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Page 20

SECTION 6  WATER 

CONNECTIONS 

6.A   Water Piping

NOTE:

 

This boiler must be installed in a closed 

pressure system with a minimum of 12 psi (82.7kPa) 

static pressure at the boiler.

Section 6.D on page 21 shows typical plumbing 

installations. Be sure to provide unions and isolation 

valves at the boiler inlet and outlet so it can be isolated 

for service. Check local codes for specific plumbing 

requirements before beginning the installation.
An ASME pressure relief valve is supplied with these 

boilers, and is pre-set at 30 PSI. The valve outlet 

piping should be discharged to a drain and must be 

piped to discharge near the floor.  It cannot have a 

threaded end at its termination point nor be of a closed 

circuit design.
A pressure reducing valve (automatic feed) must 

be used to maintain the system at constant proper 

pressure. Supply properly installed purge valves to 

eliminate air from each circuit.
A drain valve is installed on the lower right side of the 

boiler and is used for draining the unit for service. If 

the boiler is being drained so that it will be left in a 

space that may freeze, it is critical to remove the two 

lower plugs from the left side of the heat exchanger. 

See Section 9.E on page 40 This is the only way to 

ensure all the water is out of the heat exchanger. 

Be sure at least one air elimination device is installed 

in the system to eliminate trapped air from the system.
Hot water piping should be supported by suitable 

hangers or floor stands, NOT by the boiler. Due 

to expansion and contraction of copper pipe, 
consideration should be given to the type of hangers 

used. Rigid hangers could transmit noise through the 

system caused by the piping sliding in the hangers. 
A properly sized expansion tank must be included in 

the system. 

6.B  Oxygen Permeable Systems

This boiler must not be directly connected to a heating 

system utilizing oxygen permeable tubing. Provide a 

water-to-water heat exchanger between systems to 

prevent corrosion of ferrous metals such as the boiler’s 

piping, wet walls, etc. Air elimination devices are not 

sufficient protection and corrosion damage is not 

covered under the limited warranty.

6.C 

Anti-freeze

Non-toxic HVAC anti-freeze may be added to the 

hydronic system provided the concentration does not 

exceed 50%, and the anti-freeze contains an anti-

foaming agent and rust inhibitor. Follow the anti-freeze 

manufacturer’s recommendations for yearly or biannual 

replacement of system anti-freeze. Never use toxic 

automotive anti-freeze in a boiler system.

The use of an anit-freeze will reduce the heat transfer 

capabilities of the water.  

 

NOTE:  The use of an anti-freeze will reduce the heat 

transfer capabilities of the water.  

NOTE:  Not all manufacturer supplied pumps are 

capable of maintaining the reduced temperature rise 

required with glycol concentrations greater than 35%. 

If glycol concentrations required are greater than 35% 

a field supplied pump should be used.

 

 CAUTION

Different glycol products may provide varying degrees 

of protection.  Glycol products must be maintained 

properly in a heating system, or they may become 

ineffective. Consult the glycol specifications, or 

the glycol company, for information about specific 

products, maintenance of solutions, and set up 

according to your particular conditions.

 

NOTE: The minimum return water temperature of 

the unit, in order to avoid condensation in the vent, 

is 130°F.  The unit's control is equipped to protect 

against low temperatures, however the pumps must be 

installed and wired properly for this feature to function. 

The system pumps must be wired to the system pump 

terminals, and a boiler pump must be installed and 

wired to the boiler pump terminal (models 125 - 200 

are built with LLH / boiler pump systems that are wired 

at the factory).  See Figure 28 on page 27.  If the 

system is not setup this way, condensation may occur 

which could damage venting systems.

   

 

LAARS Heating Systems

Summary of Contents for MINI-THERM JX

Page 1: ...ment Installation and service must be performed by a qualified installer service agency or gas supplier AVERTISSEMENT Assurez vous de bien suivres les instructions donn es dans cette notice pour r dui...

