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LAARS Heating Systems

Page 26

Manifold 

pressure 

port. 

  

4.11 Gas Setup and Adjustment

For the Step by step process to measure 

CO2

 values on the Mascot ST, please refer to 

Step 19 thru Step 24 in Section 4.13 of this 

Installation Manual. 

Offset Fire 

Adjustment 

Screw

Adjust ONLY when in 

MIN Fire and when 

using a combustion 

analyzer. 

 

See Section 4.12 for 

step by step details.

Inlet Gas 

pressure port

Table 10. 

CO2 Values

Table 12. 

Manifold Pressures

WARNING

       

Installer is required to verify combustion settings as part of 

the installation process. CO should not exceed 300 ppm. 

Standard Factory Setting is for MIN Fire. 9.0% CO

2

 @ 0 - 2,000 ft altitude (Natural Gas). 

4.10 Gas Supply Pressure

  Refer to the illustration. Check the gas inlet pressure 

measurement from inlet gas pressure port.(Loosen the 

port bolts before you check the gas inlet pressure.)

1.   The appliance and its individual shutoff valve must 

be disconnected from the gas supply piping system 

during any pressure testing of that system at test 

pressures in excess of 1/2 psi (3.5 kPa). 

2.  The appliance must be isolated from the gas supply 

piping system by closing its individual manual shutoff 

valve during any pressure testing of the gas supply 

piping system at test pressures equal to or less than 

1/2 psi (3.5 kPa).

Natural Gas

LP Gas

Maximum 

Pressure

10.5˝ 

WC

Maximum 

Pressure

13.0˝ 

WC

Minimum 

Pressure

3.5˝ 

WC

Minimum 

Pressure

8.0˝ 

WC

Table 11. 

Min and Max Inlet Gas Line Pressures

Customer Service and Product Support:  

800.900.9276 • Fax 800.559.1583

Headquarters: 

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

 

Litho in U.S.A. © Laars Heating Systems 1503  Document  4286

800.900.9276 

 Fax 800.559.1583 

(Customer Service, Service Advisors)

20 Industrial Way, Rochester, NH 03867 

 603.335.6300 

 Fax 603.335.3355 

(Applications Engineering)

1869 Sismet Road, Mississauga, Ontario, Canada L4W 1W8 

 905.238.0100 

 Fax 905.366.0130

www.Laars.com

Document 4286

M

ascot ST Gas Conversion Kit

pg 4 of 4

Table C

Table D

Figure E (Conversion label)

25.

    Once the CO2 and manifold pressure 

measurements for both MIN and MAX Fire are 

correct (for your altitude) turn OFF the Control 
Display 

 and set DIP switches 6 and 7 to the 

OFF position for Nominal Fire (normal operation). 

Turn the Control Display

 back on when done. 

26.

    Write in the correct Conversion Date and the 

Technicians Name to the included gas conversion 

sticker. See Figure E.  Then apply that sticker 

adjacent to the rating plate.

27. 

  Put the water heater cover back on and assemble/

tighten the 4 screws that hold the cover in place.

This unit was converted on ____/____/___to _____gas
with kit #____________by______________________
(name and company __________________________
accountable)_________________________________
___________________________________________

Cette unité a été converti ____/____/____ten ______gaz 
en utilisant le kit numéro _____       par______________
(nom et société_________________________________ 
responsable)___________________________________
_____________________________________________

WARNING

       

Always make sure that the Control Display is turned 

OFF

 before changing any DIP switch. Then turn Control 

Display back ON to continue with CO2

 measurements. 

High Altitude  

Setting level

‘LP’  

CO2 

Values

‘NG’  

CO2 

Values

MSTWW199

2" or 3" VENT

2" or 3" VENT

0~2,000 ft

10.7

MAX

10

9.7

MIN

8.5

2,000~5,000 ft

10.2

MAX

9.1

10.3

MIN

9.7

5,000~8,000 ft

10.3

MAX

9.1

10.4

MIN

9.8

8,000~10,000 ft

10.5

MAX

9

10.6

MIN

9.8

 AVERTISSEMENT

Ce conversion doit être installé par un organisme de 

service conformément aux instructions du fabricant 

et tous les codes et les exigences de l’autorité 

compétente. Si les informations contenues dans ces 

instructions n’est pas suivi à la lettre, un incendie, 

une explosion ou de la production de monoxyde 

de carbone mais résultat causant des dommages 

matériels, des blessures ou des pertes de vie. Le 

service est responsable pour la bonne et complète 

l’installation de ce kit. L’installation n’est pas correcte 

et complète jusqu’à ce que le fonctionnement de 

l’appareil converti est vérifi ée comme 

spécifi é dans 

le manuel d’instruction fourni avec le 

kit.

