RV Water Heater Repair and Replacement, Tanked and Tankless
Written by RV Systems Lead, RV Systems and Electrical Lead, OCRV Center. Reviewed by Claims Coordinator
In shortWhich source still works tells you the fault. Gas out but electric fine points at ignition or a blocked burner tube. Repairs and swaps run $350 to $4,500 at $260 per hour.
How is an RV water heater diagnosed and replaced?
RV water heater work covers Suburban and Atwood tanked units, Truma and Girard tankless units, their gas valves, electrodes, thermostats and anode rods. Rancho Santa Margarita owners bring units to Yorba Linda, where LP pressure is read on a manometer and the opening is measured before any replacement is ordered.
- Hot on shore power and cold on propane is an ignition question
- A Suburban steel tank needs an anode rod, an Atwood clad tank does not
- Bypass valves left in the winter position produce cold water from a healthy heater
- Tankless retrofits need gas capacity and an opening that actually fits
- Price range
- $350 to $4,5001 to 18 labor hours at $260 per hour
- Labor rate
- $260 per hourMechanical and electrical department
- LP handling
- $45 flatHazmat and disposal charge where LP or chemicals are involved
- Typical turnaround
- 1 to 4 shop daysLonger where a tankless retrofit needs cabinetry work
- Written estimate
- $150Credited in full against an authorized repair
- Units serviced
- Suburban SW6DE and SW10DE, Dometic and Atwood G6A-8E, Truma AquaGo, Girard GSWH-2
Last verified
Almost every hot water complaint arrives described as no hot water, and almost every one of them contains the diagnosis already, in the part of the sentence the owner did not think mattered. Which source did you try. Was there hot water and then it went cold, or has there been nothing since the trip started. Did the reset button click. Those three answers separate an ignition fault from a thermostat fault from a bypass valve somebody left turned in October.
Two very different pieces of hardware live under this heading. A six or ten gallon tanked heater with a burner, an electric element and a steel or aluminium clad tank. Or a tankless unit that heats on demand and is sensitive to flow rather than to capacity. They fail for unrelated reasons and the retrofit between them is a real project rather than a swap, so both get treated properly here.
The question that resolves most hot water faults
Which source still works. Almost every tanked heater on the road runs on propane, on a 120 volt element, or on both, and the two systems share only the tank and its thermostats. So hot water on shore power with nothing on propane places the fault firmly on the gas side: the burner tube, the electrode, the gas valve or LP pressure. Nothing on either source moves the suspicion to the thermostat pair, the cutoff, or a tank that is not actually full of water.
Owners frequently discover during this conversation that one side has been dead for a long time. A coach that lives on a hookup at home covers a failed burner for months, and the problem only surfaces on the first trip where propane is the only option. That is worth knowing before you conclude the unit failed suddenly, because it also tells you how long the burner has been sitting with a tube full of whatever moved into it.
- Gas dead, electric fine: burner tube, electrode, gas valve or LP pressure
- Electric dead, gas fine: element, its thermostat or the 120 volt supply
- Neither works: thermostat pair, cutoff, or the tank is not full
- Works then goes cold fast: capacity, mixing valve or a scaled tank
- Cold water from a working heater: bypass valves still set for winter
Suburban steel and Atwood clad tanks are not the same appliance
This distinction matters more than any other in the category and most owners have never had it explained. Suburban builds a porcelain lined steel tank and fits a sacrificial anode rod, because steel and hot water are a corrosion pair and the rod is designed to be consumed instead of the tank. That rod is a maintenance item. Ignore it and it disappears, and once it is gone the tank wall is what corrodes next.
Dometic, formerly Atwood, builds an aluminium clad tank that does not use a sacrificial rod at all. There is nothing to inspect and nothing to replace, which is genuinely simpler. It also means that when an owner is told their heater needs a new anode rod, the first useful question is which tank they actually have, because half the time the answer is that no such part exists on their unit and somebody was reading from the wrong page.
| Item | Suburban SW series | Dometic and Atwood G series |
|---|---|---|
| Tank material | Porcelain lined steel | Aluminium clad |
| Anode rod | Fitted and consumable, inspect yearly | Not fitted, nothing to check |
| Drain | Anode rod doubles as the drain plug | Separate plastic drain plug |
| Common water side failure | Rod consumed, then tank corrosion | Drain plug threads and scale |
| Ignition | Electrode with gas valve and board | Electrode with gas valve and board |
Burner tubes, electrodes and LP pressure under load
A burner tube is an open pipe pointing at the outdoors through a louvred door, and insects treat it as accommodation. A mud dauber nest or a spider web inside the tube disrupts the air fuel mix, which produces a yellow lazy flame that either fails to satisfy the sense circuit or sooty combustion that streaks the outside panel. Pulling and cleaning the tube, then resetting electrode geometry to the specified gap, resolves a large share of gas side complaints without any parts at all.
