Boilers
Lochinvar Knight Fire Tube Condensing Boiler
8 of 10 catalog products carry at least one real, seller-observed equipment-only price (SupplyHouse, Active Plumbing, Home Depot, AF Supply), gathered 2026-08-24 -- 80% against the >=70% gate. Two products (weil-mclain-evergreen, htp-elite-premier-ep110) were researched but no real seller price could be reached (login-gated distributor pages) and were left unpriced rather than estimated, per this platform's own rule against silent substitution. A genuine, disclosed limitation found this run: platform/core/pricing.py's PER_TON_BANDS dictionary defines $/ton plausibility floors and ceilings for heat-pump, mini-split, central-ac and furnace only -- boiler (and solar-panel) have no band defined at all. Confirmed by reading validate_observation() directly: when bands.get(scope) returns None for an unbanded category, the function returns (True, None) unconditionally, so every boiler price observation currently passes validation regardless of its $/ton figure. This means the exact failure mode PROCEDURE.md documents for heat-pump (a $1,707-for-a-3-ton listing that was actually a financing figure) could not be caught here even if it existed, because no floor exists to catch it. Not silently patched -- platform/core/ pricing.py was read but not edited as part of this pass, per instructions. For reference, this run's own 8 real observations imply a $/ton range of roughly $124-$684 (Rheem Prestige RCBH199DVLN's $2,048 list at 199,000 BTU/h is the low outlier worth a second look before trusting it as-is; IBC SL 260's $6,163.53 at 260,000 BTU/h is the high end). A future pass should propose a real boiler band -- something in the neighborhood of $150-$900/ton would bracket what this run actually observed with margin -- rather than leave the category permanently unchecked.
Fire-tube condensing boiler with 10:1 turndown, built for the residential and light-commercial hydronic market.
Our take
Lochinvar is what a lot of hydronic contractors put in their own houses. Fire-tube heat exchangers are more forgiving of imperfect water quality than the water-tube designs used by some competitors, which shows up as fewer failures at year eight. Unglamorous and durable.
Best for
Hydronic systems where longevity matters more than the last point of AFUE.
Watch out for
Sold through wholesale only. Get at least two contractor quotes — installed pricing on hydronics varies enormously.
What sellers are actually charging
Real listings, read on the date shown. Prices change — click through to check before you act on any of them.
| Seller | What you get | Price | Seen |
|---|---|---|---|
| SupplyHouse.com
online retailer |
Lochinvar Knight Fire Tube KHB110N
KHB110N |
$4,838 | 2026-08-16 |
Equipment price is not installed price. The listings above are what the hardware costs. Installation — labour, electrical, refrigerant lines, permits, removing the old system — is typically a similar amount again, and varies more between contractors than between brands. Where we have an installed figure it is labelled as such and comes from someone who actually installs.
What owners and installers report
Collected from trade forums, owner communities and video reviews. Every report links to the original. We synthesise and quote briefly — we don't republish other people's writing.
Every report below traces back to a single source. The sections are broken out by topic because that's how they read, but treat this as one data point, not independent corroboration across topics — a second source agreeing (or disagreeing) would change that.
Recalls and safety notices
Official recalls and safety actions from regulators. Rare, but decisive — a recall outranks every specification on the page.
CPSC recalled roughly 34,300 US units (plus 3,642 in Canada) across multiple Lochinvar/A.O. Smith/State Proline condensing boiler lines sold under the model prefixes ACB, KHB, SCB, WHB, WHN, WHL, APN, EPB, EPC and NKB/NKC — this catalog's Knight Fire Tube KHB line is named explicitly. A flue grommet can deteriorate or dislodge, allowing carbon monoxide to leak. Seven incidents were reported, including one nonfatal CO poisoning affecting two people. Free repair was offered.
“Flue Grommet Can Deteriorate and Dislodge, Posing Carbon Monoxide Poisoning Hazard” — forum participant, 2020-06-18
CPSC recall: Lochinvar condensing residential boilers — carbon monoxide poisoning risk (2020) · U.S. Consumer Product Safety Commission · 2020-06-18 · read it in context
Reliability and failures
What breaks, when, and how often — from people several years in.
An owner of a Lochinvar Knight KBN-399 (a larger, different capacity variant in the same Knight product family as this catalog's KHB110N — not a confirmed identical failure mode, but the same manufacturer and platform) reported a heat-exchanger failure after three years, quoted $9,000 for the replacement exchanger versus $8,500 for an entirely new boiler, and described the warranty response as unhelpful.
“Very disappointed in Lochinvar...Rules are Rules and there was nothing that could be done” — Kenny Greene_2 homeowner, 2022-01-01
Lochinvar Knight KBN 399 Heat Exchanger Failure · HeatingHelp — The Wall · 2022-01-01 · read it in context
Sources are linked so you can verify any of this yourself. We don't mirror content — Amazon in particular permits no republication of review text, so where we use retailer data we show the aggregate rating and link out. How we collect and weight this →
Compare against
Navien NFC-175 Condensing Combi Boiler
High-turndown condensing combi boiler providing both hydronic heat and domestic hot water from one wall-hung unit.
Viessmann Vitodens 100-W Condensing Boiler
German-engineered condensing boiler with a stainless Inox-Radial heat exchanger and a 10:1 turndown ratio in line with the rest of this catalog's condensing boilers.
Weil-McLain Evergreen Condensing Boiler
Stainless condensing boiler from the most established US residential boiler brand.
Rheem Prestige RCBH199DVLN Condensing Combi Boiler
199,000 BTU/h condensing combi boiler, a real currently-stocked substitute for the now-defunct Triangle Tube Prestige line this catalog originally targeted.
Before you buy this
Ask about turndown ratio, not just efficiency — a boiler that can't modulate down to your house's actual heat loss on a mild day short-cycles, and short-cycling is what wears a boiler out early. Confirm whether your radiators or baseboard were sized for the supply temperature this boiler will actually deliver. And ask for a heat-loss calculation instead of matching the old unit's output.