Page 2: ...0 6 D Typical Plumbing Diagrams 21 SECTION 7 ELECTRICAL AND WIRING DIAGRAMS 7 A Safety Warnings 23 7 B Main Power 120V 15 Amp Circuit 23 7 C Outdoor Sensor 23 7 D Field Connections 24 7 D 1 TB1 Term B...

Page 3: ...System 36 9 B System Start Up Seq of Operation 36 9 C Proper Pilot Flame 38 9 D Lighting Instructions Decal 39 9 E System Shutdown 40 SECTION 10 MAINTENANCE 10 A Removing the Covers and Panels 40 10...

Page 4: ...justing high limit to anything other than 190 F 88 C Installing an outdoor sensor for the purpose of setting the Reset Curve Changing the temp readout from Fahrenheit to Celsius or back to Fahrenheit...

Page 5: ...ater 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...

Page 6: ...njury 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 mor...

Page 7: ...Connections See 7 B on page 23 See 7 D on page 24 Gas Valve Pilot Ignitor Sensor Shown with front cover off Field Connections TB1 DHW Relay Connections TB3 Field Connections TB2 Low Loss Header Vent...

Page 8: ...nt cover and allow for advanced settings and installations that have outdoor reset and Low Water Cut Off LWCO with manual reset and several other advanced settings See SECTION 8 on page 30 Figure 4 Sy...

Page 9: ...4 Front View Draft Diverter Damper 6 15 3cm 3 1 4 8 3cm Low Loss Gas Supply Header A D B V 1 1 4 NPT Female OUT Supply IN Return 1 1 4 NPT Female 53cm 23cm F2 11 8cm 4 5 8 21 9 1 8 Max E Right View 1...

Page 10: ...Installation Clearances the minimum clearance between hot water pipes and combustible construction is 1 2 5 cm 2 A minimum of 15 381mm access must be available in front of the boiler for burner remov...

Page 11: ...es Improper venting of this appliance can result in excessive levels of carbon monoxide which can result in severe personal injury or death AVERTISSEMENT Cette chaudi re doit tre ventil conform ment a...

Page 12: ...openings one within 12 inches 305mm of the ceiling the other within 12 inches 305mm of the floor NOTE In Canada follow Canadian Standard CAN CSA B149 1 or local codes Outside Air Supply When combusti...

Page 13: ...p is designed so that it can be easily removed for normal boiler service and inspection without removal of the venting Avoid terminating boiler vents near air conditioning or air supply fans The fans...

Page 14: ...d expected system water temperatures Also ensure the boiler s anti condensing features are utilized by properly wiring the system pumps See Figure 28 on page 27 WARNING Do not store any chemical clean...

Page 15: ...c e d i s n i o t e c n a r a e l C G H Clearance to each side of centerline extended above meter regulator assy 3 ft 91 cm within a height of 15 ft 4 6 m m c 1 9 t f 3 t e l t u o t n e v r o t a l u...

Page 16: ...ANSI Z223 1 NFPA 54 AVERTISSEMENT Lorsqu une chaudi re existante est retir e d un syst me de ventilation commun le syst me de ventilation commun est susceptible d tre trop grand pour une ventilation a...

Page 17: ...ed gas meter Gas supply pressures to the heater are listed in Table 3 SECTION 4 Gas Connections 4 A Gas Supply and Piping Follow this guideline checklist for the gas supply installation 1 Gas piping i...

Page 18: ...e DO NOT ATTEMPT TO CONVERT THIS HEATER FOR USE WITH ANY OTHER TYPE OF FUEL AVERTISSEMENT Le unit est con u pour tre utilis avec du gaz naturel ou du gaz LP mais seulement des navires de l usine comme...

Page 19: ...eadloss See Table 5 Primary Secondary systems and boilers with LLH systems can be used to avoid needing larger system pumps Water Flow Requirements Electrical Data All Sizes with Low Loss Header witho...