Manifold pressure

‘NG’  type combustibility

‘LP’  type combustibility

MSTWW199

MAX FIRE

-0.11” to -0.17” WC

-0.07” to -0.11” WC

MIN FIRE

-0.10” to -0.16” WC

-0.06” to -0.10” WC

H2373700-

Customer Service and Product Support:  

800.900.9276 • Fax 800.559.1583

Headquarters: 

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

 

Litho in U.S.A. © Laars Heating Systems 1503  Document  4286

800.900.9276 

 Fax 800.559.1583 

(Customer Service, Service Advisors)

20 Industrial Way, Rochester, NH 03867 

 603.335.6300 

 Fax 603.335.3355 

(Applications Engineering)

1869 Sismet Road, Mississauga, Ontario, Canada L4W 1W8 

 905.238.0100 

 Fax 905.366.0130

www.Laars.com

Document 4286

M

ascot ST Gas Conversion Kit

pg 4 of 4

Table C

Table D

Figure E (Conversion label)

25.

    Once the CO2 and manifold pressure 

measurements for both MIN and MAX Fire are 

correct (for your altitude) turn OFF the Control 
Display 

 and set DIP switches 6 and 7 to the 

OFF position for Nominal Fire (normal operation). 

Turn the Control Display

 back on when done. 

26.

    Write in the correct Conversion Date and the 

Technicians Name to the included gas conversion 

sticker. See Figure E.  Then apply that sticker 

adjacent to the rating plate.

27. 

  Put the water heater cover back on and assemble/

tighten the 4 screws that hold the cover in place.

This unit was converted on ____/____/___to _____gas
with kit #____________by______________________
(name and company __________________________
accountable)_________________________________
___________________________________________

Cette unité a été converti ____/____/____ten ______gaz 
en utilisant le kit numéro _____       par______________
(nom et société_________________________________ 
responsable)___________________________________
_____________________________________________

WARNING

       

Always make sure that the Control Display is turned 

OFF

 before changing any DIP switch. Then turn Control 

Display back ON to continue with CO2

 measurements. 

High Altitude  

Setting level

‘LP’  

CO2 

Values

‘NG’  

CO2 

Values

MSTWW199

2" or 3" VENT

2" or 3" VENT

0~2,000 ft

10.7

MAX

10

9.7

MIN

8.5

2,000~5,000 ft

10.2

MAX

9.1

10.3

MIN

9.7

5,000~8,000 ft

10.3

MAX

9.1

10.4

MIN

9.8

8,000~10,000 ft

10.5

MAX

9

10.6

MIN

9.8

 AVERTISSEMENT

Ce conversion doit être installé par un organisme de 

service conformément aux instructions du fabricant 

et tous les codes et les exigences de l’autorité 

compétente. Si les informations contenues dans ces 

instructions n’est pas suivi à la lettre, un incendie, 

une explosion ou de la production de monoxyde 

de carbone mais résultat causant des dommages 

matériels, des blessures ou des pertes de vie. Le 

service est responsable pour la bonne et complète 

l’installation de ce kit. L’installation n’est pas correcte 

et complète jusqu’à ce que le fonctionnement de 

l’appareil converti est vérifi ée comme 

spécifi é dans 

le manuel d’instruction fourni avec le 

kit.

Manifold pressure

‘NG’  type combustibility

‘LP’  type combustibility

MSTWW199

MAX FIRE

-0.11” to -0.17” WC

-0.07” to -0.11” WC

MIN FIRE

-0.10” to -0.16” WC

-0.06” to -0.10” WC

H2373700-

Summary of Contents for MSTWW

Page 1: ...ases which could cause serious injury property damage or death Improper installation and or operation will void the warranty AVERTISSEMENT Assurez vous de bien suivres les instructions donn es dans ce...

Page 2: ...Lengths 20 4 7 2 Direct Venting 20 4 7 3 Indoor Combustion Air 21 4 8 Vent Air Pipe Termination 21 4 9 Gas Supply and Piping 23 4 10 Gas Supply Pressure 26 4 11 Gas Set Up and Adjustment 26 4 12 Gas...

Page 3: ...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 suppl...

