Heat Pumps and Electric Heating - emergency heat does not come on when flipping switch

i have a heat pump and when the temperature goes below 32 degrees, i turn on the emergency heat and it does not come on.
sometimes with the emergency heat button on i would turn on the fan and then hot air would start coming after aminute or so,then i would switch the fan button to on and it stays on.

this trick does not work most of the time .

what do i need to do?

Do you have gas or electric heat strip emergency heat? Really need more info in order to help since it can be a number of things. If it is gas can you tell if there is an LED code coming out of the furnace if it even has an LED equipped board.

thank you for your reply, electric heat strip

Kinda sounds like a bad fan control. I don't know what controls are in your system without a model number and brand name, but if it is controlled by a sequencer than it may be going bad. The sequencer or fan control will turn on the fan soon after the heating elements turn on. If the fan doesn't start then the elements turn off on high limit safety. When you turn the fan on manually at the stat then the heating elements will stay on since they won't have the opportunity to overheat and go off on limit since the fan control isn't a factor now. It may not work everytime since the high limits are opened and will have to cool down before the heating element will come back on. Sometimes the high limits get wore out and stick open and the heating element won't work at all.