Thursday, September 22, 2011

Heat Pump not keeping up?

I have a heat pump system and live in central NC. I have had the system checked out twice by two different companies. A couple of weeks ago the outside temperature was around 20ish. The heat pump system ran all night long and all day if it did not get above 38 degrees outside. I have a thermostat that allows you to see how long the system runs during a 24 hr period. Some days it ran hour for hour. Both companies came out and said the system is working fine. Most of the time when they checked it out, they set the thermostat to like 90 degrees and then checked everything. Well I just tried it. It is 41 degrees outside, the system has run attempting to reach 73 degrees and it was struggling at 71. I went to change the thermostat to 90 and it took like 15 mins to reach 75 degrees. Could it be the normal running heat strips are going bad?Heat Pump not keeping up?
Heat pumps have 'emergency heat' which is electric resistance heat. When you set it to 90 degrees and the current temp is 71 it will kick in the electric resistance on MAX which will heat your house fast. When the temperature is close the heat pump is going to try to heat the house and as the temperature drops farther from the set point more and more electric resistance will be stepped in (starts on low and goes in small increments to it finally gets to the max)

Heat from the heat pump is 2-5 times cheaper than electric resistance heat. Your thermostat has settings on when to use the heat pump and when and how much electric resistance heat to use. Sounds to me that you have it set to step based on the temp difference. As it gets colder in your house more heat is called for, an as it gets warmer the heat turns down so it never actually gets to the set point but instead finds a happy spot colder than your set point. If you find it uncomfortable your hvac guy can re-program it to your desires.Heat Pump not keeping up?
It's not the heat pump because you cycled the system when the outside temperature was 41 * with a temperature rise inside of 32 *. Heat pumps are better at air conditioning your house than heating it because when the outside air temperature falls below 32 * F heat transfer from the outside air to the freon at the condenser is poor. That is why these systems are equipped with auxiliary heat to supplement the heat pump with the heat loss on very cold days. Check us out @ Homelinepros .com.Heat Pump not keeping up?
When you pushed it to 90, the heat strips should have fired and you then have normal furnace. Sounds like the strips are not working. The other possibility is the system is way undersized.Heat Pump not keeping up?
It sounds fine. Heat pumps don't work well under 32. Emergency heat of it should kick on.

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