Shield SNA285-125 Installation & Service Manual Download

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Troubleshooting

Table 13E

(continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Water Heater

Interface

FAULT

DESCRIPTION

CORRECTIVE ACTION

Manual Reset

High Limit

(will require a manual

reset once the condition

has been corrected. Press

the RESET button on the

display to reset.)

The outlet water temperature has exceeded
the fixed setting of the manual reset high
limit.

• Verify that the system is full of water and that all air

has been properly purged from the system.

• Verify that the water heater is piped properly into the

heating system. Refer to Section 6 - System Piping
for the proper piping methods for the Shield water
heater.

• Check 120 VAC to water heater pump motor on a call

for heat. If voltage is not present, check wiring back
to the main control board.

• Replace the main control board if necessary.

• If 120 VAC is present on a call for heat and the water

heater pump is not operating, replace the pump.

• Check resistance of water sensors and compare to

Table 13B on page 64 of this manual. Replace
sensor if necessary.

Fan Low

Fan Speed Low

(will require a manual

reset once the condition

has been corrected. Press

the RESET button on the

display to reset.)

The actual fan RPM is 30% lower than what
is being called for.

• Vent/air intake lengths exceed the maximum allowed

lengths. Refer to Section 2 - General Venting for
proper lengths.

• Check for obstruction or blockage in the vent/air

intake pipes or at terminations.

• Check the wiring connections at the fan and at the

main control board.

• Replace the fan.

• Replace the main control board.

Blown fuse.

• Replace fuse F4 on the control board, see page 62

of this manual.

APS

Open

(will require a manual

reset once the condition

has been corrected. Press

the RESET button on the

display to reset.)

Air pressure switch contacts are open.

• Check the wiring connections to switch. Wires

should be connected to the common and normally
closed terminals.

• Air intake lengths exceed the maximum allowed

lengths. Refer to Section 2 - General Venting for

proper lengths.

• Check for obstruction or blockage in the air

intake pipes or at terminations.

• Check reference hoses connected to the air pressure

switch for blockage or obstruction.

• Inspect the burner. Reference page 60 of this

manual for removal and cleaning procedures.
Replace if necessary.

• Inspect the heat exchanger. Reference page 61 of

this manual for removal and cleaning procedures.
Replace if necessary.

• Faulty air pressure switch. Replace switch.

Installation & Service Manual

Summary of Contents for SNA285-125

Page 1: ...her 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 near by phone Follow the gas supplier s instructions If you cannot reach your gas supplier call the fire department Installation and service mu...

Page 2: ...placement 42 8 FIELD WIRING Low Voltage Connections 43 Power Cord Connection 43 Runtime Contacts 43 Alarm Contacts 43 9 CONDENSATE DISPOSAL Condensate Drain 46 10 START UP Check for Gas Leaks 47 Inspect fill Condensate System 47 Final Checks Before Starting the Water Heater 47 50 11 OPERATING INFORMATION How the Water Heater Operates 51 Temperature Control 51 Protection Features 51 Water Heater Te...

Page 3: ...ing property damage personal injury or death 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 near by phone Follow the gas supplier s instructions If you cann...

Page 4: ...wing gas to flow only if the gas valve is powered and combustion air is flowing 17 Heat exchanger access cover Allows access to the combustion side of the heat exchanger coils 18 Heat exchanger inlet temperature sensor This sensor monitors the inlet water temperature to the heat exchanger 19 Heat exchanger outlet temperature sensor This sensor monitors heat exchanger outlet water temperature 20 Hi...

Page 5: ...de inside unit Models SNR150 100 SNA285 125 29 17 5 16 33 26 9 25 13 8 2 23 14 30 27 3 22 Right Side inside unit Models SNR150 100 SNA285 125 The Shield How it works continued 32 2 35 36 7 13 34 28 24 31 Rear View Models SNR150 100 SNA285 125 5 Models SNR150 100 SNA285 125 Installation Service Manual TM ...

Page 6: ... 125 2 15 35 32 36 34 7 28 25 24 Rear View Model SNA500 125 Right Side inside unit Model SNA500 125 Right Side inside unit Model SNA400 125 Model SNA400 125 Model SNA500 125 9 26 35 22 8 23 15 16 33 17 29 5 30 9 26 27 25 8 23 15 16 17 29 5 3 Installation Service Manual TM ...

