Overlooking Valves and Pilot Light Issues

It’s wild how just bumping a thermostat or brushing a valve can ruin your whole day, but most people don’t realize leaks often start with missed valve checks or screwing up the pilot light. Energy.gov says nearly 20% of emergency failures involve botched shutoffs or pilot errors. I never thought a tiny flame could cause days without hot water, but here we are.

Pressure Relief Valve Maintenance

Pressure relief valve—the awkward brass thing near the top or side. I always assumed that’s for pros, but that’s just lazy thinking. It sticks, rusts, or refuses to seal after a few flushes. National Board of Boiler and Pressure Vessel Inspectors says “failure to test or lift the relief valve” is a top cause of ruptures. But really, when’s the last time you actually lifted that handle and checked for drips?

There’s never a neat warning—just a weird gurgle, or nothing at all, then suddenly water’s pouring out. I read a plumber’s forum post: “If water dribbles after a test, you’re overdue for a new valve.” Not a scare tactic. Skip these checks and you’re basically asking for leaks, scalds, or random cat freak-outs. I’ve accidentally bumped the thermostat thinking it’d fix the noise. It never does.

Turning Off and Relighting the Pilot Light

Twist the gas shutoff too far, forget to relight the pilot, and now you’ve got a tank of cold soup. Thermocouple acting up again? Happens all the time if you skip the instructions or let dust build up where the flame sits. Some 2025 troubleshooting guide says most pilot outages are from drafts, dirt, or a thermocouple at a weird angle.

Every DIY manual blames “user error,” which is hilarious because who actually enjoys relighting a pilot? It should be simple. It’s not. Miss a step, smell gas, start over. Sometimes I whack things with a wrench like that’ll help (it doesn’t). Once, in a rush, I melted the insulation on some wires. Don’t do that. If you mess up, best case you wait hours for hot water; worst case, you’re panic-dialing the gas company.

If the pilot goes out again after flushing, maybe the thermostat’s too low, or there’s air in the line, or crud in the jet. Unless you obsessively check each step, you’re basically stuck with cold showers and a lot of regret.

Gas vs. Electric Water Heater Flushing Mistakes

Can someone explain why people never read the label on their tank heater? It’s not a cereal box, but you’d think it was. The routines for gas and electric are totally different, and yet, yeah, I’ve drained the wrong tank while half-watching TV. Not my proudest moment.

Specific Considerations for Gas Units

Alright, so, gas water heaters. You ever try draining one and realize—oh, right, that thing’s still blazing hot because you forgot to touch the gas valve? Been there. Seriously, you’re supposed to let these cool for two hours, minimum, or you might end up like my buddy who, no joke, cracked the inner glass liner. (Didn’t even know there was a glass liner until it was in pieces. Classic.) The Department of Energy says to wait, but who actually waits? Not enough people, apparently.

Sediment is a whole different beast here. It builds up, makes a weird crusty layer, and then the burner just cooks the bottom of the tank until something warps or leaks. I called AO Smith’s support line once and could practically hear the sigh when I mentioned “sediment.” And those rubber gaskets? Useless after a while—they dry out, you get leaks, and suddenly you’re mopping up before you even put your tools away. Why do they even make these things with rubber bits that can’t handle a little air?

Electric Water Heater Safety Steps

Electric heaters, man. Don’t trust that little red light. I’ve zapped myself before, thinking, “Oh, the light’s off, I’m good.” Nope. Wires were still hot. Apparently, 43% of people mislabel their breaker panels (I read that in some 2019 safety study, but who knows if it’s higher now).

Nobody wants to mess with the heating elements for cleaning—except, according to ProPlumbers Magazine, that’s where most of the gunk and efficiency loss hides. And the anode rod? People ignore it until it’s a rusty stub, even though you can get a new one for twenty bucks online. I’ve flushed an active heater before and, wow, tech support at Rheem says that’s how you get “instantaneous metal fatigue.” I’d rather swap an anode rod than buy a new tank, but I still put it off. Why is maintenance always such a pain?

Neglecting Tankless Water Heaters During Maintenance

Tankless units. Don’t even get me started. People love to brag about “endless hot water,” but then they skip maintenance for years and call me when it’s leaking everywhere. I’ve lost count of how many times I’ve seen a laundry room disaster because someone didn’t flush the thing. All those efficiency promises? Out the window if you ignore it. These things are supposed to last 15-20 years, but good luck getting there if you never touch it.

Special Flushing Steps for Tankless Units

Tankless flushing is its own weird ritual. I’ve watched people dump CLR in (don’t do that, unless you like voiding warranties instantly). Vinegar or citric acid, sure, but you have to shut off the power first or you risk shocking yourself. Manuals always say “attach hoses, circulate solution for 45 minutes,” but who actually times it? I do, now, after messing it up once. And isolation valves—sometimes they’re there, sometimes not. Why do some installs just skip them? Makes no sense.

I started installing sediment pre-filters for clients with hard water because Rheem’s techs said some city water is so bad you have to flush twice a year. Nobody at the store tells you that, of course.

Common Mistakes with Tankless Water Heaters

DIY videos are almost always missing something. I’ve seen people follow along and end up with rotten-egg-smelling water or, worse, a fried circuit board. One HVAC guy I know scorched his eyebrows because he trusted a YouTuber with a million subs.

People forget to check the rubber washers on their hoses, or they don’t close the water supply first, so water gets everywhere—electronics included. (And, no, those boards are definitely not water-resistant.) From what I’ve seen in manufacturer reports, most premature failures come from skipped or botched flushes. Like, 70% of the time.

And hard water scale? If you let it pile up for a few years, good luck. Tankless units don’t just corrode—they leak and short out. Then you get a bill you weren’t expecting because you thought a flush was optional. Spoiler: it’s not.