We have a gas water heater that wasn’t new when we moved in 36 years ago. I’ve replaced the thermocouple (flame to gas valve) a couple of times, most recently a year or so ago. The high pressure relief valve, which I also replaced, is sound and not leaking.
Just in the last week, although the thermostat is set to maximum heat, the water temp has been dropping. I’m taking my showers on full hot water, and am wishing it were a little hotter, and my wife’s baths are similarly not as hot. The heater’s cycling appropriately – it isn’t, for instance, shutting off and then starting up again ten minutes later.
My first hypothesis is that the thermostat built into the gas valve is failing (either directly or because of built up sediment), which would mean, given the heater’s age and the fact that the drain doesn’t work so I can’t draw off sediment, that it’s time for heater replacement. We do intend to replace it as part of our larger home update project; I just hadn’t planned to do it now.
Is there some other possible inexpensive failing part or diagnostic step that I’m missing?
Bill Houghton
Replies
Do you know what a sacrificial anode is? Can you get to the one on your heater?
Drain the tank completely, and remove the anode. If it's all gone - very possible - then the muck inside the tank is what's left of a corroded tank. It's replacement time.
If you can disconnect the empty tank, do so - then tip it and shake it. Do you hear anything rattling around? If so, your siphon tube has either fallen off or rusted off. Taking the plumbing apart you might be able to re-attach it.
Odds are, you've lost the race and will be replacing the heater. The good news is, your gas bill will drop, showers will be fun again, and you'll wonder why you waited so long.
Sacrificial anode problems wouldn't cause loss of heating -- just loss of the heater.
A strong nation, like a strong person, can afford to be gentle, firm, thoughtful, and restrained. It can afford to extend a helping hand to others. It's a weak nation, like a weak person, that must behave with bluster and boasting and rashness and other signs of insecurity. --Jimmy Carter
That's what I was getting at .... the element being buried in scale - the remains of a rusted tank.
The heat exchanger runs vertically through the center of the tank. It would take a lot of sediment to severely affect it's operation. Certainly scale can have an effect, but the anode doesn't prevent scale.
A strong nation, like a strong person, can afford to be gentle, firm, thoughtful, and restrained. It can afford to extend a helping hand to others. It's a weak nation, like a weak person, that must behave with bluster and boasting and rashness and other signs of insecurity. --Jimmy Carter
Actually, the flue runs through the center. The flames circle the flue on the bottom of the tank
The flue is the heat exchanger.
A strong nation, like a strong person, can afford to be gentle, firm, thoughtful, and restrained. It can afford to extend a helping hand to others. It's a weak nation, like a weak person, that must behave with bluster and boasting and rashness and other signs of insecurity. --Jimmy Carter
Nooooooooooo The flue is a hole in the center of the heat exchanger.
Can I yank your chain some more??? :)
I'm no plumber .... call mine a 'working theory. All I know is that old, corroded, leaky water heaters -ones supplied with darn near de-ionized water - weigh one heck of a lot more than the new replacements. Ditto for old car radiators. That muck at the bottom of the tank has to come from somewhere, and my best guess is it's the remains of the missing anode- and the rusted tank.
Hence my belief that if the anode is gone, so is the tank.
The gunk in the bottom is mostly from the water.
A strong nation, like a strong person, can afford to be gentle, firm, thoughtful, and restrained. It can afford to extend a helping hand to others. It's a weak nation, like a weak person, that must behave with bluster and boasting and rashness and other signs of insecurity. --Jimmy Carter
Dan is right, on a heater that old you can expect everything to disentergrate once you try to loosen a fitting -- be prepared to replace the entire tank once you start. I'm still suspecting it is the diptube. If you think you can remove, and replace, the fitting where the water enters at the top of the tank a replacement plastic diptube is very inexpensive and just drops in, but be ready for everything to be corroded and just fall apart once you start working on it. But I'd say you got your money's worth out of that old heater!Woody
I have a lot of doubt that a water heater thats over 36 years old is worth the time, expense, and irritation of trying to squeeze a little more time out of it, sorry.
Check the dip tube, to make sure the cold water is coming in at the bottom of the tank, not pouring in at the top and rapidly cooling off the water that is exiting the tank, leaving the hotter water down below.Woody
I think you wanted to reply to the OP?