Page 7: ...re manufactured with a different control module for altitude operation but the operation given in this manual remains the same as the standard models A high altitude label as shown in FIG A is also affixed to the unit 7 Maximum allowed working pressure is located on the rating plate Model Number Note Change N to L for L P gas models CSA Input Modulation Btu hr Note 2 Water Content Gallons Water Co...

Page 8: ... the appliance indoors could result in severe personal injury death or substantial property damage Provide clearances Clearances from combustible materials 1 Hot water pipes at least 1 from combustible materials 2 Vent pipe at least 1 from combustible materials 3 See FIG s 1 1 and 1 2 on page 9 for other clearance minimums Clearances for service access 1 See FIG s 1 1 and 1 2 on page 9 for recomme...

Page 9: ...or closet installations CPVC material MUST BE used in a closet structure due to elevated temperatures Failure to follow this warning could result in fire personal injury or death 9 1 Determine water heater location continued RECOMMENDED SERVICE CLEARANCES Top 18 457 mm Right Side 24 610 mm Front 24 610 mm RECOMMENDED SERVICE CLEARANCES Top 18 457 mm Right Side 24 610 mm Front 24 610 mm Installatio...

Page 10: ... laundry facilities These areas will always contain contaminants WARNING WARNING 1 Determine water heater location Products to avoid Spray cans containing chloro fluorocarbons Permanent wave solutions Chlorinated waxes cleaners Chlorine based swimming pool chemicals Calcium chloride used for thawing Sodium chloride used for water softening Refrigerant leaks Paint or varnish removers Hydrochloric a...

Page 11: ...de When resizing any portion of the common venting system the common venting system should be resized to approach the minimum size as determined using the appropriate tables in Part 11 of the National Fuel Gas Code ANSI Z223 1 NFPA and or CAN CSA B149 1 Natural Gas and Propane Installation Code DANGER WARNING 1 Determine water heater location continued 11 Installation Service Manual TM Failure to ...

Page 12: ...allation Multiple appliances may be installed side by side with no clearance between adjacent appliances because this appliance is approved for zero clearance from combustible surfaces Consult the Venting section of this manual for specific installation instructions for the appropriate type of venting system that you will be using Figure 1 3_Combustion Air Direct from Outside 1 If air is taken dir...

Page 13: ...75 484 cm2 150 968 cm2 150 968 cm2 50 323 cm2 SNR200 100 50 323 cm2 50 323 cm2 100 646 cm2 100 646 cm2 200 1 291 cm2 200 1 291 cm2 67 433 cm2 SNA285 125 72 465 cm2 72 465 cm2 143 923 cm2 143 923 cm2 285 1 839 cm2 285 1 839 cm2 95 613 cm2 SNA400 125 100 646 cm2 100 646 cm2 200 1 291 cm2 200 1 291 cm2 400 2 581 cm2 400 2 581 cm2 134 865 cm2 SNA500 125 125 807 cm2 125 807 cm2 250 1 613 cm2 250 1 613 ...

Page 14: ...stion air opening a minimum of approximately 25 Check with louver manufacturers for exact net free area of louvers Where two openings are provided one must be within 12 30cm of the ceiling and one must be within 12 30cm of the floor of the equipment room Each opening must have net free area as specified in the chart above Table 1B Single openings shall commence within 12 30cm of the ceiling CAUTIO...

Page 15: ...or more details Figure 2 3 PVC CPVC Concentric Sidewall Termination See page 26 for more details Direct venting options Sidewall Vent 2 General venting Installation Service Manual TM Figure 2 2 Stainless Steel Two Pipe Sidewall Termination See page 23 for more details ...

Page 16: ...rmination See page 31 for more details Figure 2 8 Stainless Steel Vertical Vent Sidewall Air Direct venting options Vertical Vent Figure 2 5 Stainless Steel Two Pipe Vertical Termination See page 29 for more details Figure 2 7 PVC CPVC Vertical Vent Sidewall Air Direct venting options Vertical Vent Sidewall Air Installation Service Manual TM ...

Page 17: ...gs For concentric vent installations the inner vent tube must be replaced with field supplied certified vent material to comply with this requirement 4 The 3 Concentric Vent Kit available from Lochinvar see Section 3 Sidewall Termination Optional Concentric Vent and the 3 Concentric Vent Kit available from IPEX are both approved for use on the Shield Water Heater Both kits are listed to the ULC S6...

Page 18: ... a second coat of cement to the pipe h While the cement is still wet insert the pipe into the fitting if possible twist the pipe a 1 4 turn as you insert it NOTE If voids are present sufficient cement was not applied and joint could be defective i Wipe excess cement from the joint removing ring or beads as it will needlessly soften the pipe PVC CPVC Air intake vent connections 1 Combustion Air Int...

Page 19: ...e air inlet pipes are properly supported The PVC CPVC or ABS air inlet pipe should be cleaned and sealed with the pipe manufacturer s recommended solvents and standard commercial pipe cement for the material used The PVC CPVC ABS Dryer Vent or Flex Duct air inlet pipe should use a silicone sealant to ensure a proper seal at the appliance connection and the air inlet cap connection Dryer vent or fl...

Page 20: ...88 KB285600 9454BUREZ 1 9492 5400CI 9414TERM 2SVSLA04 2SVSTP04 2SVSRCX04 2SVSTEX0490 This adapter must be used in addition to the water heater adapter for Saf T vent pipe as shown in FIG 3 11 unless approved vent other than standard diameter is used Consult a Heat Fab representative for questions The Shield water heater uses model specific combustion air intake and vent piping sizes as detailed in...

Page 21: ...VK3007 30 feet Table 2D Concentric Vent Kit Equivalent Vent Lengths Installation Service Manual TM DO NOT mix components from different systems The vent system could fail causing leakage of flue products into the living space Use only approved stainless steel PVC or CPVC pipe and fittings For PVC CPVC use with primer and cement specifically designed for the material used Vent air piping and termin...

Page 22: ...ldup where flue products impinge on building surfaces or plants d Avoid possibility of accidental contact of flue products with people or pets e Do not locate the terminations where wind eddies could affect performance or cause recirculation such as inside building corners near adjacent buildings or surfaces window wells stairwells alcoves courtyards or other recessed areas WARNING Sidewall vent a...

Page 23: ...elow any of these within 4 feet horizontally 6 Locate terminations so they are not likely to be damaged by foreign objects such as stones or balls or subject to buildup of leaves or sediment ALTERNATE VENTING ARRANGEMENT IF SPACE PERMITS BIRD SCREEN 12 MIN 12 MIN 15 MAX COUPLING TO BOILER INTAKE AIR CONNECTION FROM BOILER VENT PIPE CONNECTION BIRD SCREEN Figure 3 1C Alternate PVC CPVC Venting Arra...

Page 24: ...ugh the wall into the vent plate openings Seal all gaps between the pipes and wall Use RTV silicone sealant to seal the air pipe Use the glue cement primer listed in Table 2A on page 18 to seal the vent pipe 3 Mount and secure the vent plate to the wall using stainless steel screws Seal around the plate to the wall assuring no air gaps 4 Assemble the vent cap to the vent plate see FIG 3 4A Insert ...

Page 25: ...LL TERMINATION PLATE GALVANIZED THIMBLE VENT PIPING Figure 3 4B Alternate Sidewall Termination Assembly w Field Supplied Fittings Prepare wall penetrations Alternate Field Supplied Option 1 Air pipe penetration a Cut a hole for the air pipe Size the air pipe hole as close as desired to the air pipe outside diameter 2 Vent pipe penetration a Cut a hole for the vent pipe For either combustible or no...

Page 26: ...ishes 4 Cut one 1 hole 5 inch diameter for CVK3003 installations or 7 inch diameter for CVK3007 installations into the structure to install the termination kit 5 Partially assemble the concentric vent termination kit Clean and cement using the procedures found in these instructions a Cement the Y concentric fitting to the larger kit pipe FIG s 3 7 and 3 8 b Cement the rain cap to the smaller diame...

Page 27: ...lation or other materials to accumulate inside the pipe assembly when installing through the hole 7 Install the rain cap and small diameter pipe assembly into the Y concentric fitting and large pipe assembly Ensure small diameter pipe is bottomed and cemented in the Y concentric fitting for CVK3003 installations and fastened tightly into the rubber adapter for CVK3007 installations 8 Secure the as...

