Water Heater Repair or Replace: Five Failures Worth Fixing

Take an invoice with three words on it. Gas control valve. Then $640, and underneath, $2,100 to put in a new heater instead. Those two figures are a worked example carried through this article; substitute whatever is written on your own quotes.

Neither of them tells you which option is right. Two other numbers do, and both are printed on a sticker eighteen inches from where the plumber was kneeling.

The two numbers on the tank, not on the quote

Find the rating plate: a foil or paper label on the jacket, usually near the top on the front, sometimes under the outer door on a gas unit. You want the serial and the model number.

The serial gives you the date. Rheem's own guide to locating and reading its water heating serial numbers breaks the ten digits into month, year, plant line code, then five consecutive digits, and gives the example 12 09 D 01234 for December 2009. Bradford White does it with letters instead: its own serial number date code reference says the first two characters are the year and then the month, on a year cycle that skips I, O, Q, R, U and V and a month cycle that runs A through M and skips I. So a serial beginning NF is June 2016. The published table pairs every letter with two years twenty apart — N is 2016 or 2036 — which on a heater already standing in your basement resolves itself.

The model number often gives you the warranty term. Bradford White's limited residential water heater warranty, form 238-39699-00ZAN dated 03/25, spells this out with worked examples on the chart itself: RG240T1N carries a one-year glass-lined tank warranty, RG240T6N six years, RG240T10N ten. Parts run six years, subject to the exceptions printed on the same chart. A.O. Smith puts a warranty-code letter in the model number too, prints the mapping on the certificate, and shows ENS 40 and XCR 50 as examples; terms there are six, eight or ten years. (All documents in this article read 28 August 2026.)

Then there is the question of when the clock started, and the brands disagree on the penalty for not knowing. Bradford White runs its term from the date of installation, "or without proof of installation, from three (3) months after the date of manufacture." Rheem's residential certificate of limited warranty, form AP16695-2 (09/14), measures from the date of original purchase and falls back to date of manufacture plus thirty days. Rheem's own policy summary, covering the same residential line, instead says coverage begins at the date of installation and falls back to date of manufacture plus ninety days. Two Rheem documents, two default start dates two months apart, and neither of them is your receipt — a question worth putting to a distributor before you need the answer rather than during a claim. If that sounds like a small thing, it is the same mechanism that halves an HVAC parts warranty when a registration window closes, and it is decided the same way: by a document nobody handed you.

Five failures where the repair still buys years

These are cheap parts on a sound tank. On a unit inside its parts term they may cost you a service call and nothing else.

1. Pilot will not stay lit on a gas unit. On a standing-pilot heater the thermopile generates the millivolts that hold the gas valve open, and it wears out. Bradford White's ICON control reports faults as a sequence of LED flashes, and one of those codes separates low thermopile voltage from a gas valve that has actually failed. The code list is specific to the model and the control fitted to it, so read the diagnostics page in the manual for your own unit rather than a table found loose online, and hand the reading to the technician. A thermopile is a small part. A control valve is not, and telling the two apart is most of the decision.
2. No hot water at all, electric. A failed upper element is one of the things that produces exactly this, and an element is a serviceable item rather than a reason to scrap a tank. The manufacturer's own maintenance schedule asks for a bi-annual check of the seal around the elements, and for the power supply to be disconnected and a professional called at any sign of leaking there.
3. Lukewarm water, or hot then cold, electric. Thermostats and the high-limit cutout sit behind the access panels, and the same schedule asks for an annual check of thermostat operation. The parts are inexpensive. The panels are still not yours to open: the manual's caution reads, "For your safety, do not attempt to repair thermostat(s), heating elements, or electrical wiring. Refer such repairs to a qualified service technician." A high limit that keeps tripping is also a symptom to chase rather than a part to keep replacing.
4. The relief valve is discharging. Worth fixing, but check the diagnosis before anyone buys a valve. The Bradford White electric water heater installation and operation manual, 238-44422-O0AB revised 08/26, says a valve that "discharges periodically" may be reacting to thermal expansion in a closed water supply system, and warns against plugging the outlet for any reason. If your house has a pressure-reducing valve, a backflow preventer or a meter with a check valve, the honest repair may be a thermal expansion tank rather than a new relief valve.
5. Nothing has failed and the tank is seven years old. The anode rod is the only maintenance item that lengthens the life of the thing you are deciding about. The same manual asks for inspection every two years, notes that "the use of a water softener may increase the speed of anode consumption," and asks for more frequent inspection on softened or phosphate-treated water. A house on softened water eats anodes faster than one on hard water, which is the reverse of what the phrase "hard on the water heater" leads people to expect.

Two the arithmetic never rescues

The tank. Rheem publishes the rule as policy rather than opinion. Its summary of United States residential water heater warranty policy — Rheem's document, in a copy hosted by a third party — reads: "Rheem or Ruud Residential water heaters should be repaired if they are not leaking. They should be replaced only if they are leaking." Before accepting that verdict, establish where the water is actually coming from. A weeping relief valve, a dripping drain valve and a loose union all put water on the floor and none of them is the tank. Dry everything, put paper towel under each fitting, come back in two hours.

