Need advice system boiler

[Ricky786]

Morning everyone need some advice if possible please. New system boiler installed by a company. boiler on the ground floor and mega flow. Pressure of hot and cold fine ground floor and first floor but loft has dropped from 8l per min to 3per min on hot and cold. 22mm hot goes to the first floor and then 15mm to the loft and cold is in 15mm all the way to the loft.
Any ideas to increase the pressure and get this sorted.

 

[Agile]

Merely replacing a system boiler should not have disturbed the Megaflow flow rate or the cold water flow rate either.

I cannot guess what the installer has done.

Possibly he turned off the stop cock and has not fully turned it back on.

Many would say call the installer back to investigate for you.