water heaters 110802042613 water heaters

8/8/2019 Water Heaters 110802042613 Water Heaters

1/12

Buying a new

water heater

Sizing and

installing a water

heater system

Avoiding waste in

using hot water

There are three ways to reduce hot waterexpenses: use less hot water, improve the effi-ciency of your present hot-water heater or pur-chase a new high efficiency model. This guideoffers help in all three areas.

Buy new, or keep the old?

Water heaters have an average life expectancyof 10-12 years, but they can last much longer.Most are not replaced until the tank fails andbegins leaking. In many cases, however, it iswise to change the heater long before water

begins leaking on the floor.

An old water heater can operate for years atvery low efficiencies before it finally fails. It isoften cheaper to remove an operating, but inef-ficient, older unit and replace it with a newhighly efficient model.

There are also instances when even a properlyoperating model should be replaced. For exam-ple, if you have an energy efficient furnace thatexhausts through the side of your house, andyour chimney is in need of repair or a liner, youmay want to consider replacing the existingwater heater with one that will exhaust throughthe basement wall. Fixing the chimney whilecontinuing to pay more for hot water may costconsiderably more than simply capping thechimney and buying a new water heater thatdoesnt need a chimney.

If your water heater tank is leaking, then your

course is clear: buy a new unit. But if it isnt,your answer is less obvious.

Ask yourself the following questions:

Does the water heater make popping orcracking noises?

Have you been forced to turn up the tempera-ture setting over time to maintain an ade-quate supply of hot water?

Do you have very hard water?

Look under the burner. Is there a buildup ofrust or other deposits?

Open the drain tap at the bottom of theheater. Is the stream of water equal to anyfaucet? If the stream is small or nonexistent,then you have a big buildup of scale insidethe heater that is wasting energy and can also

mean that your water heater is approachingthe end of its useful life.

CAUTION: If your heater is old and does have a

scale buildup, you may not be able to close the

drain tap. Be prepared to shut off the water with

the valve at the top of the tank and use a wrench

to tighten the drain tap. The water heater gas

valve should be placed on pilot when doing

this.

Minnesota Department of Commerce 1

Related Guides:

Low Cost/No Cost Ideas

New Homes

Combustion & Makeup Air

ndoor Ventilation

Appliances

TECHNIQUES

TACTICS

&TIPS

HOME

ENERGY

GU I DE

WATER

HEATERSMinnesota Department of Commerce Energy Information CenterWater heating is often the second largest energy expense in the Minnesota home, and mayaccount for up to 20 percent of annual household energy costs.


2/12

If you answered yes to several of these ques-tions, a new hot-water heater is probably a

good investment.

If your answers indicate that the heater is oper-ating well, call the Energy Information Centerand ask for the Home Energy Guide, Low Cost& No Cost Energy & Money Saving Ideas.(Ordownload it from the department web site). Itcontains several good tips on improving theoperation of hot water heaters.

Switching fuelsBefore switching to a different fuel, make sureit will really save you money. Bear in mind thatfuture variations in fuel prices are very difficultto predict. (See sidebar, Comparing fuel costs).Find out how much it will cost for piping andwiring. Make sure there is proper space for thewater heater. Check to see if additional plumb-ing will be needed.

If you use or are considering electricity as a for water heating, call your utility and ask hoff-peak rates or interruptible rates can savemoney.

If you must replace an old water heater, youmay save money by using a different fuel not always. If gas is already used for clothes

drying or space heating, replacing a malfunctioning electric hot water heater with a natugas unit may be a good decision.

Buying a new hot water heater

When purchasing a new water heater, buy aenergy efficient model. It will cost a little mobut the extra cost will pay for itself in a fewyears time. After that, the better efficiency wsave you money for the life of the water hea

Dont rely on design features alone to assureenergy efficiency. Read and use the rating foon the yellow and black Energy Guide tagfound on all new water heaters. The tag wilyou the estimated yearly cost of operating thunit.

The best indicator of a water heaters efficienis its Energy Factor (EF). The EF takes intoaccount both the efficiency of heat transfer ithe water and the standby heat loss of the sage tank. The Energy Information Center recommends an EF of 0.64 or greater for gas wheaters, and an EF of 0.93 or greater for elewater heaters.

