While these are Âpressure relief valves, the acronym for that is PRV, which is reserved for Pressure Regulator Valve. So, the popular term for the one you mention is, T&P. That means Temperature and Pressure, and that is really not just more descriptive, but more about your question: "Are (these) valves likely to cause problems?"

They are there to solve problems, but interestingly enough, they are a bit of a nuisance. The two conditions are both capable of opening the valve. But the valve is kept closed by a spring. It so happens, that  especially with older installations  once a valve is opened and allowed to close naturally, it is more likely to leak.

The reason for that, is that the valve is installed in the new condition, with all forces at rest. But if the Temperature and/or the Pressure increase to the danger point, the valve is expected to open. This suggests that moderate over-heat or moderate over-pressure will partially change the spring position or its stored energy.

Then, a small influence can open it. This is usually apparent in the appearance of a minor leak. It is the nature of a seat-type valve to have a Âhome position. That is, once built, the rubber washer settles on the metal seat, forming a fit natural to the variety of parts and their tolerances.

Disturbing this fit changes the nature of the valve, which tends to stay changed as long as the heater is under heat and line pressure. Conversely, if you were to shut OFF the water, remove, clean, chill and reinstall the valve, it should be in Âas new condition and then operate that way. Of course, it could do that without all this.

But when they become leakers after opening, it is for a good reason. The ordinary and reliable solution  especially for professional service people  is to replace the valve with new. This avoids call-backs and is less labor-intensive ($$.)

Your other concern, "My wife is convinced it'll rust out in no time and we'll need a new one." Baloney. Women are just fickle that way. For instance, if she uses a Lawyers-page from the local telephone directory to bookmark her romance novels, you can be sure sheÂs like that.

DonÂt worry, once it dries up sheÂll be very comfortable with it  the water heater, that is.

Pinoke

Thanks Pinoke, for your comprehensive and very helpful reply.

I'll babysit it for a few days and see what it does. Right now it appears to occassionally spontaneously spit out a bit more- and when we go downstairs the floor's damp again.

Not a large amount, but troubling in light of the concern about rust. I appreciate your reassurance on that account. The heater does sit right on the floor and it'll take it a while to dry once the problem is fixed. So I wasn't sure she was wrong.

Thanks again,

Mark