The other half of the gas story is pressure, and it has to be read while the appliance is firing. A regulator can measure correctly at rest and sag once a burner draws on it, particularly on a coach where a furnace and a refrigerator are competing for the same supply. That is a manometer job, not a guess, and it is the reason a heater that a previous shop declared faulty sometimes turns out to have been starved rather than broken.
Before you proceed
Sooting above the burner opening is a combustion warning, not a cosmetic one. A unit producing soot is producing carbon monoxide, and it should not be run in an occupied coach until the tube and flame have been inspected.
The bypass valves that cause a fault that does not exist
Behind the heater on nearly every unit sits a set of two or three valves whose job is to isolate the tank so antifreeze can circulate through the coach without filling six gallons of it. In winter position the tank is out of circuit and empty. In summer position it fills and heats. Every autumn, somebody sets those valves and every spring somebody forgets to set them back.
The result reads like an expensive failure. Cold water at every tap while the heater sounds like it is working. Or the element energising into an empty tank, overheating, and tripping the cutoff, which owners then reset until something is genuinely damaged. We check valve position before opening anything, feel the tank fill, and label the valves on the way out so the next person to winterize the coach can see which way is which.
Tankless units and what a retrofit actually involves
On demand units like the Truma AquaGo and the Girard GSWH-2 trade tank capacity for continuous supply, and they are excellent in a coach with adequate gas and reasonable flow. Their failure pattern is different from a tanked heater. They are sensitive to scale, to flow rate at the fixture, and to inlet water temperature, and at very low flow some installations produce alternating hot and cold at the shower head, which is a plumbing and habit issue as much as an appliance one.
A retrofit from tanked to tankless is not a swap. The aperture in the sidewall is a different size, the burn rate is far higher so the gas supply and regulator capacity have to be confirmed, condensate and flue arrangements differ, and the interior trim and surround usually need rebuilding. We measure the opening, check gas capacity and quote the cabinetry before recommending it, which is the opposite order from how these get sold at a show.
What this costs, and why the coach comes to us
Water heater work bills at $260 per hour across a band of $350 to $4,500, with the low end covering a burner clean and verification and the top covering a tankless retrofit with cabinetry. Parts carry standard markup, sales tax applies to parts and materials, labor is not taxed, and a $45 hazmat and disposal charge applies wherever LP is handled. A written estimate is $150 and credits in full against an authorized repair.
We do not offer mobile service on gas appliances and there is no roadside version of this work. A manometer reading under load, an electronic leak check on every joint disturbed, and a full heat cycle observed on both sources are the minimum standard for releasing an LP appliance, and none of that happens usefully in a driveway. The run from Rancho Santa Margarita up the 241 to the 91 is short and it is the right way to have a gas appliance signed off.
On cost
Where a tank has begun corroding through its lining we will say replacement rather than sell a rod and a flush. A rod in a tank that is already weeping is money spent to delay the same job by one season.
Which vehicles we do this on
Gas and diesel motorhomes, Class C units where the heater sits in a tight cabinet behind the dinette, trailers and fifth wheels with the familiar exterior access door, truck campers where the whole appliance bay is the size of a suitcase, and Sprinter based builds where a tankless unit is often the only thing that fits. Access varies enormously and it is the main reason two identical heaters can be four hours apart in labor.
What is included
- Source by source isolation
- The unit is run on propane and on the electric element separately, with current draw and gas pressure measured on each, so the fault is placed on one side before parts are discussed.
- Manometer reading at the appliance
- LP pressure is read while the burner fires, not statically. A regulator that measures fine at rest and sags under load is a common finding and it is invisible without the gauge.
- Burner, tube and flue inspection
- The burner comes out, the tube is inspected and cleaned, and the flue path is checked. This is the most productive twenty minutes in the whole category.
- Anode and tank condition assessment
- On steel tanked units the rod comes out and gets shown to you. On clad units we explain why there is no rod to check rather than sell you one.
- Bypass valve position verified and labelled
- Winterizing valves are set to summer, confirmed by feeling the tank fill, and labelled so the next person to touch them knows which way is which.
- Leak check on every gas joint disturbed
- Electronic detection and a manometer drop test on anything we opened. A $45 hazmat and disposal charge applies where LP or chemicals are handled.
How the work runs
Ask which source, then prove it
45 minutes
The unit runs on propane and on the element in turn while we watch current and gas pressure. Owners are frequently surprised that one side has been dead for a year, because the other side quietly covered for it every time they were plugged in.