Buy the right size hot-water heater: Too smaand you may run out of hot water in the midle of a shower; too large and youll pay for water that is never used. To find the proper

determine the time of the day when yourhousehold uses the most hot water. Use thechart on page 6 to list where and how manytimes the hot water is used in one hour durthe peak period. Multiply the number of useby the average amount of hot water consumby each activity and add the totals to find yopeak demand.

The peak hour demand capacity, referred to

2 Minnesota Department of Comme

Figure 1

Gas water heater

Cold water inlet

Glass lining

Sacrificial anode

Dip tube

Flue baffle

Insulation

Drain valve

Burner

Chimney

Hot Water outlet

Draft hood

Relief valve

Discharge pipe

Vent pipe

Gas supply line

Gas Shutoff valve

Temperature setting control

Thermostat

Burner supply line

Pilot light

Thermocouple


3/12

he first-hour rating (FHR), is more importanthan the actual size of the tank because it is anestimate of how much hot water the unit willdeliver in an hour. The FHR is displayed on theEnergy Guide label. Look for a new waterheater with an FHR that is close to the estimateof your households peak hour demand. If you

only reach your peak once a week, and use lesshot water the rest of the time, consider adjust-ng your use to spread out demand and buy amaller heater.

Mobile home water heaters

t is very important to install the correct type ofgas water heater in a mobile home ( or manu-actured housing). If your mobile home has anexterior access door you may use a standardmobile home water heater with an open drafthood (atmospheric vent). If your water heateraccess door opens to the interior or your waterheater is located in a cabinet or closet, youmust install a direct vent mobile home waterheater. A direct vent water heater is designed toprevent the accidental spillage of flue gases intohe home. The letters DV will appear in themodel number.

For both types, it is important to seal the com-

partment housing the water heater from otherparts of the house. Seal off any holes forplumbing pipes or electrical wires between thecompartment and the home. Make sure that theaccess door seals tightly and is made of a fireesistant material like sheetrock. Often the floor

of the water heater compartment needs to beepaired or replaced because of water damage.

Make sure that a combustion air intake isnstalled through the new flooring and that the

pressure release valve, (T&P valve), has anextension that passes through the floor into thecrawlspace. It is recommended that a contractorcertified to work on manufactured housinghould do the installation.

Types of water heaters

A conventional water heater is a fairly simpleappliance. It consists of a storage tank and aource of heat. The tank is usually steel and

coated with glass or enamel to prevent corro-sion. It is covered with insulation and enclosedin a steel jacket.

The most common sources of heat are a gasburner or an electric resistance heating element.Both are controlled by a thermostat that respondswhen hot water is drawn from the tank.

Gas hot-water heaters. The most common sizenatural gas water heater is 40 gallons. Typicalgas models have a burner under the tank andan exhaust stack/heat exchanger, which runsthrough the middle of the tank (Figure 1). Theexhaust stack has two functions: it is a vent forthe burner and it transfers heat to the water. Adouble-wall (class B) venting system is used toexpel flue products through the roof of the

Energy Information Center 3

Figure 2

Power vented water heaters can

be vented through a sidewall or

vertical vent.

Source:CenterPoint Energy Minnegasco


4/12

house. These units use room air for combustionand exhaust, and are often referred to as atmos-pheric-vent units.

A major difference with some newer gas waterheaters is in how the exhaust gases are ventedfrom the house. Following is a description ofthe types of new gas water heaters that areavailable.

Power-vented water heaters are similar toatmospheric models in that they rely on roomair for combustion, but they feature a re-engi-neered exhaust (Figure 2). Power-vented unitsrequire no chimney or chase. They can bevented through a sidewall or vertical roofvent and can be placed up to 40 feet from theside venting.

Atmospheric direct-vent water heaters(sometimes referred to as sealed combustiare particularly good for airtight energy efcient construction because they use outsidair for both combustion and exhaust. Intakair for combustion and exhaust gases are ducted to and from the side of the house.

They operate independently of other exhausystems in the house. Like a power-ventedunit, an atmospheric direct-vent water headoes not need a chimney and allows forgreater installation flexibility.

Powered direct-vent models (also sometimreferred to as sealed combustion) combine tfeatures of power- and direct-vent models. Ooutside air for both combustion and exhausused. Because of the power-assisted exhaust

the unit can be placed up to 40 feet from asidewall. It uses PVC plastic pipe as a ventinmaterial. This unit is perfect for airtight construction and offers flexible installation.