A gas control or control module on a tank past its warranty term. This is the expensive single component on a residential heater, and once the tank has no coverage left the money buys an unknown number of years on a vessel already past the term its maker was willing to insure. Two things sit outside that arithmetic. Gas control, burner and gas piping work is service-technician work, so the repair quote carries a service call whatever the part itself costs; the warnings page of the manual for your own gas model puts that in the manufacturer's own words, and it is worth reading before assuming any of it is a homeowner job. And Bradford White's warranty excludes failures caused by "disconnection or alteration of factory installed components, or addition of non-approved components or apparatus," so a control fitted outside the manufacturer's channel can cost whatever tank coverage is left. On an expired tank that is nothing. On a live one it is the entire reason not to.

What a covered part actually pays for

Less than the phrase suggests, and less complicated. Shingle warranties train homeowners to expect a proration table, a schedule that reduces the payout year by year. There is no such table in any of the three residential water heater documents above. Coverage is closer to binary: inside the term you get a part or a replacement heater, outside it you get nothing. And a replacement unit carries only the balance. Bradford White writes that example into the document itself, a ten-year tank that leaks in year nine being replaced with a unit warranted for one.

What the certificates do reduce is everything around the part. Bradford White's excluded costs list runs to freight and delivery, removal and reinstallation charges, "any material, and/or permits required for installation, re-installation, or repair," the cost of returning the failed unit, and any handling or administrative fee a contractor or distributor is allowed to charge in your jurisdiction. A.O. Smith's residential limited warranty, document 100293072 rev C, compresses the same idea into one sentence: the owner "shall be liable for and shall pay for all charges for labor or other expenses incurred in the removal, repair or replacement." Rheem's residential certificate gives one year of full coverage including in-home labour, then five years of parts only.

Permits appear on that exclusion list. A water heater swap is permitted work in most jurisdictions and a warranty replacement does not change that. A reasonable moment to remember what unpermitted work leaves behind at closing.

Five clauses that void coverage before anything breaks

Read these against your own installation before you file anything, because a claim is where they get checked.

That last row is the one landlords miss. A.O. Smith's coverage runs to the original purchaser "so long as he or she continuously occupies the single family dwelling in which this water heater is initially installed," and drops to a single year where the heater serves more than one dwelling unit. Bradford White goes the other way on ownership: its warranty "extends to the first buyer and to any subsequent owner(s) as long as the water heater remains installed at its original place of installation," which makes it the only one of the three that survives a sale. Rheem's residential certificate says plainly that it "is not transferable."

Thermal expansion earns one more sentence because it sits in the warranty and the plumbing code at once. IRC section P2903.4, linked here in the 2018 edition, covers thermal expansion control; which edition your jurisdiction adopted, and what it amended, is a question for your building department rather than for any national article. The manufacturer's requirement applies whatever your city adopted, because it is a condition of the warranty rather than a condition of the permit.

Turning it into a division

With the tank sound and the part identified, the decision reduces to one question, the same one that runs under any repair-or-replace call on home equipment: how many years does this repair buy per dollar, against how many the replacement buys per dollar?

Take the invoice at the top. $2,100 for a new heater, against a six-year tank warranty on the model most likely to be quoted. Treat six years as a floor rather than a forecast and that is $350 a year, less if it runs longer. The $640 repair then has to buy roughly 1.8 years to break even, and the honest input is not a national average but your own service history for this unit. Two calls in the last three years is a different machine from none in eight.

One line on the replacement quote can move the whole thing. If the unit proposed is over 55 gallons, look at the technology. Under 10 CFR 430.32(d), an electric storage water heater over 55 gallons has to meet a minimum uniform energy factor set by formula rather than a flat number — 2.0440 − (0.0011 × rated gallons) at the low draw pattern, which works out near 1.98 on a sixty-gallon tank. A resistance element cannot reach 1.0, let alone that, so above 55 gallons the rule has already picked heat pump for you and the replacement quote should say so. That table governs units manufactured before 6 May 2029; a second one takes effect for units built on or after that date.

Photograph these before anyone drains the tank

Once the old heater is on a dolly the evidence leaves with it, and every warranty document above wants the rating label intact to process a claim. Rheem's certificate goes furthest, reserving the right to demand either the failed heater with all component parts and the label attached, or "the complete original rating label (photocopies are not acceptable)" removed from it. Its policy summary also allows Rheem to deny any claim submitted more than ninety days after the defect occurred.

So, before the truck arrives: the full rating plate including model and serial, square on and in focus. The relief valve and its discharge pipe. Wherever the water was appearing, paper towel still in place. The gas control on a gas unit, or the closed access panels on an electric one — if what is behind them needs photographing, the person with the panels off should be the technician. And whatever paperwork you own with an installation date on it, even if that turns out to be a bank statement.

Five minutes with a phone. It is the difference between a claim and an argument.