On Jun 18, 11:58 am, "Edwin Pawlowski" wrote:
"coustanis" wrote in message

Ok, the room that has the radiator pipes in the concrete slab has been
isolated and I put about 22 pounds of compressed air into it. After 4
or 5 days it had lost most of the pressure. In a day or so it will
probably be empty.
I assume then that there is a leak in that room unless there is some
other furnace phenomenon that would cause a system to not hold
compressed air. Since I don't see any water I assume it's in the
concrete pad.

Your connectors or your valve may have a leak also. Check them with a
bubble solution to be sure they are not part of the problem.



BUT...

The furnace it still losing pressure.

You don't have a furnace, you have a boiler. Furnaces heat air, boilers
heat water.

Since all the pipes are either
visible or within the walls if this wood and sheetrock
house, I would assume that if there were an additional leak that I
would see a wet wall, a puddle or water dripping from a ceiling. I
see no water.

You are probably correct.

Someone in a previous thread said it could be a bad expansion tank.
The expansion tank is brand new and was installed after this pressure
problem started. The auto feed valve is closed and has always been
so, even when the system was not losing pressure. I'm not sure what
to do next or what to check. I can isolate another loop but I'm
wondering if it's a leak at all in this part.
Does anyone have any ideas?

At least twice I've suggested you leave the valve open to be sure all the
air is purged. Have you tried that? Seems as though no. Another poster,
hvacmedic, also stated the valve should be open and gave a detailed
reasoning behind it all. Listen to the pro.

I believe it will overpressure if I do that but I will do it tonight.
If it over pressures I'll replace the auto fill valve and let you know
what happens.
I'll also get some detergent / water mix and check the connectors.
Thank you for the suggestions. I do appreciate it.