We are renovating all the bathrooms in our house that was built in the early 70s.
The plumber has replaced most of the copper pipes with PEX tubing. He has not replaced copper entirely and has coupled copper with PEX (see pics below). He connected the main water supply copper pipes to 1/2" PEX but then connected them to 3/4" PEX later.
Shouldn't the main supply line be connected to the wider PEX if at all? How does one check that the clamps are properly fixed onto the connectors?
He has run PEX right next to main heating duct from the furnace in the mechanical room (that supplies heat to the house) and in other places as well. Is this safe? Is a minimum clearance required between the PEX and heat vents?
Please see pictures of the shower rough-ins in two bathrooms. Is it normal to have so many joints and connectors? Any thoughts would be most appreciated.