Payne PG95ESA Error Code 33: Limit Circuit Fault

What Does Code 33 Mean?

Status code 33 (three short flashes followed by three long flashes) means the high-temperature limit switch or the flame rollout switch is currently open. It is the live, in-the-moment version of the overheating problem: the switch has opened to cut gas to the burners because operating temperature climbed too high, most often because air isn't carrying heat away from the heat exchanger fast enough.

Because the PG95ESA is a single-stage furnace firing at one fixed rate, sufficient airflow is essential to keep it in its temperature range. The most common cause of code 33 is a dirty air filter; loose blower-wheel connections, undersized or restricted ductwork, and (less often) a flame rollout switch tripped by a combustion problem can also open the limit circuit.

The relationship to code 13 matters. Code 33 flashes while the switch is open; if it stays open longer than 3 minutes, the control escalates to code 13, the limit circuit lockout, and holds the furnace off for about 3 hours. Catching and clearing the airflow cause at the code 33 stage — a fresh filter and open vents — can keep the furnace from ever reaching the 13 lockout.

What You'll Notice

• The amber LED flashes three short flashes followed by three long flashes (code 33)
• The burners cut out while the blower keeps running, and the supply air goes cool
• The furnace short-cycles — it heats briefly, overheats, and shuts the burners off — and may recover, then trip again
• If the condition persists past 3 minutes the code changes to a code 13 lockout and heat stops for about 3 hours
• A dirty or clogged air filter is usually found at the return, or several supply/return vents are closed or blocked

Common Causes

How to Fix It: Replace the Air Filter and Clear Airflow Restrictions

What You'll Need

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

Steps

1. Turn off electrical power at the breaker and shut off the gas supply valve Set the furnace circuit breaker to OFF and turn the manual gas shutoff valve to OFF (handle perpendicular to the pipe). If you smell gas, leave immediately and call your gas company.
2. Inspect and replace the air filter Pull the filter from the return duct or filter slot. If it is dirty, clogged, or more than about 3 months old, replace it with the correct size, with the airflow arrow pointing toward the furnace. A restricted filter is the leading cause of this fault.
3. Open all supply and return vents Confirm every register and return grille is fully open and clear of furniture, rugs, and curtains. Closed or blocked vents starve the blower of return air and overheat the heat exchanger.
4. Check for obvious duct or blower restrictions Look for a collapsed or crushed flex duct near the furnace and heavy dust on the blower wheel through the access opening. Note anything abnormal for a technician rather than disassembling the blower yourself.
5. Restore gas and power, then run a cycle Turn the gas valve to ON and the breaker to ON, then set the thermostat to call for heat. Watch a full cycle to confirm the burners stay lit and the supply air stays warm.

When to Call a Professional

Contact a licensed HVAC technician if:

• Code 33 keeps returning after a fresh filter and with all vents open
• The flame rollout switch has tripped (a manual-reset button that must only be reset after the combustion cause is found)
• The blower wheel is loose, noisy, or clearly not moving enough air
• The fault escalates to a code 13 lockout repeatedly despite good airflow

✓ Verified against manufacturer service manual — March 2026