Backdrafting and combustion air. The EneInformation Center recommends sealed combustion natural gas water heaters. The mainadvantage is that they greatly eliminate thepotential danger of the hot-water heater bac

drafting into the house, which can be a probin even moderately tight homes. Backdraftinoccurs when fuel-burning appliances are notreceiving enough combustion air.

A sample of 7,000 houses that were tested inthe Minneapolis-St. Paul area indicated thatabout 20 percent of the atmospheric waterheaters failed to draft properly when subjectto a worst case spillage test. The problemappears to have greater potential with system

vented by masonry chimneys on an outsidewall. The best option to remedy this situatioto either install a new power-vent water heaor add a power vent kit (see below) to the exing water heater.

In many homes, a new energy efficient furnthat vents out of the sidewall of the house hreplaced the original heating system. If thewater heater continues to be vented through


Figure 3

Typical electric water heater.

Hot water outlet

Power line

Upper thermostat

Lower thermostat

Insulation

Shutoff valve

Cold water inlet

Relief valve

Discharge pipe

Upper heating element

Sacrificial anode

Dip tube

Lower heating element

Drain valve

Glass lining


5/12

lue, backdrafting can occur. Additional combus-ion air is often needed to correct this problem.For information on testing for and installing acombustion air supply in your home call theEnergy Information Center and ask for a copyof the Combustion and Makeup Air HomeEnergy Guide.

The Energy Information Center also recom-mends that you purchase an electronic carbonmonoxide alarm. Make sure it is listed by theUnderwriters Laboratory and has a digital dis-play and memory feature.

Power-vent kits. Kits are available that modifyan older atmospheric-vent water heater toexhaust through the sidewall. The kits essential-y turn the old unit into a power-vented one but

can be expensive to buy and install. In somecases, the cost can be as much as a new sealedcombustion water heater. As with any productadded to an appliance, power-vent kits shouldhave an American Gas Association,Underwriters Laboratory or other appropriateisting agency approval. Also make sure the kitwill not void your warranty.

Remember: any modification work done onyour vent system must be inspected andapproved by your local building inspectionoffice.

Electric water heaters. Most electric modelsuse resistance coils inside the tank (Figure 3).Electric water heaters typically have slowerecovery rates that many gas models. They

make up for that with larger tanks.

Although electric water heaters are generally

more expensive to operate than natural gasmodels, they do have some advantages overgas. Electric units have no flue pipe, so you canput one almost anywhere in your home, fornstance, in a closet, or under a sink.

The entire tank is surrounded with insulationo less heat is lost when compared to a stan-

dard gas model.

Off-peak electric options. Storage heating isan inexpensive and efficient method of electricwater heating (Figure 4). Many utilities offerlow cost off-peak night electrical rates for waterheating. Water is heated at night, storing all youneed for daily use. Providing adequate water

heater storage capacity is an issue at least 100gallons of capacity is recommended, but largerhomes may need up to 160 gallons.

Another option is interruptible electric waterheating, which allows the utility to temporarilyinterrupt electricity to the water heater duringtimes of peak electrical usage usually for afew hours only on the hottest or coldest days ofthe year.

Check with your local electric utility to find outif it offers time-of-use rates or interruptiblerates for residential customers. Some utilitiesoffer incentives for installing storage heaters foroff-peak applications or control devices thatshut off the water heaters for interruptible ser-vice.

Space heat-water heater combinations.Almost all high efficiency boilers can be made


Figure 4

An electric storage water heater

commonly used for off-peak and

interruptible electric service.Source: Water HeaterInnovations, Inc.; Eagan, MN.


6/12


7/12


8/12

uses it to heat the hot water. Whether or notthis is a disadvantage depends on the cost ofthe fuel used and annual efficiency of yourspace heating system.

One disadvantage of the HPWH is its slowrecovery rate: 10 to 15 gallons per hour, some-what less than the recovery rate of a typical

electric water heater. To avoid hot water short-ages, the size of the hot water tank should beincreased to accommodate for the reduced heatinput.

A good application for a HPWH in new homesis to integrate it into the mechanical ventilationsystem (Figure 6). In winter the HPWH recoversheat from stale air before exhausting it to theoutside. In summer the ventilation airflow isreversed, and the HPWH recovers heat and

removes humidity from outdoor air as it entersthe house.

