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3E. Hi-Limit Switch Checkout

After running the heater for a long enough

period, bring the water temperature within the range of
the hi-limit switch and slowly back off the high limit
setting until the heater shuts off. The main burners
should reignite when the hi-limit switch is reset and
turned back up to its original setting. The heater
should now run until it shuts off automatically on
operating control.

Should overheating occur or the gas supply fail

to shut off, turn off the manual gas control valve to the
heater.

3F. Shut-Down Procedure

Shut down the heater following the instructions

found on the inside of the heater.

Where there is a danger of freezing, shut off the

water supply and remove the drain plugs on both sides
of the heater jacket. Drain every part of the system
subject to damage from freezing temperatures.

SECTION 4.
Maintenance

4A. General Instructions

1.

Oil the water circulating pump in accordance
with the manufacturer's instructions.

2.

If a strainer is used in a pressure reducing valve
or in the piping, clean it every 6 months in
accordance with the manufacturer's instructions.

3.

At startup and every 6 months after, look at the
pilot and main burner flame (see Figure 28). If
the flame has the appearance of sooting tips,
check for debris near orifices. Call service
technician.

4.

Inspect the venting system for blockage, leakage,
and corrosion at least once a year.

5.

Keep the heater area clear of combustible
material, gasoline, and other flammable liquids
and vapors.

6.

Be sure all combustion air and ventilation
openings are not blocked.

7.

Check for black carbon soot buildup on the
external surfaces of the heat exchanger every 6
months.

8.

Do not use the heater if any part has been under
water. Replace anypart of the control system and
any gas control which has been under water.

NOTE: After installation and first startup, check

the heat exchanger for black carbon soot buildup after
the following periods of operation: 24 hours, 7 days,
30 days, 90 days, and once every 6 months thereafter.

Figure 27.  Temperature controls.

Manual Reset Temp. Control

Temperature Controller

Heaters on constant flow have the temperature

control sensor bulb in the heater inlet and the manual
reset hi-limit sensing bulb located in the heater outlet.
Set the temperature control dial (see Figure 27) at the
designed system temperature. Set the hi-limit switch
40 to 50°F (4 to 10°C) above the supply temperature to
the system.

Heaters on intermittent flow have the

temperature control sensing bulb in the storage tank
and the manual reset hi-limit sensing bulb located in
the heater outlet. Set the hi-limit switch 40 to 50°F (4
to 10°C) above the supply temperature to the system.

3D. Adjustment for Minimum Input Rate

(models with modulating gas valve)

Adjust the red knob on the modulating gas valve

to the dial number for the desired water temperature
(see Table 7). Adjusting the red knob to number "1"
sets the gas flow rate to minimum. The control is
factory set at "5" which is satisfactory for most
installations.

Temp.

Dial No.

°F

°C

1

120

49

2

127

53

3

135

57

4

142

61

5

150

66

6

157

69

7

165

74

8

172

78

9

180

82

Table 7.  Water Temperature Setting.

Содержание Fire-Coil 175-400

Страница 1: ...on will void the warranty WARNING 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...

Страница 2: ...mperature Controls 15 3D Adjustment for Minimum Input Rate models with modulating gas valve 18 3E Hi Limit Switch Checkout 18 3F Shut Down Procedure 18 SECTION 4 Maintenance 4A General Instructions 18 4B Replacement of Gas Controls 19 4C Heat Exchanger 20 4C 1 Inspecting the Heat Exchanger 20 4C 2 Cleaning the Heat Exchanger 21 SECTION 5 Troubleshooting 5A Gas Pressure Tests 21 5A 1 Checking the M...

Страница 3: ...number and model this information can be found on the rating plate installation date and name of the installer Shipping costs are not included in the warranty coverage Some accessory items are shipped in separate packages Inspect everything for damage immediately upon delivery and advise the transporter of any shortages or damage Any such claims should be filed with the transporter The transporter...

Страница 4: ...dance with CAN1 B149 1 or 2 and local codes The authority having jurisdiction may require the installation conform to the Standard for Controls and Safety Devices for Automatically Fired Heaters ANSI ASME CSD 1 Any changes to the heater gas controls gas orifices wiring or draft diverter may void the warranty If field conditions require a change to any of the above consult the factory All gas fired...

Страница 5: ...otal volume of all the gas fired appliances within the enclosure Alcove Installation acceptable An alcove suitable for the installation of a heater is a restricted section of a room not separated from the room by a door or partition and which meets the minimum clearances specified in this manual When the ceiling height exceeds 8 feet you are only allowed to consider 8 feet when calculating the tot...

Страница 6: ...s Flashing 4x4 Stringer Roof Base Rail 20 Gauge Galvanized Sheet Metal Cap Roofing Avoid locations where wind deflection off nearby structures might cause wind loading and downdraft conditions Where downdraft conditions exist locate the heater at least 3 feet 0 91 m from the structure 2C 3 Flooring Typical Installation Do not install the heater directly on carpeting without placing a non combustib...

