GSW builds its water heaters to be safe, energy efficient and reliable.

Many components, like our exclusive Turbulator dip tube, are available on many models and can help maintain optimum efficiency and extend tank life by reducing sediment at the bottom of the tank.


Atmospheric Vent Gas Water Heater 

The Atmospheric Vent is an entry-level gas heater. Air is drawn from inside the home and the exhaust is vented into a chimney or through the roof. The GSW Atmospheric Vent water heater features the Flame Guard® Safety System, which reduces the risk of accidental fires involving flammable vapours from products such as gasoline, paint thinner or solvents.

Direct Vent Gas Water Heater 

A Direct Vent heater is used when conventional chimney venting is not an option and an electrical source is not close by. The heater must be installed near an outside-facing wall as it draws combustion air from outdoors using the included 90” coaxial vent pipe. The exhaust is vented outside without a blower meaning it operates silently. The GSW Direct Vent heater is ideal for tight installations where space is at a premium.

Power Direct Vent Gas Water Heater 

A Power Direct Vent heater is ideal when using inside air for combustion is not an option and a longer vent run is required, possibly as a result of the heater being in a smaller room that does not have a wall facing outdoors. The air is drawn from outside using a vent pipe and a rotatable motorized blower forces the exhaust outside. The GSW Power Direct Vent is a very energy efficient heater which saves you money on energy costs and it’s more environmentally friendly.

Power Vent Gas Water Heater 

A Power Vent heater is used when conventional chimney venting is not an option. Air is drawn from inside the home while a rotatable motorized blower forces the exhaust outside. The GSW Power Vent heater is a very energy efficient heater which saves you money on energy costs and it’s more environmentally friendly.

High efficiency gas

Envirosense® Power Direct Vent Water Heater 

The Envirosense Power Direct Vent is a high efficiency condensing gas water heater. It has a spiral heat exchanger that helps keep hot combustion gases in the tank longer which means the water will heat up faster. This makes it ideal for larger homes with multiple bathrooms or luxury appliances such as whirlpool tubs. The Envirosense Power Direct Vent is ENERGY STAR® Qualified and with its advanced features, it is one GSW’s premium water heaters.

Envirosense® Power Vent Water Heater 

The Envirosense® Power Vent is an ENERGY STAR® Qualified high efficiency condensing gas water heater. It has a spiral heat exchanger that helps keep hot combustion gases in the tank longer which means the water will heat up faster. With a 22” diameter, the Envirosense® Power Vent can be installed in less space than a 75-gallon heater but will deliver greater recovery rates and lower operating costs.

Envirosense® SF Water Heater

Superior hot water delivery is now more attainable than ever. The Envirosense® SF provides flexible, powerful and highly efficient performance to the everyday home. The fully condensing Envirosense® SF design is so advanced, it can deliver continuous hot water at a constant flow of over 2.5 gallons per minute.*

Polaris™ Gas Water Heater 

The Polaris™ high efficiency condensing gas water heater is the perfect choice for combination systems. It is an extremely efficient water heater that’s also great for radiant and forced air hydronic heating applications. The Polaris™ has a high grade 444 stainless steel tank with brass connections for years of dependable, trouble-free service.


Condensing Tankless Gas Water Heater 

Condensing tankless heaters use a secondary heat exchanger that uses exhaust to pre-heat the water before it reaches the primary exchanger resulting in higher efficiencies. The GSW powered by Takagi condensing tankless water heaters are state-of-the-art with an Universal Energy Factor of 0.93.

Space Saver® Electric Tankless 

The Space Saver® point of use electric tankless water heater puts hot water right where you need it.

Discontinued: Non-Condensing Tankless Gas Water Heater 

Non-condensing tankless heaters use a single heat exchanger to heat the water as it passes through it. The GSW powered by Takagi non-condensing tankless water heaters can provide you endless hot water when sized properly.


Space Saver® Electric 

Featuring a variety of models designed for installations in cottages, offices, mobile homes or other places where space is limited, the Space Saver® line of residential electric water heaters provides optimum reliability, performance and energy efficiency.

Standard Electric Water Heater 

Standard electric water heaters are easy to install and can be located almost anywhere in your home. GSW offers a wide variety electric heaters based on gallon capacity, physical size, electrical configuration and water connection location.

Hybrid Electric Heat Pump Water Heater 

The Hybrid Electric Heat Pump water heaters offer a cost effective, energy-efficient option for consumers who want to save money on their electric utility bills. These heaters absorb ambient heat from the surrounding air to the heat water using a compressor and environmentally-friendly R134a refrigerant.

