Boiler Blows up

I'm sure someone will correct me if I'm wrong, but I don't believe lack of water would cause your boiler to explode. The pressure relief valve would still operate. The purpose of a low water cut off is to keep the boiler from dry firing which would likley crack the boiler. A defective or improperly installed pressure relief valve could cause a boiler to build excessive pressure and explode. Sometimes a novice will install an extension on a pressure relief valve with a threaded termination. A no-no but even worse is if pressure is excessive the PRV starts to drip, they run to home depot and buy a cap to screw on the end of the pipe. That's a recipe for a rocket.

You are correct that lack of water will not in itself cause an explosion. I simply stated the first in the chain of events. How many of you out there check your PRV every year and replace when it drips? Come on now, be honest. If it drips it most likely is rusting shut to the point of being inoperative at some point in the future. Who knows when? They really don't cost that much so please check and replace on a regular basis.

How do you check it?

Pull the lever and flush it out. If it continues to drip under normal pressure replace it. The thing you are lookin for is it able to open without sticking and then getting a waterproof seal under normal operating pressure.

Most people will not do this beacuse they are afraid they will have to buy a new one. Many will continue to drip after testing.

It's likely when you test the PRV you will cause it to leak. It's not that the valve functionality has failed but the re-seating of the valve gasket is not exactly the same as it was and it will drip. If you find lots of rust and corrosion you have other problems. It's likely you have excess air in your boiler and the O2 is promoting corrosion.

My solution to the drip after testing is to make it easy to change the PRV. I install a service valve between the boiler and the valve. I find I almost always have to replace the valve after testing. A simple cleaning of the seating surfaces is all that's needed. But that's almost impossible to do with it in place. Yes, I know the cautions about having a valve. I wire the handle in the open position and tag it with a caution sign. If anyone knows a published plumbing code that does not allow properly installed and tagged service valve please post a reference.

I would never ever install a valve there!!! I don't have any paperwork on hand but I have no doubt it's out there. It's just too dangerous even if it's tagged and wired. Even if it's on your own boiler. If you die suddenly, what about the next guy??? No sleepovers at your house!

Well, each to their own installation practices. I too have been told a valve was a no-no. I think it's an urban myth that it's against a plumbing code. I have looked and can't find any such exclusion.

If you sleep over at my house you will be comfortably warm, courtesy of Anthracite coal. And you can use as much hot water in the shower as you want, that too is heated with Anthracite.

Properly tagged and wired in the open postion? as opposed to a dripping PRV causing more corrosion?? Well I'll take the wired open and labeled shut off valve, and a properly tested PRV..

On this note,, why not make PRV's without threads, so that an idiot can't plug it or cap it?? This is the same thing the shut off valve does.. negates the safety function of the PRV..

A PRV is unlikely to be tested if everytime it is it leaks and requires a complete drain-down of the boiler system to replace or clean..

You can't legislate common sense or outlaw stupidity... proper labeling and wiring open of a valve makes perfect sense.. Or as someone else suggested, removing the handle from the valve,, but this is not as 'positive' as wiring the handle in the open position... or get a locking handle valve..

Greg L

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You said it all {negates the safty function of the PRV} Nuff said.

I'd like to see a authenticated case of a PRV "rusting closed" and causing an explosion. They are made of brass, the spring is outside the seal along with brass or stainless shaft. The only thing that can rust is the spring and that would only make it trip sooner. Can the sping build enough rust to hamper movement? I don't believe for an instant that can hapen let alone build enough pressure to explode. It might blow off at a higher than rated pressure, but it will open long before an explosion. The only reason they leak is if you test them, use them as a hot water tap, or if you have a problem, like a bad expansion tank. Install it when the boiler is new, don't touch it for the next 50 years.Sleep well.

Do you test your dry chemcial fire extinguishers? No. why? It ruins the seal. (But you should shake them every 6 months to keep the powder loose. Businesses have to shake them every 30 days and document that they've been shaken)

No sleepovers at your house either Freddy! I've seen things you can't imagine and refuse to debate or offer any more advice to anyone. It will now have a fee attached just like before I retired!

Aren't dripping relief valves cured with a pipe plug

Quote:
Aren't dripping relief valves cured with a pipe plug
stoker-man
EFM Rep.

yes they are cured, once then a probable kaboom. This is why I suggested the 'idiot-proof' PRV,, with no threads on the outlet, so no plug can be threaded in.

Greg.

No threads on the outlet. Sounds like a good idea if you want to rust up your boiler from drips or have 3rd degree burns when it blows off in your face becauce you could'nt route the pipe the proper distance fron the floor.