Page 28: ...f flue gases Dimension A in FIG 3 13 represents the distance between pipes or rain shields as touching or a 2 inch maximum separation Figure 3 13 Concentric Vent and Combustion Air Termination Dimension A as Touching or 2 inches Maximum Separation Figure 3 12 Concentric Vent Sidewall Attachment DO NOT use field supplied couplings to extend pipes Airflow restriction will occur and may cause intermi...

Page 29: ... least 1 foot above the air intake When the vent termination uses a rain cap as illustrated in FIG 4 1B maintain at least 36 914 mm above the air inlet The air inlet pipe and vent pipe can be located in any desired position on the roof but must always be no further than 2 feet apart and with the vent termination at least 1 foot above the air intake Figure 4 1A Vertical Termination of Air and Vent ...

Page 30: ...oupling must be at least 1 foot above the air intake When the vent termination uses a rain cap as illustrated in FIG 4 1B maintain at least 36 914 mm above the air inlet The air inlet pipe and vent pipe can be located in any desired position on the roof but must always be no further than 2 feet apart and with the vent termination at least 1 foot above the air intake 4 Maintain the required dimensi...

Page 31: ...ee FIG 3 11 page 27 When using the alternate screw assembly method drill a clearance hole in the rain cap and a pilot hole in the vent pipe for the screw size being used Failure to drill adequate holes may cause cracking of PVC components allowing combustion products to be recirculated Failure to follow this warning could result in personal injury or death 2 Cut one 1 hole 5 inch diameter for CVK3...

Page 32: ...ect vent appliances are vented near each other each appliance must be individually vented see FIG 4 7 NEVER common vent or breach vent this appliance When two 2 or more direct vent appliances are vented near each other two 2 vent terminations may be installed as shown in FIG 4 7 The vent terminations must be at least 36 inches away from the first two 2 terminations It is important that vent termin...

Page 33: ...eneral Venting Sidewall Direct Venting and Vertical Direct Venting sections for vent material specifications vent length requirements and vent termination requirements Combustion and ventilation air must be supplied to the equipment room per the requirements on pages 12 14 of this manual for proper operation of the Shield water heater when utilizing the single pipe method Figure 5 1 Vertical Venti...

Page 34: ...isted temperature and pressure relief valve will release the manufacturer from any claim which might result from excessive temperature and pressures Keep clear of the combination temperature and pressure relief valve discharge line outlet The discharge may be hot enough to cause scald injury The water is under pressure and may splash Hydrogen gas can be produced in an operating water heater that h...

Page 35: ...gallon will usually have a pH which can be aggressive and corrosive causing non warrantable damage to the pump and associated piping Corrosion due to water chemistry generally shows up first in the hot water system because heated water increases the rate of corrosive chemical reactions The following chart Table 6A details the relationship of water temperature and time with regard to scald injury a...

Page 36: ...SION TANK BUILDING RETURN SYSTEM CIRCULATOR COLD WATER SUPPLY FLOW CHECK VALVE TYPICAL BALL VALVE TYPICAL UNION TYPICAL HOT WATER SUPPLY MIXING VALVE IF REQUIRED SEE PG 35 Figure 6 2 Single Unit Installation Service Manual TM ...

Page 37: ...OLD WATER SUPPLY FLOW CHECK VALVE TYPICAL EXPANSION TANK BUILDING RETURN SYSTEM CIRCULATOR BALL VALVE TYPICAL HOT WATER SUPPLY UNION TYPICAL MIXING VALVE IF REQUIRED SEE PG 35 Figure 6 3 Multiple Units Installation Service Manual TM ...

Page 38: ...ICAL EXPANSION TANK THERMOMETER TYPICAL COLD WATER SUPPLY 140 HOT WATER SUPPLY HIGH TEMPERATURE BUILDING RETURN UNION TYPICAL LOW TEMPERATURE BUILDING RETURN 180 HOT WATER SUPPLY MIXINGVALVE Figure 6 4 Two Temperature Single Unit Installation Service Manual TM ...

Page 39: ...NA400 125 SNA500 125 5 Purge all air from the gas supply piping 6 Before placing the water heater in operation check the water heater and its gas connection for leaks a The appliance must be disconnected from the gas supply piping system during any pressure testing of that system at a test pressure in excess of 1 2 PSIG 3 5 kPa b The appliance must be isolated from the gas supply piping system by ...

