Rinnai RH180 Hybrid Code 05
Air screen restricted. The air screen on the front of the cabinet — Rinnai calls it the HTT Engine Air Screen — is loaded with lint and dust and the unit is not getting the combustion air it wants. This is the one code on the RH180 that starts as housework: the manual's own detection section names code 05 as the signal that the screen needs cleaning, and walks a homeowner through it. The escalation is what to watch for. If 05 keeps flashing after the screen is clean, Rinnai sends you to the code 10 checklist, which is the vent system and is not yours.
DIY fixThe verdict
No parts needed — reset or re-check a setting
Free, and about fifteen minutes. Power the unit off, pull the air screen door off the front, wash the screen with dish soap and a soft brush, dry it and put it back. If the code survives a clean screen, stop — the next list Rinnai gives is the vent, and that is a professional's job.
Typical cost: $0–$250
US estimate for parts and labor. Prices vary by region and by who does the work — see how we estimate costs.
What the manual says
The meaning above is transcribed from the manufacturer's diagnostic documentation for the RH180 Hybrid — not averaged across the brand.
Source: Rinnai RH180 Operation and Installation Manual (100000319) (p. 35), read Sep 2026 — the manufacturer's own documentation for this exact series.
What you can safely check
- Press the round power button on the right of the controller and wait for the display to go blank.
- Slide the air screen door latch to the right, swing the door open and lift it off the front panel.
- Scrub the screen with mild dish soap and a soft brush, rinse it with clean water and dry it with a lint-free towel.
- Look the screen over for damage while it is out — Rinnai sells the assembly as part number 108000030 if it is torn.
- Refit the door: line the tab up with the slots, rotate it closed and slide the latch left to lock it.
- Power the unit back on. If code 05 returns with a clean screen, contact a qualified service provider rather than working through the vent checks yourself.
Frequently asked questions
Is code 05 on my RH180 the same as code 05 on a Rinnai tankless unit?
No, and this is a good example of why this site splits by series. On the Non-SENSEI tankless range, code 05 is the bypass flow control device and ends in a valve replacement. On the RH180 it is a dirty air screen you can wash in the sink.
How often should I be cleaning the screen?
Rinnai says to inspect it periodically rather than on a schedule. If the unit sits in a laundry room, near a dryer vent, or anywhere dusty, it will load up faster — check it when the code appears and then note how long that took.
Code 05 on other Rinnai series
The same code number can mean something different on another series — make sure you're reading the page for your exact unit: