No, certainly not. PVC pipes can only take a certain tempreature and in most cases cannot withstand tempreatures above 60 degrees celcius. if a thermostat fails in a geyser and the hot water over boils and you run water through your PVC pipes, they can melt causing severe damage. the best pipes to use are copper and galvanised depending where you live.
Copper can be used for both hot and cold water. PVC is against many codes to use for domestic water supply because it can leach toxic chemicals into the domestic water supply.
PVC is never used for hot water CPVC is used for hot
You cannot use pvc on hot water, only cpvc
water pipe
natural gas line
Sleeving, or relining. It depends on the type of application.
Possibly the same reason it has a blue line in the USA to show it is compatible to type L tubing used for domestic water supply.
what type of material the pipe is made out of.
COPPER TUBING TYPE "L" BUT make sure it is propelr drained in the winter months if freezing is possible
Coated Copper Pipe that is approved for underground only.
No, hard water is in the water, it is not caused by the type of pipe.
Shut off valve at the wall? Turn the main water line off and change it. How you change it would depend on what type it is and how it attaches to the pipe.
Hexagon
This is a sign of residue in the hot water pipes. i guess at your part of the world, you must be using corrosive type of water pipes. The heat in the water helps oxidization of the inside of pipe and when the same pipe is not used to transfer of water in the pipe, existing water in the pipe caused corrosion so when the tap is opened after a while, the water that comes out is brown. To avoid this, you need to use the tap more often to stop the brown build up inside the pipe.
B-vent pipe.