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Carrier · Furnace

31 High-heat pressure switch or relay did not close or reopened

High severity 59TP6A

What the control is telling you

The high-heat pressure switch (HPS) or its relay did not close, or opened again, during high-heat operation.

Applies to: 59TP6A two-stage variable-speed ECM multipoise condensing gas furnace, all sizes (040-10 to 120-22)

Likely causes

  • Defective control relay (HPSR)
  • Gas valve miswired
  • Any of the code 32 causes (venting, tubing, drain, inducer)

Test and repair steps

  1. Warning: Shut off 115-V power and gas, and lock/tag out before working inside the furnace; there may be more than one power source.
  2. Check gas valve wiring against the wiring diagram (Fig. 67).
  3. Go through all code 32 checks vent, tubing, condensate drain, inducer.
  4. If HPS fails to close while LPS is closed, the furnace runs low-heat gas flow for up to 2 minutes after ignition waiting for HPS.
  5. If the switch and venting are good, suspect the relay on the control and replace the control.

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Source: Carrier 59TP6A Installation, Start-up, Operating and Service Instructions, Fig. 66 Troubleshooting Guide (cont.), p.89; Sequence of Operation, p.85. Summarized in our own words; check the original manual for your model.

Homeowner looking at this code? See what it means for you and when to call a technician.

For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.