Why the legalett radiant floor system works.
Air trapped in radiant floor.
Thus creating a vacuum this will suck air into the system.
But much of the sensible cooling will be done by the radiant floor.
Eventually this air can become trapped in the hot water lines.
The closed system expansion tank is pre charged and should not need any pressure.
You will need one or two wall mounted fan coils in order to keep the humidity low enough so that no condensation occurs on the floor air dew point floor temp.
When water is heated in a hydronic heating system also known as a hot water heating system dissolved air is driven out.
An air system can also be used to supply central air conditioning and air cleaning.
If pressure is dropping below the 15 psi it is an indication of air still trapped in your system.
Air is the worst thing that can happen to any hydronic radiant heating system.
In the summer it can also be used to cool the floor.
Legalett air heated radiant floor heating systems are entirely embedded in concrete including the heater box.
Air trapped within a closed radiant system is the most common cause of inefficient system performance.