Страница 7: ... fans can pick up exhaust flue products from the heater and return them inside the building creating a possible health hazard Avoid horizontal runs of the vent pipe and 90 degree elbows reductions and restrictions Horizontal runs should have at least a 1 4 inch 6 3 mm rise per foot in the direction of flow Support a vent connector for the design and weight of the material used to maintain clearanc...

Страница 8: ... 2 If there is a vent cap or drafthood installed they must be removed before removing the grate top assembly On indoor installations sizes 175 250 the drafthood switch must be disconnected at the left side of the heater 3 If the unit is in the low profile outdoor configuration remove the hex head screws see Figure 15 and lift the grate top assembly straight up 4 Remove the screws that fastens the ...

Страница 9: ...DUIT GAP CLOSURE GROMMET DRAIN VALVE METAL CHANNEL FOR CAPILLARY TUBE TERMINAL STRIP HEAT EXCHANGER ASSEMBLY GAP CLOSURE DRAIN PLUG DRAIN VALVE REAR TILE COVER HEX HEAD SCREWS MANUAL RESET HIGH LIMIT SWITCH BOX Figure 15 Heat exchanger reversal 2 Stage Operating Controller Inlet Outlet High Limit Header Modulating if installed Retaining Clip ...

Страница 10: ...F 2 Water Chemistry Natco equipment is designed to be used in a variety of water conditions With the proper pump the water velocity in the heat exchanger tubes is kept high enough to prevent scaling from hard water yet low enough to avoid erosion by soft water NOTE It is possible to have hard and soft water in the same city Check with the local water companies Figure 18 Hole location left side Att...

Страница 11: ...07 kPa it could damage the heater through lack of circulation If for any reason the water is turned off temporarily to service the equipment for example airlock could be a problem when the heater If an installer sees damage to any water handling equipment at the installation site it should be repaired as soon as possible to help reduce maintenance costs If there is erosion resize the pump to reduc...

Страница 12: ...2 1 13 3 4 1 19 11 Hard 46 2 9 23 4 7 1 14 8 4 Soft 17 0 7 11 1 3 4 37 21 Normal 17 0 7 11 1 3 4 37 21 Hard 23 1 5 19 5 5 9 27 15 Pressure drop includes head loss of heat exchanger and through 30 feet 9 1 m of pipe and normal fittings when heater is installed with storage tank Pipe and fittings are assumed to be 1 1 2 inch 38 mm Remote Temperature Control for Heater Main Circulating Loop With Own ...

Страница 13: ...ank Opening Not Available To Drain Heater Service Valve Pump To Drain Conventional Tank Figure 21 Hot water supply with horizontal tank Note Heavy line indicates heater to tank circulation loop Hot Water Return from Building Hot Water to Building Check Valve Bldg Loop Circ Pump Cold Water 24 Inch Min Drain Conventional Tank Heater To Drain Service Valves Figure 20 Hot water supply with vertical ta...

Страница 14: ...nes Under certain circumstances thermal circulation will occur in the cold water pipe supplying the water to the heating system This happens in a multi story building when the cold water pipe rises from its connection to the system To correct the problem a check valve in the cold water line supplying the heater will prevent thermal circulation and a small expansion tank will permit heated water to...

Страница 15: ...e figures in Table 5 should be used to size the gas piping from the gas meter to the heater Figure 23 T Fitting and sediment trap MANUAL SHUT OFF VALVE GAS SUPPLY INLET T FITTING 3 76 mm MIN UNION NIPPLE CAP TO BOILER INLET Distance from Gas Meter 0 100 feet 100 200 feet 200 300 feet 0 30 m 30 60 m 60 90 m Heater Nat Nat Nat Size in mm in mm in mm 175 1 00 25 1 25 32 1 25 32 250 1 25 32 1 25 32 1 ...

Страница 16: ...interlock the pump and heater so the heater cannot come on unless the pump is running 4 Connect all field installed devices draft switches relays timers outdoor temperature reset devices etc see Figs 18 and 19 to the heater wiring at points labeled Field Interlock 2I Combined Space Heating Potable Water Heating Systems 2I 1 Combined Space Heating The VW and PW heaters are not to be used as a sourc...

Страница 17: ... electric power to the appliance to off 5 Turn manual gas valve off 6 Wait 5 minutes to clear out any gas then smell for gas including near the floor Be sure to smell next to the floor because some types of gas are heavier than air and will settle on the floor Caution This heater is equipped with an ignition device which automatically lights the burner Do not try to light the burner by hand 7 Turn...

Страница 18: ...al example of wiring schematic System 1 IGNITION SYSTEM NO 1 STANDING PILOT ON OFF OR MECHANICAL MODULATION Volume Water Heaters 325 400 Version B Natural or Propane Gas PUMP INCLUDED ON PW MODELS FIELD SUPPLIED ON VW MODELS ...

