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Water heaters for use with Natural and L.P.G.

GWH 425 EF

Flow Modulated with Electronic Ignition and Power Venting

Suitable for heating potable water only - Not approved for space heating purposes

(Intended for variable flow applications with steady cold water inlet temperatures)

GWH-425-EF-N
GWH-425-EF-L

720 

607

 017 

US

 (

04.

10) 

A

L

Warning: 

If  the  information  in  this  manual  is  not

followed  exac tly,  a  fire  or  explosion  may  result
causing property damage, personal injury or death.
Do  not  store  or  use  gasoline  or  other  flammable
vapor and liquids in the vicinity of this or any other
appliance.

Improper 

installation, 

adjustment, 

alteration,

service  or  maintenance  can  cause  injury  or
property  damage.  Refer  to  this  manual.  For
assistance  or  additional  information  consult  a
qualified  installer,  service  agency  or  the  gas
supplier.
In  the  Commonwealth  of  Massachusetts  this
product must be installed by a licensed plumber or
gas fitter.

Upon  completion  of  the  installation,  these
instructions  should  be  handed  to  the  user  of  the
appliance for future reference.

What to do if you smell gas

• Close gas valve. Open windows.

• Do not try to light any appliance

• Do  not  touch  any  electrical  switch;  do  not  use  any

phone in your building

• If  you  cannot  reach  your  gas  supplier,  call  the  fire

department.

• Immediately call your gas supplier from a neighbor’s

phone. Follow the gas supplier’s instructions.

• Installation  and  service  must  be  performed  by  a

qualified installer, service agency or the gas supplier.

Summary of Contents for GWH 425 EF

Page 1: ...vice or maintenance can cause injury or property damage Refer to this manual For assistance or additional information consult a qualified installer service agency or the gas supplier In the Commonwealth of Massachusetts this product must be installed by a licensed plumber or gas fitter Upon completion of the installation these instructions should be handed to the user of the appliance for future r...

Page 2: ...y of this or any other appliance WHAT TO DO IF YOU SMELL GAS Close gas valve Open windows 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 neighbor s phone Follow the gas supplier s instructions If you cannot reach your gas supplier call the fire department Installation and service must be performed...

Page 3: ... water faucet is shut off the gas valve automatically closes and the burners turn off followed immediately by the exhaust system Your hot water faucet is an ignition key to turn on the water heater giving you control over your hot water energy use Every time you turn off your hot water faucet the energy consumption for hot water returns to zero FEATURES Electronic Pilot Ignition On Off switch to a...

Page 4: ...S FOR ALCOVE OR CLOSET INSTALLATIONS FRONT VIEW SIDE VIEW MODEL 425 EF On a combustible wall surface the unit should be mounted away from the wall to provide adequate clearance of the vent pipe See page 5 for instructions TOP A 12 FRONT B 4 BACK 0 SIDES 4 FLOOR C 12 VENT DIAMETER 4 MODEL 425 EF ...

Page 5: ...the location of your new heater For your safety and for proper heater operation you must provide an abundant supply of combustion air and a proper venting installation The heater may still operate even when improperly vented It will however be less efficient and could eventually damage the heater It could even result in human sickness or death due to oxygen deprivation and carbon monoxide poisonin...

Page 6: ...ust be provided with two permanent openings one commencing within 12 inches of the top and one commencing within 12 inches of the bottom of the enclosure Each opening must have a minimum free area of one square inch per 1000 Btu hr if all air is taken from inside the building 2000 Btu hr if all air is taken from the outside by horizontal ducts 4000 Btu hr if all air is taken from the outside by di...

Page 7: ... of studs and then the heater should be attached to the support boards See Fig 2 NOTE Additionally the 425 EF should be spaced away from any combustible wall surface to provide the necessary clearance that the venting material specifies must be maintained between the vent pipe and a combustible surface See VENTING section Also review the FXHOOD horizontal vent terminator instruction sheet provided...

Page 8: ...han 45 degrees is considered and elbow Note Single wall pipe should not be used in concealed unoccupied or unheated locations Listed thimbles or collars are necessary to pass through wall partitions If the vent system passes through combustible areas where the vent clearance requirements cannot be maintained it is permissible to chase straight sections of sealed 4 inch single wall vent through 5 i...

Page 9: ...r to prevent negative air from freezing the 425 EF see Fig 5 for restrictions in location of vent terminal G181_274 Approved Vent Terminal FXHOOD or other approved terminal The FXHOOD is design approved with the 425 EF and has a built in back draft flapper to prevent negative air from freezing the 425 EF see Fig 5 for restrictions in location of vent terminal 4 single wall venting only Use stainle...

Page 10: ...ngs and so that proper clearances are maintained See Fig 5 a The vent terminal shall not be less than 7 feet above a public walkway b The vent terminal shall terminate at least 3 feet above any mechanical air inlet within 10 feet c The vent terminal shall not be within a 6 foot radius from a gas meter or regulator d The vent terminal shall be a minimum of 6 feet from any combustion air inlet e The...

Page 11: ... to the inlet of the 425 EF regulator For semi rigid copper piping 5 8 up to 20 feet and 3 4 up to 50 feet distances For Black Iron piping 1 2 up to 30 feet and 3 4 up to 150 feet distances Flex line tubing is NOT recommended but if used then oversize it THESE FIGURES ARE FOR 425 EF SUPPLY ONLY ALL OTHER APPLIANCES IN THE BUILDING WILL NEED TO BE INCLUDED IN THE PIPE SIZING National Fuel Gas Code ...