The most common cause of smelly water is a bacteria that is already present in water, but grows rapidly when kept in a warm water environment such as water heaters or hot water storage tanks. This bacteria reduces sulfates that are also contained in the water to a point where they are converted into sulfides. Sulfides, when mixed with hydrogen produce an unpleasant rotten egg odor called hydrogen sulfide gas. Sometimes, hydrogen is already present in the water and is increased by the anode rod(s) found in your water heater.

Permanently removing the anode rod(s) is not a suggested remedy as this will void your tank warranty.

A solution for this problem is to chlorinate your water heater or hot water storage tank. A chlorine feeder may be the only permanent solution to iron or sulfur bacteria infestation. You can also try changing the anode rod from magnesium to aluminum.

This problem will rarely occur as a result of a water heater or storage tank. Rusty coloured water is caused by the water coming in contact with bare metal. In order for this to happen, a lining failure would have to be so significant that it would allow the water to come in contact with enough bare metal to discolour the contents of even a small tank. Fortunately, with today’s high quality glass-lined tanks, this is a very rare occurrence. Instead, the common cause of rusty coloured water is bacteria that reduces the iron found in water. This bacteria is found in soil, water wells, water treatment plants and water distribution piping systems. The bacteria feeds off this soluble iron and, if not treated and allowed to flourish, will result in stained laundry, tablewear and plumbing fixtures. If this bacteria exists in your heater or tank, you may require new anode rod(s), as they will fail prematurely in these conditions. To solve this chlorinate your water heater or hot water storage tank.

Gases such as oxygen, chlorine, carbon dioxide, hydrogen sulfide, and others are soluble in water. As the pressure increases, the amount of gas that water can hold in a solution decreases which cause the cloudy effect. “Milky” water caused by dissolved gasses can be greatly reduced with aerated faucets

The use of water softeners in hard water areas and even moderately soft water areas is becoming a common occurrence. This practice has a potentially detrimental effect on the performance of the anode in the water heater which can cause a reduction in the life of the water heater. Customers using water softeners should expect more rapid anode consumption. Anodes should be inspected more often and replaced when nearing the end of their useful life.

It is recommended that the tank be drained and flushed every 6 months to remove sediment which may buildup during operation. The water heater should be drained if being shut down for extended periods of time.


To drain the tank, perform the following steps:

  • Turn off the gas to the water heater with the manual gas shut-off valve.
  • Close the cold water inlet valve.
  • Open a nearby hot water faucet.
  • Connect a hose to the drain valve and terminate it to an adequate drain.
  • Note: The drain hose should be rated for at least 94°C (200°F). If the drain hose does not have this rating, open the cold water inlet valve and nearby hot faucet until the water is no longer hot.
  • Open the water heater drain valve and allow all the water to drain from the tank. Flush the tank with water as needed to remove sediment.
  • Close the drain valve, refill the tank, and restart the heater as directed under “Operating Instructions”. If the water heater is going to be shut down for an extended period, the drain valve should be left open.
  • Important: Condensation may occur when refilling tank and should not be confused with a tank leak.
  • Turn off water supply.
  • If floor drain is not near water heater, connect a garden hose to drain valve and direct to floor drain.
  • To speed the flow of water, open a hot water tap to let air into tank at a single-handled faucet nearby.
  • Allow water to run until water is clear and no discolouration in water.
  • Turn drain valve off once water is clear.
  • Turn water supply back on. Fill tank with water.
  • Make sure tank is completely filled with water. Turn nearby faucet off.
  • Check for leaks.


NOTE: Make sure power is turned off in the case of electric heaters. Electric elements will burn out if they are operated in a dry tank.

Turn off water supply.

  • If floor drain is not near water heater, connect a garden hose to drain valve and direct to floor drain.
  • To speed the flow of water, open a hot water tap to let air into tank at a single-handled faucet nearby.
  • Allow water to run until water is clear and no discolouration in water.
  • Turn drain valve off once water is clear.
  • Turn water supply back on. Fill tank with water.
  • Make sure tank is completely filled with water. Turn nearby faucet off.
  • Check for leaks.
  • Restore power.

Glass-lined water heaters are supplied with sacrificial magnesium anode rods that protect the interior of the tank through cathodic action. As the rod works, it slowly dissolves over time and must be replaced when it is totally consumed.


