Ihave a 2.5 Ton York Heat Pump E1FD030S06 and AHU Model FA4B. Last night, it got down to 64 inside the house, so I tried the heat for the first time and seemed to be working great. When I got home today and took my dog outside (No, he does not "go" on condensors) I went over to the unit to see how it looked and there was ice on the very small copper lines inside the unit. I think these lines were comong from the distributor. Also, there was what I think was water dripping from the line that enters what I belive to be the distributor. The outside air temp was 52 degrees at the time. Is this normal?