Can Too Much Pressure In A Hot Water Heater Cause It to Explode?

Water heater explosions can often be seen making it to the headlines of local news. There’s a high probability that you may personally be aware of instances including damage caused by water heater bursts from increased pressure. While it goes without saying that an explosive water heater can pose fatal consequences, just what is it that causes a water heater to explode? How much is your very own water heater is at risk of exploding and what can you do to ensure that you’re never met with such an occurrence?

Water heaters have more or less become a necessary installation for modern homes and rightly so. However, there’s more to it than buying and installing a water heater along your plumbing lines if you want your investment to be safe and durable for your family. While a new water heater may appear to sit stagnant for years serving your family with hot water on-demand; it might be very well the case that you end up overlooking necessary maintenance bouts contributing in the wear of your hot water heater. This is usually in the form of testing the pressure valves of your water heater every 6 months and ensuring that excess pressure is released efficiently at instances of requirement.

In this write-up, we discuss the most probable cause of hot water heater explosions, what causes too much pressure in hot water heaters and how exactly can you ensure to avoid high pressure build-up in your domestic water heater.

What Causes a Hot Water Heater to Explode?

What Causes Water Heater explosions

Among other reasons like sediment build-up and weakened water heater walls due to corrosion, the most prevalent cause of hot water heater bursts is too much pressure inside the tank. Most water heaters are designed to endure internal water pressure of up to 150 PSI. Meaning, there’s a limit to the amount of pressure your water heater can endure without breaking apart. Exceeding this maximum permissible value without being able to release excess pressure is what causes a water heater to explode.

Now, water pressure inside the water heater tank also depends on the water temperature among other factors. This can be explained by the fact that water expands upon heating. When water is heated inside an enclosed casing, the volumetric expansion exerts pressure on the walls of that container. Domestic hot water heaters can generally withstand pressure corresponding to water temperatures of 120 – 125°F quite well. Your water heater however becomes susceptible at temperatures above 140°F.

There’s not much leeway if you’d look closer at these numbers. This is the reason why commercially manufactured hot water heaters have a relief valve that allows for correction in cases where pressure exceeds the permissible limits.

What is a Temperature and Pressure Relief Valve?

Can Too Much Pressure In A Hot Water Heater Cause It to Explode?

A temperature and pressure relief valve, true to its name, is a corrective mechanism included in the design of all types of hot water heaters that come with a tank to ensure safety against hazards related to excess water temperature and pressure. A T&P valve aids in releasing extra pressure thereby ensuring that your heater stays guarded from unwanted mishaps.

The T&P valve is triggered to open in two circumstances. One, where water temperature exceeds the safe scale for which the heater has been designed and another when there is too much pressure inside the tank. At both instances the temperature and pressure valve opens up until the excess temperature or internal pressure is corrected. In case of a disproportionate temperature rise, the valve opens draining the hot water while allowing intake of cold water until the temperature is brought down. Similarly, too much pressure in the water heater is corrected after the T&P relief valve opens and releases the extra pressure. Out of the many reviews we’ve conducted, we found hot water heaters from Bradford White and Rheem to be fairly reliable with the safety aspect.  

As evident, the temperature and pressure relief valve is literally the only thing ensuring that your hot water heater functions meticulously without the fear of exploding. It is hence critical to keep an eye on the T&P relief valve of your water heater. If you find out the valve isn’t efficiently releasing water or is leaking in a manual inspection, this could be a clear water heater explosion warning sign. In such a case, you must immediately get the valve serviced or yet better replaced by a plumbing professional.

Preventive Measures Against Water Heater Explosions

While you surely have a protective mechanism guarding against temperature and pressure build-ups, it’s best that the valve is triggered only occasionally. You can ensure that the pressure stays within the stipulated range by making sure that your water heater’s temperature is set not more than 125°F at all times. Further, if for other reasons, your water heater gets pressurised, you must make sure that the T&P release valve is functional. As a rule of thumb, you should be inspecting it every six months.

Alternatively, you could opt for a tankless gas water heater if high pressure in hot water heaters is a common sight in your area of residence. Tankless water heaters produce hot water on demand and have a completely different working principle. With these, you need not constantly worry about your water heater bursting.

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