Carrier 58MVC Error Code Status Code 32: Low-Heat Pressure Switch Did Not Close or Reopened

What Does Code Status Code 32 Mean?

Code 32 is the low-heat counterpart to code 31. The 58MVC has separate pressure switches for different heat stages, and code 32 specifically indicates that the low-heat pressure switch either failed to close when the inducer started a low-heat cycle, or opened during low-heat operation. If the switch opens during the blower on-delay period, the blower will run for the selected blower off-delay time.

The root causes are the same as code 31 — blocked exhaust vents, plugged condensate drains, disconnected pressure tubing, or a failed pressure switch. Because the low-heat stage requires less draft than medium or high heat, the low-heat pressure switch is calibrated to a lower threshold. This means it can sometimes be more sensitive to partial blockages or marginal draft conditions.

If you're seeing both code 31 and code 32, the problem is almost certainly in the shared venting or condensate drainage system rather than a specific pressure switch failure. Start with the same basic checks: exhaust vent, condensate drain, and pressure tubing.

Common Causes

How to Fix It: Check Venting, Condensate Drain, and Pressure Tubing

What You'll Need

• Flashlight
• Wet/dry vacuum (optional, for condensate drain)

Steps

1. Turn off power at the breaker or power switch AND shut off the gas supply Locate the furnace circuit breaker and turn it OFF. Find the gas shutoff valve on the supply line to the furnace and turn it to the closed position (perpendicular to the pipe). If you smell gas, leave immediately and call your gas company.
2. Inspect the exhaust vent pipe for blockages Follow the PVC exhaust vent pipe from the furnace to where it exits the building. Look for any obvious blockages, disconnections, sagging sections, or damage. Check the exterior vent opening for ice buildup, debris, bird nests, or insect nests. Clear any obstructions you can safely reach. Ensure all vent pipe joints are properly connected and sealed.
3. Check the condensate drain for clogs Locate the condensate drain line exiting the furnace. Check that it is not plugged, kinked, or frozen. Verify the condensate trap has water in it (a dry trap can cause draft issues). If the line appears clogged, try clearing it with a wet/dry vacuum applied to the drain outlet.
4. Inspect the pressure tubing connections Find the small rubber or silicone tubes running between the inducer housing and the pressure switch(es). Confirm they are firmly connected at both ends, not cracked or split, and not kinked or filled with water. If a tube contains water, carefully disconnect it, drain the water, and reconnect it.
5. Restore power and gas, then test Turn the gas supply valve back to the open position (parallel to the pipe). Turn the breaker back ON. Set your thermostat to call for heat and monitor the furnace through a complete heating cycle.

When to Call a Professional

Contact a licensed HVAC technician if:

• Code 32 returns after clearing vent blockages and checking the condensate drain
• You cannot access or inspect the full exhaust vent run
• The inducer motor sounds abnormally loud or does not start
• The pressure tubing looks intact but the switch still won't close
• Both code 31 and code 32 appear and persist after basic troubleshooting
• The condensate drain keeps clogging repeatedly (may need professional cleaning or rerouting)