Error code · Water Heater

GE GeoSpring PF/PH Code F35: Evaporator Outlet Sensor T3b Not Reading

Medium · inspection needed

Code: F35
Appliance: Water Heater
Brand: GE
Warranty: 30-day workmanship

What F35 means

F35 on GE Profile GeoSpring PF and PH heat pump water heaters made from 2025 is a T3b sensor failure. T3b reads the temperature of refrigerant leaving the evaporator, and the control compares it with T3a to judge how well the coil is working. When T3b gives a bad reading, the heat pump may be stopped to protect it. The unit then leans on its electric elements, so hot water recovers more slowly.

Common causes of F35

T3b sensor and connector
Wiring damage along the sensor lead
Control board sensor input

✓ One safe check you can try

1. Write down the code and the model number. 2. Make sure the area around the unit is open so room air can move through it. 3. Do not open the heat pump housing or touch the coil. 4. Call us and we will test the T3b circuit along with T3a.

! Why to stop there

T3b is read against T3a, so we look at both together.
A loose connector can mimic a dead sensor.
We quote the price in writing before replacing anything.

Opening a panel yourself does not automatically cancel a manufacturer warranty, but it can cause accidental damage, and some manufacturers set their own service conditions. Check your warranty terms, or ask us, before deciding.

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Other Water Heater codes

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F35F35 questions

How is F35 different from F34?

F34 is the evaporator inlet sensor and F35 is the outlet sensor. We check both when either one shows, since the control compares the two to judge how the coil is working.

Can I keep using the unit?

Yes in most cases for hot water, using electric heating. The heat pump portion may stay off until the sensor is repaired, so running costs go up in the meantime.

Do you replace the sensor on the first visit?

Often yes, if it tests bad and we have the part. Either way the work is quoted first, and the repair carries a 30-day workmanship warranty.

Book a visit

Still seeing F35?

A technician diagnoses it on site and gives you the price in writing before any work starts.

(713) 547-5545