unit is most likely low on refrigerant due to a leak, or compressor in the outdoor unit is not running.
your central air need re-gassing It means that you are probably low on refrigerant.
The suction line will be the larger line going into the compressor.
Install on cold water line.
Do you mean, like, the Earth? The equator. If you mean the line going from side to side across the middle of a circle then... the diameter of a circle
Symmetry
The broken line on your side means you can cross over while the people in the other lane can't.
no passing on your side of the road. only the other side
No passing, when it is on the other side you can pass.
A cold front
Simply ,the bigger of the 2 going into the out side/inside unit,and if running in summer,cold and sweating.
For a cold front I believe there are blue triangles that are upside down in a line. For a Warm front I believe there are red triangles that are right side up on a line.
Check piping. Make sure cold line going into cold side of water heater and hot side coming out hot side. Cold feed for water heater should come off main cold line. Make sure valves are open to and from water heater.