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"Custom Vac was recommended to me by a friend, so I was quite confident that they would be a good company to replace my furnace. Brian Baker, of Custom Vac, proved to be very knowledgeable, helpful and personable. Rather than upgrade to a high efficiency gas furnace, Brian recommended that I install an electric furnace and an electric water heater. After some consideration, I decided to take his advice and go with the electric."
Robert Taylor
Safety Valves and Explosions

"Tank goes through the Roof"

That was the headline this fall in Parkland County, Alberta where once again a (DWH) domestic water heater exploded, ripping through the mobile home and landing over 160 feet away.

Very shook up and lucky to be alive the couple were tossed from bed at 2:30 AM. " It went up like a missile through the building," said county fire chief Jim Phelan. " It went through the roof, over the tree line, over the neighbour's fence and landed between the fence and the neighbour's car." The mobile homes interior was destroyed, the neighbour's car scraped, but miraculously the residents of the home, Barret Doupe and his girlfriend Carmen Hansen, were not hurt in the incident.

When you close you eyes and imagine what this scene looked like. Now ask yourself, Could this happen in my home? Yes, because domestic water heaters are too often thought of only when they leak, or fail to provide us with hot water.

The most well known explosion dates back to 1982 when a domestic water heater in an elementary school in Oklahoma killed six children, a teacher and injured another 42. The cause after the investigation was a faulty safety valve (pressure and temperature relief valve). The janitor removed the probe from the valve and reinstalled it, the reason, the valve had been leaking. But how could a water heater have so much explosive power and cause so much devastation? Lets look at Table 1

Table 1
Comparison of Explosive Energy
One pound of Black Powder = 960 ft. lbs. of explosive energy
One pound of Smokeless Black Powder = 1260 ft. lbs. of explosive energy
One pound of Nitro-Glycerine =2,000,000 ft. lbs. of explosive energy
One 30 gallon water heater (full) + 90 psig = 331ºF + Rupture = 3, 138,400 ft. lbs of explosive energy
One cubic inch of water flashed into steam expands 1700 times or one cubic foot
One pound of water flashed into steam = 750,000 ft. lbs. of explosive energy

Similar incidents in St. Paul, Min. in 1993 injured two people and killed the family dog and in 2001 a tank shot through the roof of a Seattle suburb video store. Just think about it a 30-gallon water heater having the same amount of explosive force as 1.57 lbs of Nitro-Glycerine.

Over the years Technicians have discovered many potential hazards and have been able to make the corrections before an explosion could happen. Photos 1 & 2 are examples of the dangers that may be in your home.

Photo #1 Safety valve missing

Photo #2 Improperly sized and
Installed safety valve

Water heater explosions are typically caused by a sudden and massive conversion of water in the tank into steam, causing an "over pressurization of the [hot water tank] vessel. This can happen when the operating control and safety device (pressure temperature relief) on the tank fail, causing the pressure build-up. All water heaters have high temperature limits (shutoff devices), which are designed to either cut power to the electric elements or shut off the gas to a burner when a dangerous temperature is sensed. When this fails to occur the temperature pressure safety valve should open and relive the unsafe condition. But when these both fail an extremely hazardous condition arises and an accident is certain to occur, as was the case in Alberta in 2005.

"Too many times Technicians find safety valves that are inoperable, the wrong size or capacity rating, wrong size discharge tube or worse, some or all of the safety components missing all together," said Baker. Over In the last five years there has been a tremendous increase in the numbers of unsafe water heaters being installed in homes and buildings because homeowners have chosen either (DIY) Do-it-Yourself or resorted to hiring less expensive, unqualified persons.

Water heaters and many other products that were once not available to the public at-large can now be purchased from local home renovations stores. However, installing many of these products, water heaters included, requires far more knowledge than simply connecting a few water lines. All water heaters must be installed in conformance to codes and standards that are always changing. "Consumers should realize that having to pay for upgrades to gas piping, electrical, venting and or chimneys are in their best interest. Codes and standards are minimums and the safety requirements are set in place to protect them, their families and others such a neighbours," said Baker.

Installing your own water heater might seem simple enough on the surface, but it's far from that and the numbers of improper and faulty installations are proof. You must be a qualified tradesperson to install a water heater in Manitoba and adhere to the codes, standards and regulations. Just because a store sells a product doesn't mean that anyone can install it. People thinking of installing their own water heater should think twice since they may be placing their insurance coverage in jeopardy. Be sure to read the small print in your policy. Further, if you hire someone to install a water heater ask the company for proof that whom they are sending is qualified. A reputable company should not hesitate to provide you with proof of their Technicians qualifications.

Baker said, "In 2005 his company found an replacement electric water heater that had been installed with elements 33% more wattage than the previous tank connected to undersized wire, why a fire had not yet started was anyone's guess, just plain dumb luck." Technicians also found a water heater installed under a kitchen counter in a condo with no safety valve or drain valve.

Trade Tech's are trained to look for and to test appliances in accordance with manufacturers installation instructions and to Industry standards. The average consumer does not have the knowledge or skills needed. What may appear to be a cost savings venture could turn out to be a 2:30 AM major news story. "Its only luck so far that loss of property and life in Manitoba has been kept at bay," said Baker.

"Homeowners and tenants both, need to realize the potential hazards with water heaters by adding them to their routine home maintenance check list, because at present there is no way anyone in Manitoba can know if their water heater is in compliance or if it was ever inspected, " said Baker.

  • **Every six months, open the hot water tanks drain valve and let five gallons of water out, or wait until the water becomes clear. This to eliminate or minimize the build-up of sediment in the tank.
  • **Test the pressure relief valve about once a year. Open the valve manually (be careful, the water is very hot). If it doesn't open to let water escape, the valve needs to be replaced immediately. If the valve opens but won't re-seat itself you will need to have the valve replaced.
  • Have all gas appliances tested and cleaned once a year by a qualified Technician.
** Note: If your tank is fitted with a special type of leak sensing device use caution to not get the sensing element wet. For tanks fitted with these devices, you may wish to have a qualified Technician perform this for you.

How to be safe and a save few dollars when replacing your tank?
  • Provide clear access to the work area.
  • Drain the water heater prior to the arrival of the installer.
  • Carry out the old tank from the home and discard it yourself.

Most consumers don't realize the life-style benefits that water heaters offer us everyday until they fail to provide us with that glorious, endless supply of hot water. Most important, don't panic, and rush to have your leaking water heater installed within the hour. Your needs and family size may have changed; the cost of energy may make alternatives a better choice; and newer higher efficiency models may now be available. With so many choices available today you should take some time to decide what is right for you. One, two or even three days without hot water is not the same as going without heat. Its also important to establish a good working relationship with your service Technician and Contractor, they will be able to provide you with the information you need to make an informed decision within a reasonable time frame.

Well. what are you waiting for? Go check your water heater today. If you are unable to do this or think something might not be right, don't hesitate to call in the professionals.

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1567 Logan Avenue
Winnipeg, Manitoba
R3E 1S5
T. 204-775-7744
T. 204-772-5799
F. 204-774-8557


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