Page 12: ...nary number of fittings GAS LINE SIZING Nominal Iron Length of Black Iron Pipe Feet Pipe Internal Size Diameter inches inches 10 20 30 40 50 60 70 80 90 100 125 150 175 200 1 4 0 364 32 22 18 15 14 12 11 11 10 9 8 8 7 6 3 8 0 493 72 49 40 34 30 27 25 23 22 21 18 17 15 14 1 2 0 622 132 92 73 63 56 50 46 43 40 38 34 31 28 26 3 4 0 824 278 190 152 130 115 105 96 90 84 79 72 64 59 55 1 1 049 520 350 2...

Page 13: ...tape is to be used at this joint The flexible hot water outlet line is supplied attached to the heater Be certain there are no loose particles or dirt in the piping Blow out or flush the lines before connecting to the water heater Full port valves should be installed on both the cold water supply and hot water outlet lines to facilitate servicing the heater see Fig 7 For installation on a private ...

Page 14: ...of the heater CAUTION Label all wires prior to disconnection when servicing controls Wiring error can cause improper and dangerous operation Verify proper operation after servicing The 425 EF requires an electrical power supply from 120VAC 60Hz circuit and must be properly grounded A means for switching off the 120 VAC power supply must be provided The heater is wired as shown in the wiring diagra...

Page 15: ... burner and an automatic ignition control system 4 Set the ON OFF switch flip down cover plate on front panel strip marked to the position In this position the water heater is ready to use 5 Verify that the power supply to the appliance is turned on To operate the heater set the ON OFF switch to position The switch is located behind the flip down cover plate on the front panel strip To shut down t...

Page 16: ...cold climate areas it might be necessary to set the control all the way clockwise to the right for maximum temperature rise Do not supply the 425 EF with preheated water For this type of application purchase a solar model 125 B LPS or 125 B NGS If the inlet water temperature to the water heater is very warm the heater can produce temperatures that may be found to be too hot A temperature balance s...

Page 17: ...rature settings and the water has a high mineral content periodic descaling may be necessary The heating coils should be flushed with a descaling solution Consult your dealer or service person TROUBLE SHOOTING see maintenance table Introduction The 425 EF pilot and burners are ignited by a water flow valve Numerous water related problems can cause this water valve to malfunction such as Insufficie...

Page 18: ...e pilot light ignites At that point retighten the screw one and a half turns See Fig 14 5 Pilot electrovalve switch may need to be replaced see fig 9 Measure millivoltage at pilot electrovalve see Fig 9 6 Control Box may need to be replaced see fig 9 Check wire connections and test operation of control box see Fig 9 PILOT SPARKS CONTINUOUSLY WITH NO WATER RUNNING 1 Microswitch needs adjustment If ...

Page 19: ... SPARK AT THE PILOT White vinegar should be applied first to any corrosion before the loosening of screws HOT WATER TEMPERATURE FLUCTUATES UNIT DEACTIVATED 1 Unbalanced pressure in waterlines The added restriction caused by the 425 EF in the hot water system can result in uneven pressures between the cold and the hot In such cases when mixing cold water at the tap the lower hot water pressure may ...

Page 20: ...20 6 720 607 017 ...

Page 21: ...ressure test nipple 4 Main gas burner 5 Pilot gas tubing 6 Gas valve 7 electric control box 8 Power cord 9 on off switch 10 Temperature adjustment selector 11 Microswitch 12 Gas inlet gas pressure test nipple 13 Exhaust Fan 14 Flexible hot outlet 5 11 1 4 9 10 12 2 6 8 7 13 3 14 6 720 606 601 12 1AL ...

Page 22: ...22 6 720 607 017 Fig 16 INTERIOR COMPONENTS DIAGRAM AND PARTS LIST ...

Page 23: ...021 NG 16 Diaphragm switch 8 708 504 049 LPG 17 Pilot electrovalve 8 708 501 249 18 Burner electrovalve 8 708 501 250 19 Cold water pipe 8 700 705 627 20 Exhaust fan assembly 8 707 204 023 21 Exhaust fan cable 8 704 401 168 22 Outlet flex hose 8 700 703 139 23 Washer 8 700 103 658 24 Water valve 8 707 006 361 25 Water valve cover 8 705 500 101 26 Diaphragm 8 700 503 092 27 Water inlet filter 8 700...

Page 24: ...24 6 720 607 017 Fig 17 Flow chart of 425 EF ...

Page 25: ...vice delivery for these parts Expedited or upgraded shipping will be charged to the customer Service labor costs This warranty does not cover any labor costs associated with service removal or re installation of part s All such costs must be borne by the Purchaser Additionally this warranty does not cover any labor costs associated with service removal or re installation of the original water heat...

Page 26: ...k Waitsfield Vermont 05673 Phone 866 330 2730 Fax 802 496 6924 www protankless com techsupport protankless com 6 1 e g a p e e s E L B A T E C N A N E T N I A M R A E Y Y R E V E S R A E Y 2 Y R E V E S R A E Y 5 3 Y R E V E E V L A V R E T A W E T A C I R B U L E V L A V R E T A W D L I U B E R N E E R C S R E T L I F R E T A W T C E P S N I Y L B M E S S A T O L I P T C E P S N I Y L B M E S S A...

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