American Standard electric heat pump. Model #twe042c140c0. Hopr this helps?

Thanks for giving us the model#. Now all we need to know is the problem your having with the system.

Doesn`t help at all

Sorry that was my 2nd post. The problem I'm having is that I can't keep the fan on. The heat pump is functioning but the air handler makes a loud humming noise and the fan won't always come on. When it does it will run for a while and shut off. Had the same problem a few months ago and the tech replaced the time delay relay. Ran well until yesterday