Error Code Ph: Ambient Temperature Limited
Possible Cause
- Ambient temperature beyond the operating range
- T4 sensor fault
Troubleshooting
- Is the temperature below or above the operating temperature - The main board is protecting the unit (Cooling 0-125°F)
If the T4 sensor fails - Replace the sensor (chart below)
T1 / T2 / T3 / T4 Sensor Temperature/Resistance Chart °F °C KΩ 0 -17.8 93.535 10 -12.2 67.795 20 -6.7 49.652 30 -1.1 36.710 40 4.4 27.386 50 10.0 20.610 60 15.6 15.648 70 21.1 11.987 80 26.7 9.265 90 32.2 7.225 100 37.8 5.683 110 43.3 4.509 120 48.9 3.606 130 54.4 2.902 140 60.0 2.350 150 65.6 1.914 160 71.1 1.574 170 76.7 1.276
WARNING:
Information in this article is intended for use by individuals possessing adequate backgrounds of electrical and mechanical experience and who comply with all federal, state, and local laws, rules, orders, or regulations related to the installation, service, or repair of a heating or central air conditioning product. Any attempt to install, service, or repair a heating or central air conditioning product may result in personal injury and/or property damage. The manufacturer or seller cannot be responsible for the interpretation of the information contained herein, nor can it assume any liability in connection with its use.