"If all else fails, read the directions"
Opps, sorry, I thought that I had.Woody
Yep, a broken dip tube is a good possibility.
A strong nation, like a strong person, can afford to be gentle, firm, thoughtful, and restrained. It can afford to extend a helping hand to others. It's a weak nation, like a weak person, that must behave with bluster and boasting and rashness and other signs of insecurity. --Jimmy Carter
Gotta agree with you on that call Shacko, although we try to fix everything first at our place.
Especially a gas WH, 35 years is good even for an electric, most develop a leak on a weld at about 30 years or less.
I replaced my own elect WH at 30 years, as the 'bother' with a big leak is not something I'd like to deal with.
Replace son's gas WH when it was 15 YO even though heating, etc well but with the hint of a slow leak (bulged side sheet metal, son thought one of the GKs had kicked it).
Tore it down after replacement, all the gas apparatus was good, one pinhole leak on a weld had not yet dripped to the floor, but was starting, as for the anode.... Like Reno said, the WH being old, the anode was GONE except for a few inches of stub.
Houghton, do yourself a favor and avoid WH failure water damage and replace it over the coming long weekend!!!!!!! I got the gas WH for son as a 'scratch and dent' at HD for $250, and had the old one pulled and the new one in within an hour, 'nother 1/2 hours to 100% double'triple check all connections with soap bubbles. .
You've beat the odds by a long shot--36+ yrs.
Replace it now before it's an emergency or before it floods the place. This way, you get to pick the time and it gives you time to shop and scrounge if you're into that (I am, and you must be too if you're looking to keep such an old WH crippling along.)
Just for the heck of it, when you take the old one out, strip off part of the jacket and see if there's been small pinhole leaks thru the tank that sealed themselves up by mineral deposits, etc. If there are, you can congratulate yourself on having averted a major flood when one develops that's too big to seal.
36 years, i can't even grasp that. here a gas hw is good from 9-13 years,i don't think i've ever seen one go longer.
i would bet a little money your new one is done in half the time this one has gone.
the older i get ,
the more people tick me off
Thanks all.I know I need to replace it - it's a question of whether I can keep it limping along until we're done with the bath remodel we're currently in the middle of, or whether we need to divert from that to a water heater replacement.Bill
The thing is, if you monkey with it at all something's going to break anyway (and it won't be pretty). Either don't touch it and live with the symptoms (and risk) you have or go ahead and replace it now.
A strong nation, like a strong person, can afford to be gentle, firm, thoughtful, and restrained. It can afford to extend a helping hand to others. It's a weak nation, like a weak person, that must behave with bluster and boasting and rashness and other signs of insecurity. --Jimmy Carter
There's a good possibility that the fins inside the heat exchanger have corroded loose and are no longer conducting heat from the flame to the water -- all the heat is going up the chimney.
You've gotten at least twice average life out of the thing, so maybe it's time to bite the bullet and replace it.
Is the temperature of your shower always low or does it start off hot and then slowly start to cool off ... do you have to keep turning up the hot water the longer you are in there? If that is the way it is acting I would go with the diptube option.
Steve
Of course, there's no way he's getting a dip tube out of a 35-year-old water heater without breaking something.
A strong nation, like a strong person, can afford to be gentle, firm, thoughtful, and restrained. It can afford to extend a helping hand to others. It's a weak nation, like a weak person, that must behave with bluster and boasting and rashness and other signs of insecurity. --Jimmy Carter
False alarm, for the moment: somehow, in all the trips my son and I have been taking through that closet (which is also the attic access) for our current remodel, the temperature setting switch got jiggled to a lower temp.
Hot water restored.
My fingers remain crossed: I know we've been on borrowed time for all 36 of the years we've been here.
You need to buy some lottery tickets today!Woody
temperature setting switch got jiggled to a lower temp.
just shows how much us 'experts' overlook, huh?? <G>
Kinda of like in the movie 'Sling Blade' when he notices the mower is out of gas.
If it's in a closet you may be in for a shock when you replace it and the new unit isn't allowed to be placed there. The rules have gotten stricter.
A strong nation, like a strong person, can afford to be gentle, firm, thoughtful, and restrained. It can afford to extend a helping hand to others. It's a weak nation, like a weak person, that must behave with bluster and boasting and rashness and other signs of insecurity. --Jimmy Carter