heat pump air flow question
don't know all the terminology so bear with me..
2 zone electric heat pump, when zone 1 is on by itself all is good, when zone 2 is on by itself all is good, when both zones are on at the same time zone 1 is good, zone 2 is really weak with air.
In the basement there is this duct work that loops around at the furnace with a weighted handle on it, does this control the amount of air that would flow to both zones when both are calling for heat/air?
or what else could be the cause?
Thanks in advance