Page 4: ...1 9 9 FUEL N Natural P Propane CONFIG W Wall Hung ALTITUDE A 0 10 000 Feet REVISION 1 First OPTIONS X Standard PUMP X no Pump 1 M SECTION 2 Product Characteristics 2 1 Model Nomenclature The Model Nom...

Page 5: ...Premixed Fuel Modulation Metal Fiber Infrared Gas Valve System Air ratio valve Minimum Flow Rate 0 5 GPM Internal Pipe Material STS 304 Dimensions W17 3 H28 7 D14 8 Weight 88 lbs Sub Heat Exchanger Wa...

Page 6: ...g Systems Page 4 Description Diameter A Vent Pipe Collar 3 B Air Intake Collar 3 C Gas Inlet 3 4 D DHW Outlet 3 4 E DHW Inlet 3 4 F Condensate Drain 1 2 G Cold Water Inlet Filter _ 2 3 Dimensions Air...

Page 7: ...essure Switch 14 Gas Inlet 15 Gas Inlet Pipe 16 Freeze Protector Sensor 17 Domestic Hot Water DHW Outlet 18 Condensate Trap Cleanout Name of Component 19 Cold Water Inlet 20 Cold Water Inlet Filter 21...

Page 8: ...UR SAFETY READ BEFORE OPERATING If you do not follow these instructions exactly a fire or explosion could result causing property dam age personal injury or loss of life A This appliance does not have...

Page 9: ...is Water Heater if any part has been under water Immediately call a qualified technician for inspecting the Water Heater and replacing any part of the control system and gas control which have been un...

Page 10: ...s open position 4 Check the Gas Valve Check that the manual gas shut off valve that supplies the Mascot ST is opened 5 Check the area around the appliance and remove any combustible or flammable mater...

Page 11: ...a freeze protection function The ceramic heater is installed inside of the heater s internal pipe to protect the heater from freezing Do not wipe the appliance or control panel with wet cloth Electri...

Page 12: ...ath or substantial property damage The Water Heater which has gas control system components must be protected from any possible danger during operation and service If new Water Heater replaces the exi...

Page 13: ...drill 4 holes 0 47 dia with a 1 2 drill bit into the wall through the Bracket If mounting to a concrete wall then use the concrete anchors If onto wood or 5 8 16 mm plywood then use the wood screws Do...

Page 14: ...f total input rating of all equipment in the enclosure When communicating to the outdoors through horizontal ducts each opening shall have a minimum free area of not less than 1square inch per 2000 Bt...

Page 15: ...emp cher l accumulation de condensat et si n cessaire les chaudi res de cat gories II et IV doivent tre pourvues de dispositifs d vacuation du condensat The Mascot ST is standard as a Natural Gas Wat...

Page 16: ...ding but not limited to ANSI Z224 1 NFPA 54 CSA B149 1 CSAB149 2 and ULC S636 Failure to follow this manual and applicable codes may lead to property damage severe injury or death INSTALLATIONS IN CAN...

Page 17: ...rmal insulation covering pipe and fittings is prohibited Do not apply an electric damper draft hood or vent damper with this Water Heater Do not locate vent termination where exposed to prevailing win...

Page 18: ...enter line extended above meter regulator assembly 3 ft 91 cm within a height 15 ft above the meter regulator as sembly I Clearance to service regulator vent outlet 3 ft 91 cm J Clearance to non mecha...

Page 19: ...inside corner H Clearance to each side of center line extended above meter regulator assembly 36 in 91 cm within a height 15 ft 4 57 m above the meter regu lator assembly I Clearance to service regul...

Page 20: ...e 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 leve...

Page 21: ...ent tre prises pour chaque appareil toujours raccord au syst me d vacuation commun et qui fonctionne alors que d autres appareils toujours raccord s au syst me d vacuation ne fonctionnent pas 1 Scelle...

Page 22: ...exhaust temperature Tightening Water Heater Collar Socket to Vent Pipe Inlet Pipe Canada has adopted standard ULC S636 which requires the following additional items The following steps for cement appl...

Page 23: ...um allowable length 5 feet 1 5M for each additional 3 inch 90 degree elbow 2 5 feet 0 75M for each additional 3 inch 45 degree elbow 8 feet 2 4M for each additional 2 inch 90 degree elbow 4 feet 1 2M...

Page 24: ...ons with Sloped Roof Horizontal Vent Termination cont Direct Vent Optional Sidewall Snorkel Terminations Concentric Vent Termination Direct Vent Optional Horizontal and Vertical Concentric Vent Side w...

