(Source : http://www.heatpumpcentre.org/en/aboutheatpumps/Sidor/default.aspx)

1. Watch this video (with captions)

2. Now read a detailed description of the heat pump’s operation.

3. GeoExchange heat pumps : watch the video (no time scale – also available on YouTube, with a time scale)

4. « Btu Buddy »  episodes
(on the website of the Air Conditioning/Heating/Refrigeration News)

Bob is a service technician who is well trained and nationally certified. However, he sometimes suffers from the same confusion that all technicians occasionally do — the facts that he gathers may or may not point to the obvious cause of the problem or the best solution. But Bob has something that no one else has. He recalls his long-time HVACR mentor and imagines him accompanying him as “Btu Buddy,” someone who reminds him to take time to stop and think before rushing to judgment, helping keep him on the right track, even with facts that are confusing.

Btu Buddy 24: Looking At A Heat Pump Drawing A Lot Of Power (2005)
Btu Buddy 25: Changing A Four-Way Valve On A Heat Pump (2005)
Btu Buddy 26: Checking A Heat Pump With Dirty Indoor Coil (2005)
Btu Buddy 31: A Heat Pump Blowing Cold Air (2005)
Btu Buddy 81: Frosting Heat Pumps (2009)
Btu Buddy 94: A Heat Pump That’s Not Getting Up to Temperature (2011)