The vents may have obstructions such as insulation or boxes or some other material.
Roof turbine vent stopped spinning.
Put a roof turbine on that hole it starts spinning but it is blocking the flow of air to the outside not speeding it up.
Clear away any debris or insulation blocking the vents to re activate the spinning turbine.
These are located in the track where the pipe coming out of the roof meets the spinning part of the vent.
Be sure to lubricate the bearings.
If it did then it s as if you had some sort of a perpetual motion machine.
Place the stepladder under the attic access space.
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.
If the vents are blocked by insulation boxes or other obstructions heat will not be able to escape through them and they will not spin.
The turbines are adjustable so that the spinning part is level even though the roof is slanted.
If they spin freely but just sit there when on your roof i d say they aren t level.
It was very annoying.
Climb up and take a good look at the turbine vents from the inside.
The blockage will prevent the heat from escaping through the vents and that may be a reason why the vents are not spinning.
If you decide to add more turbine vents to your roof be sure to buy ones that are aluminum.
Climb the ladder remove the access panel and enter the attic.
These will not rust.
I ambled around the roof shooting wd 40 specialist spray stay gel lubricant into all the vents getting them spinning smooth and easy.
Our turbine roof vents whirlybirds were really noisy and had some rattling that was causing some vibration in the house.
In addition pay attention to the maximum roof pitch that will work with the turbines.
You can usually adjust the level by turning the turbine body.
Climb up into your attic and look at the vents from the inside.
Put a hole in the roof and the hot high pressure air will move outside to equilize pressure.
