this is a bad idea as you are effectivley sealing your heating system from the atmosphere. Its called an open vent for a reason.
The pump may be sited in a bad position related to your cold feed or vent pipe
The guy who did this doesn't sound very good
You would never put any pipes inside a wall cavity.
You are correct the aav should be above the highest overflow in your bathroom.
I wouldnt let the guy anywhere near my house, get a competant plumber to fix the problems and send him the bill.
Id take out the trap on your bathwaste and clean all the gunk, hair and neng out of it.
Your toilet might not be suffering from a blockage.
Modern cisterns are smaller and hold less water. The float operated valve arm may be set too low or perhaps you have put a brick in your cistern.
Blue water is caused by a high copper content in your water supply, This isnt from the pipes but the various strata that the water filters through to reach your spring. A water softener will remove some of the compounds in your water.
The best way to do it:- Turn off mains water stopcock, Open relevant tap, This will drain the HWSC. I would personally take the guts out of the valve, clean out the buildup in the seating and replace the spindle, dont forget to use a potable water jointing compound around the thread. Alternatively I...