Page 40: ... requirements 1 Pressure required at the gas valve inlet pressure port Maximum 14 inches w c with no flow lockup or with water heater on Minimum 4 inches w c with gas flowing verify during water heater startup 2 Install 100 lockup gas pressure regulator in supply line if inlet pressure can exceed 14 inches w c at any time Adjust lockup regulator for 14 inches w c maximum Propane gas Pipe sizing fo...

Page 41: ...st the temperature set point on the control panel of the electronic control module to call for heat 7 Observe the gas supply pressure as the burner fires at 100 of rated input Percent of burner input will be displayed on the control panel 8 Ensure inlet pressure is within specified range Minimum and maximum gas supply pressures are specified in this section of the manual 9 If gas supply pressure i...

Page 42: ... Gas Supply Check Model SNA400 125 DETAIL LOOSEN THE SET SCREW ONE 1 FULL TURN AND PLACE THE MANOMETER TUBING OVER THE PRESSURE TAP Figure 7 6 Inlet Gas Supply Check Model SNA500 125 DO NOT adjust or attempt to measure gas valve outlet pressure The gas valve is factory set for the correct outlet pressure This setting is suitable for natural gas and propane when configured for LP requiring no field...

Page 43: ...o disconnection when servicing controls Wiring errors can cause improper and dangerous operation WARNING NOTICE CAUTION LOW VOLTAGE WIRING KNOCKOUTS Figure 8 1 Routing Field Wiring Auxiliary device proving switch 1 When the operation of an external limit needs to be verified before the water heater fires remove the jumper wire from terminals X B and connect them to the contacts on the external lim...

Page 44: ...44 8 Field wiring Figure 8 3 Low Voltage Field Wiring Connections BUILDING MANAGMENT SYSTEM ALARM BELL LOW WATER CUTOFF Installation Service Manual TM ...

Page 45: ...EMPERATURE HIGH LIMIT SENSOR FLUE GAS SENSOR FLAME SENSOR LOW WATER CUTOFF BLOCKED DRAIN SWITCH DISPLAY PANEL CONTROL BOARD BLOCKED AIR INLET PRESSURE SWITCH LOW VOLTAGE CONNECTION BOARD CONTROL BOARD ALARM BELL ALARM CONTACTS RUNTIME CONTACTS WHR PUMP IGNITER BLOWER GAS VALVE DISPLAY PANEL INPUTS OUTPUTS Installation Service Manual TM ...

Page 46: ...C certified PVC or CPVC pipe fittings and cement 5 A condensate removal pump is required if the water heater is below the drain When installing a condensate pump select one approved for use with condensing water heaters and furnaces The pump should have an overflow switch to prevent property damage from condensate spillage The switch should be wired to the auxiliary device proving switch terminals...

Page 47: ...e switch located at the top of the trap FIG 10 1 3 Fill with fresh water until the water begins to pour out of the drain 4 Replace the cap Press the cap onto the trap until the cap makes contact with the drain 5 Replace the retaining screw WARNING The condensate trap FIG 10 1 must be filled with water during all times of water heater operation to avoid flue gas emission from the condensate drain l...

Page 48: ...play until HTR Off appears in the display window 2 Remove the screws securing the top panel to the unit Remove the panel from the unit to gain access to the flue sensor 3 Locate the flue sensor in the top of the vent connection Remove the flue sensor and grommet from the unit Note Combustion measurements will be made at this point 4 Press the SHUTDOWN button on the display until HTR Standby appear...

Page 49: ...49 Figure 10 2 Operating Instructions Models SNR150 100 SNA285 125 10 Start up continued Installation Service Manual TM ...

Page 50: ...50 Figure 10 3 Operating Instructions Models SNA400 125 SNA500 125 10 Start up Installation Service Manual TM ...

Page 51: ...s 215 F the control will reduce the maximum fan speed If the flue temperature exceeds 240 F the control will shut the unit down The unit will restart automatically once the flue temperature drops 25 F and the minimum off time has expired The control monitors the temperature difference between the heat exchanger inlet and the heat exchanger outlet sensors If this difference exceeds 25 F the control...

Page 52: ... value is 6 3 F Temperature units F C The control can be configured to display temperature in either C or F This setting can be changed by the user or the installer The default is F Night setback temperature Once the internal clock has been set correctly the night setback feature can be used to program a lower tank set point The temperature range for this parameter is 32 F to 140 F The feature is ...

