[a. r. jones]

I have an attic mounted hydronic furnace that has stopped heating but the ac seems to be working.

I have been told by a repair house that services hydronic systems that the whole system will have to be flushed.

How can I fix it myself?

 

[TarheelTerp]

I have an attic mounted hydronic furnace that has stopped heating
but the ac seems to be working.

First... "hydronic" means forced hot water and a boiler (not a furnace)
Second... hydronic and boilers have NOTHING to do with AC

How can I fix it myself?

To start... Go take a photo of what you have and post it here.
Include the make and a model # too.

 

[beenthere]

Might have air in it that needs purged. As above, post pics.

 

[hvactech126]

First... "hydronic" means forced hot water and a boiler (not a furnace)
Second... hydronic and boilers have NOTHING to do with AC



To start... Go take a photo of what you have and post it here.
Include the make and a model # too.

Not true. There are air handlers with hot water coils and evaporator coils....... Unlikely though that it is in an unconditioned space (attic)