) located at the11:00 O-clock &am

U.H.E Service ManualPage 25Hot Surface Ignition Models:Are safety circuits in normal position?Does blowerenergize?Is there 120VAC across the white and

LAARS Heating SystemsPage 26Blower Replacement ProcedureStep 5. Disconnect wire harness from blower.Step 6. Disconnect intake vent and gas supply fr

U.H.E Service ManualPage 27Reset buttonDoes blowerenergize?NSequence of operation:The blocked vent pressure switch monitors the pressure in the exhaus

LAARS Heating SystemsPage 28Check Exhaust Tube PressureExhaust Pressure Switch Testing and ReplacementExhaust Tubepressure tap locationExhaust tubea

U.H.E Service ManualPage 29Exhaust Pressure Switch Replacement ProcedureStep 1. Position main power switch to “OFF” position.Step 2. Loosen adhesive b

U.H.E Service ManualPage 3IntroductionThe LAARS heating system Ultra High Efficiency Water Heater uses a low Nox premix power burner located at the to

LAARS Heating SystemsPage 30Is igniter resistanceless than 150 Ohms (cold)?(see “check igniter resistance” below)Refer to ignition module illustrati

U.H.E Service ManualPage 31Hot surface Igniter Replacement ProcedureStep 1. Position main power switch to “OFF”Step 2. Disconnect (unplug) water heate

LAARS Heating SystemsPage 32With flame sensor Disconnectedfrom ignition module, checkcontinuity to ground.Is there continuity to ground?NYFlame Sens

U.H.E Service ManualPage 33Flame Sensor Replacement ProcedureStep 4. Fold back insulation in front of combustion assembly to expose flame sensor.(see

LAARS Heating SystemsPage 34Ignition Module Replacement ProcedureStep 1. Position main power switch to “OFF”.Step 2. Disconnect (Unplug) water heate

U.H.E Service ManualPage 35Transformer Replacement ProcedureStep 4. For Hot Surface Ignition models, refer to ignition module illustration below, Disc

LAARS Heating SystemsPage 36Reset heater, observeheating cycle. Does switch open?YDoes switch open priorto 350°F?DO NOT OPERATE HEATERSystem over he

U.H.E Service ManualPage 37Vent Safety Switch Replacement ProcedureStep 1. Position main power switch to “OFF”.Step 2. Loosen adhesive backed rubber e

LAARS Heating SystemsPage 38Disassembly Procedure for Access to Anodes & Flue BafflesStep 1. Position main power switch to “OFF”.Step 2. Disconn

U.H.E Service ManualPage 39Anode inspection and replacement Step 1. Turn off water supply and drain water heater.Step 2. Disassemble water heater per

LAARS Heating SystemsPage 4Tools Required for ServiceIt is intended for this manual to be used by qualified service personal for the primary purpose

LAARS Heating SystemsPage 40Flue baffle inspection and replacementStep 1. Disassemble heater per “Disassembly Procedure for Access to Anodes & F

U.H.E Service ManualPage 41Powered Anode Replacement UHE100T399 models onlyPowered Anode Replacement for UHE100T399 onlyThe powered anode control modu

LAARS Heating SystemsPage 42Collector Cover Installation ProcedureStep 1. Remove old silicone from top surface of collector flange and collector cov

U.H.E Service ManualPage 43Product Handling - Carefully uncrate the heater. Move in place with a hand truck (Do not use the venting pipes for handles)

LAARS Heating SystemsPage 44R44DateModel NumberSerial NumberVenting (PVC, CPVC):Intake 90's (qty)Vent size 3" or 4"Exhaust 90's

U.H.E Service ManualPage 45Customer must specify complete model number and serial number when ordering service parts.451 Combustion Surround Assy.2 Bu

LAARS Heating SystemsPage 46Customer must specify complete model number and serial number when ordering service parts.46AA Latch AssyBB Screw 8-32 x

U.H.E Service ManualPage 47Customer must specify complete model number and serial number when ordering service parts.47Electronic Control ModuleScrew

LAARS Heating SystemsPage 48NOTESAC Alternating CurrentBTU/H British Thermal UnitsCO Carbon MonoxideCO2 Carbon DioxideDC Direct CurrentDSI Direct Sp

U.H.E Service ManualPage 5UHE60T125UHE60T150UHE60T199UHE100T150UHE100T199UHE100T250UHE100T300UHE100T399125,000150,000199,999150,000199,999250,000300,0

LAARS Heating SystemsPage 66Thermostat Sensor 11,900 Ohms @ 70°F, ECO opens @ 201°F Max., ECO close @ 100°F Min.Thermostat Board Max temp 180°F, Mi

U.H.E Service ManualPage 7Vent TablesNotes:1) Multiply the total number of 90° elbows (intake and exhaust) by 5 feet. Do not include thetermination fi

LAARS Heating SystemsPage 81Thermostat calls for heat.2Blower energizes, pressure switch contacts are normally closed. If the pressure switch conta

U.H.E Service ManualPage 9Lockout conditions:The system will go into lock out mode for the following reasons:Blocked vent pressure switch contacts ope