Rheem Water Heater Error 10 — Vent Air Pressure Fault

What Does This Error Mean?

Error 10 is a vent air pressure problem.
The vent fan inside the unit isn't producing the expected pressure differential — either the fan is weak, the vent path is partly blocked, or the pressure switch itself has failed.
Inspect the outside vent first (clear any debris).
If clean, the issue is internal and needs a licensed installer.

Affected Models

Rheem RTGH series
Rheem RTG-95
Rheem RTGH-95DVLN
Rheem Performance Platinum tankless

Common Causes

Vent partially blocked by debris (lint, leaves, bird nest)
Vent fan motor failing or noisy
Pressure switch tubing pinched or disconnected
Pressure switch itself failed
Excessive back-pressure from a too-long or kinked vent run

How to Fix It

Inspect the outside vent termination.

Trace the vent to where it exits the house.
Look at both openings.
Clear any partial blockage — a vent that's 50% clogged still throws Error 10 even though air is moving.
Pay attention to lint accumulation if the vent runs near a dryer vent.
Listen to the vent fan.

Power-cycle the unit and start a hot tap.
You should hear a small fan inside the heater spin up.
If it sounds like a normal fan, it's working.
If it grinds, whines, or doesn't spin at all, the fan motor is the cause.
Check for unauthorized vent modifications.

If anyone has added length to the vent, added bends, or changed the termination, those changes can throw Error 10.
Tankless heaters have strict vent length and bend specifications.
Compare current setup to the install manual — if it's been modified, that may be the cause.
Don't try to access the pressure switch.

The pressure switch is internal to the combustion area.
Working on it means opening the gas-side of the unit.
This is licensed-installer-only.
Don't try to bypass or 'reset' the switch — that defeats a safety designed to prevent CO buildup.
Schedule service if vent is clear.

If the outside is clean, the fan sounds normal, and Error 10 still triggers, call a licensed installer.
Common fix is replacing the pressure switch (about 80 USD part) or the vent fan (about 150 USD part).
Both are technician-level repairs.

Frequently Asked Questions

Can wind cause Error 10?

Strong wind blowing into the vent termination can cause intermittent Error 10 trips by interfering with the vent's expected pressure.
If you only see Error 10 on stormy days, that's the cause.
A wind shield or vent extension may help — ask the installer about options for your climate.

Is Error 10 dangerous?

It's a safety code, not an immediate emergency.
The unit shuts down on Error 10 specifically to prevent CO buildup from improper venting.
Don't bypass it.
The protection working means you and your family are safe — fix the underlying cause, don't disable the protection.