Tadiran Not Heating — Heat Mode Not Working

What Does This Error Mean?

If your Tadiran air conditioner is set to heat mode but blowing cold or lukewarm air, common causes are outdoor temperatures too low for heat pump operation, the defrost cycle running temporarily, a refrigerant leak, or the reversing valve being stuck.

Affected Models

Tadiran Inverter Series
Tadiran Alpha
Tadiran Superior
Tadiran Elite

Common Causes

Outside temperature is below the unit's rated heating range (some models stop heating below -10 °C)
Unit is in a defrost cycle — this lasts 3–8 minutes and is normal
Refrigerant is low, reducing heating capacity significantly
Four-way reversing valve is stuck in cooling position
Unit is in dry or fan-only mode — not heat mode

How to Fix It

Verify the mode is set to Heat

Check the remote control display. Make sure the mode icon shows a sun (heat) symbol, not a snowflake (cool), fan, or droplet (dry). It is easy to accidentally select the wrong mode.
Set the temperature higher than the room temperature

The target temperature on the remote must be higher than the current room temperature for heating to activate. If the room is 20 °C and you set the target to 18 °C, the unit will not heat.
Wait if the unit was just switched on

Tadiran heat pump units take 3–5 minutes to begin producing warm air after startup. The fan may blow cool air briefly during this warm-up.
Wait if the outdoor unit is frosting

In cold weather, the outdoor unit periodically runs a defrost cycle (3–8 minutes). During this time the unit may briefly blow cool air indoors. This is normal — wait for the cycle to complete.
Check outdoor temperature

If outdoor temperature is below -10 °C or -15 °C (depending on model), the heat pump may be at or below its rated heating limit and heating output will be very low.
Call a technician if heating is weak in normal conditions

If outdoor temperatures are mild but heating output is poor, the refrigerant may be low or the reversing valve may be stuck. Both require a technician.

When to Call a Professional

Yes, if the issue is not defrost cycle or mode selection.

Tadiran Air Conditioner Not Heating

Heat pump air conditioners like Tadiran split systems are reverse-cycle: they move heat from outdoors into your home in winter. This is why heating can be affected by cold weather in ways that cooling is not.

Check These First (No Technician Needed)

Mode is set to Heat (sun icon on remote)
Target temperature is above room temperature
Defrost cycle — wait 10 minutes and check again
Outdoor temperature — very cold outside? Output will be reduced

When to Call a Technician

If you have checked all of the above and heating remains weak or absent in mild weather, a refrigerant or reversing valve issue is likely. These require specialist tools and certification to diagnose and repair.

Frequently Asked Questions

My Tadiran heats perfectly in autumn but struggles in winter. Is it broken?

Not necessarily — heat pumps lose efficiency as outdoor temperature drops. At 0 °C, a heat pump delivers roughly half the heating output it provides at 10 °C. At -10 °C, many standard models are at their limit. An inverter model with an extended heating range performs better in cold climates.

What is the defrost cycle and is it normal?

In cold weather, ice can form on the outdoor coil. The defrost cycle reverses the refrigerant flow briefly to melt this ice. You may hear a gurgling sound and see steam from the outdoor unit. Warm air from indoors is temporarily used to melt the ice, so you may feel cool air for 3–8 minutes. This is completely normal.