Page 53: ...g spark voltage to the spark electrode and opening the gas valve HTR IGNITION TANK 123 9F 129 5 If the control does not detect flame by the end of the trial for ignition the control performs a 10 second postpurge another prepurge and tries to light the burner again If the burner does not light after 4 trials the control locks out for 1 hour and then tries another set of 4 trials HTR POSTPURGE PREP...

Page 54: ...e Press to toggle between digits when entering the hour minutes etc or when entering date and time Figure 11 1 Control Panel Use the control panel FIG 11 1 to set temperatures operating conditions and monitor water heater operation 11 Operating information Installation Service Manual TM ...

Page 55: ...o clear the combustion chamber and vent system of residual flue products Service The unit has been placed in a temporary mode that will allow the unit to fire at 100 of rate for the purpose of combustion analysis TANK F The tank temperature is displayed Open The control does not detect the tank sensor Shorted The tank sensor wires or the sensor itself has become shorted Press the Next arrow key on...

Page 56: ...e flue sensor wires or the sensor itself has become shorted Press the Next arrow key on the electronic control module display to access Screen 4 4 FAN SPD RPM The control will display the actual fan motor RPM FLAME SIG uA The control will display the flame signal in dc microamps Press the Next arrow key on the electronic control module display to access Screen 5 5 FAULT 01 MM DD YY fault FAULT 01 ...

Page 57: ... and connections Perform start up checkout and performance verification per Section 10 in this manual Flame inspection stable uniform Flame signal at least 10 microamps at high fire Clean the heat exchanger if flue temperature is more than 54 F above return water temperature Check anode rods Check Delta T Temperature Rise If combustion or performance indicate need Clean heat exchanger Remove and c...

Page 58: ...aterials gasoline and other flammable vapors and liquids 2 Verify that air intake area is free of any of the contaminants listed in Section 1 of this manual If any of these are present in the water heater intake air vicinity they must be removed If they cannot be removed reinstall the air and vent lines per this manual Inspect water heater interior 1 Remove the front access cover and inspect the i...

Page 59: ...ld be re inspected AT LEAST ONCE EVERY THREE YEARS by a licensed plumbing contractor or authorized inspection agency to ensure that the product has not been affected by corrosive water conditions and to ensure that the valve and discharge line have not been altered or tampered with illegally Certain naturally occurring conditions may corrode the valve or its components over time rendering the valv...

Page 60: ...indow 2 If the flame is unsatisfactory at either high fire or low fire turn off water heater and allow water heater to cool down Remove the burner and clean it thoroughly using a vacuum cleaner or compressed air Do not use compressed air to clean burner if performed inside a building 3 Remove the burner reference FIG 12 2 below 4 When replacing the burner ensure gasket is in good condition and pos...

Page 61: ...ded depending on the job site conditions Current NIOSH recommendations can be found on the NIOSH website at http www cdc gov niosh homepage html NIOSH approved respirators manufacturers and phone numbers are also listed on this website Wear long sleeved loose fitting clothing gloves and eye protection Apply enough water to the combustion chamber lining to prevent airborne dust Remove the combustio...

Page 62: ...ing water heater startup Check control module fuses ALWAYS check control module fuses before replacing control module or any major components blower etc If one of these fuses is blown it can prevent the control module or other components from operating 1 Turn OFF power to the water heater at the external disconnect switch 2 Remove top access cover 3 Remove the control module cover 4 Inspect fuses ...

Page 63: ...oard Blown fuse Replace fuse F3 on the main control board see page 62 of this manual No Burner Operation Tank temperature set point satisfied Review temperature setting Unit locked out on fault Consult display for specific fault Refer to fault descriptions on page 66 of this manual for corrective actions Unit Does Not Modulate Above 50 Flue sensor open Verify that the flue sensor is located in the...

Page 64: ...ance Ω 68 14 773 176 1 707 86 9 804 194 1 266 104 6 652 212 952 122 4 607 230 726 140 3 252 248 560 158 2 337 Checking temperature sensors The water heater temperature sensors inlet water outlet water tank water and flue are all resistance type devices The following tables show the correct values for the sensors at various temperatures Use an ohmmeter to read the resistance of the sensor at a know...