Ground source (Geothermal) heat pumps. Forhomes with an adequately sized ground-sourceheat pump heating system, two water heatingoptions are available. Both systems are general-ly installed to pre-heat water in an extra tem-pering tank.

Desuperheater water heaters attach to theheat pump and make use of the compressowaste heat. A desuperheater water heater csatisfy 60% of domestic hot water require-ments during the cooling season and 40%during the heating season. While it providevery economical heat during the air conditing and heating seasons it does not contribto heating water during spring and fall per

ods when the compressor is not operating.

Water source HPWHs are another way totake advantage of a geothermal heating sytem. A small water source heat pump is tiinto the ground source loop to preheat waThe water will be pre-heated year-round,without the need for the space heating compressor to be operating. Note that with thisystem the ground loop will need to be siz

larger to serve both the space heating andwater heating needs.

Solar water heaters. Solar water heaters careduce the annual fuel cost of supplying hotwater to your home by more than half.Throughout the year, the solar water heater tem pre-heats the water before it reaches theconventional water heater. During the summthe system may provide all the required hea


Dont set watertemperature too

high

Very hot water can cause

scalding burns and be a

severe hazard, especially

to small children or theelderly. To reduce the

danger of scalding, turn

the temperature setting

down to 120 degrees. In

most cases, that will be

the low setting.

The water heater may not

have a temperature control

setting marked in degrees;

measure the temperature

at the tap with athermometer.

Figure 6

A heat pump water heater as part of a ventiilation system.


9/12

Although the cost of a solar water system ishigher than that of conventional water heaters$3,500 to $5,000 installed), the cost may be jus-ified if the traditional energy costs are high.

A solar water heater typically includes collec-ors mounted on the roof or in a clear area ofhe yard, a separate storage tank near the con-

ventional heater in the home, connecting pip-ng, and a controller. There are many types ofolar water heater systems, but only two are

appropriate for the Minnesota climate, theclosed-loop heat exchanger and drainback sys-ems. Both of these types have protectionagainst winter freezing.

The Minnesota Building Code requires thatolar collectors and solar water heating systems

old or installed in the state must bear a certifi-cation label from the Solar Rating andCertification Corporation (SRCC). Look for theSRCC label and compare performance by usinghe rating numbers. Use only quality equipmentand experienced installers. Obtain competitivebids from at least three firms.

Heating water with wood. Wood is sometimesused to heat water and there are a few productson the market for this purpose. Anyone who isconsidering this should be cautioned that it is dif-icult to do safely. Installing a tempering tank inhe same room, but which is not connected to thewood stove, is one safe way. Some wood-fueledboilers can provide domestic hot water needs.

t is recommended that you buy a wood boileror water heater that has been tested and listedor heating potable water by UnderwritersLaboratories or equivalent agencies.

nstalling a water heating system

nstallation. When installing your new hot-water heater, place it as near as possible towhere the largest amount of hot water is used.Use pipe insulation and heat traps to conserveenergy.)

Pipe insulation. Water pipes extending vertical-y from the hot water storage tank are actually

part of the tank itself. The lighter hot waterflows up the pipe, replacing cooler and heavierwater. Insulate both pipes with foam or fiber-glass from the tank to the heat trap, or to thefirst horizontal run. Insulation should be kept atleast three inches from the draft hood and flue.

Heat traps. Heat traps may be natural or

mechanical and may reduce the amount of heatlost when water isnt being used by 12 percent.Some new high efficiency heaters have theminstalled at the factory. The natural trap is apiece of tubing bent in the form of a U.Mechanical traps are available with a ball typecheck valve.

Water heaters without heat traps and with verti-cal pipes should have the traps installed on

both the inlet and outlet pipes. The heat trapshould be as close to the tank as possible.

Tempering tanks. A tempering tank pre-heatswater by absorbing heat from household airand is worth considering if an inexpensivesource of space heat is available, such as awood stove. These may also be used seasonallyby using warm outdoor air to preheat theincoming water. Tempering tanks may be made

New federal efficiency standards

The new standard will raise the Energy Factors for water heaters manufactured after

January 20, 2004 as follows:

Storage type

water heaters

Volume New Minimum

(Gallons) Energy Factor

Gas 30 0.61

40 0.59

50 0.58

Electric 30 0.93

40 0.92

50 0.90

60 0.89

70 0.88

80 0.86

The new standard may also modify installation requirements for some units.



