Bryant 355MAV Error Code 32: Low-Heat Pressure Switch Did Not Close or Reopened

What Does Code 32 Mean?

Status code 32 on the Bryant 355MAV means the low-heat pressure switch failed to close on a call for low-heat, or it opened during a low-heat cycle. The 355MAV is a two-stage furnace with separate pressure switches for high-heat and low-heat operation. The low-heat pressure switch requires less draft to close than the high-heat switch, so code 32 can sometimes indicate more subtle airflow restrictions.

If the pressure switch opens during the blower on-delay period, the blower will run for the selected blower off-delay. Notably, if the switch opens within 5 minutes after ignition, the control will restrict the next heating cycle to high-heat only — this is the furnace's way of compensating for the reduced draft condition.

The same types of blockages that cause code 31 can cause code 32: blocked vent pipes, plugged condensate drains, disconnected pressure tubing, or wind backdraft. On the 355MAV, low inlet gas pressure (when a low gas pressure switch is used) is also a possible cause specific to low-heat operation.

Common Causes

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

What You'll Need

• Flashlight
• Mirror (optional, for checking vent pipe interior)

Steps

1. Turn off power at the breaker or power switch and shut off the gas supply valve Locate your electrical panel and turn the furnace breaker to OFF. Find the gas shutoff valve on the gas line leading to the furnace and turn it to the closed (perpendicular to the pipe) position. If you smell gas, leave immediately and call your gas company.
2. Inspect the exhaust vent termination outside Go outside and find where the furnace exhaust vent exits your home. Check for any visible blockage: snow, ice, bird nests, leaves, insect nests, or debris. Clear any obstructions. In winter, ice buildup around the vent termination is a particularly common cause. Also check the intake air pipe if your furnace uses a two-pipe system.
3. Check the condensate drain The 355MAV is a condensing furnace that produces water during operation. Locate the condensate drain line running from the inducer housing or collector box to a floor drain or pump. Make sure it is not kinked, clogged, or frozen. If water is pooled around the inducer, the drain is likely blocked.
4. Visually check the pressure tubing Locate the small rubber or vinyl tubes running from the low-heat pressure switch to the inducer housing. Confirm they are connected at both ends, not kinked, cracked, or visibly clogged. If a tube has disconnected, push it firmly back onto the barb fitting.
5. Check for excessive wind conditions If this code appears mainly on windy days, strong gusts may be causing backdraft through the vent termination. Note whether the problem correlates with weather conditions — this information will be useful if you need to call a technician about installing a wind guard.
6. Restore power and gas Turn the gas supply valve back to open (parallel to the pipe). Turn the breaker back ON. Set the thermostat to call for heat.

When to Call a Professional

Contact a licensed HVAC technician if:

• The exhaust vent and condensate drain appear clear but code 32 persists
• The furnace runs fine on high-heat but consistently fails on low-heat
• The inducer motor sounds unusually loud, weak, or does not start at all
• Water consistently pools in the inducer housing despite clearing the drain
• The problem only occurs during windy weather (may need vent termination modification)
• You suspect low gas pressure may be involved (if a low gas pressure switch is installed)