Rheem Pressure Switch Failed Open
The Short Answer: “Pressure switch failed open” on a Rheem, Ruud, or Richmond power-vent tank means the inducer ran (or tried) and the switch never closed — no proved draft, so the gas valve stays shut. That is a blocked termination, condensate in the vinyl tube, a cracked hose, a dead blower, or a failed switch. It is a carbon monoxide lockout. Do not jumper it. Do not fire the burner without the fan.
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Search Intent & The Real Problem
The tank is cold. The control, EcoNet text, or a tech’s readout says pressure switch failed open. On many Honeywell/Resideo power-vent valves that is a 3-flash. Failed open is the opposite of failed closed: open = never proved, burner never should light; closed-stuck = the control thinks there is draft when the fan is off, and the inducer can run forever — fan keeps running. Atmospheric Rheems with a draft hood do not have this switch. Paloma tankless code 10 is an air/exhaust cousin, not this tank prove. Generic dead fan: blower not working. This page is the Rheem failed-open lockout.
What other guides get wrong
They tell you to pull the hose off the switch and inhale so the burner will light. That is a jumper. They sell a $20 switch for a nest in the sidewall or a trap full of condensate. They paste tankless code 10 onto a tank-type 3-flash. They mix failed-open with failed-closed. And they oil a sealed inducer, then tape a rusted Category III joint as a “repair.”
Step-by-Step Troubleshooting
Step 1: Confirm it is a power-vent Rheem, then name open vs closed
| What you have | Failed open means | Not this |
|---|---|---|
| Power-vent / PDV tank, blower on the outlet, 120 V cord | Switch never closed on a call — no prove | Atmospheric draft hood |
| LED 3 flashes, pause, 3 (many Honeywell PV charts) | Same complaint — read the sticker | Electric 5-flash |
| EcoNet / diagnostic text “pressure switch failed open” | Prove circuit | A thermocouple |
| Fan silent, valve never opens | Blower or 120 V first | A new switch |
| Fan spins, no click at the switch, no burner | Tube, condensate, vent, switch | Gas orifice |
| Fan never stops, switch welded closed | Failed closed | This page |
| RTG / Prestige two-digit 10 | Tankless air/exhaust | Different machine |
| Atmospheric gas, 7- or 9-flash | FVIR / chamber | 7-flash, 9-flash |
- What to look for: Rating plate that says power vent / PV / PDV. Photo of the LED and the diagnostic label. Ruud and Richmond share this control. If the furnace died in the same hour, think shared vent or shared 120 V — heater and furnace.
- Required tools: Flashlight, phone camera. Jacket sticker wins over any blog chart.
A unit that lights, runs ~5 minutes, then throws failed-open as the switch heat-soaks is still this circuit — shuts off after 5 minutes.
Step 2: 120 V, the blower, and condensate — before you condemn the switch
- What to look for: Disconnect or emergency switch off. Shared GFCI popped after rain. Outlet dead. After a storm start at dead after a power outage. Condensate trap full, a pump that quit, ice at a sidewall drain, water in the blower housing. Vinyl sensing tube cracked, off the barb, kinked, or full of water — that is the #1 “failed open” I see. Nest, lint, or a downspout dumping into the termination. Wind-driven rain: gas after rain, tankless after rain as the same weather physics.
- Required tools: Eyes, a known-good night-light in the receptacle. Clear debris from the outside only. Do not shove a hose into the vent — you will flood the fan and the switch.
The blower is the draft. A silent shaft with a call is a motor, capacitor, or a control that never called it because another safety is already open — chamber sensor. Do not fire it anyway.
Step 3: Termination and the vent run — look, do not tape
- What to look for: Sidewall cap packed with cottonwood, a bird nest, snow, or a dryer vent blowing lint across it. Too many elbows or a crushed pipe versus the listing on the rating plate. Disconnected Category III stainless or PVC in the attic. Pitch that dumps condensate back into the blower instead of the trap. A wet collector or dripping vent joint is vent pipe leaking, and that water opens the switch.
- Required tools: Eyes from the ground. Binoculars if the termination is high. No furnace tape. No foil.
Prove pressure is a few tenths of an inch w.c. You do not set that with your lungs. Manifold gas pressure is a different measurement and is licensed (NG ~3.5–7 in. w.c. / LP ~10–11 in. w.c. at the appliance — confirm the rating plate).
Step 4: The switch itself — look, do not jumper
- What to look for: Inducer spinning, tube seated and empty, termination clear — still failed open. Then the diaphragm, the electrical contacts, or the board never sees the close. A switch that clicks by hand with power proven dead and still will not make on a call is the part or the harness. Scorched spades. Water inside the plastic body. Do not jumper the two terminals “to see if it fires.” That is how you vent CO into the living space. Do not pinch the hose closed to fake a vacuum.
- Required tools: Visual. Meter only if you are qualified and the disconnect is locked off. Covers stay on if you smell exhaust.
Need the tank dark while you wait? Apartment shutoff. Spark with a spinning fan and a closed switch is ignition, not this page — Rheem won’t light, Honeywell igniter.
Step 5: Board, collector leak, and when the tank is the victim
- What to look for: 120 V proven, blower spinning, tube dry, cap clear, switch that still will not close — control or harness. Water in the cabinet from a leaking collector drowning the prove circuit. A 12-year tank with a rusted blower housing that will not reseal is a replacement conversation, not a $20 switch. House static over ~80 psi dumping the T&P (typical 150 psi / 210°F) is a different puddle; never cap it. Electric 4500 W / 240 V ~18.8 A / ~12–13 Ω numbers do not apply here — this is a 120 V prove circuit. After any control or blower swap, leak-test and combustion-test are licensed. Do not purge gas fittings because the switch is open.
- Required tools: None once the easy checks passed. Photo of the sticker for the truck.
Richmond and Ruud use the same Rheem PV guts — Richmond gas valve if the LED is a different count. One reset after you clear a nest is fair. The same 3-flash an hour later is the switch, the blower, or the vent — licensed.
When DIY Ends: Calling a Licensed Pro
You may confirm the disconnect, reset one GFCI, clear an exterior termination, reseat a dropped vinyl tube, and photograph a 3-flash. You may not jumper the pressure switch, tape the vent, oil the motor, or fire the burner with the inducer unplugged. Blower, pressure-switch, and Category III vent work is licensed. A failed-open lockout is the heater refusing to dump CO into the house. Same-day licensed repair beats a weekend with the combustion door cracked “for draft.”
Frequently Asked Questions
Q: What does pressure switch failed open mean on a Rheem? A: The power-vent inducer did not prove draft, so the switch stayed open and the gas valve never opened. Blocked vent, condensate in the sensing tube, dead blower, or a failed switch. It is not a thermocouple. Do not jumper it.
Q: Can I bypass a Rheem water heater pressure switch? A: No. Jumping it or sucking the hose is how carbon monoxide reaches the living space. Clear the termination and the condensate path, then hire a licensed plumber if failed-open returns.
Q: Why does my Rheem say failed open after the blower runs? A: The fan spun but the switch never closed — cracked or wet vinyl tube, restricted vent, weak blower, or a bad switch. A silent blower is 120 V or the motor. Either way, do not light it without a proved draft.