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Mighty Therm VW - PW Volume Water Heaters

Page 17

SECTION 3.
Operating Instructions

3A. Normal Operating Sequence

NOTE: Safe lighting and other performance

criteria were met with the gas manifold and control
assembly installed on the heater during tests specified
in ANSI Z21.13.

WARNINGS

Vent pipes, drafthoods, and heater tops get hot!
These surfaces can cause serious burns. Do not
touch these surfaces while the heater is in
operation. Adding a vent cap reduces the
temperature on the top.

For your safety, when starting the heater, keep your
head and face well away from the lower firebox
opening to prevent any risk of personal injury.

LP GAS: To avoid possible injury, fire and
explosion, read and follow these precautions and all
instructions on this heater before lighting. This
heater uses LP gas which is heavier than air and
will remain at ground level if there is a leak. Before
lighting, sniff at ground level.
If you smell gas, follow these rules:

1. DO NOT light matches. DO NOT turn electric

lights or switches on or off in area. DO NOT use
an electric fan to remove the gas from area.

2. Shut off gas at LP tank.

3. Telephone gas company and fire department for

instructions. Give your name, address and
phone number.

If your LP tank runs out of fuel, turn off gas at the
heater. After the tank is refilled, the heater must be
relit in accordance with the instructions found on the
inside of the heater. DO NOT attempt repairs on the
gas control or heater. Tampering is dangerous and
voids all warranties.

3B. Start-Up Procedure

Lighting instructions can be found on the inside

of the heater. To start up the heater:

1.

Make sure the system pump is running and there
is water flow.

2.

Remove the control access panel.

3.

Set the temperature control (see Figure 28) to its
lowest setting.

4.

Turn 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 manual gas valve on.

8.

Reset all safety devices (some units have manual
resets on hi-limit switch, low water cutoff, etc.).

9.

Replace control access panel.

10.

Turn electric power to the heater on.

11.

Set temperature control to desired setting.

12.

If the heater will not operate:

a. Turn gas to heater off following the

instructions found on the inside of the heater
and call a qualified service technician or gas
supplier.

b. Turn main electrical switch off.

c. Close all manual gas valves.

3C. Setting the Temperature Controls

The hi-limit switch is factory set and should not

be adjusted.

WARNING

Adjusting the temperature control past the
recommended setting can result in a scalding injury.
Hot water can produce third degree burns in 6
seconds at 140°F (60°C) and in 30 seconds at
130°F (54°C).

Water temperature can be adjusted at the

temperature control (see Figure 28). The temperature
control is adjusted to its lowest setting when it is
shipped from the factory. The 130°F (54°C) setting is
the recommended starting point for setting the
temperature control.

The recommended setting will result in

satisfactory energy savings. Lowering the temperature
may result in reduced energy costs. Connecting the
heater to a separate storage vessel and lowering the
temperature setting, may reduce energy losses during
standby periods when hot water is not being used, and
may meet normal hot water needs. For increased hot
water usage, a higher temperature setting may be
necessary to meet increased demand. Reset the
temperature setting to a lower level after periods of
increased usage are over.

Summary of Contents for Mighty Therm PW-175

Page 1: ...allation and or operation 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 lif...

Page 2: ...re 17 3C Setting the Temperature Controls 17 3D Adjustment for Minimum Input Rate models with modulating gas valve 20 3E Hi Limit Switch Checkout 20 3F Shut Down Procedure 20 SECTION 4 Maintenance 4A...

Page 3: ...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 immediate...

Page 4: ...y 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...

Page 5: ...as 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 p...

Page 6: ...ible Floors 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 conditio...

Page 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...

Page 8: ...ver 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 l...

Page 9: ...AL 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 reve...

Page 10: ...ten the conduit by sliding the retaining nut over the two brown wires inside the control compartment then screwing it down finger tight on the conduit elbow 27 Straighten the capillary tubing and fast...

Page 11: ...ssociation CGA for outdoor installations such installations are not recommended in areas subject to freezing temperatures unless proper precautions are taken Consult the local factory representative o...

Page 12: ...Normal 34 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 throu...

Page 13: ...ank Opening Not Available To Drain Heater Service Valve Pump To Drain Conventional Tank Figure 22 Hot water supply with horizontal tank Note Heavy line indicates heater to tank circulation loop Hot Wa...

Page 14: ...ng that goes to a floor sink and install a drain valve If a floor sink is not available install a hose bib 8 Hot water tanks in an existing installation are likely to have silt deposits on the bottom...

Page 15: ...e gas piping from the gas meter to the heater 5 Install a sediment trap drip leg ahead of the gas controls see Figure 24 Fit the trap with a threaded cap which can be removed for cleaning 6 Install a...

Page 16: ...exactly as shown in the wiring diagram supplied with the heater See Figure 26 and 27 for a typical example of a wiring diagram 3 Electrically interlock the pump and heater so the heater cannot come on...

Page 17: ...n 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 t...

Page 18: ...e 26 Typical 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...

Page 19: ...Figure 27 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 IN...

Page 20: ...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 m...

Page 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...

Page 22: ...tem for leaks 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 el...

Page 23: ...ively starting with the two center bolts Maximum torque is 20 inch pounds 27 Nm Do not over torque 8 Pressure test the heat exchanger for leaks with city water supply before re installing see Figure 3...

Page 24: ...structions found on the inside of the heater 11 Disconnect the manometer tubing from the gas valve and replace the 1 8 inch 3 2 mm NPT fitting with the original plug 5B Electrical Troubleshooting This...

Page 25: ...inal see Figure 35 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 he...

Page 26: ...usible link 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 Nev...

Page 27: ...ter from firing 4 Make sure the pilot burner is positioned next to the main burner see Figure 39 and there is no soot or dirt on it 5 Make sure the electrode part of pilot assembly is clean the termin...

Page 28: ...eter does 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 tubin...

Page 29: ...ltage 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 curren...

Page 30: ...10690300 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 Nu...

Page 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...

Page 32: ...Drive Moorpark CA 93021 805 529 2000 FAX 805 529 5934 20 Industrial Way Rochester NH 03867 603 335 6300 FAX 603 335 3355 480 S Service Road West Oakville Ontario Canada L6K 2H4 905 844 8233 FAX 905 84...

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