Payne PG8MAA Error Code 33: Limit Circuit Fault
What Does Code 33 Mean?
Status code 33 on the Payne PG8MAA means the Integrated Furnace Control (IFC) currently sees an open limit or flame-rollout switch. In response the blower runs for 4 minutes, or until the switch closes again, whichever is longer, to bring the heat-exchanger temperature back down.
Code 33 is the early-warning stage of an overheating problem. If the switch closes again quickly, the furnace recovers and 33 stops flashing once the blower stops. But if the switch stays open longer than 3 minutes, the fault escalates to status code 13, a roughly three-hour lockout. A tripped flame-rollout switch is different: it does not reset itself and must be manually reset by a technician.
On this single-stage multipoise furnace, the usual causes are airflow restrictions — a dirty filter, a restricted duct system, or closed registers. Less common causes such as a loose blower wheel, a defective blower motor or capacitor, bad switch connections, or a rollout switch opening from inadequate combustion air require a technician.
What You'll Notice
- The blower runs for several minutes even though the furnace is not producing heat.
- Heating cuts out and the fan keeps running to cool the unit down.
- The filter is dirty, or registers and returns are blocked or closed.
- The problem tends to appear during the coldest weather, when the furnace runs longest.
Common Causes
How to Fix It: Clear the airflow restriction before it locks out
What You'll Need
- Replacement furnace filter (correct size) 🛒 Find at FiltersFast · 🛒 Find at Amazon
- Flashlight
Steps
- Turn off electrical power at the breaker and shut off the gas supply valve before servicing Switch the furnace breaker or power switch to OFF and turn the manual gas shutoff valve to OFF (perpendicular to the pipe). If you smell gas, leave immediately and call your gas company.
- Replace the air filter Remove the filter from the return duct or blower compartment. If you cannot see light through it, install a new filter of the correct size with the airflow arrow pointing toward the furnace.
- Open registers and returns, and check for obvious duct blockages Confirm all supply and return grilles are open and unobstructed. Look for any obviously crushed, disconnected, or blocked ductwork you can see without disassembly.
- Restore power and gas, then run a heat cycle Turn the gas valve and power back on, set the thermostat to call for heat, and watch a full cycle to see whether code 33 returns.
When to Call a Professional
Contact a licensed HVAC technician if:
- Code 33 continues or escalates to a code 13 lockout after the filter is changed and registers are open
- The blower wheel sounds loose or rattling, or the blower will not run at full speed
- There are signs of flame rollout, or a rollout switch has tripped and will not reset
- Going further would require testing the limit switch, blower motor, or its capacitor
Frequently Asked Questions
Is code 33 the same as a lockout?
Not yet. Code 33 is the active fault while the blower cools the furnace; if the limit switch stays open more than 3 minutes it escalates to the code 13 lockout.
My filter looks fine — what else causes code 33?
Closed or blocked registers, a restricted duct system, a loose blower wheel, or a weak blower motor or capacitor can all cause overheating. The airflow items are DIY; the mechanical ones need a technician.
Sources
✓ Verified against manufacturer service manual — March 2026