  • Locate the anode rod on top of the water heater. It is accessible through the hole closest to the center of the tank. There will be insulation covering it and there may be a plastic cap over the access hole. The anode rod has a 1 1/16th inch hex head.
  • Turn off the power if electric. If gas, turn valve from “on” to “pilot” on the water heater.
  • Turn off the cold/inlet water supply to the heater.
  • Drain off approximately 5 gallons of water from the unit.
  • Using a 1 1/16th socket wrench, remove the anode rod. (It could be well tightened from the factory.)
  • Inspect anode rod for consistent pitting. If pitting is consistent and thicker than 3/8” in diameter, reinstall rod. If rod is less than 3/8” in diameter, or bare inner core is exposed, other than at each end, replace anode rod.
  • Turn water supply back on and ensure the tank is completely filled up with water by opening all the hot water faucets in the house to release the air in plumbing system. Allow the water to run for three minutes before closing the faucets.
  • Turn the power back on, or turn the dial on the gas valve from “pilot” back to “on” depending upon your unit.
  1. Turn off the electrical switch or shut off main gas supply.
  2. Close the cold water inlet valve to the heater.
  3. Open a hot water faucet within the system to relieve tank pressure.
  4. Drain 2-5 gallons of water to allow the addition of bleach to the tank. Use a hose connected to the drain valve if an open drain is not adjacent to the heater. CAUTION: Water may be HOT.
  5. Remove anode rod or disconnect the hot water outlet pipe from the heater.
  6. Using a funnel in the anode rod or hot water opening, add one gallon of household chlorine bleach (e.g. Clorox, Javex ) for every 25 gallons of tank capacity. Re-pipe the heater.
  7. Reinstall anode rod(s) after inspecting and replacing as needed
  8. Open the cold water inlet valve at the heater and fill the tank with water. Then draw the water to every hot water fixture, until the smell of chlorine is detected. Operate dish and clothes washers until a noticeable amount of the chlorine is detected as well. All hot water lines must receive treatment.
  9. Close inlet valve and leave the bleach mixture in the system for a minimum of 2 hours.
  10. Drain the bleach mixture from the tank through the heater drain valve and close the heater drain valve.
  11. Open cold water inlet valve and completely fill the tank with fresh water. To ensure that the water heater is full of water and that all the air has been purged from the system, run all the hot water faucets in the house continuously for three (3) minutes. If you can still smell chlorine at the faucets run them until there is no longer any odour. Do not supply power to this water heater until you have verified that the unit is completely filled with water.
  12. Check for water leaks at all fittings used; repair as necessary.
  13. Turn on the manual electrical switch or gas valve and ensure tank is full of water to prevent dry-firing.

If an inspection of the filter shows a build-up of dirt or debris on the filter, it should be cleaned. The filter can be vacuumed to remove the build-up. Visually inspect the flame arrester by placing a mirror underneath the water heater. A flashlight can be used to illuminate the slots in the flame arrester if necessary. Routine cleaning of the flame arrester is recommended if the inspection shows accumulation of debris on the flame arrester.

Use a vacuum cleaner to remove all loose debris in the flame arrester. If necessary, a soft bristle brush can be used to dislodge any remaining debris.

  1. Turn off the power if electric. If gas, unplug and turn off the incoming gas supply to the water heater.
  2. Turn off the cold inlet water supply to the heater.
  3. Open a hot water faucet located nearby and leave it open. Turn off water supply to house if single handle faucets could be opened during this procedure.
  4. Open the drain and drain off approximately 5 gallons of water from the heater.
  5. Disconnect the cold water supply line from your water heater.
  6. Put a thick layer of rags around the threads of the cold water inlet nipple to avoid damaging the threads when you unscrew the nipple.
  7. Using a pipe wrench, unscrew the cold water inlet nipple-dip tube combination. A helper may be required to steady the heater.
  8. Inspect for damage, such as a split, crack or fracture; replace the dip tube if necessary. If dip tube is completely missing, check the hot water outlet to eliminate the possibility of mix-up at installation.
  9. Wrap threads of the new dip tube with white teflon tape or use teflon pipe dope (TPD)
  10. Install the dip tube into tank and tighten.
  11. Reconnect the cold water supply line to the heater.
  12. Turn water supply back on and ensure the tank is completely filled with water. Open a faucet to release air from the plumbing system.
  13. If electric turn the power back on; or if gas, turn on the gas supply to the unit and follow the lighting instructions on the side of the water heater.

