Hi,I installed a new trane air heat pump about 6 months ago.now outside temp is 6 and my pump is not working.aux heat is coming on automatically.when temp goes to 8 or 10,heat pump comes on again automatically.installer told me that heat pump will do job till -9.9,, when -10 heat pump will shut off automatically and furnace will kick on... I have brand new furnace from trane 96% high efficiency... so tell me why my pump stops working on plus temp instead of minus

Are you taking about temperature in Centegrade?

This article may be useful: http://www.thathomesite.com/forums/load/hvac/msg1223495111526.html?9

There are two balance points of interest:

1. One is where the HP just makes up for the losses. Basicically it's when the heatpump runs all the time.

2. There is a second point where the heatpump is totally ineffective.

This article Heat Pumps and Setback Thermostats (http://www.stretcher.com/stories/970120c.cfm)
Suggests that one temperature is around 30 deg F where it starts to lose it's efficiency.

It also suggests that at 15 deg F it shuts off.

So, during the 15-30 range based on this example, the HP and aux heat should both be on.

Below 15, only the aux heat operates.

EMERGENCY HEAT just makes sure the compressor never turns on. It's used when the compressor has problems.

A lot of this depends on the thermostat and the system.

Some of this finnesse may be done automatically by the system. Certain thermostats, can be wired with an outdoor sensor and the balance points are set in the thermostat.

Did you get this fixed?
I have the same issue, they installed my outdoor temp cutoff sensor a few days ago while temps were above freezing Celsius and not that it's -4(27F) heat hump won't go on only the furnace works. With the windshield factor it is 15F though but that should not be a factor in all of this


hi,i installed a new trane air heat pump about 6 months ago.now outside temp is 6 and my pump is not working.aux heat is coming on automatically.when temp goes to 8 or 10,heat pump comes on again automatically.installer told me that heat pump will do job till -9.9,,,,,,when -10 heat pump will shut off automatically and furnace will kick on....i have brand new furnace from trane 96% high efficiency....so tell me why my pump stops working on plus temp instead of minus

Start your own thread please