Page 20: ...system utilizing oxygen permeable tubing Provide a water to water heat exchanger between systems to prevent corrosion of ferrous metals such as the boiler s piping wet walls etc Air elimination devic...

Page 21: ...es Indirect Tank Air Scoop Zone Pumps mustbesized properly Valves Check Valves DHW Pump Drains Drains Drains Drains Check Valve Valves Indirect Tank Check Valve Valves Indirect Tank DHW Pump DHW Pump...

Page 22: ...and 100 Low Loss Header is standard on models 125 150 and 200 and Optional for models 50 75 and 100 Figure 16 Low Loss Header with Zone Pumps and DHW Typical Plumbing Diagrams continued KEY PUMP CHECK...

Page 23: ...nly 7 A Safety Warnings NOTE All internal electrical components have been pre wired No attempt should be made to connect electrical wires to any other location except the terminal blocks and line volt...

Page 24: ...the optional DHW Relay Kit will control the boiler to the high limit setpoint See SECTION 8 for functionality 7 D 1 c Field Interlocks Field Interlocks allow for auxiliary limits or LWCO Breaking the...

Page 25: ...sation due to low inlet water temperature 7 D 2 c Aux Power This terminal and the 120V N terminal provide constant high voltage to accessories such as power vent combustion air and or zone relay syste...

Page 26: ...Air System Laars Power Vent Kit L1 N T1 T2 T3 L1 N T1 T2 T3 L N 1 2 4 Example Fields Controls CAS 4 Wiring to JX Combus on Air System Example Laars Power Vent Kit and Fields Controls CAS 4 Wiring to...

Page 27: ...d the total capacity of the transformers See Zone Valve manufacturer s installation instructions for valve electrical requirements Three Wire Zone Valves need an Isolation Relay if not using a zone co...

Page 28: ...4V L PILOT VALVE 24V L MAIN VALVE 24V N Y GAS VALVE S BLOCKED VENT SWITCH SWITCH ROLL OUT 24VAC 120VAC R O A A OAS COM W W SD X1 X2 X4 Y Y R R CONNECTOR DAMPER O Y Y R R R R TRANSFORMER BOILER PUMP CO...

Page 29: ...X1 2 X1 8 X1 5 MAIN VALVE 24V N 24V L 24V L SPARK IGNITOR GENERATOR SPARK J1 WATER TEMP SENSOR FACTORY INSTALLED X3 5 POWER VENTER PROOF OF FAN not supplied FACTORY JUMPERED VENT DAMPER PROOF OF OPEN...

Page 30: ...it to Celsius or back to Fahrenheit To change the economy settings 8 A 2 The HI LIMIT Dial Program Select The high limit is factory set at 190 F To adjust turn the HI TEMP dial until the desired setti...

Page 31: ...ctive IMPORTANT NOTE If the sensor installation has been modified to a single function sensor well this LED will not illuminate indicating that the control is not providing low water cut off functiona...

Page 32: ...proceed to Step 3 If you are using outdoor sensor and you ve programed your Reset Ratio then skip the Economy dial and proceed to Step 4 Always finish with Step 4 to ensure the high limit is properly...

Page 33: ...eset press and hold the Mode button The LED will illuminate solid red after 10 to 30 seconds but continue to hold the Mode button for 60 seconds and the LWCO will shut down the boiler and the LOW WATE...

Page 34: ...l regulate the boiler s temperature based on the temperature outside On cold days the boiler will run at higher temperatures to meet the heating load in the house On warmer days the boiler will run at...

Page 35: ...f the LOW WATER light is ng the control has been programmed to provide lock rotection in the event a low water condition is detected Manual Reset Low Water Cut Off ORTANT The system must be checked by...

Page 36: ...prevent air locked zones and boiler damage M START UP Carbon monoxide hazard The vent damper must be fully open and the flue must be clear before the main burner fires If the burner fires when the ve...

