We have a Carrier 58STA/STX Furnace that is only short cycling in Heat and not A/C. When it cuts off it is throwing Code 33 which is pointing to the following issues:
- Dirty Filter or Restricted Duct System – Replaced Filters & Using a MERV 2, still trips
- Loose Blower Wheel – Removed today and was not loose/excessive play
- Defective Switch or Connections
- Defective Blower Motor or Capacitor – Capacitor was at 50% of nominal, replaced and still occurs, have not done anything with blower motor.
- Inadequate Combustion Air Supply (Flame Rollout Switch Open) – Flame Rollout Switch stays closed
- Restricted Vent Sizing – Spec'd to House
- Excessive Wind – Happens on Windy or Calm Days
If I either remove the filter or remove the blower access cover it does not throw the code.
Best Answer
I was able to figure out it was the Draft Safeguard that was tripping. After digging around online some more there were a couple recommendations:
Right when we purchased the home we redid the flooring immediately from linoleum that had a threshold at the closet to engineered hardwood and we did not put a threshold at the closet (effectively increasing the gap at the bottom). I both verified the intake was clear and also placed towels at the door gap and let the furnace run in which it finally did not short cycle.