Page 65: ...e maximum listed in the General Venting section Dirty damaged burner Refer to page 60 in this manual for the burner removal and inspection procedure Clean or replace the burner as necessary Low water flow through the heat exchanger Refer to Section 6 System Piping for minimum flow rates Air in the piping system Properly purge all air from the piping system No Pump Operation Blown fuse Replace fuse...

Page 66: ...that the plastic hose from the gas valve to the air inlet is connected and is not damaged Verify that the vent air intake pipes are correctly installed and that there are no obstructions Check for 24 VAC to the gas valve at the 2 pin connection on the side of the main control board during the ignition attempt If no voltage is present replace the main control board If 24 VAC is present at the main ...

Page 67: ...resent at the main control board check the wiring between the main control board and the gas valve Replace the wiring if necessary Do not disconnect the wiring from the gas valve and attempt to measure voltage at that point The main control board can detect if the gas valve is not connected and will display the GV Relay Fail fault If 24 VAC is present check the outlet of the valve to ensure the va...

Page 68: ...d Press the RESET button on the display to reset The actual fan RPM is 30 lower than what is being called for Vent air intake lengths exceed the maximum allowed lengths Refer to Section 2 General Venting for proper lengths Check for obstruction or blockage in the vent air intake pipes or at terminations Check the wiring connections at the fan and at the main control board Replace the fan Replace t...

Page 69: ...sensor if necessary Sensor Shorted will require a manual reset once the condition has been corrected Press the RESET button on the display to reset Either the heat exchanger inlet water heat exchanger outlet water or tank temperature sensor has been shorted S1 Outlet Sensor S2 Inlet Sensor Check the sensors and their associated wiring Repair or replace the sensor or wiring if damaged Measure the r...

Page 70: ...perature Verify that the system is full of water and that all air has been properly purged from the system Verify that the water heater is piped properly into the heating system Refer to Section 6 System Piping for the proper piping methods for the Shield water heater Check for 120 VAC to the water heater pump motor on a call for heat If voltage is not present check wiring back to the main control...

Page 71: ...ontrol board Replace the main control board if necessary If 120 VAC is present on a call for heat and the water heater pump is not operating replace the pump Verify that the water heater pump is set to the proper speed or that the water heater pump is the proper size Reference Section 6 System Piping for water heater pump specifications Low 24 VAC 120 VAC input to the main control board has droppe...

Page 72: ... is not within the specified range reference the chart below for possible causes and corrective actions Table 13F Troubleshooting Chart Combustion Levels POSSIBLE CAUSE CORRECTIVE ACTION Vent Air Intake Length or Obstruction Refer to Section 2 General Venting for the proper venting and air intake methods for the Shield water heater Check for obstructions at the vent air intake terminals Gas Supply...

Page 73: ...G 13 3 Using a screwdriver turn the screw 1 8 turn counterclockwise to increase CO2 levels or 1 8 turn clockwise to decrease CO2 levels After one adjustment on the valve follow the Combustion Analysis Procedure on page 72 of this manual to measure the combustion If combustion is still not within the specified range repeat the procedure This procedure SHOULD NOT be performed more than four 4 times ...

Page 74: ...SPARK ROD INTEGRATED CONTROL GROUND JUNCTION BOX INTEGRATED CONTROL 120 VAC LOW VOLTAGE HIGH VOLTAGE CAUTION HIGH VOLTAGE SPARK LEAD BLOWER TERMINAL STRIP TERMINAL STRIP 2 1 X2 2 GND X6 2 CN2 12 NOTES 1 Where possible switches are shown without utilities gas water or electricity connected to the unit As such actual switch states may vary from those shown on diagrams depending upon whether utilitie...

Page 75: ...VOLTAGE HIGH VOLTAGE X3 PC INTERFACE CN2 6 Notes 1 All wiring must be installed in accordance with local state provincial and national code requirements per either N E C in USA or C S A in Canada 2 If any original equipment wire as supplied with the appliance must be replaced it must be replaced with wire having same wire gauge AWG and rated for a minimum of 105 C Exceptions Replacement high volta...

Page 76: ...2738 reflects edits made to the Gas Valve Adjustment Procedure for Model SNA400 125 on page 69 Revision D ECO C03223 reflects edits made to the high altitude section on page 7 Revision E ECO C03735 reflects the addition of stainless steel venting hydro changes and the addition of the Anode Rod s section Revision F ECO C03974 reflects Delta T updates and additions SWH I S Rev F 6 09 ...

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