I have a hydronic underfloor heating system. Near the boiler, there are two "taps". It is where you connect a hose to them and refill the boiler. One of them is near the side of the boiler about 2/3 meters above the floor, the other is just near the base of the boiler. Now, the second "tap" is leaking slightly. Since it is just near the bottom of the boiler, it can be expected that if you try to replace the tap washer hot water would come pouring out.

So the question is how can I change the tap washer? If I shut tight the first "tap", would it stop the water coming out of the second tap due to air pressure? What is the best way to solve the problem? Also, I believe there are some inhibitors added in the system, which I would not like to lose too much.

Also, an auto air bleed valve in the control panel lets out a few drops of water everyday, I wonder if this is normal or if this is cause by air pockets due to the leaking "tap" or does it indicate a faulty air valve?

Thanks.

OK I have solved the leaking valve prob by taking it out and cleaning (washing) it, removing all dirt inside.

Now my remaining question is, do you really need an inhibitor in the system? If it is necessary, any homemade alternatives available (eg baking soda, vinegar?).

Thanks.