GSW serial numbers contain a lot of information, including when the heater was manufactured. This can be determined by looking at the first four numbers, ignoring any letter that may start the serial number. The first two numbers represent the year the heater was built. If your heater was built before 2008, the next two numbers represent the month. If your heater was built after 2008, the next two numbers represent the week.

For Example
Serial number: U0106413635
This heater was manufactured in June 2001

To see if your water is still under warranty click here to go to our warranty validation page.

Please note that warranties are based on use in residential applications.
Reduced warranty for commercial applications.

Insulation blankets available to the general public for external use on gas water heaters are not necessary with GSW products. The purpose of an insulation blanket is to reduce the standby heat loss encountered with storage tank heaters. GSW water heaters meet or exceed the National Appliance Energy Conservation Act standards with respect to insulation and standby loss requirements, making an insulation blanket unnecessary.

Piping in series can cause the first heater to fail sooner than the second as you are using the full capacity of the first heater and only upon an increased demand, is the second heater cycled on. The better choice is to pipe in parallel which allows you to use both heaters equally. It allows the system to act as one heater rather than independent. By drawing hot water out of both heaters equally, you are able to equalize the life of your heaters.

These noises are an indication of scale build-up that you will need to remove. The task can prove to be relatively easy if you follow the steps to complete the process properly.

  1. Turn off the heater.
  2. Drain the heater.
  3. Remove the anode.
  4. Create a solution of one part vinegar to one part water to a quantity that fills the heater to capacity.
  5. Turn the water heater back on and leave the solution to work for at least two hours.
  6. Drain the heater
  7. Once the cleaning solution has been completely drained, you must rinse out the heater.
  8. Fill the water heater with fresh water to its capacity and leave it for a few minutes before letting it drain. This is a process that must be repeated in order to ensure the water heater is properly rinsed.
  9. Replace the anode.
  10. The tank can then be refilled, turned on and used as normal.

The most common reason a T&P valve is dripping water is thermal expansion. The water in a water heating system expands when it is heated and has a greater volume.

Follow these easy steps to diagnose thermal expansion:

  • Turn the heater thermostat all the way down, and install a water pressure gauge with dead hand on the drain valve. Open the drain valve, so the gauge reads system pressure.
  • Open a hot water tap and allow 15% to 20% of the tank’s volume to run out.
  • Shut off the drain valve and make sure that no other fixture in the system, hot or cold, is open. Make sure that outside fixtures, if they are on the same system, are turned off too.
  • Check the water pressure gauge, and turn the pointer so it lines up with the pressure indicating needle. Turn the thermostat back up to its normal position, so the heater cycles on. Watch the pressure gauge.
  • If the system is closed, the pressure will start to climb steadily and rapidly. A small amount of thermal expansion control may be built into the system because of trapped air pockets or a water hammer arrestor. In that case the pressure will increase slightly, hold steady for a short time and then rapidly increase.
  • The temperature and pressure relief valve (T&P) or PRV should open and release water once the pressure reaches the maximum setting on the valve. The valve will close once the pressure falls below the pressure setting of the valve.
  • The PRV is installed between the check valve and the water heating system. The expansion tank is installed between the PRV and the water heating system. Follow the manufacturer’s instructions for installing the expansion tank.
  • Run the thermal expansion check again. The pressure should increase only slightly then hold steady throughout the recovery cycle. The expanded water is flowing back from the heater and into the pressurized storage bladder of the expansion tank. Air pressure will force this water out of the expansion tank into the supply once usage resumes.

WARNING: Thermal expansion of water, if not compensated for in system design, will lead to the early failure of components. These failures are not covered by the manufacturer’s warranty, so it is extremely important that everyone be aware of the causes, symptoms and solutions to thermal expansion in a closed water heating system.

How to install a pressure-reducing valve and expansion tank.

The ideal fix involves the use of a pressure reducing valve, if supply pressures are above 60 to 70 psi, and a properly sized expansion tank.

DO NOT DEPEND ON THE T&P VALVE TO HANDLE THERMAL EXPANSION! The T&P valve, according to the makers of those valves, was designed as an emergency relief device only. The T&P could be subject to reduced effectiveness or failure.

Water accumulating on the floor or in the drain pan is generally caused by one of the following conditions:

  • Condensation
  • Drain valve leaking
  • Temperature and pressure relief valve leaking
  • Leak from piping on and near the inlet and outlet
  • Leak at gas valve threaded connection (gas models only)
  • Leak from gaskets for electric elements (electric models only)
  • Leak in heater tank

CONDENSATION: Condensation should only be noticeable after a long draw of hot water. Once the temperature of the tank is above 110oF, condensation should stop.

