Boiler Pressure relief valve (T&P) still leaking. Please help.

[Stormin Mormon]

Them boiler explosions sure hide in dark corners, you think? Don't like to be found.

[Stormin Mormon]

Must be well hidden, after all the guy said they blow and cause injuries all the time.

- . Christopher A. Young Learn about Jesus

.

[Ed Pawlowski]

Could not easily find numbers, but this has some photos of what has happened to a couple of them.

I bet the lawyers know though

[Pete C.]

Except the majority of those are gas explosions and fires, not actual superheated water / steam boiler explosions.

[Pete C.]

Again, the vast majority of incidents are gas leak fires and explosions. Actual residential boiler explosions i.e. super heated water flashing to steam when the containment fails are quite rare.

[Norminn]

When I worked as a factory nurse, I had to take care of three guys after a steam pipe burst....they had been on a ledge next to the pipe when it let go and all had bruises from landing hard in their hasty retreat. Must have had healthy hearts, because it took a bit for them to unwind, thinkin' how it might have ended. Shoot, there were select departments, like punch press, that I never wanted to hear from. Eventually, all were represented but not as bad as it could have been. Only amputation I ever had to care for was the tip of a finger, and I worried more about the supervisors who gathered around having a heart attack.

[trader_4]

Those are some great pics of it happening, that's for sure. The remaining question is how often and I still think it's very rare for a residential boiler.

[Ed Pawlowski]

It is rare for a couple of reasons. Most residential boilers are water, not steam. For a steam boiler, both the PRV and water feed have to fail as well as the high limit pressure switch and low water cut off for it to overheat

With a residential water boiler, you have a steady supply of water at

50PSI or so to feed and keep the temperature below 212.

[TimR]

I know this is a dumb question but I've always wondered.

Why do we call it a boiler if it doesn't boil anything?

A steam system, sure, that boils water into steam.

But a hot water "boiler" just makes water warmer, it never boils it.

[Ed Pawlowski]

The construction of water and steam boilers is nearly identical. Some will do either with just some adjustment of the controls Calling it a boiler differentiates them from furnaces.

Boilers heat water Furnaces heat air

[TimR]

Okay, but the hot water heater for your shower also heats water (why would you want to heat water if it is already hot - oh, never mind) but you don't call it a boiler.

[Ed Pawlowski]

My hot water is heated by the boiler but I know of the appliance you are speaking of. It has either electric elements or a gas or oil burner below it. I guess you could call it a kettle?

I think this is a case of common use trumps technical terms.

[Vic Smith]

Yep, exactly. I always felt silly calling them a "boiler" when I got a part, but that's how it goes. The typical residential "boiler" is far different than an actual boiler. It's basically a water heater and circulator. I don't think my last hot water system ever got beyond about 180F. And pressure readings were virtually head pressure. Actual boilers for steam radiators are much more dangerous. High pressure boilers such as the ones I operated as a Boilerman in the Navy - 900F superheated steam at 1275psi - are another story entirely.