Check the valves before condemning the appliance
20 minutes
Bypass valve positions, low point drain state and tank fill are confirmed first. A heater with an empty tank delivers cold water, overheats its element and trips its cutoff, and every one of those symptoms points at a fault that is not there.
Pull the burner and read the gas
1 to 2 hours
Burner out, tube inspected, electrode gap measured, flame observed and LP pressure taken on a manometer while it fires. Most gas side complaints are resolved and verified inside this step without a part being ordered.
Open the tank on a suspected water side fault
1 to 3 hours
Anode rod out on steel tanks, drain plug pulled, tank flushed and inspected for scale and flake. This is where a decision between a maintenance repair and a replacement actually gets made, with the evidence on the bench.
Fit or retrofit
3 to 14 hours
A like for like tanked replacement drops into the existing opening. A tankless retrofit means measuring the aperture, confirming gas capacity for a much higher burn rate, adapting the surround and rebuilding trim, which is where the top of the range comes from.
Fire, cycle and leak check
1 hour
The unit runs a full heat cycle on each source, the relief valve is observed, temperatures are taken at a fixture, and every gas joint we disturbed is checked electronically and with a pressure drop test before release.
What this costs
$350 to $4,500
1 to 18 labor hours at $260 per hour, mechanical and electrical.
- Hazmat and disposal $45 flat when chemicals, refrigerant or LP is involved.
- Parts at $100 or less carry 100 percent markup. Parts over $100 carry 35 percent. Special order parts require a full non refundable deposit at order.
- Sales tax of 7.75 percent applies to parts and materials. Labor is not taxed.
- A 50 percent deposit is taken at authorization on any job over $2,000, with an additional 25 percent when parts arrive on any job over $10,000. Final balance is due at pickup.
- A burner clean, electrode reset and gas pressure verification sits at the bottom of this range.
- A tankless retrofit with aperture and cabinetry work sits at the top.
- A $45 hazmat and disposal charge applies on any job where LP is handled.
How estimating is billed
- Written repair estimate: $150, credited in full against an authorized repair.
- In depth diagnostic, scan and programming: $285 per hour, one hour minimum, credited in full against an authorized repair.
- In shop pre purchase inspection: $400 to $1,200 depending on unit size and systems count.
- Insurance walk ins are accepted during posted hours. All inspection and estimating work is performed in shop at the Yorba Linda facility.
What you will notice first
- Hot water on shore power but nothing at all when running on propane
- Nothing on either source, and the reset button clicks when pressed
- The burner lights, runs for a few seconds and drops out again
- Hot water that smells strongly of rotten eggs within a day of filling
- Popping or kettling noises from behind the exterior access door
- Water running from the pressure relief valve on the outside wall
- A tankless unit that alternates hot and cold at low flow
- Soot streaking on the outside panel above the burner opening
How this fails, and what we do about it
| Failure mode | How we diagnose it | The fix |
|---|---|---|
| Obstructed burner tube | Gas side dead, electric side fine. Pulling the burner shows a nest or debris in the tube and often a yellow flame pattern on the tube walls. Soot above the exterior opening is the outside clue. | Clean the tube, reset burner and electrode geometry to the manufacturer's gap, then verify LP pressure on a manometer while the unit fires and watch three consecutive clean lights. |
| Failed flame sense at the electrode | The burner lights and drops out within seconds, repeatedly. Electrode gap out of tolerance, ceramic cracked or the sense lead corroded at its terminal. | Replace the electrode assembly and lead, set the gap to spec, and confirm the control holds the valve open through a full heat cycle rather than one light. |
| Anode rod fully consumed on a steel tank | Rotten egg smell in the hot water, sometimes with dark flakes at the drain plug. Pulling the rod finds it eaten to the core wire on a Suburban tank. | Fit a new rod, flush the tank and sanitize. Where the tank wall has already begun to corrode through the porcelain lining, replacement is the honest answer and we say so with the rod in hand. |
| ECO thermostat tripping repeatedly | The reset clicks in and the unit works, then trips again. Either the thermostat pair has drifted, the tank is scaled so heat concentrates, or the unit was run with the tank not fully filled. | Replace the thermostat and ECO as a pair, descale, and confirm the tank filled properly by checking the bypass valve positions before blaming the control. |
Why it happened
- A mud dauber or spider nest inside the burner tube, which is the single most common gas side failure on a coach that sat through a warm autumn
- An electrode or thermocouple out of position or carboned, so the flame lights and the control never sees proof of it
- LP regulator pressure low or a line partly obstructed, which produces a lazy flame that lights and then fails the sense circuit
- A fully consumed anode rod in a Suburban steel tank, after which the tank itself starts corroding and the smell arrives
- Scale on an electric element or across the tank floor, which insulates the heat source and makes the unit pop as it cycles
- Winterizing bypass valves left closed to the heater, so the tank sits empty and the coach delivers cold water from a unit that is working perfectly
Parts and brands we work with
- Suburban SW6DE and SW10DE tanked heaters with porcelain lined steel tanks
- Dometic and Atwood G6A-8E and GC6AA-10E units with aluminium clad tanks
- Truma AquaGo Comfort and Combi Eco Plus for on demand and combined heating installs
- Girard GSWH-2 tankless units and Furrion replacement doors and surrounds
- Camco magnesium and aluminium anode rods, drain plugs and pressure relief valves
- Suburban gas valves, ECO thermostat pairs, electrode assemblies and circuit boards
What not to try yourself
- Pressing the reset button repeatedly. The cutoff tripped because something got too hot, and forcing it back in without finding out why is how an element burns out or a tank scorches.
