Diagnosing heat pump defrost thermostat

I diagnosed this heat pump the day before the day I made this video. I had to go to a town 40 miles away to get the part. In the mean time I jumped past the bad defrost thermostat. This in effect caused it to defrost every 90 minutes of run time for 10 minutes. Good thing to we got wet snow and high winds that night. I originally diagnosed the bad stat by wiring the fan motor through a switch so I could turn it off and on at will. This allowed me to test the temperature that the defrost thermostat was making and breaking at. The original complaint was noisy operation and icing of the coil.

Category:

Science & Technology

Tags:

• HVAC
• heat pump
• defrost thermostat
• defrost control
• defrost sensor
• diagnosing defrost thermostat
• diagnosing defrost

[tstatech]

@redhot916spd You got it. If your referring to the defrost termination thermostat it is in it's factory position on one of the U-tubes near the bottom of the outdoor coil.

[redhot916spd]

so you essentially put the fan on switched power and then applied a thermometer to test temperatures? where did you apply the thermostat at , thanks for the tips :)

[tstatech]

@fritzhvac - Thanks, I found many bad defrost thermostats in several different brands last winter. More than the average winter. Wander what this summer will bring. Last year was a year for weak or open capacitors.

[fritzhvac]

Good video, we live in the same climate zone, I feel your PAIN !!! ( frekin freezing in winter , and hot as you know what in the summer) !!! lol

Keep up the good work !!!