10/12

Tip

Keep household items such

as water softener salt,

kitty litter, clothes dryer

fabric softeners away from

the water heater. These

items are corrosive and

may shorten the life of the

appliance.

from an old water heater with insulationremoved, or a simple water storage tank. Makesure the tank is clean and free of any toxicmaterials.

Using less hot water

Avoiding waste in using hot water is an effec-

tive and low cost way to reduce energy costs.Turn down water temperature. You dont needthe water to be any hotter than 120 or 125degrees. Temperatures over 125 degrees increasethe risk of scalding. Many new dishwashers fea-ture a temperature boost setting which allowsfor a lower water heater temperature.

Fix leaky faucets. A hot water faucet leakingone drop per second will waste about 60 gal-

lons of hot water a week. This could cost youup to $35 or more a year. Leaks can usually befixed by replacing the tap washer. Turn off thewater below the sink or tub (or at the mainsupply if you dont have a shut-off valve belowthe fixture), take the faucet apart, replace thebad washers, and put the faucet back together.

Install flow restrictors on faucets. Flow restric-tors will save money on both the water bill andwater heating costs. They reduce the amount ofwater used for tasks that require flowing waterwithout greatly changing the feel of the flow.Restrictors cost anywhere from less than a dol-lar to about $3. To install, simply unscrew theaerator at the end of the faucet and push therestrictor in. If you dont have aerators on yourfaucets, consider installing them. If you can doit yourself, it will be worth it in water and ener-gy savings.

Install a water-saving showerhead. A typicalshowerhead uses between four and nine gallonsof water a minute. A water-saving showerheaduses between two and three gallons per minute,which means it can save you one to seven gal-lons per minute; and most of the water is hot. Ifyour water heater is set at 120, and if yourfamily takes two five-minutes showers a day,you can lower your yearly gas bill by over $20or your electric bill by about $40 (based on sav-

ing two gallons of water per minute during shower). If more than two gallons per minutare saved, the savings will increase.

Purchase ENERGY STAR appliances. Whereplacing water consuming appliances such clothes and dishwashers, choose energy efficmodels that use less hot water. The best way

assure efficiency is to purchase ENERGY STAqualified models. (See Appliances HomeEnergy Guide).

Gravity-Film Heat Exchanger (GFX). The Gis a vertical, counterflow heat exchanger thaextracts heat out of drain water and uses thaheat to preheat the cold water before it enteyour water heater. It will preheat cold wateras much as 20 to 30 degrees, and by some e

mates, can achieve 25% to 40% savings on rdential water heating costs.

The GFX replaces about five feet of verticaldrain line and can be installed where drainspiped, including inside stud walls. This is agreat opportunity in a new home or remodeproject to significantly improve energy perfomance at a modest cost of approximately $3

Other easy hot water savings tips

Wash only full loads of laundry or adjust water level for smaller loads. Use cold watwhenever possible.

Run the dishwasher with full loads only.

Use cold water to flush away food in yourgarbage disposal.

Turn off your water heater, or place it on lowest setting, if you are going to be gonea few days or more.

Dont let the hot water run when you areshaving, washing dishes by hand, or doingsimilar tasks.



11/12

Additional web resources

Minnesota Department of Commerce: www.commerce.state.mn.us

Additional Home Energy Guides: (Energy Info Center > Home Energy Guides)

Research paper: Ventilation and Depressurization Information for Houses UndergoingRemodeling (Consumer Info and Services > Buildings and Builders > Residential Buildings)

Gas Appliance Manufacturers Association (GAMA): www.gamanet.org

Consumers Directory of Certified Efficiency Ratings for Heating and Water HeatingEquipment (Publications > Product directories)

American Council for an Energy Efficient Economy (ACE3): www.aceee.org

Information on finding and using energy efficient appliances (Consumer Resources)

U.S. Department of Energy, Energy Efficiency and Renewable Energy: www.eere.energy.gov

Lots of information about energy conservation and renewable technologies including waterheating (Information for consumers > shortcuts to technology, water heating)

Typical householdhot waterflow rates

Faucets

.75 gallons to 2.5 gallons

per minute

Low-flow showerheads

1.2 gallons to 2 gallons per

minute

Standard showerheads

.5 gallons to 3.5 gallons

per minute

Clothes washers and

dishwashers

1 to 2 gallons per minute


Summary

When looking at a new water heater, be sureto compare the energy efficiency of differentmodels by checking the Energy Guide label.Choose an EF of at least .64 for natural gasand propane, and an EF of at least .93 forelectric.