Page 25: ...rify that the appliance is fitted for the proper type of gas by checking the rating plate Mascot ST will function properly at elevations up to 10 000 feet 3050 m Refer to Section 4 12 for High Altitud...

Page 26: ...n the gas supply line should be installed close to the unit To facilitate any future maintenance it is also recommended that an approved gas union fitting Gas line close position Gas line open positio...

Page 27: ...tion recommended to be the first appliance to gas supply line Connection 1 2 3 4 Gas pipe size Manual gas shut off valve Gas meter G Capacity not less than total capacity of connected appliances Other...

Page 28: ...in place This unit was converted on ____ ____ ___to _____gas with kit ____________by______________________ name and company __________________________ accountable _________________________________ WAR...

Page 29: ...o get into the Installer mode 2 Rotate dial to 9 HA while in installer mode Press the dial to select 9 HA Choose the correct value from the following four options 0 2 0 1 999 ft 0 609 m 2 5 2 000 4 99...

Page 30: ...ufacturer s instructions supplied with the kit Installation must conform with local codes and the latest edition of the National Fuel Gas Code ANSI Z223 1 and CAN B149 Failure to follow instructions c...

Page 31: ...ir Gas Mixture AGM Chamber Figure C Figure B away from the blower Keep track of this disassembly as you will need to re assemble exactly as it comes apart Keep all screws and washers 10 Remove the Nee...

Page 32: ...17 Change dip switches 6 and 7 to a Minimum fire state MIN Fire is 7 ON and 6 OFF 18 Turn ON the Mascot ST 19 Open the manifold pressure port by loosening the screw two turns as shown in Figure D 20...

Page 33: ...ed on ____ ____ ___to _____gas with kit ____________by______________________ name and company __________________________ accountable _________________________________ _________________________________...

Page 34: ...3 4 Pipe 500 150m of equivalent length Lengths in excess of these limits will require an external recirculation pump CAUTION Water Quality Potable water is defined as drinkable water supplied from a...

Page 35: ...rials for the condensate drain lines such as 1 2 PVC CPVC Polypropylene pipe or included plastic hose NOTICE For Category II and IV water heaters be installed so as to prevent accumulation of condensa...

Page 36: ...he National Electrical Code NFPA 70 and or CSA C22 1 Electrical Code Part 1 in Canada ELECTRICAL SHOCK HAZARD For your safety turn off electrical power supply at service entrance panel before making a...

Page 37: ...set DIP Switch 5 to OFF for LP Propane hange dip switches 6 and 7 to a Minimum fire state MIN Fire is 7 ON and 6 OFF rn ON the Mascot ST pen the manifold pressure port by loosening the screw two turns...

Page 38: ...LAARS Heating Systems Page 36 4 19 Wiring Diagram Figure 3 Wiring Diagram...

Page 39: ...Mascot ST Tankless Water Heater Page 37 4 20 Ladder Diagram Figure 4 Ladder Diagram...

Page 40: ...SMW250 03 1 RS 485 RS485 SELV 5VDC 2 RS485 SELV 5VDC 3 CN4 LWD1140 06 1 FAN Not Used 2 GND SELV 30VDC 3 VDD SELV 14VDC 4 Fan power start coil SELV 30VDC 5 Fan power end coil SELV 30VDC 6 Fan speed fe...

Page 41: ...VDC 7 VDD SELV 24VDC CN10 SMW250 08 1 DHM DHM Stepper motor coil Y phase SELV 14VDC 2 DHM Stepper motor coil Y phase SELV 14VDC 3 DHM Stepper motor coil X phase SELV 14VDC 4 DHM Stepper motor coil X p...

Page 42: ...nt LOW Range 95 120 F 35 49 C DHW Set Point HIGH Range 121 140 F 49 5 60 C D Toggle C F E Scroll Select Turn to scroll tap to select clockwise or counterclockwise The Control Display has a Control Dia...

Page 43: ...oint can be adjusted WARNING Do not use this appliance if any part has been under water Immediately call a qualified service technician to inspect the appliance and to replace any part of the control...

Page 44: ...e Control Display will go through a Start Up checklist and briefly show a sequence of diagnostic codes before entering into the Operating Mode It will then display the following information Indicate E...

Page 45: ...rpm value C Lc Lock Mode Lock mode is used On or unused oFF d OP OP Temperature Current Operating Temperature E dH DHW temperature Current DHW temperature F Eh Exhaust Temperature Current Exhaust tem...

