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Temperature rise out of range - Goodman *MVC95/*CVC9

Goodman/Amana *MVC95/*CVC9 two-stage ComfortNet

What is going on

Supply air too hot or too cold compared to the rating plate rise range.

Likely causes

  • Heating blower tap set too low or too high
  • Dirty filter or restricted ducts
  • Wrong gas input

Check in this order

  1. Run the burners about 10 minutes with all registers open and dampers in their final position.
  2. Put thermometers in the supply and return ducts close to the furnace, out of sight of the heat exchanger.
  3. Rise = supply temp minus return temp. It must be inside the range on the rating plate.
  4. Too high raise the heating blower tap (S4 switches 7-8). Too low: lower it. Use the display airflow number to confirm.
  5. Check gas input clock the meter (natural gas) and compare to the rating plate. Final manifold pressure must stay within 0.3 in. w.c. of spec.

Applies to: GMVC95/AMVC95 upflow and *CVC9 counterflow two-stage furnaces

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Source: Goodman *CVC9/95 & *MVC95 Installation Instructions IO-341D (08/2010), Temperature Rise p.39; Gas Input Rate p.39; Circulator Blower Speeds p.40-42. Written in our own words; check the manual for your exact model.

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.