DRAIN VALVE LEAKING: Check to see if the heater drain valve is closed tightly. If the leakage cannot be stopped by the handwheel, replace the drain valve.

TEMPERATURE AND PRESSURE RELIEF VALVE LEAKING: If the leakage is from temperature and pressure relief valve or its discharge pipe, it may represent relief valve activation. The relief valve relieves water slowly when actuating on pressure. A closed system can cause pressure to increase in the system. This condition is called thermal expansion. The incoming water pressure should also be checked and compared with the valve’s rating. If the supply water pressure is higher than the valve’s rating, a pressure reducing valve will be needed.

LEAK FROM PIPING ON AND NEAR THE INLET AND OUTLET: In warm or humid locations, condensation can accumulate and run down flue tubes, cold water supply pipe, and heater connections. Check connections and fitting for possible leaks.

LEAK AT GAS VALVE THREADED CONNECTION (GAS MODELS ONLY): Remove valve and reapply pipe joint compound.

LEAK FROM GASKETS FOR ELECTRIC ELEMENTS (ELECTRIC MODELS ONLY): These gaskets can be replaced. The element threads may need to be resealed.

This is referred to as “water hammer”. Water hammer occurs in a piping system when water flowing through a pipeline is stopped abruptly. When water hammer occurs, a high intensity pressure wave travels back through the piping system until it reaches a point of some relief. The shock wave will then surge back and forth between the point of relief and the point of stoppage until the destructive energy is dissipated in the piping system. The violent action accounts for banging, thumping, and/or intense vibration in the pipeline. Although noise is generally associated with the occurrence of water hammer, it can occur without audible sound or noise. Quick closure always causes some degree of shock with or without noise. The common cause of water hammer is single lever faucets (sinks/lavatories) or automatic solenoid valves (dishwashers, washing machines, etc.). The speed of the valve closure time is directly related to the intensity of the surge pressure.

The only effective means of control is to install water hammer arrestors. These devices have diaphragms which separate an air chamber from the water in the piping system. As the shock wave reaches this device, the air chamber absorbs the shock. Arrestors should be located as close as possible to the source of the shock wave.

Heat traps are installed on some residential water heaters to comply with the many utility incentive programs, and certain new construction or replacement product requirements in place throughout the country. Devices such as impulse sprinklers and water pumps can cause the pulsating. The noise is sometimes conducted through piping and framing of the house annoying the occupants.

Since there is no simple way to correct pulsation of the water supply, removal of the heat traps is sometimes the only practical alternative. The heat traps may be removed from the heater without affecting the safe operation of the heater.

The removal of the heat traps will cause a small reduction in the overall efficiency of the water heater.

The installation of a drain valve generally requires the draining of the tank. Make sure power is turned off in the case of electric heaters, or the gas control is turned to PILOT in the case of gas heaters. Electric elements will burn out if they are operated in a dry tank, and damage will occur if the gas burner comes on with a gas heater which is not filled with water.

  • Turn off water supply and power supply.
  • Drain tank. To speed the flow of water, open a hot water tap to let air into tank.
  • Remove existing valve.
  • Clean the tank threads of any dirt or foreign matter that might affect the proper thread sealing of the new valve.
  • Install new drain valve using a high quality thread sealant (either plumbers tape or approved pipe dope).
  • Fill tank with water and check for leaks. Make sure tank is completely filled with water.
  • Restore power.

Water heaters can often fail prematurely due to improper sizing. The storage capacities as well as the recovery rate are both important factors when sizing a water heating system. Improper sizing can also lead to complaints of not enough hot water. It is important to consider not only the volume of water required, but the temperature that is required. When a large volume of water is needed within a small amount of time, this water is generally supplied from storage. This volume is referred to as the dump load. When choosing the appropriate storage tank size, the actual and usable storage will need to be addressed. If water is required at a certain gallon per minute rate, this water will generally be supplied by the recovery of heater. Keep in mind that any dump loads also need to be included in this recovery.

Some signs of an undersized water heater are:

  • Heavy condensation
  • Rust chips on the burners and flue tubes
  • Not enough hot water
  • Premature tank failure(s)

When a water heater is properly sized, some condensation will occur. However, excessive condensation is not normal and will corrode the heater.

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