The attached link is the importance of checking relief valves. When I was a service manager we tested many relief valves that would leak after being tested so they needed replaced. We got many complaints from homeowners that we made it leak so they were not going to pay for it.
What is the price of keeping your family safe.

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Good info! I do lift that manual operator ever few months. However, in the big-boiler world, "testing" relief valves means pressurizing them to verify their set-point. I certainly don't do that for my residential hot-water boiler, but I replace my relief valve every five years or so - some time when my boiler, for maintenance, is depressurized and drained below the relief valve elevation.

By the way, having an isolation valve ahead of the relief valve might be handy, but it is, of course, verboten.

 

I think if you lift the lever, be ready to replace it.
Unless you do it often, then things don't build up under the seat.

I have yet to find one that would not release at pressure, found many that leak.
More often people will replace them with plugs or caps,cause they don't have the parts at hand to fix it.

I love seeing them piped into a floor drain and running like a half open faucet :-)

 

There are actually TWO tests you run on a relief valve. One test is for verifying the ACCURACY of the valve. That's a pop test which tests the pressure at which it opens and re-seats... but doesn't necessarily need to be done on a residential boiler. I do Commercial Steam boilers and this test has to be done once a year.

The other test is to simply verify that the valve is not binding or seized closed. This is the test that needs to be done fairly regularly... maybe once a month and all boiler owners should be doing this. It's done by simply lifting the try lever and feeling for smoothness in the lift. If any binding is felt or it does not re-seat properly then the valve should be replaced. (It's done on Commercial steam boilers once every 24 hrs of running time in Manitoba... or every 8 hours for high pressure boilers)

 

WOW, talk about wearing out safety valves!

I spent over thirty years in the field and we almost never tested safety valves at pressure. We most certainly did not test them every shift either. Our high pressure boilers were hand-lifted quarterly, every three months, and removed and certified every three years.

One problem with hand testing is that it should be done with a minimum of two-thirds of the rated pressure on the valve, that means for a valve set at 150 psi (pretty much standard for domestic water heaters) you should have a minimum of 100 psi on the valve. BUT, most residential properties have domestic water pressures of less than 75 psi which theoretically is too low for hand lifting. Another problem is people are often afraid of the safety valves and will meekly ease the handle up and let the valve dribble a bit and then slowly release the handle. The proper method is to smartly pull the handle to the full open position and let it blow for a second or three to make sure you get a good flow of water (or steam in the case of a steam boiler) and then let the handle snap shut. Allowing the good flow through the fully opened valve does wonders on reducing the "valve leaking after testing" syndrome.

 

We (Manitoba, Canada) have about the toughest steam boiler regulations in North America. Not only is it required to test the pop pressure once a year but we also have to record the seat pressure and the maximum level of rise in the boiler at full throttle with all relief valves open. If the valve isn't within specs it gets replaced. Just did an 800 horse boiler last week. Two of the four valves closed a little late by maybe 2 pounds and we were ordered to replace them.

There is no such thing as residential steam boilers here anymore because the regulations are so stiff that it costs a small fortune to operate them. Indeed in our Provence you must be a Power Engineer of proper class to run even a steam boiler.... small or large.