Trane IS20464-6223 Pressure Switch

The Trane IS20464-6223 Pressure Switch is a factory OEM SPDT (single-pole, double-throw) pressure switch used as the draft-proving and airflow-proving safety control on Trane gas furnaces. It is the current Trane replacement for the older D345654P01 switch, and distributors also catalog it under the Trane service number SWT03924, so a search by any of the three numbers lands on the same part. Inside the molded housing a flexible diaphragm senses the pressure difference the inducer draft motor creates and moves a snap-acting contact set. That contact change tells the integrated furnace control board that combustion air is moving and the vent path is clear, so the board is allowed to continue to ignition and gas valve operation. If the switch does not close on a call for heat, the furnace will not fire — which is exactly what a safety control is built to do.

Ratings and construction. Distributor data for this switch lists SPDT snap-acting contacts rated 28 VA pilot duty at 24 VAC and 125 VA pilot duty at 120 VAC, an operating temperature range of -40°F to 190°F, and 1/4 inch quick-connect spade terminals. The switch in the photo has a light-gray molded cover with port positions and a P2 marking on the face, a black diaphragm base, a single barbed hose connection at the bottom edge, a brass-colored quick-connect terminal on the body, and a factory barcode label reading 83232687. Because the contacts are SPDT, the switch provides a common terminal with both a normally open and a normally closed path; land each wire on the same terminal the original switch used and the furnace control will see exactly the signal it expects.

Diagnosing before you replace. A furnace that starts the inducer and then sits without lighting, or one that flashes a pressure switch fault code, does not always have a bad switch. Check the vent pipe and combustion-air path for blockage, confirm the inducer motor is at full speed with a clean wheel, inspect the vacuum hose for cracks, pinches or trapped condensate, and on condensing models verify the condensate trap and drain are clear. With the inducer running, read the pressure at the switch with a digital manometer and check continuity across the contacts with a meter; if the draft is good and the contacts stay open, the switch has failed. Never jumper a pressure switch to force a furnace to run — that defeats the safety. Remove power first, replace brittle hose at the same time, and match the replacement to the number on your original switch, since Trane uses several pressure switches with different set points.

Key Benefits

• OEM Trane Safety Control: The same SPDT snap-acting design the furnace was built around, so the draft-proving function behaves the way the control board expects.
• Pilot-Duty Rated Contacts: 28 VA at 24 VAC and 125 VA at 120 VAC pilot duty, with an operating range of -40°F to 190°F for cold garage and attic installs.
• Direct Replacement for D345654P01: Supersedes the older D345654P01, and is listed under SWT03924 as well, which makes the cross-reference simple.
• Quick-Connect Wiring: 1/4 inch spade terminals and a barbed hose connection make the swap a quick, tool-light job.

Common Questions

• What does this switch replace? It is the replacement for the Trane D345654P01 pressure switch and is cataloged by distributors as SWT03924 and IS20464-6223.
• What are the electrical ratings? SPDT snap-acting contacts rated 28 VA pilot duty at 24 VAC and 125 VA pilot duty at 120 VAC, with a -40°F to 190°F operating range.
• How do I know if it is the switch or the hose? With the inducer running, compare the manometer reading at the switch to the original set point and check continuity across the contacts. Good draft with open contacts means a failed switch; low draft usually points to a blocked vent, a plugged hose or a weak inducer.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.