Defrost light (red light) is on in heat mode and unit not working on heat. Has happened since a power outage.

Hi,
The red light indicates it's either heating or in defrost mode
Check the outdoor unit if the compressor is running - the large pipe on the outdoor unit should be hot on heating or cool to touch on cooling
When in heating mode - the indoor fan will not start until the indoor coil is warm enough
If the reversing valve that changes from heating to cooling is faulty then you may encounter the same symptoms too
Probably need a Refrig Tech to have a look at it?
Good luck

This is a very common feature on these types of simple, high-volume, low-cost home appliances known as a safety fault. This fault will temporarily (or permanently) disable the appliance and happens for several reasons: (1) an over-temp (high heat) occurrence, (2) an over-power (power surge) occurrence, (3) an under-power (power outage or trickle power) occurrence, (4) an over-time occurrence (auto-off fails), (5) a short-circuit occurrence (exposed/crossed/frayed wires, etc.). Fortunately, it uses a digital "fuse" system and can be reset by the user. However, there is no universal reset process on SoftHeat products so you just have to play with it until you figure it out (customer service dept is no help). Mine is a Kaz SoftHeat HP980PT, with a red power indicator/power-off button and 4 green heat setting buttons. Mine faulted after a heavy storm caused multiple power outages and power surges in my neighborhood. The green light on the highest heat setting button was flashing on mine. Here's how I fixed it: (1) unplugged both ends of power cord and straightened out the cord, then plugged back in to the heating pad end. (2) While holding down the flashing light button, I plugged back in to the wall outlet. (3) While still holding down the flashing light button, pressed and held down the red power-off button, then while still holding down the red power button, I released the flashing light button, followed by releasing the power-off button. This stopped the flashing green light and caused the red power indicator light to stay on (steady-on). It works fine now. Note: Some models have an actual hard fuse in addition to the digital fault feature or possibly only a simple fuse (without the digital fault system). These fuses can the found at many retail stores and then very easily replaced. I hope this helps some of you!!!

Unless you just installed or had the thermostat installed recently, I would not point at the thermostat as the problem. With what you have described I would suggest have your units serviced as it sounds like a loss of charge, or failed defrost control board. The "Aux" comes on when the unit is using secondary heating (electric heat strips). That occurs when the demand temperature (what you set it to) in Heat mode is more than the current room temperature, usually ~2-4 degrees higher. Also happens in defrost mode. Defrost is a heat pump cycle that melts any build up of ice on the condenser unit (outside unit). That process is simply the unit running in cool mode which will heat up the outside unit to melt any ice. Defrost cycles vary with manufacture but usually you can tell if is in defrost by looking at the outside unit, during defrost the unit will be warm or hot sometimes there is steam and the compressor will be running but not the fan. Defrost only happens on heat pumps in "Heat" mode. Rheem has a 10 yr compressor and parts warranty, so call the installer or Rheem authorized service company.

Its the reversing valve shifting, it normal and you will hear it in the heating mode as well, you will hear it in the heating mode as well, during a defrost cycle.

You refrigerator was made by Frigidaire Adaptive Defrost Controls Frigidaire Refrigerator Trouble Shooting and Diagnosing
On the initial plugin, or when power is restored to the fridge after a power outage:
If terminating thermostat is open, the fridge enters a compressor (cooling) cycle.
If the terminating thermostat is closed, the first defrost cycle occurs 1 hour
after initial plug-in.
Maximum defrost cycle time is 24 minutes.
Minimum time between defrost cycles is 6 hours. (compressor runtime)
Maximum normal clock time between defrost cycles is 12 hours.
Maximum time between defrost cycles (in "vacation" mode) is 72 hours.
Vacation mode is not entered unless the door has not been opened in at least 24 hours.
Note that the ADC will only enter the defrost mode if the terminating thermostat is closed. If the terminating thermostat is open when defrost is initiated, the ADC board will wait for six minutes and then return to the cooling mode.
ASSUMING that the fridge has been on and running,
and the terminating thermostat is closed,
defrost is initiated by pressing the door (light) switch
at least five times within six seconds.
The defrost heater should start heating up within 8 seconds.
If the above procedure caused the heater to heat up, the ADC board is probably bad; replace it.
If the defrost heater does not heat up, test the defrost heater, terminating thermostat and cold control for continuity as follows:
Unplug the fridge from the wall. Unplug the ADC board from its connector.
Test the connector for continuity between the following leads:
Defrost Heater = DEF TERM (blue) to DEF OUT (brown).
Terminating Thermostat = DEF TERM (blue) to NEUTRAL (lt blue).
Cold Control = COLD CONTROL (orange) to L1 (black).
Replace the defective component.

Make sure that the electronic timer is in manual mode, it needs to be for the oven to work. After a power outage it normally reverts back to auto. mode.

Possible defrost board. Get service tech to check this . Had the same problem change board it was ok. RUSS

Some units have a dehumidify setting to overcome this as they go through a defrost. You can either manually defrost running on heating for a few minutes, or have it defrost when it goes out on fault as happened.

In heating mode, the outdoor unit should run to build up pressure and hence heat. To facilitate this, the indoor unit fanmotor will only come on once a sufficient pressure is reached. If you are a bit low on refrigerant, this may not happen. Or it could also indicate a leaking four way reverse valve.

It sounds like the unit is going into a defrost cycle, which is normal for heat pumps and means all is working ok when it gets around 35 or colder they start to do this more often when the red light goes back off , the outdoor fan should come back on. You may also notice steam (may look like smoke) coming from outdoor unit. Is that what happens??