heat-pumphvacthermostat
I had a new HVAC single heat-pump system installed with dual zone controls:
2 thermostats and 2 dampers for separate zones.
The system works, but the zone control board does not have any time delay between one zone turning off and the other zone calling for heat/AC. Normally, a thermostat enforces a 5 minute time delay before restarting after power is removed.
Will the short off-time damage the compressor over time even though it doesn't trip the overload?
A heat pump thermostat prefers to operate the heat pump under "usual" conditions as that is expected to be less expensive. It will invoke the back up (or "emergency heat") when any of several conditions occur:
Some (advanced) thermostats might have an adjustable delta temperature value, but it does not look like the TH8320 does. According to the installer manual (see page 17), there is a deadband adjustment, option 0310. Besides directly controlling the deadband, it might also be used as the temperature delta or half of it. Try adjusting the deadband, save it, and then adjust the setpoint temperature above the current reading (which will drift up as your hot hand and body will warm the thermostat) and see if the delta is affected.
If the outdoor fan comes on and the compressor does not, you need a "hard start kit" this is either a potential relay and start capacitor as in my diagram or a PTC thermistor solid state start assist device that piggy backs onto the run capacitor. This is assuming your compressor is cold to the touch and has not been starting. If your compressor has been starting and is off due to the thermal overload being open Then it is due to the capacitor being bad or refrigerant being low or the compressor is mechanically tight or electrically shorted to itself internally, this is not something a homeowner will usually be able to do unless walked through it step by step.
Best Answer
Some newer compressors have a built-in delay to protect them from damage. You should check the number of recommended cycles per hour in the manual to find out if this is an issue for your unit.
Damage could be caused by overheating over time, or a flooded start - depending on the design of the unit.