SaferProducts incident

Failure type

Fire / ignition

Incident narrative

SaferProducts.gov consumer incident report 20260730-4D813-2147313188. Severity: Incident, No Injury. Product: Rinnai RUR98i REU-KBP3237FFUD-US (Natural gas instant hot water heater. Model RUR98i and the entire line). Incident: I wanted to report an engineering flaw in Rinnai tankless water heaters. I am now on my second Rinnai tankless water heater. When I moved into my home I had a, what I thought was the best tankless water heater, in my home a model RUR98i. This year I had to have it replaced as it was not heating the water well. The unit would have cost more in labor to tear it down and put back together, before parts than to buy a new one. So we replaced it. I finally got to tear it down to see what was wrong with it. Initially they thought the fins were worn down from heat cycles. When I got it apart it was perfect inside. All but one problem and it was not a failed part. The ceramic plates that crate infrared heat were the small holes were plugged and a layer of fine material covers the ceramic blocks. This was blocked with dust and very small insect parts. These units should have 2 filters on them that are serviceable. A fine mesh screen like that for a cloths dryer for the intake side. It also needs a fine stainless steel screen filter for the exhaust side. A perfectly good unit was totaled because of the lack of a couple of simple serviceable debris screens. This also caused a buildup of unburnt natural gass outside near the exhaust vent. This could cause a dangerous build up of gas that can go through a window causing Asphyxiation or cause a fire. When I contacted the gas company that did the initial installation they said it was a normal smell of initial unburnt gas added odor on start up, but I never thought it was normal. It was incomplete combustion due to poor air fuel mixture. Th