If they spin freely but just sit there when on your roof i d say they aren t level.
Roof turbine vents not spinning.
Inspect your turbine vent and make sure the top spinning portion is securely anchored to the standpipe using sheet metal screws.
The faster it spins the more air it exhausts.
Climb up into your attic and look at the vents from the inside.
The popular ridge and soffit ventilation systems and the traditional metal pot vents are also passive ventilation systems.
A turbine may fail to spin if the bearings become rusty or.
If the vents are blocked by insulation boxes or.
Examine the turbine from the exterior from the roof.
I ambled around the roof shooting wd 40 specialist spray stay gel lubricant into all the vents getting them spinning smooth and easy.
As soon as it starts to spin it vacuums air out of your attic.
If the flashing is loose against the roof secure it with.
A turbine vents spins with the slightest breeze.
It s not uncommon for insulation to have been jammed tight out to the edge of the roof.
In fact when i was headed to the last vent i noticed the the others were spinning on their own quietly with only the slightest hint of wind wafting by.
They sell foam channels you can staple to the underside of the room to allow for airflow while still allowing insulation to be installed.
Since they are only 4 years old i m guessing they were replacements so maybe the wrong ones were installed not all turbines work with all roof pitches or these just haven t been leveled correctly.