Buy the smallest size you can. Dont try tobuy a water heater so you can shower, andwash clothes and dishes all at the same timewithout running out. Instead, plan your hotwater use. This is especially important if youhave a large family.

Locate the water heater as close as possible towhere the largest volume of hot water isused. Since heat is constantly lost through hotwater pipes, the shorter the pipe runs thelower the heat loss.

Insulate the water pipes and install heat trapsif your water heater does not have one.

Take easy, low-cost or no-cost measures toavoid waste in using hot water.
http://www.commerce.state.mn.us/http://www.gamanet.org/http://www.aceee.org/http://www.eere.energy.gov/http://www.eere.energy.gov/http://www.aceee.org/http://www.gamanet.org/http://www.commerce.state.mn.us/


12/1212 Mi D f C

MinnesotaDepartment of

Commerce

Suite 500

85 7th Place East

St.Paul, MN 55101-2198

www.commerce.state.mn.us

Energy InformationCenter

Twin Cities:

651-296-5175

TTY: 651-297-3067

Statewide toll free:

1-800-657-3710

E-mail:[email protected]

This information will be

made available, upon

request, in alternative

formats such as

large print, Braille,

cassette tape, CD-ROM.

This publication was

produced with funds from a

U.S. Department of

Energy State EnergyProgram grant. However,

any opinions, findings,

conclusions, or

recommendations

expressed herein are

those of the author and do

not necessarily reflect the

views of the Department

of Energy.

Minnesota Home Energy Guides

This guide is one in a series of publications designed to help Minnesotans save energy in their homes. Copiethe titles listed below are available by calling or contacting the Minnesota Department of Commerce.

CD-ROM contains all of the Home Energy Guides as well as several other publications of interest to homeoers, builders and contractors.

Appliances advises consumers on what to look for in energy efficient appliances and includes information onefficient operation and maintenance of refrigerators, freezers, washers, dryers, dishwashers, cooktops, ovens, ahome office equipment.

Attic Bypasses explains how to find those hidden air passageways and fix them to prevent costly heat loss damage to roofs, ceilings, walls, and insulation.

Basement Insulation discusses options to improving basement comfort, many not even involving insulation. also provides details on exterior basement insulation, special foundation products and recommendations on inrior insulation.

Caulking and Weatherstripping describes how to identify sources of air leaks, lists various types of caulk an

weatherstripping, and provides illustrated how-to-apply instructions.

Combustion & Makeup Airdescribes the causes of dangerous combustion air problems and tells how to insan outside combustion makeup air supply. It also tells how to test your home for combustion air problems.

Energy Saving Landscapes describes how to use trees and shrubs for long-term energy savings, and lists treeappropriate for energy-savings.

Home Cooling tells you how to cool without air conditioning, and provides information on buying and operaenergy efficient air conditioners.

Home Heating describes proper maintenance techniques and helps you become an educated shopper if you a

buying a new heating system.

Home Insulation helps the homeowner evaluate the benefit of added insulation, providing information on buing and installing insulation.

Home Lighting looks at new technologies for residential lighting, identifying four basic strategies and providexamples for putting them into practice.

Home Moisture describes symptoms of moisture problems, lists common indoor and outdoor causes, and discusses preventive and corrective measures.

Indoor Ventilation describes the types of home mechanical ventilation systems that are available, the amounventilation air needed, and how best to operate and maintain the system.

Low Cost/No Costaddresses the often overlooked energy saving tips for all areas of your home.

New Homes discusses a wide range of options for increasing energy efficiency beyond the normal building crequirements. Subjects covered include insulation, ventilation, air-vapor controls, heating and cooling, windowdoors, and appliances.

Water Heaters helps you determine whether to buy a new water heater or improve the old one. It explains tefficiency of different types of water heaters and provides installation tips.

Windows and Doors helps you decide whether to replace or repair windows or doors and gives a good summ040315B

water heaters 110802042613 water heaters

Documents