Your friend's work around with the thermal switch sounds as if it was in lieu of a third stage on your thermostat. Honeywell makes a three stage thermostat (3 heat - 2 cool) The TH8110U that would do that for you. And there are others. A bit of an expense though, considering that what you have essentially accomplishes the same thing.

Not enough info provided here. Either a faulty thermostat that is providing a false positive error message or a problem with HP. I would shut system off and call your Installing dealer for a service call. IMO

Post your electric rate in cents per kw-hr, and your gas rate in either $ per ccf or $ per therm. The heat output of a gas furnace is very similar to electric resistance strips if enough kw are used. Utility costs decide which is cheaper. 5 kw electric strips put out air temps about 15F greater than room temperature. So a typical 10kw strip heat puts out 100 degree air if the room temp is 70F (70 + 30 = 100). This# is based on 1200 cfm air flow from the indoor fan. 15kw = 115F which is more in the range of gas furnace temps. The air handler must be sized to handle this heating load. These temps are for the strip heat only and do not include any btu's from the heat pump. The heat pump itself puts out air temps from about 90F to 100F based on outdoor air temps. The 90F supply temp air from the heat pump combined with 20 kw aux electric strips provides minimum 120F output air when needed. Heat pumps provide enough heat up until the balance point, which is around 32F or so based on home construction/insulation (mine is 25F). At temps lower than the balance point, aux heat is needed - either furnace or strips. The good thing with the strips is they can run along with the heat pump. The furnace cannot run when the heat pump is in heating mode; its one or the other. When the heat pump goes into defrost mode, the air output is in the low 50's. 10 kw provides 30F to temper the air into the low 80's so it doesn't feel too cold while the heat pump is defrosting. The furnace will provide 120F air during a defrost cycle. The heat pump is typically 300% efficient down to 35F ambient. Heat pumps make cheap heat. One comment about the XP-19. It's "up to 19 SEER". Not all combinations get 19 SEER. Model numbers can be used to determine actual SEER. Also, dual-compressor systems like the XP-19 are more for hot and humid summers than for heating. In the cooling mode, running on 1st stage saves $$ and reduces humidity. Once on 2nd stage, it loses its operating $$ benefits. A 14/15 SEER usually provides the best combination of purchase price and operating cost. If you can afford a "19 SEER" system, go for it. Whichever SEER you get, you want as close to 12 EER and 9 HSPF as you can get for low operating costs in cooling and heating respectively. Good luck.

yes try the capacitor first! cheapest root and that is probably what it is. or you could have blown breaker. i'm sure you didn't kill the motor!