Страница 19: ...Figure 26 Typical example of wiring schematic System 12 IGNITION SYSTEM NO 12 ELECTRONIC IGNITION ON OFF OR MECHANICAL MODULATION Volume Water Heaters 325 400 Version B Natural or Propane Gas PUMP INCLUDED ON PW MODELS FIELD SUPPLIED ON VW MODELS ...

Страница 20: ...mmable liquids and vapors 6 Be sure all combustion air and ventilation openings are not blocked 7 Check for black carbon soot buildup on the external surfaces of the heat exchanger every 6 months 8 Do not use the heater if any part has been under water Replace anypart of the control system and any gas control which has been under water NOTE After installation and first startup check the heat excha...

Страница 21: ...ttempt to repair the gas valve Such attempts will void the warranty and could lead to dangerous results If the gas valve is found to be defective replace it by following these instructions 1 Turn off electrical power to the heater 2 Turn off the main gas supply at the manual gas cock outside the heater jacket or at the meter 3 Remove the front access door on the heater 4 Turn off the gas valve to ...

Страница 22: ...aks using a soap solution Caution Since some leak test solutions including soap and water may cause corrosion or stress cracking rinse the piping with water after testing 22 Reconnect the electrical wires to the gas valve in accordance with the wiring diagram found on the inside of the heater 23 Install the front access door on the heater 24 Turn all electrical power to the heater on 4C HEAT EXCHA...

Страница 23: ...ively starting with the two center bolts Maximum torque is 20 foot pounds 27 Nm Do not over torque 8 Pressure test the heat exchanger for leaks with city water supply before re installing see Figure 32 9 When placing the heat exchanger back in the heater carefully hold the refractory insulation blocks apart and lower the heat exchanger into place Be sure the sheet metal covers which protect the in...

Страница 24: ...the inside of the heater 11 Disconnect the manometer tubing from the gas valve and replace the 1 8 inch NPT 3 2 mm fitting with the original plug 5B Electrical Troubleshooting This section describes procedures for checking the electrical power and control components of the heater Read all of these procedures before starting repairs Problems with heaters not firing are usually caused by something r...

Страница 25: ...erminal see Figure 34 The voltmeter should read 20 to 28VAC 3 If the voltmeter does not show voltage check the electrical power supply 4 If the voltage is less than 20VAC the electrical circuit to the heater may be supplying less than 103VAC This could be due to high pump load or air conditioners or other appliances on the circuit 5B 3 Testing the Electrical Power Supply The electrical components ...

Страница 26: ...k fire If the water flow is too low the switch remains open and prevents the heater from firing regardless of the temperature control setting The flow switch is factory mounted and wired Never attempt to repair the flow switch If the flow switch is found to be defective replace the flow switch To test the flow switch 1 Remove cap from flow switch 2 Touch a voltmeter lead to each terminal of the fl...

Страница 27: ...er from firing 4 Make sure the pilot burner is positioned next to the main burner see Figure 38 and there is no soot or dirt on it 5 Make sure the electrode part of pilot assembly is clean the terminal connection is tight and the stainless steel lead is at least 3 8 inch 9 5 mm from the heater chassis and other metal parts 6 Check for proper spark gap 5B 10 Testing the High Voltage Ignition Lead C...

Страница 28: ...not show voltage replace the ignition control 6 If the voltmeter reads 20 to 28VAC but there is no pilot ignition check for a air in gas lines b restrictions in gas line valve or pilot tubing c clogged pilot orifice If these are correct then replace gas valve see Section 4C WARNING Never attempt to repair the gas valve Such attempts will void the warranty and could lead to dangerous results 5B 14 ...

Страница 29: ...tage at one terminal and not the other examine the external control It may require service or replacement 2 If everything appears all right measure flame sensing current by connecting a direct current DC microamp meter between terminal No 12 and the GND BURNER terminal on the ignition control see Figure 41 NOTE Separate the microamp meter leads from each other and clear the heater chassis for most...

Страница 30: ... 16 Fuse 2 Amp E0084400 17 Switch Flow Outdoor E0013000 18 Fusible Link 175 thru 250 E0099403 19 Switch Toggle On Off E0077000 20 Switch Hi Limit Manual Reset E0015900 Item Description Part Number 21 Temp Controller Auto Reset E0014400 Model 250 E0141302 24 Switch Drafthood E0121000 VENT SYSTEM 26 Vent Cap R0318602 05 27 Drafthood R0318702 05 28 Drafthood Vent Cap Adapter Plate 10535302 05 29 Flue...

Страница 31: ...0071700 61 Bushing Brass P0018500 62 Bracket Holddown 10726300 63 Clamp Holddown 10726200 Item Description Part Number JACKET COMPONENTS 64 Jacket Assembly 10568302 05 65 Door 10448902 05 66 Deflector Rear 10563706 10 67 Deflector Lower 10563606 10 68 Gap Closure In Out 10448202 69 Gap Closure Return 10448302 ...

Страница 32: ...National Combustion Company Inc 104 07 180th Street Jamaica NY 11433 718 291 8400 FAX 718 291 6870 Litho in U S A 0610 H0210400A ...

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