Page 46: ...40 F When changing DHW setpoint the DHW icon will flash S24 Changing between Celsius and Fahrenheit When the button D is pressed for more than 5 seconds temperature unit will toggle between C and F Th...

Page 47: ...Reset Number of Ignition 8 dl Maximum fan Adjust to maximum fan value default 0 9 HA High Altitude Settings Choose from 0 2 2 5 5 8 and 8 10 thousands ft of altitude These changes are to be made only...

Page 48: ...5 Control Display and Operation Flashing Indicate Example Error Er will flash Er 11 Error Code Er 11 Display and Controller are communicating NOTE When communication between the Control Display and t...

Page 49: ...esistance is zero replace the sensor 5 If the problem persists replace the main control Soft Lock 20 High Limit Overheat Switch Closed is Normal Open is Fault Press the Power button to clear the Error...

Page 50: ...OP Follow the instructions on page 2 this manual and call a qualified service technician or the fuel gas utility Press the Power button to clear the Error Code If Error happens again 1 Check the water...

Page 51: ...ondition is remedied If Error happens again 1 Check the water heater cover Ensure it is secure Flame detection sensor can detect an external light source 2 Check flame detection sensor Ensure connecti...

Page 52: ...LAARS Heating Systems Page 50 1 Flame Detection 6 2 Fault Tree Analysis Section 6 Error Codes 2 Gas Detection...

Page 53: ...age 51 3 Fan Air Proving 6 2 Fault Tree Analysis Section 6 Error Codes 4 I T DHW OP Sensor detects Error code contents E31 Inlet water NTC open or short E32 DHW NTC open or short E33 OP NTC open or sh...

Page 54: ...ect Check if the supply and manifold gas pressures are in accordance with specifications Make sure that the water flow sensor with three wires has been properly connected on the top of heat exchanger...

Page 55: ...on control panel but water heater is oper ating Occurs when the communication is lost from the control to the display Check for loose connec tions and proper pin alignment engagement on the Control s...

Page 56: ...ent at blower connections Water heater is in standby mode and fan is not running If FAN SPEED is not 0 RPM then replace the fan IGNITION FAULT Even if water heater went through 8 ignition attempts but...

Page 57: ...charge end of the condensate drain tubing Make sure that no flue gas is escaping from the condensate drain tubing If flue gas is continuously escaping it is a serious problem Call your qualified servi...

Page 58: ...ront cover And then reconnect the power supply to the water heater 8 Press Power button on the front panel to turn on water heater Cleaning cold water Inlet Filter Draining the Water Heater 1 Place a...

Page 59: ...er Visually inspect for leaks around internal water piping Also inspect external water piping circulators relief valve and fittings Immediately call a qualified service technician to repair any leaks...

Page 60: ...wall Is there space for a drain which is close to the Water Heater Are there any combustible materials near the Water Heater and vent pipe Is the air supply sufficient for proper operation of the Wat...

Page 61: ...ater heater Is the pressure relief valve of DHW Plumbing at least 3 4 in diameter Have you installed the pressure relief valve on the hot water outlet pipe near the Water Heater Final check Burner fla...

Page 62: ...40210024 14 ST1018 PCB Bracket H140210024 15 ST1019 Manual Switch S264100048 16 ST1020 Flow Control Valve H160400003 17 ST1021 Water Inlet Pipe ASS Y S549100114 17 1 ST1022 Water Inlet Pipe S311300013...

Page 63: ...Mascot ST Tankless Water Heater Page 61 Cover Assembly...

Page 64: ...35 ST1042 Burner Assembly 35 1 ST1043 Burner Head 35 2 ST1044 Ignition Rod Bracket 35 3 ST1045 Ignition Rod 35 4 ST1046 Burner Fixing Bracket 35 5 ST1047 Overheat Sensor Burner 35 6 ST1048 Metal Fiber...

Page 65: ...2 49100113 31 6 ST1035 Condensate Gutter 160510018 32 ST1036 Blower Assembly 42100043 32 1 ST1037 Blower 51200026 32 2 ST1038 O Ring 29100019 32 3 ST1039 AGM Actuator 850150044 33 ST1040 Silencer Elbo...

Page 66: ...LAARS Heating Systems Page 64 Notes...

Page 67: ...Mascot ST Tankless Water Heater Page 65 Notes...

Page 68: ...chester 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 Litho in U S A Laars Heating Systems 1503 Document 1316 D...

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