Page 37: ...he manual gas valve and verify that the burner flame is extinguished and the boiler continues to try to restart continuous retry of pilot You can then allow the boiler to restart by opening the manual...

Page 38: ...and the pilot should be adjusted down using the valve s pilot adjustment screw shown in Figure 42 If the flame is small and the inner cone does not engulf the pilot ignitor sensor then the pilot is u...

Page 39: ...ndie ou une explosion entra nant des dommages des blessures ou la mort A Cet appareil est muni d un dispositif d allumage qui allume automatiquement la veilleuse Ne tentez pas d allumer la veilleus ma...

Page 40: ...his panel off in normal operation High voltage and temperatures could cause a hazardous condition 10 A 1 Access Cover Removal To remove the front access cover simply turn the lock at the top center of...

Page 41: ...l 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...

Page 42: ...n 10 B Maintenance WARNING The Warranty does not cover damage caused by lack of required maintenance lack of water flow or improper operating practices AVERTISSEMENT La garantie ne couvre pas les domm...

Page 43: ...or power on any switch on the boiler 5 To perform voltage checks on 120VAC attach one meter lead to either terminal 2 or 3 of TB1 Use the other lead to check for power at any high voltage terminal or...

Page 44: ...efficiency Replace heat exchanger 6 Pump noisy Air in volute Bleed air from volute Check pump alignment Worn bearings Replace worn parts 7 Boiler pounding or knocking Water flow too low through boiler...

Page 45: ...ature drops to the automatically calculated Target Temp Differential Is the Green LED TEMP ACTIVE On The Control is Not Powered The Temp Active LED will be on at all times when the control is powered...

Page 46: ...VAC on the Gas Valve WARNING 11 D 2 Troubleshooting Flow Chart 2 burners on from previous page Is There 24 VAC on the PV terminal of the Valve If Flame Light is solid spark should be off and 24VAC sho...

Page 47: ...and system piping is simplified Primary Secondary Piping Two or more interconnecting circulating loops each with its own pump Primary Boiler Circuit Secondary System Circuit Reverse Return Piping Bal...

Page 48: ...X 5 R 3 4 0 3 X 5 R e d i S A3 Panel 8 3 0 3 X 0 2 8 3 0 3 X 5 1 8 3 0 3 X 2 1 8 3 0 3 X 0 1 8 3 0 3 X 7 8 3 0 3 X 5 t n o r F A4 Front 5 4 0 3 X 0 2 R 5 4 0 3 X 5 1 R 5 4 0 3 X 2 1 R 5 4 0 3 X 0 1 R...

Page 49: ...Page 49 C2 A7 A2 A9 A1 A8 A10 A3 A4 A12 A13 A14 D3 B2 B4 B5 C6 C3 B6 D13 D2 B8 B9 A15 D1 A6 A5 A16 A17 B1 B7 C1 D4 C5 C4 B4 B3 MINI THERM JX Residential Boilers...

Page 50: ...L0039000 L0039000 L0039000 L0039000 2001 5000 L0032900 L0032900 L0032900 L0032900 L0032900 L0032900 5001 8000 L0032800 L0032800 L0032800 L0032800 L0032800 L0032800 8001 10000 L0032700 L0032700 L00327...

Page 51: ...2 not shown 1 H2413100 INSTRUCTIONS INSTALLATION DHW RELAY KIT JX n 1 5X7002 DHW PANEL ASSY JX ECN DECIMALS XX DRAFT CHECK RELEASE REVISIONS K REV CF 6JUL20 DWG CHANGE IN WRITING BY LAARS HEATING SYST...

Page 52: ...6 Fax 800 559 1583 Headquarters 20 Industrial Way Rochester NH USA 03867 603 335 6300 Fax 603 335 3355 9 Brigden Gate Halton Hills Ontario Canada L7G 0A3 905 203 0600 Fax 905 636 0666 www Laars com Li...

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