Tankless Water Heater Repair in New Hampshire
Tankless units fail loudly. A code on the display, a burner that lights and drops out, water that swings hot to cold halfway through a shower. The code narrows it down. It doesn't tell you what actually broke, and that's where most tankless service calls go sideways.
In Hot Water handles tankless repair across southern New Hampshire, and we pull the unit's fault history and check combustion, gas supply, and venting before we touch a part. We're veteran-owned, based in Litchfield, and backed by the 30 plus year reputation of Jolt Electric & HVAC.
Homeowners call us when they're done paying for the same repair twice. We find the real cause, explain it in plain language, and get your hot water back for good.
Hot Water Experts, Built on Full-System Expertise.
As your local water heater experts serving southern New Hampshire, we specialize in installation, repair, replacement, and maintenance for all types of water heaters. Whether you are dealing with an emergency breakdown or planning an upgrade, our team is here to help with fast service and honest recommendations.
System-First
Mindset
We diagnose the root cause, not just the symptom.
Precision
Installs
Tighter connections, better sizing, and smarter efficiency.
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Clear communication and honest pricing. No fluff, just results.
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Tankless Water Heater Repairs We Handle Most Often
Scale inside the heat exchanger, the coil that actually heats your water as it flows through the unit, is the first thing we check on any New Hampshire unit, and it causes more tankless failures here than anything else. A tank heater tolerates hard water by letting sediment settle in the bottom. A tankless unit has nowhere to put it, so minerals plate directly onto narrow passages where surface temperatures run highest.
That's why descaling intervals matter so much in this area. Moderately hard water needs a descale about once a year. Genuinely hard well water, which plenty of homes around Litchfield, Manchester, and Nashua have, needs it every six to nine months.
Most manufacturers make annual descaling a warranty condition, so a neglected unit can fail and lose its warranty claim in the same visit. If your installer never added isolation valves, we add them during any repair that opens the water side.
Common tankless repairs we handle include
- -Scale and mineral buildup inside the heat exchanger.
-Ignition failures and repeated flame loss.
-Dirty flame rods, worn ignitors, and restricted combustion air.
-Gas lines that can't deliver full volume at high fire.
-Flow sensor faults and minimum activation flow problems.
-Blocked vent terminations, condensate pooling, and unsealed vent joints.
-Control boards, thermistors, and mixing valves.
-Isolation valve installation and full descaling service.
We handle every step of the process, from removing your old unit to ensuring your new system is installed safely and up to code. Our goal is to set you up with reliable hot water you can count on every day.
What Your Tankless Unit's Fault Code Is Actually Telling You
Every manufacturer numbers its codes differently, so we read the symptom, not just the number. A shop that looks up the code, swaps whatever the manual suggests, and leaves has a decent chance of being back next month.
An overheat or high limit lockout usually means scale is restricting flow through the heat exchanger, not that a sensor went bad. An air supply fault in February is often a vent termination packed with snow or glazed over with ice.
A unit that runs fine alone but stumbles when a second fixture opens is usually an undersized gas supply, not a failing unit. Same code, different repairs, and only one of them holds.
No ignition or repeated flame loss
Air supply or exhaust vent faults
Overheat and high limit lockouts
Reduced hot water flow or temperature swings
These are the four fault patterns we see most often on tankless units across southern New Hampshire:
Tankless Repair or Replacement: How We Decide
Tankless units commonly run 20 years or more, so the math tilts toward repair far longer than it does with a tank. Control boards, ignitors, flame rods, flow sensors, and thermistors are all worth replacing on a unit under 12 years old.
Here are the lines we draw. A cracked or leaking heat exchanger is a replacement, not a repair. So is a unit whose parts the manufacturer no longer supports, because a rebuild you can't get parts for isn't a repair plan.
And when a long-serving non-condensing unit needs a major component, the efficiency gain from a new condensing model usually wins on total cost. We'll show you both numbers and let you make the call.
We repair and service every major type of tankless setup, including:
- Gas tankless units, condensing and non-condensing. Electric tankless and point-of-use heaters. Whole-home systems with recirculation loops. Multi-unit setups for homes with heavy simultaneous demand.
Sometimes the answer is neither. A few times every winter we find a unit that isn't broken, it's undersized.
Tankless capacity is rated at a specific temperature rise, and groundwater feeding a New Hampshire home in January comes in far colder than the spec sheet assumes. A unit that keeps up in August can't lift water from the low 40s to 120 degrees in February. We measure the incoming temperature and calculate the real rise before recommending anything.
Schedule Your New Hampshire Tankless Water Heater Repair
If your tankless unit is throwing a code, dropping out mid shower, or falling behind now that the incoming water is colder, call In Hot Water or request your estimate online.
We'll diagnose the actual cause, tell you what we found in plain language, and fix it so it stays fixed. We serve homeowners across southern New Hampshire, from Litchfield and Manchester to Nashua and the surrounding towns. Never run cold again.