Leak Above Hot Water Heater (with pics)

[nittybitty]

This hot water heater is about 9 years old and so is the plumbing above it. The water appears to be coming from in between the big copper/brass screw and the end of the black thing (what's the black thing callled?):







It seems like a seal or a washer inside the black thing has malfunctioned and is letting the water seep out.

The water dripping is pretty warm and the drip is very consistent. The water meter in front of the house isn't moving at all, so I am not sure where the pipe or water is coming from - the pipe comes out of the wall, down to this black thing, then down and out of the black thing and back into the wall.

I guess my question is: Is this something I can fix myself and where do would I find the valve to turn this water off.

[jadnashua]

Not absolutely sure, but it looks like a PRV (pressure reduction valve). Somewhere in the plumbing, there should also be an expansion tank. While the thing should not leak, if the expansion tank (bladder) has failed, the pressure can rise and the weakest link will leak. While a PRV can be rebuilt, the rebuild kit is often about the cost of a new one, and that is usually the better way to go. The bolt on the end is adjusted to change the pressure setting, then the nut is tightened down to hold it there.

You may want to pick up a water pressure gauge, screw it onto say the drain valve of the WH, or any other hose fitting in the house, and check the pressure.

[hj]

It is a pressure regulating valve, and the ONLY way water can leak from that point is when it breaks and the diaphragm ruptures. Replace it. Do NOT waste time and money trying to repair it.

[Gary Swart]

Based on the fact you didn't know that this bell shaped device is a pressure regulating valve, I would say you do not have the experience to attempt this yourself. You should have a thermal expansion tank somewhere in the system, and the pressure in that tank needs to be matched to the PVR. While this is not an overly complex job, it is a bit more than just screwing the old one off and the new one on. There are times the best DIY advice is "call a plumber."

[hj]

One problem with the PRV where it is, is that it is only regulating the hot water pressure. If you have a pressure balanced tub or shower valve, the pressure balancing unit is working ALL the time to modulate the cold pressure equal to the reduced hot pressure. Normally it is in a "neutral position" until there is a momentary imbalance. It is like your car's steering. When it is aligned right the steering wheel is in a neutal orientation and you just have to rest your hand on it, and make slight adjusments to go around pot holes. IF the wheels are misaligned you have to keep the steering wheel "turned" to the left or right to go straight. This induces stress and wear on ths system.

[Runs with bison]

One problem with the PRV where it is, is that it is only regulating the hot water pressure.

The big orange tag says that is the "main shut off" valve just before the PRV, so it appears to have all of the water in the home covered.

[Gary Swart]

I'm going to stand by my advice to get a plumber on this job. The close confines of everything will be difficult for a novice to deal with as well as the problems I cited originally.

[hj]

So it does, although it is rare to find a main shutoff next to the water heater, at least in this area.