I have a 2 month old heatpump, when it shifts into and out of defrost it makes a terrible noise sometimes you can hear it travel up the lineset in the wall. Spoke with company that did the install thinks it may be a sticking tx valve and to keep an eye on it and give him a call if it continued. My concern is any damage that may be occuring to the unit in the meantime. I had two of the same units installed and the other is much more quiet. Should I get a service tech now and not wait ?