- Poking a burner tube clear with wire and refitting it without checking flame pattern and gas pressure. A partly cleared tube produces carbon monoxide as well as a lazy flame.
- Fitting a magnesium anode rod to an aluminium clad Atwood or Dometic tank. There is no rod fitting on those tanks for a reason and forcing one in damages the drain boss.
- Running the heater with the bypass valves closed to see whether it works. An empty tank fired on either source is exactly how a good unit becomes a replacement.
Which vehicles we do this on
Vehicles we perform Water Heaters on
Class A GasClass A gas motorhome repair covers the molded front and rear caps, the vacuum bonded laminated sidewalls, the EPDM roof and the F53 chassis underneathClass CClass C motorhome repair centers on the cabover bunk, the joint where the coach body meets the factory van cab, and the stick built or laminated house behind itTravel TrailerTravel trailer repair covers A frame tongue welds, the front cap that takes road debris, the roof front radius seam, sidewall delamination starting at a window corner, and equalizer and axle wearStandardStandard fifth wheel repair concentrates on the pin box and upper deck welds, the floor at the step up transition, the front cap above the pin and the roof front radius seamTruck CamperSlide in truck camper repair concentrates on the wing walls, the jack brackets bolted through them, the cabover nose over the truck cab and the tie down attachment pointsSprinterSprinter van collision repair covers the unitized steel shell, the rear and sliding door openings, the roof structure and the upfit that hangs off all of itThe first thing I do is put my hand on the bypass valves, and I would guess one in six no hot water complaints ends right there. The second thing is pull the burner, because a spider nest in the tube is so common that finding one has stopped being interesting. What I care about is the anode rod, and specifically whether the owner has ever seen one. On a Suburban steel tank that rod is the only thing standing between water and the tank wall, and by the time somebody notices the smell it has usually been gone for a season and the tank is already on borrowed time.
Appendix: questions and answers
- Why do I get hot water on shore power but nothing on propane?
- The fault is on the gas side, since the two sources share only the tank. In order of likelihood: a nest or web blocking the burner tube, an electrode out of gap so flame sense fails, low LP pressure under load, or the gas valve. A burner clean and a manometer reading resolve most of them.
- Does a Suburban tank need an anode rod and does a Dometic one?
- A Suburban porcelain lined steel tank needs one and it is consumable, so it should be inspected yearly and replaced when eaten. A Dometic or Atwood aluminium clad tank has no anode rod at all and nothing to check. Knowing which tank you own prevents buying a part your unit cannot accept.
- What does a rotten egg smell in the hot water actually mean?
- Sulphate reducing bacteria reacting with a consumed anode rod or a corroding tank wall, usually on a steel tanked unit that has sat with warm water in it. We pull the rod, flush and sanitize the tank. Where the lining has already failed underneath, the smell is a symptom of a tank on its way out.
- My bypass valves were left set for winter. What damage does that do?
- The tank sits empty, so every tap runs cold while the unit appears to work. Worse, an energised element in an empty tank overheats within minutes and trips the cutoff, and owners reset it repeatedly. That sequence is how a healthy heater becomes an element replacement or a scorched tank.
- Is a Truma AquaGo a sensible replacement for a six gallon tank?
- Sometimes, and it depends on three measurements rather than on preference. The sidewall aperture has to accept a different footprint, the gas supply and regulator must carry a much higher burn rate, and fixture flow has to be enough to trigger and hold the burner. We measure all three and quote the trim work before recommending it.
- How often should the thermal cutoff trip for a legitimate reason?
- Effectively never. It is a safety device, not a working control, so a unit that trips it is telling you something got too hot: a drifted thermostat, a scaled tank concentrating heat, or an element energised into a tank that was not full. Repeated resetting without diagnosis is what turns that into a replacement.
Open a file on this repair
Tell us the vehicle, what happened and whether a claim is open. We will tell you what the scope looks like and what it takes to get you back on the road.
Or call (949) 799-3387