Payne PG80ESA Error Code 33: Limit Circuit Fault

What Does Code 33 Mean?

Status code 33 on the Payne PG80ESA is a Limit Circuit Fault — a limit switch, draft safeguard, flame rollout switch, or blocked vent switch (if used) is open right now. The Furnace Control CPU stops the burners and runs the multi-speed ECM blower for at least 4 minutes, or until the open switch closes, to pull heat off the heat exchanger.

Code 33 is the live warning; code 13 is its lockout. If the switch stays open longer than about 3 minutes, the board keeps flashing 33 until the blower stops and then requires a manual reset, and a persistent open condition escalates to the Limit Circuit Lockout (code 13), which auto-resets only after three hours. Seeing 33 repeatedly is the furnace telling you the overheat is recurring before it latches out.

On this single-stage 80% furnace the usual trigger is an airflow restriction — a clogged filter, closed registers, or a dust-loaded blower — that overheats the heat exchanger and opens the high-temperature limit. The same circuit also carries the flame rollout and draft safeguard switches, which trip on combustion or venting problems instead of airflow; a tripped flame rollout has a manual-reset button and must be diagnosed by a technician, not just reset.

What You'll Notice

• The blower keeps running (often for several minutes) while the air coming out is cool, because the burners have been cut off
• The furnace short-cycles: it heats briefly, drops out, then the blower runs to cool down
• The diagnostic LED flashes three short then three long flashes (code 33)
• The filter is dirty, or several registers/returns are closed or blocked
• In severe cases a manual-reset button has popped on the flame rollout switch

Common Causes

How This Is Diagnosed

The airflow path is checked first because it is the most common and the only homeowner-safe cause: filter condition, open registers and returns, and a dust-loaded blower wheel. If airflow is clearly adequate and code 33 persists, a technician measures blower performance (motor and capacitor) and tests each safety switch and its wiring for an intermittent open.

A key branch is whether the open switch is the high-temperature limit (an airflow/overheat story) or the flame rollout / draft safeguard (a combustion or venting story). The latter is diagnosed by inspecting the burners, heat exchanger, and vent for the reason it tripped, and the rollout switch is only reset after that cause is corrected.

How to Fix It: Restore Airflow: Replace the Filter and Open the Vents

What You'll Need

• Replacement air filter (correct size for your system) 🛒 Find at FiltersFast · 🛒 Find at Amazon
• Flashlight

Steps

1. Turn off power at the breaker/switch and shut off the gas supply Set the furnace service switch and breaker to OFF, then turn the manual gas shutoff valve to OFF (handle perpendicular to the pipe). If you smell gas, leave immediately and call your gas company from outside.
2. Replace the air filter Pull the filter from the return duct or filter slot. If it is dirty or older than about three months, replace it with the correct size, arrow pointing toward the furnace. An overly restrictive filter can trip the limit even when it does not look fully clogged.
3. Open all supply and return vents Make sure every register and return grille in the house is fully open and unobstructed. Closing off rooms reduces airflow across the heat exchanger and is a frequent cause of repeat code 33.
4. Check the blower wheel for heavy dust With power off, look through the blower access opening. A heavily dust-caked blower wheel moves less air and can cause recurring limit trips; if it looks bad, note it for a technician instead of taking anything apart.
5. Restore power and gas, then test Turn the gas and power back ON. If code 33 had escalated and requires a manual reset, cycle power off for about 30 seconds. Set the thermostat to call for heat and watch a complete cycle.

When to Call a Professional

Contact a licensed HVAC technician if:

• Code 33 returns after the filter is replaced and all vents are open
• The flame rollout switch has tripped (manual-reset button popped) — a combustion or venting problem
• The blower runs weakly, cycles oddly, or is noisy
• You see soot around the burners or suspect a blocked or disconnected vent
• The furnace repeatedly overheats within a single call for heat

✓ Verified against manufacturer service manual — March 2026